Worst Automotive Parts / Components of All Time: GM HEI Ignition Module
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- Опубликовано: 30 июл 2024
- A new take on the series, highlighting the best and worst of various components. In this episode, learn more about the GM HEI ignition module used on vehicles from the mid 70s - mid 90s.
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I've owned a couple of HEI equipped vehicles. A 1975 GMC w/ 454 and a 1981 Eldorado. I had the truck for 15 years and never had a problem with the module. The Eldo was blowing one about every month. A close examination of the factory wiring showed a ground that was missing on the car. There was a thin metal strap in the distributor cap that was missing. Once the ground was restored it never blew another module, but it did blow a couple of transmissions. That is another story.
Exactly I eliminated blowing modules by running a separate ground from Distributor body to good engine ground. Been good for 5+ years now. Still carry a spare just in case but gladly haven’t needed it.
@@warricksmith2640 wow are you serious that's pretty hilarious, they could have actually prevented the problem had they build it better.
@@warricksmith2640 and I don't even mean the part itself, just the ground!!!
I've been thru the ground fix suggestion to no avail, they still last about 2 years in my 75 Corvette. I always carry a spare and have used it twice on the road.
I meant to add that I took one of these AC Delco failed modules apart once; the electronics are filled with a clear epoxy. Under a microscope I found an integrated circuit that had tiny jumpers welded to it and the other end of the leads welded to the circuitry. One of those wires was open in the middle. Looked just like a blown fuse would look. The ends of the tiny wire were round as if they were over headed. I suspect over voltage from some failed component overstressed the wire and it blew.
I had a 1976 Nova 5.7 that had 250,000 miles before the valves pounded out, it had the factory HEI module still in the distributor. At tuneup always clean and replace the white module paste under the module, lube the centrifugal weights. Then check the vacuum advance canister, along with the Cap and 8mm plug wires. Then always install a new distributor HEI Rotor and Spark plugs.
If you take care of your machine it will take care of you.
The rest of the known automotive world installs an HEI and makes an oil pump primer out of the old points distributor.
The problem with electronic ignitions, beyond the thermal/weather related issues, is that their life cycle curve is basically a cliff. Unlike points and condenser systems, they don't gradually degrade with perceptible differences in performance. They're simply on/off and as Mr. Murphy states, they fail at the worst possible time.
Awesome analogy .
Wow, completely corrwct!
I've replaced at least a half dozen in the same vehicle over the years. The most recent was just last week and I got a SLIGHT warning. (not a great warning cuz I didn't realize what it was warning me of) Shut it down hot. Went to buy milk. Came back and it stuttered on startup like it was somewhat flooded. ( it NEVER does that). Drove it home and parked it no issues. Wouldn't go again. Installed spare I bought only 2 months previous. Didn't even trouble shoot it. Just prayed it wasn't a dud right out of the box like the LAST one I got at NAPA!
Hei was a huge upgrade from points
Hi Adam, just wanted to add some thoughts for clarity on the issues seen with GM's HEI modules. The original modules were white in color when they were incorporated in the familiar large-body HEI distributors in the fall of 1973 for select 1974 model year vehicles. By the fall of 1974, all passenger cars (the 1975 models) received HEI ignition systems to meet the increasing demands for Federal Emissions requirements and basically provide a "hands-off" approach to maintenance on the distributor which affects ignition timing (as anyone with points will know that regular maintenance is required) and ultimately the emissions out the tail pipes. Unfortunately, as you stated, things weren't so hands-off. The original white modules were VERY problematic. This stemmed from the fact the internal control chip designed by Motorola had an output transistor (the main switch for turning the coil on and off to generate spark) was not adequately designed to protect itself from back EMF (this is the spike that occurs when the magnetic field collapses when the power to the coil is turned off). To add to the problem, GM increased the spark plug gaps to coincide with the higher available voltages from the HEI system to ignite the leaner fuel mixtures being used by the industry at that time. The weakness in the module was exploited by these conditions. Many times not only did the module have to be replaced, but also the integrated ignition coil as a shorted module with constantly supply un-interrupted power to the coil, thus overheating and shorting out the internal windings. GM was then faced with a full on replacement campaign to change out the white HEI control modules with the more reliable black colored modules. Spark plug gaps were also closed to reduce the risk of misfire/back EMF events.
The biggest issue is owners using supplied (or purchased on their own separately) silicone grease/dielectric grease/"tune-up" grease under the module. Completely WRONG. A good heat sink compound paste needs to be used. It is opaque white in appearance as the silicone stuff is clear or translucent. It is critical to provide the thermal conductivity between the bottom plate of the HEI module and the mounting pedestal in the base of the distributor with the use of the heat sink paste compound.
You did hit the nail on the head with N.O.S. parts. Modern components (even genuine GM replacements) are all made off-shore and the quality is lacking. Even simple replacement points for points distributors are lacking!
I've been in the electronics industry for decades and worked on cars and electronics for a long time. My classic car retains the original Delco distributor with points as I know as well as others, with electronics, it is not a matter of IF it will fail, it is WHEN it will fail.
Ah, then you should be familiar with the early Ford Duraspark ignition modules whose failure rate was so high that Ford was starting to get a bad reputation for the cars so equipped...1974 and newer. They would either stop functioning altogether or develop a "hot open" when the ignition would fail after some minutes of driving, only to work again when they cooled down.
Ford improved the module circuitry on replacement modules, the upgraded ones were identified by sticker on the module which read "Motorcraft..Tested Tough" If we didnt see the sticker or a quality aftermarket module such as NAPA/Echlin or Standard Plus--we replaced it, and NOT with the Wells junk that was common in the day.
These failed at least as often as the GM HEI modules, and the other problem with the GM distributor was replacement of the rotor with a cheap aftermarket unit which would often burn through in the center shorting the spark directly to the distributor shaft.
You are dead on man.......down to the RIGHT grease that goes underneath which I have seen guys do soooo many times years back.I still run 3 G.M. s with this style module installed right with quality part is and excellant design.
Your last two paragraphs sound like good reasons to swap-in an MSD distributor. [:\
@@pancudowny Unfortunately, MSD is not as good as it once was. They have issues now too. A lot of this stuff is now made in China and it's all crap.
BTDT...You are exactly correct in every portion of the failure mode description. The original black GM modules are the only ones that are worth using as a replacement. Other aftermarket modules are junk, Pertronix included. The white thermal conductivity paste (don't use the clear grease, source the white from an electronics store) is also a key element in the reliability chain as heatsinking is absolutely necessary with these modules. It's also a good idea to tape a piece of 320 or 400 sandpaper to a piece of glass or other very flat surface and lap (rub) the metal base of the new module on the sandpaper to ensure flatness. I had one module with one of the two staked eyelets (rivets) that extended below the metal base mounting surface of the module, ensuring a terrible heat transfer surface. A SPARE IN THE GLOVE BOX, WITH TOOLS, is mandatory!
I love the gm HEI ignition system ! an upgrade with accel components never failed me ! what did fail on me was using a cheap rotor ! the carbon nub that makes contact with the center tab would burn thru and cause a misfire or no start ! and always carry a spare module ! the real beauty of gms HEI is it only needed power and rotation to operate ! chryslers had the dreaded ballist resistors i owned 2 and always kept spares in the glove box ! pretty cool channel you got ! very knowledgeable and informative !
i cannibalised my k1500 1986 for awhile and my 1970 b-bbm ran better with it. but yes on that engine all old school or new 2010-up engine management not the uncanny valley in-between the 2
!
Anybody saying it's not a good system I disagree.
Also rotor burn you check and there's no spark so you think HEI module. but don't forget that rotor look for a burn hole hard to find when it's black plastic. if you can't see try an old good wire on the center button the other end to everything connected crank it if you see spark it's the rotor for sure not the module.
@@edwardmartinez9459 the voltages are unreal ! i upgraded my 68 c10 to hei and got a mile down the road on a rainy day it started running bad ! i forgot to tighten the distributor hold down clamp ! truck was still running and i went to turn it and got knocked on my ass ! I'll never forget that ! never had a prob with hei since !
I never forget my first and only experience with a failed module back in 1997. Going 70 MPH in my 1981 Trans Am in the "fast lane" of the local interstate and cruising, suddenly the engine shut down and all the warning lights came on. I was able to shift the automatic transmission to neutral and nurse the car to the shoulder. This is an interstate with 5 lanes, mind you and it happened around 4 PM semi-rush hour. Like others have mentioned, the problem is that its failure is sudden death, and you get no advance symptoms whatsoever.
I heard of people wiring a backup module to a toggle switch to avoid becoming stranded.
@@catsaregovernmentspies my k1500 seamed to always fail in the driveway sofar🙏🤞 after starting up and putting in gear aka stuck at the house 🏡 and easy fix vs no mans land. and yes keeping cold 50-65 f and using better tremale pastry lol from the computer 🖥geeks does help as does keeping the turning + battery/alt 👌ect.
@Logan Forney race cars do it every time. And yes, my truck has one thermo pasted to bare metal on the firewall, wired on a switch. My tach fails, I switch and Ignition!!!!!!!!! I like to street race to the speed limit in my old jalopy and patina'd 79 chevy 3/4 all-time AWD that looks like a slow one. It's overbored, sbc 400, with AFR 227, drag race cylinder heads with offset lifters prove otherwise. People will pass me at full speed when I shut down at the speed limit. I've got them until I do. I had a Honda passport really upset in a 60 zone. I left him at the light, he floored it and caught up to me at 40 mph. I floor it to 60, completely dusting him for a few seconds when I shut down and he goes peeling by me with bald tires to be pulled over with his speed being over 80 mph I'm sure! Lol Baiter!!!!! People hate that old chevy being fast at all.
@@shedred1967 as a teen-26 id have tried street racing but my old man would have strung me up by the rafters lol 😂and then i got married and the wife didn't want to be a widow and or stupid in my 68 C10 or k1500 and more so in the 1967-70 charger ( as one point we "shared that car" and mom hates that car 😂😁 i told her at 14 i was going to buy one so good luck stopping me ( By 21 i had it ) besides most of my bs was in a v6 sedan or the rusty C10 SBC-sm465 4:10fg lol 😂as the bbm charger is a 🚓magnet lol ) or her caddy pissed 😤😡 off so i limted my self to "testing parts " 😉😁 and or not breaking and laws or getting chout
@@shedred1967 is yours a stick? because at 16 my k1500 700r4 went bad and a buddy at the time was parting out is k1500 1-ton sm465 so my mom threw a fit somehow in her mind that = a 6c chevy on full kill lol 😂no way and she would have hate yours as "its a race car" nope lol
I've been using GM HEI ignition distributors on all the vintage and classic GM cars I've had over the years and have never had a failure. I use them today in both my 71 Nova SS and my 72 Buick GS (retro fit). I remember my brother had a Pontiac Grand Prix that had the module fail on the way home from picking the car up brand new from the dealer. That was the only case I was personally aware of. I was in the construction business for over 20 years and we had a large fleet of pickups, mixed Ford and Chevy's and I never recalled having an HEI failure. Actually, we were also in the snow removal business and everytime we had temps go below 0-5 degrees, a few of our Ford plow trucks wouldn't start (they were parked outdoors). We had to pull the ignition modules off the drivers side fender well and warm them up. Fixed. Maybe I was just lucky but I still rely on and have confidence in the HEI system. Mazda, Toyota and a few other foriegn makes had their modules in the distributors. My dad's Mazda MPV had a module failure in 1994 and the module was not replaceable. He had to buy an entire distributor at the tune of about $500. Ford Probes used the same ignition.
My experience is the same as yours. I have had north of 30 GM vehicles, never had a HEI fail. Didn't even know this was a thing. I upgraded numerous pre 74 to HEI. I also replaced DuraSpark modules with GM HEI.
getting good QC easy and ok cost, points or carbs based systems parts ect. in 2022 good luck i quit and moving forward with my classics ( 440bbm/hemi ) is modern engine control 2005-up as the aftermarket makes kits/diy for older generations of engines ect. but im not driving a pebble wining car ether so i see it doesn't matter as much if it's modified tastefully
The 1972 GS uses a slightly different shaped ram air bucket on the distributor side compared to the earlier models with that cool air setup. No fitment issues? I didn't use the radiator hose bracket off the t-stat housing on my '70 with the HEI, and I used an Edelbrock dual plane intake, the iron one was just so heavy. The aircleaner sat a little closer to the hood in my car but it worked just fine.
I remember the GM HEI the coil could put out 50k volts. When the plug wires would go bad and create an open circuit the spark would usually jump through the rotor and ground to the centrifugal weights, you could tell from the rust on them. Of course every now and then the current would hit the module. Game over. Thanks for covering this!
This is a very good series idea. A lot of people talk about engines and transmissions, not so much about individual commonly shared components.
You had to remember to use the insulating paste that came with the HEI module. If that was used, the module was good for a long time.
It's actually not for insulation, it's to help the heat transfer from the HEI module into the metal of the distributor.
@@LionWithTheLamb Exactly! Couldn't have said it better. Take care. Cheers
The only problem with many of the replacement parts was the source was quite important; as the commentator mentioned.
I would suspect that many failures were due to improper paste installation as well. And, I'm sure build quality degraded over the years as this system was changed and quality was forgotten about.
Interesting to keep a spare HEI module in the glove box... kind of like 1960s-1980s Mopar owners keeping a ballast resistor in the glove box! Never really had too many problems with the HEI, but the GM "Optispark" ignition system used on the 1990s LT1 V8s was not known to be one of the most reliable, and certainly not easy to access / repair, being behind, under the water pump. As a 1996 Buick Roadmaster Estate owner with the LT1, I can attest to this.
Exactly Lake.
95 Impala SS owner here agrees putting the water pump over the top of the distributor so coolant can leak on the ignition ,bad idea.
I used to carry around a spare Ford TFI module with me.
Try an optispark in a 92 corvette. One stroke thru a rain puddle and the car starts missing, or dies all together.
With the market flooded with only Made in China ignition points now, you might find yourself stranded more than you'd expect.
That's why I've bought several sets of 40 to 50 year old N.O.S. point sets in the swap meet section of car shows over the years. Old Standard Blue Streak or Echlin points are good.
The GM HEI units were substantially more reliable than the Ford units of the same era. I went so far as to mount a second module on the fender well of my 79 Ford truck just in case the operating unit failed. This eliminated the need to rifle around in my tool box looking for a new one on the side of the road. I would simply plug it in to the new unit. 3 times in 3 years.
I never had a factory GM module fail. As a rule I replace the module along with the cap and rotor at tune up time. Easy to change and not expensive to purchase. The aftermarket modules are junk, especially Petronics.
Yeah those Ford modules were crap but i bought the house brands from the auto parts stores. The oem fords were better built.
You can refit a GM module to a ford.
I've been driving GM HEI since 1976 (including in my 77 GMC Motrohome which you have referenced)and never had a module failure. You have to keep all the secondary components in good shape-- cap rotor wires and plugs and gapped correctly (.038") Any degredation in the secondary allows the coli voltage rise to increase very high before discharging. This proportionally (it's a simple windings count ratio) raises the back EMF to the module when it opens the primary circuit. They can take this for a while but not forever. Also the heat sink compund dries and shrinks after 30 years and does not provide good heat transfer. Furthermore some incorrectly use dielectric grease instead of white heatsink compound, which works but not as well..
One thing i notice when i did use dielectric grease After a year i would go back to look under ignition module,and the grease was still there.That clear grease that came with the module would almost or be gone under the module. Now i use the white heatsink grease .When i look under the module after a year it is still plentifully there.eleminating any chance of the module frying.Now to eliminate heat from the coil in cap by getting one to put on the fire wall.
Let's do one together on the early GM cable driven window regulators that was my bread and butter throughout the first decade of the 2000s. Grand Am, Alero, Intrigue, LeSabra, and so on.
Or go back further to the plastic tape window regulators. We had tape in bulk rolls and were required to replace the only tape. Ridiculous!! Funny how, now we almost never do electric regulator repairs on the newer stuff. my paycheck is hurting.
@@scrappy7571 yep all those were guaranteed income and now they finally figured out how to make them good.
Ford put their ignition module on the distributor in the eighties. There was a class action lawsuit and they had to warrant them to 100 thousand miles. There are companies that sell kits where you can relocate the module to the fender apron.
I seem to remember that Ford relocated that module to a bracket behind the grille.
I couldn't disagree more with your assertion that the GM electronic modules are one of the worst components in the auto industry. Leaving a person stranded was far less likely to happen with an ignition module than the "good ol' points" system. Points systems are in CONSTANT failure mode as the rubbing blocks wear, condensers fail, points arc and corrode, etc. After-market replacements were and are often cheap imitations of the originals, so you can't bash an OEM part for that failure.
I worked as a mechanic at a GM dealership and can't recall ever replacing a failed ignition module. I drove a late 70's Ford and at the very least, had to annually replace the failed 'brain box' mounted on the inner fender. Ford's electronic ignition was much more failure prone than GM's, and let's not even discuss the Mopar junk that was mounted to the air cleaner - that system was NEVER any good.
Age is not an asset to electronics so if you're asserting that the original parts are currently failing on low mileage cars from that era, then that's not even a viable argument. Replacing a GM ignition module is a quick operation, one that takes much less time than replacing and setting points.
I'm bloody addicted to this series!
Thanks Adam, much appreciated.
Nomination: Chrysler’s ballast resistor.
A legendary part. Unfortunately for all the wrong reasons.
And the rotors would burn through and ground out the spark, and the wires that were in the distributor and went through the housing would break due to the action of the vacuum advance.
Yes, burn thru rotors and burnet 8 mm plug wires.
And some electrical power would be capacitively coupled to the advance weights under the rotor and would arc at the pivots. The arcing caused pitting and freed up powered iron would quickly oxidize and form an abrasive right there in the pivot. Given time, the pivots would be undercut and the holes would be worn to slots.
We used to see both all the time.
As a 70's and 80's era GM tech, seems I remember replacing more failed pick up coils than modules. This issue went away when they eliminated the vacuum advance which would flex the wires on the pick up coil to the point of breaking. I still have a collection of GM pick up coil magnets on my tool box...
yes same here, you can only flex a wire so many times it is going to break
I remember the the first year GM-HEI ignition system back in 1974. If the module failed, the engine will stop. No warning, no engine light. You just simply call a tow truck. The testing unit that was used, was a simple box with a red light, and a green light. Obviously the green light meant good, red, bad. No variance at all.
My 1974 Impala Still had points in the distributor.
The 1974 “No-Go Nova” with the six-cylinder engine also had points…
I had an 84 Pontiac Grand Prix that never had any ignition issues and I owned that car about 15 years. I think it was the early years of these systems from 1975-1980 that had the most trouble.
Yeah I had a 1978 TransAm and I put over 150k miles on it. Only thing the "pick up coil" failed at about 30k. Otherwise no problem at all.
New to your channel by the way and enjoying. I did 17 years as a GM dealership mechanic and the biggest component failure that I remember was when they went to the plastic intake manifold gaskets on V6 engines that carried coolant through the intake. The 3.1 or 3100 they may have called it and the 4.3 come to mind. This was in the 90's and Dexcool had come out too. These were 100% failure rate for coolant leaks. Coolant would leak externally and internally at the corners of the intake. It wasn't if but when. You would pull off the intake and those plastic gaskets were in pieces. I think the idea itself was as bad as the component. Felpro came out with rubber coated aluminum gaskets that were much more durable. We were paid a flat rate per job and I did so many I was making triple time on the 3100s. You could leave the rear valve cover on then use a line wrench on the rocker arms to open the valve enough to slide out the push rods and change the gaskets
A very good series. Always fun to watch.
I sold/installed lots of ignition modules in the 80's and beyond. Yes the GM modules were quite common but FORD ignition modules were the "big seller" Stories back in the day...like Ford went ahead with manufacturing ignition modules after having over a 54% failure rate in prototype testing... Needless to say, there where broken down, mostly Ford's getting towed in to the shop from all over...
They also were color-keyed at the box
If it wasnt the newer improved circuitry Ford module (Identified by a sticker that read "Motorcraft..Tested Tough" or a QUALITY replacement module (not the cheap Wells crap) we replaced the module to head off inevitable failure.
I've had 2 trucks with the GM HEI ignition module. A 1989 Chevy C1500 and a 1992 GMC Sierra both had the 350 (5.7L). I owned both of them since new and put over 260K miles on each one. I only had to replace the module once on each of them. Luckily, I was never stranded. My friend had a 1990 Chevy C1500 and replaced the module a few times before reaching 200K miles. It turns out he wasn't using "heat sink grease" between the module and the distributor because it didn't come with the module when he bought it. The ones I bought at Autozone didn't come with heat sink grease either but adding the heat sink grease was one of the steps in the replacement procedure in my Haynes' manual, so I bought some and put it on. I like to think the grease helped, but one thing for sure: I was lucky to get so many miles from these aftermarket modules.
Hello Adam, nice explanation. In my former spare parts selling job back in the 80's and mid 90`s, the electronic ingnitions systems were a tricky stuff for all old school mechanics who believed that contact points were the real deal. No way, the electronic ignition was something positive devices for the automotive industry, thanks to Mopar, the very first one to featured such an element. The heat inside the distributor probably caused over heating component isolating the power supply, so fot my personal experience, the Mopar system was superior over the GM H.E.I one as I could see over the years, because the Ignition External Module from Mopar did not suffer for heat or humidity, because was an external fitting unit, almost placed above the inner fender dust skirt or over the fire wall. In my Chevy Celebrity I owned some years ago, and with almost over 162.000 miles. that module was the original Delco Remy factory unit!!, believe me, but was little different, with 4 or 5 contact tips rather than your 4 contact module, 1875990 GM catalog part number. They were cheaper to buy, in many brands, such as Wells, Standard, Valley Forge, General, United among many others as well, keeping a higher price for the Delco Remy unit. But to be fair and serious, the HEI ignition GM system is a world class design, very dependable, long lasting performance. Thanks for the info, very ilustrative. Salute, from Bogota, Colombia. Take care, man.
the old mopar system was very good also.nowdays though,its hard to find a good replacement ignition module as they are all chinese junk.
Mopars of the '60s and '70s used a 'power' resistor in series with primary coil circuit to drop the input voltage to 6V after startin g the engine. What happens is: that HOT resistor gets hit with rain water, causing the part to crack resulting in engine shutdown! The engine will start normally, but will shut off as soon as you release the ignition switch!
My dad's last pickup was an 86 Chevy half ton, 4.3 L Vortec V6. His Chevy ate those HEI modules like candy. The V8 version was about 20 bucks at NAPA, the V6 was $100. I was working for a division of Echlin at the time and he asked if I could get some modules with an employee discount. I found out I could buy them for about 5 bucks each, so I got 3 for him. He replaced only one and that lasted for the rest of his life. When mom sold his pickup after he passed away in 1993, the other two HEI modules were in the glove box.
Another homerun video! When I bought my very low mileage '76 Coupe DeVille back in 2002, I read about some of the horror stories of this module. Even though the car ran great, I went ahead and changed out the module with a new one as insurance. I think it was an aftermarket brand though. Regardless, the car is still running great today.
I really enjoy your videos and always look forward to the next one!
LOL... Just the thumbnail got a visceral response from me. Damn thing always failed on the hottest damn day of the summer after the engine is completely heat soaked. These were all pickups, on the farm, usually when I was trying to irrigate. 110 degree day at the end of a humid corn field. I can feel my blood starting to boil just thinking about it.
I don’t know why this made me laugh.
Remember these issues all so well! At our shop we also would see the Ford TFI modules and the 86-92 various GM vehicles with what insiders called "Phantom Stall". On those GM cars we would have to look at the date codes on numerous sensors (crank, cam, MAP/MAF) and replace the ones in question. The worst issue was the intermittent "stall and cranks but won't restart". By the time the car was towed to our shop the car would start right up and could be driven off the tow truck and we were "unable to duplicate the condition". Customers were pissed to say the least. My brother and I wound up doing a series in Motor Age Magazine on how we finally repaired these intermittent problematic cars. Needless to say it took a lot of hours of driving these cars with scan tools and lab scopes connected to various components trying to duplicate the stall condition and catch which electronic sensor was out of range.
These porch chats are great! I hope that you have time to continue with them!
Hello Adam. Your channel has quickly become “must see TV” for me. Thanks! 👍👍👍
Hey!! I have really been enjoying your channel. I just wanted to comment I have run quite a few vehicles with HEI and never had the module fail (including my 84 K10 which I've owned for 22 years). Maybe I'm just lucky. But I have had to replace the module in my 93 S10 Blazer four times in the past 11 years. I agree that new parts store electronics aren't as good as NOS. And I owned an older air-cooled Volkswagen that was notorious for eating points. Keep up the great work and thank you.
Good advice Adam on the HEI. My Chevelle had an old MSD electronic ignition and I debated putting an HEI in it instead since the MSD was failing intermittently, yes leaving me stranded a few times! It was tough to troubleshoot since MSD kept saying their ignitions don’t fail intermittently. Not true! Long story, I ended up getting a new MSD, so far after one year no issues.
Oh come on.. In 30 years of both owning and fixing old school GM rides with HEI ignitions, I think I’ve replaced maybe 2 or 3 of them in those 3 decades.
Frankly you should’ve targeted the stupid coil packs that actually do constantly fail..
I remember back in the '90s paying a Chevy dealer for a new HEI module, thinking it would be better quality than aftermarket. Maybe it was. Imagine my 'surprise' when I opened the Delco box to find 'Hong Kong' on the bottom of the new module!
Even worse were those GM HEI distributors with vacuum-advance. A wire to the captive pickup-coil would break. Then you would need to pull the distributor, drive the pin from the gear, drive off the gear, drive the shaft from the housing, etc....
Worst of the worst was the HEI on a Chevette with AC. It used the same massive HEI ignition-coil-in-cap unit as a V8, but with only 4 plug-wires. You couldn't do anything without first pulling the AC compressor AND its' bracket. Then, if you needed to remove the distributor, the fuel-pump ran off a cam on the distributor-shaft, so the pump had to come out too!
As a tech for alot of years from late 80s to early 00s. I really didn't have too big an issue with the GM modules. Honestly I dealt with way more GMs towed in with bad fuel pumps vs modules.
Now the Ford Dura Spark was always an issue. At least they made em easy to replace. 😊
They're ez to change but the connector could cause a no start and be hard to find.
The voltage regulators late 70s Fords used were definitely wear items. I recall always keeping a spare.
My '88 XJS V12 HE has a GM HEI module located inside the AMP which is mounted on the driver's side intake manifold. That HEI module is, by far, the biggest problem I have w/the car. I always keep an extra AMP and an extra HEI module (along w/tools) in my trunk. I have had modules last for as long as 2 years, while the last two I had both lasted less than 2 hrs. Prices have doubled in the last couple years (although still around $50), but it's really the issue of just shutting down somewhere out on the road that sucks....sure wish I could find an alternative.
My mother's 1978 Chev Monza with the Iron Duke 4. Went through several of these, left her stranded a few times. Knew to let it cool and then would work. Warranty replaced about 3-4 of these. This was the 1/2 moon 4 connector type, I replaced most of them myself. Used the gel as directed. Finally after these 3-4 replacements got one that worked for more than a few weeks.
I always refresh the thermal grease when doing a tune up or a new to me car.
I am not sure if I agree or disagree with your assessment of the HEI distributor and it's module. My first new car was a 1969 GTO and I have been a GM person to this day. In my 55+ years of car The only time that I was stranded was in my 1975 Nova, with HEI! The module failed when my light turned green and as soon as I began to move the module failed when I was in the middle of the intersection! I like the rest of my hot rod friends and I thought it was the end of the world when the move from points to HEI was announced. Other than that one failure I never experienced another HEI failure.The car was 20 years old as was it's module. For many decades there after the GM HEI system was used as an performance upgrade to older GM cars. Indeed many automotive after market ignition systems were HEI based. Many upgraded modules were the first modification we did to our HEI CARS. So with my experience with the HEI system throughout it's lifetime is just a WEE bit more positive than yours. Could it be the fact that your experience is based on cars that are 30 to 50 years old have something to do with your experience!?! Just Saying
My Dad had a 1977 Maverick 6 cyl. Great looking Blue, but a dog to drive. After having a 302 cubic 1968 Fairlane. The Module on the Ford Maverick went out 3 TIMES. And he worked for that company. He was very Unhappy. If it wasn't for the 1st Gen Taurus he bought, he never would have bought another Ford .
This man explains it so well I try and tell people about new electronic modules
Hey Adam, thanks for sharing another interesting porch chat;!! 👍👍🙂
Love the stories. Keep them coming.
I have a 65 El Camino,350,th350. My issue is :
I could be driving,or at an idle at a light,and it will die, loose all electrical power,I turn ignition switch off,put it neutral,turn the key,and starts right up...any clue why this is ?
Help
Thx....Amy
Adam: Always appreciate your point of view and understand that you are not a big fan of the early attempts at electronic ignition and fuel systems. GM's HEI, variable venturi carburetors, electronic Rochester carbs, and arguably the worst of all... Chrysler's Lean-burn! They were all plagued with teething problems, and the parts available now are ancient IF you can find them. However... you have what 30 or 40 cars? None are driven more than a few miles per year. Rebuild a carb and distributor and the car will stay in tune for a decade if you treat it to a trickle charger and some Sta-bil. Personally, I like modern systems MUCH better. Nine years, zero fuel or ignition system maintenance, original plugs, one new battery. Starts every time and runs like new!
I still like the older stuff. I can replace the engine in my 66 Chevy four times in the same span it takes to replace the head gasket on a PT Cruiser.
Interesting GM story you had. Being in the Corvair organization all my life and had the pleasure listening to stories from Dolly Cole (Ed COle's wife) about numerous upper management stories from the 650's through 1978. What I learned most was how they treated John Deloraen and some of the lesser known innovations he made in the early 60's..
Having had a unique situation of owning 74 Z-28s one with conventional and one with HEI. I loved the HEI (but it never made me walk) it also seemed to start easier.
Adam, I have to tell you, the majority of cars I have owned have been mid 70s to 90s GM vehicles. I don't ever remember getting stuck on the side of a road because of an ignition module failing. I believe this happened to me once over 25 years ago on an early 80s GM car. The car simply wouldn't start one day after sitting overnight and I had to get it towed, and that's what it was. But that was the only time! The car was about 15 years old and had well over 100,000 miles on it, so it didn't make me mad that it happened. I actually think Chrysler's ignition module mounted on the inner fender tended to have more problems. Usually they wouldn't fail completely in my experience, but they'd develop internal resistance, build up heat, and the gel in the back of the module would melt and ooze out - then I knew I was going to have a problem, so I replaced them when I saw that. Note I said Them - because it happened a few times on different cars. And YES - factory components are always better than aftermarket, especially on electrical items. Electrical items I would never ever buy at a regular auto parts store. Maybe NAPA, but that's it. But I do agree not to replace points because I just don't see what the big deal is that people think points are so troublesome - they're not! I also used to fix people's cars in the mid - late 90s, which were then mostly 80s Big 3 vehicles. When people moved on to foreign cars and/or newer cars in general, I really couldn't help people anymore - or maybe I didn't need to help them because there weren't as many problems to deal with. To be honest it was fun for me. I used to like to troubleshoot and figure out what needed to be done. Funny you mentioned an 86 Cutlass Ciera. That was one of our shop cars in my auto shop classes - a car someone had donated for the students to work on. That car was taken apart and put back together so many times. It had a 2.8L Varajet carbureted V6. I remember fixing a friend's 85 Cutlass Ciera while taking those classes, and it had a totally different engine (the 3.0 L V6) and it had a different carburetor on it - the Dualjet - which I rebuilt.
He explained he bought many older cars that were sitting and needed work before being road worthy to resell. Im assuming this is where he seen most of these issues on a variety of vehicles
If you ever worked on a Ford DuraSpark you will appreciate the GM HEI module. I have owned northward of 30 GM vehicles and never had an HEI module fail. I have upgraded Fords and GM points to HEI and resolved the issues.
I had several GM cars with HEI, and never had a Problem with any Ignition Module
A nice talk about electrical components on a cars , GM. I had an 87 Dodge D150 pickup with an 318 V8. I always keep Ed a spare ballast resister and voltage regulator in the glove box. I had to replace the regulator twice and the ballast resister once.
The other gizmo I remember lol
I worked at a Chevy store when hei was in its first years. We put new modules in and GM would kick them back as tested ok. They came out with a module tester and they were good. We then started using a copper conductive paste and we did away with plastic connector housing and crimped connector sides inward. The hei module problem was near zero then. The problem was pickup coil connections getting corrosion from the corrosive environment inside cap getting to the terminals. The TIM paste is absolutely necessary for survival.
TIM paste? Can you explain? Would copper anti-seize work for copper conductive paste?
@@1straightcut thermal interface media. Copper paste would be less conductive than the purpose made thermal paste. The difference may not be great but in worst case high ambient temp and high engine load with lower system voltage the power stage heat might be great enough to need the highest heat outflow possible.
Artic Silver heat sink compound used for computer processors is the best. Be sure to watch vids on how to apply heat sing compound. One solid thick line and let it self spread when torqued down.
I bought a 77 c-10 and replaced that unit as a preventive to that problem. I just fixed a 93 caprice wagon that would start fine but as it warmed up would stall and not start or restart with lots of cranking. Replace the module and problem fixed. The 93 module looks different but still mostly under the cap and still a problem. Ive heard the Accel module is better made?
I've heard these problems reported from mostly the old timers that were there when they came on the scene in the '70s, but by the time I was driving in the '90s I never heard anything about it. I've probably put a half million miles on GM HEIs without ever having a failure. Maybe I'm just lucky?
Nah, the modern modules last a lot longer and are more reliable than the parts of the 70's and 80's. It's a pretty good ignition system in modern times.
All experience is personal. I doubt you have owned a vehicle with Lucas points based ignition, but these were awful whereas in the last 40 years I have owned 13 cars, bikes and trucks with electronic ignition without ignition problems. My last experience with points was on a group climbing trip to Mexico where a VW camper would not start. The owner was perplexed because he had just laid out a lot of cash on an extensive service. I fished out a plug and found no spark. Opening the distributor and removing the rotor, the points were shut because of a loose locking screw. Using a thumb nail in lieu of a feeler gauge, I reset them and it fired up.
Interesting,,, I've always wondered about the 1980s electronic spark control system...
I recall in the mid eighties on the streets of Houston making note of all the GM pickups with the big ESC emblem on the tailgate shaking and belching black smoke and looking like they were having a problem, maybe not even related to ESC, was that a bad system ?
I installed a HEI msd street fire distibutor in my 396 swapped 63 impala. The module in it was bad from the start. I sent through 3 standard ones that would fail after about 10-15 minutes of driving. The parts store modules came with dialectic grease instead of heat sink paste and I had to buy the accel performance module to get a decent part with the proper grease
HEI was still a step up from points points and condenser left me stranded a few times
Wonder if a thermal pad on bottom mixed with some very well made thermal paste for added overkill could help the issue a little more.
Yes, I agree on leaving point ignition cars as they were, and I’ve also removed electronic ignitions that were added after the fact. Like you, I’ve never been stranded by points, and that’s over 50 years of driving, a couple times stranded by electronic modules. Unfortunately, the build quality of points has deteriorated recently too, rubbing blocks made is some cheap plastic that wears away quickly, and the points stop opening. You need to at least go with a recognized major brand, but that’s no guarantee either, we can guess where they’re manufactured.
Good Video. Had a 81 Chevy Citation Duke engine that modules fail in hot AND cold weather…32 degrees. Also distributer gear that year changed to plastic/nylon. Only car that stranded me 3 times, and I tried to maintain it like an airplane.
I had four Hei modules fail in a month. All standard motor products modules, bought at the local parts shack. I got a Davis module off summit, no problems since.
I got into by 80's ford pickup last week, started and ran fine and after about 5 minutes, stopped. Classic ford Ignition module death!
Thank you for your wisdom sir! It IS appreciated.
Good solid information my good man! Thank you kindly! 😉
I've never had problems with electronic ignition modules, though I've never driven GM's much. I did have a problem with a Ford ignition system being a bit iffy sometimes. I think your probably right, a big problem was placing the module right next to all the heat. For reference, the stuff that you use to attach the module is thermal compound, you have to use thermal compound. Without it the module will get a lot hotter than what its suppose to. I'm also going to agree that replacement parts lately just don't have the quality of OEM parts. Recently had to buy a fuel pump, needed to go through 2 of them to get a good one. Did a power steering pump on another car, needed to go through 3 of those.
Thanks for the informational video. I couldn't start my car yesterday, but it fires up and is running today. Is there a test for the module or do I just replace and be done with it?
I have felt the same, electronic ignition and the main computer left me stranded several times - I remember the shock when I asked the first time "how often do you change the electronic ignition" - and was told "it may last a day or it may last forever" - points seemed very reliable in contrast to this, give the car a tune up once a year, inspect other parts, and you are good for another year. Particularly if you are not driving in sub zero weather. I remember as the ballast resister on Mopars was a problem thinking - "gee, I have to keep one of these in the glove box?" - and my 84 Dodge Daytona dropped dead after driving over the Coronado bridge in bad weather - because of the main computer! at 8000 miles - almost new! One thought, couldn't the GM's faulty part be relocated to a better part of the engine?
I've had good luck with GM HEI modules. Not so much with Ford and Chrysler electronic ignition modules.
I have moved this component to the firewall, mounted on an extruded aluminum finned heat sink from a p.c. of course with the white paste goo on the module, make sure all 4 spade connectors are snug and I would paint the connections with dielectric grease, never had a failure mounted this way, and I will never use Accel components because a tech at Accel let it slip when I called their tech support when I worked at a H-D dealership, that Accel had an acceptable failure rate of 70% right out of the box, they would replace the bad new units free of charge, but installing 6 or 7 of the same new part that was non-op right out of the box seriously cut into my paid work time as I would be paid book time to do a job once, if the new part was bad, I'd have to R&R it until I got a "good" one. And yes, seriously I have had on more than one or two occasions had to install every single Accel voltage regulator in the shop, only to tell the customer they weren't getting a chrome "dress-up" part but the stock, factory installed black regulator was the part that worked, didn't fail instantly, and if they absolutely had to, just block sand the edges of the fins lightly, and now it's shiny and custom, but I will never ever use any Accel products for any reason because of the incredible lack of quality control this company deems acceptable, by the way, I was a Jaguar dealer tech for years after I restored Jags from the late 40s through early 70s models, I also am primarily an engine builder, and after the Jag dealership I was the lead tech at a Harley-Davidson dealer for thirteen or fourteen years, I drive the same motorcycle I've had for 41 years, and have a Citroen 2cv that I've had even longer than the bike, thanks for letting me express my thoughts based on a lifetime of experience, db
My idea exactly... Mount the module remotely to a computer heatsink with Artic Silver heat sink compound.....also use emf shielded wire.....and even extend it to mount under the dash. I went thru 4 Accelerent modules, they kept sending me free ones....I gave up & went back to a genuine GM MODULE!!!!!!!!!!
I also read once to be sure to run a separate ground wire from the grounded bolt of the module to the distributor housing, the to the block to be sure the module has a good ground for protection of the circuitry......
Thank you, very helpful video!
I built a very good HEI system for my 65 Galaxie 394 .20 over FE. I got a TFI heat sink and attached the4 pin module and mounted it on the fender well. I got the one my circle track buddy’s use with the gel. I have used this on 4 different vehicles. If someone is stuck and I just pull it off and help them get it home, put it right back on with my own looms that hook right to the factory distributor. I also have a 1996 F150 remote mounted coil mounted on the power steering bracket, in common is they have great air circulation and run cool. The secret is a well grounded heat sink, a weather packed loom and air circulation. They live forever. If you do have to get a module, go to O’Riellys and get one for a Cadillac 500, or a 454 heavy duty truck. I have pile of good ones I got at the junkyard all bagged and tagged in my closet in the house for temp and moisture control. I have not had a blown anything running 30 amp relays to all loaded circuits. My ignition is a nice hot 52,000 v and runs at alternator regulator voltage which is 12.7 volts. I plan to add an 870 DP with annular primary boosters and a VS7875 turbocharger with a blow though boost referenced fuel system and hat and a referenced dial a jet on the secondaries. 61, retired but hoping for 750 hp at the rear tires .
The HEI ignition module failing became so common , we would check for spark , if no spark we would check for battery voltage at the distributor . If the car had power to the distributor , walk to the parts room and get a module . We skipped the rest of the diagnosis . Ironically HEI went on to be extremely popular and the aftermarket has HEI available for almost all V* engines including Dodge and Ford applications . We usually replaced the dark gray colored rotors if we found one under the cap with the updated white rotor .
Interesting as always.
I have a love/hate relationship with the HEI. We use them in old jeeps and IHC trucks. They are great in that they clean up the engine comparments, and get rid of old ignition systems (ie points, prestolite, etc). And generally, maintenance free. .. but I also always carry a spare module with me.
I understood the module needed to be under there because there was a magnetic sensor inside that controlled the voltage output for the coil
There is no reason the ignition module needs to be in the distributor. There are plenty of cars where the electronic module and coil were mounted some distance away on it's own heat sink where it was cooler. This includes the Jaguar XJS which used an HEI module at one point during it's production run.
Compared to the ford and Chrysler ignition systems of the time h.e.i was the best, simplest and they all took the same parts. All the olds, Pontiac, Cadillac and Chevys shared a v8 cap and rotor or v6 and most of the 4 cylinders that made the parts cheaper and easier to get. I was told a story about my grandpa where he paid for a vacation to Florida from the mid west by fixing ford ignition boxes on the road side he just kept the 7 or 8 different part numbers in the trunk this was the late 70s early 80s I work in the auto parts industry and I still have more problems with none gm ignition systems and recommend to people that they should get a conversion h.e.i distributor for ford and amc motors that use that box on the fender
Just made a pot of hot coffee and what was waiting on the laptop for me? A new "Rare Classic Cars" video, great day.... All I can say about this video, "Been there--Done that" Thanks for posting.
I agree about there being nothing wrong with a points system. I was able to get a couple of cars going with just a screwdriver and my wife's fingernail file to clean the points and also used the file to gap the points to get them home. Didn't happen often but if the points were never changed they would pit and the gap would get way off.
I really like all your car reviews you are incredibly knowledgeable! I am a huge fan of the 68 & 69 GM a body's namely Oldsmobile cuttlass 442s and Pontiac GTOs. My Dad had a 69 Cuttlass Supreme 2 door hardtop with bucket seats and a console shift. I always dreamed of driving that car but my Dad sold it before I had the chance. I graduated high school in 1988 and there was a student that occasionally drove his Dads 1970 judge ram air III to school I was very impressed with that car. Also in Swift Current Saskatchewan there was an original 1969 GTO Royal Bobcat with the White and Blue I loved the two colours together and the hideaway head lights. I like how you say how the 1960s cars with the high compression moters were better quality than the 1970s cars which is something I always figured. I like how you rated your gorgeous blue Pontiac your favorite. I have owned some 1970s Ltds and Marquis so I find those cars interesting as well. I guess one thing I have always wondered about is how do you afford your fleet of 20 plus cars?? The insurance and storage must cost a small fortune! You are living the life I only dream of but I'm happy to have some 1970s 4×4 Ford trucks and my 5.0L Mustang Gt Cobra I still have from 1990. Anyways keep up the good work. You make me believe my dreams of an A body convertible and a nice 1950s Ford pickup truck like I drove on my Grandads farm can still happen!
My first car was a 1978 Sunbird with the Iron Duke you talked about in the other video. The original module and coil lasted until 1992 with about 90K miles on it. Sure, if you properly maintain a point ignition, it'll be dead reliable. However, it won't last 14 years. Agreed, the aftermarket ignition components won't last and I have actually gone and replaced GM components that still worked with new ones, then put the GM module in the glove box. But when I was younger in the 90's trying to squeeze power out of a small block, one of the first things I did was toss the points distributor (actually I brought it back as a core to the parts store in the HEI box... inept counter people worked to my advantage) and toss in an HEI... even a stock one. The spacing between terminals was an advantage, so was the one wire plug and play setup. Just remember, this design is still available on the aftermarket to adapt to non-GM vehicles. It's a great design, and well worth carrying a spare module just in case the old one tanks after 10-14 years.
I guess we all have different experiences, but I can honestly say I never had any ignition problems with my 78 Camaro igntion, parents never had any issues with their 77 Monte Carlo. Many of my friends had GM cars with HEI, never heard of them having any issues either. But, being a more complex ignition component, these modules are certainly more prone to some sort of failure, and are surely not "repairable" on the side of the road. I guess most points based ignition systems will give some warning before complete failure, giving the owner a chance to get the ignition serviced. I agree that there is nothing wrong with the original delco points system, especially with the adjustment window in the cap, although the HEI system probably develops more voltage at higher RPMS. But, we would never be driving these classic vehicles at extended high RPM.
I would also never convert and older vehicle to HEI, mostly because of the changes that would have to be made in the engine bay wiring harness to accomodate the newer system.
Yeah, we had the same issues when CD/no points was introduced on our OMC outboards. Granted, there were more "powerpack/module" failures than conventional points system, mostly because this system was more complex electronically. But, I also know that techs were inclined to blame the "mysterious" powerpack/module for any sort of running issues, and just replace them without adequate testing.
Some company made a "limp-home" box that would bypass the module using the wire connector outside the distributor cap, as I remember. It depended on the coil still being operational though, but I suppose keeping a spare coil along with the bypass box in the trunk and a couple of tools to change it out quickly would get you home in a time of need. Seems that the coil was very easy to change on most of these.
I’ve not had many problems with modern HEI set ups. And the modules are so small and easy to replace I just keep one in the glovebox along with a dinky little fuel pump.
I had a 1987 Ford Fiesta MKII (a European Ford) that had an ignition module that looked very similar to that. It screwed onto the side of the distributor, and you were supposed to put thermal paste between it and the distributor body. And yes, it left me stranded too.
The Chrysler electronic ignition worked pretty well. The main fail point was that ballast resistor, but those were cheap and you could keep one in the glove box. I did have a points car leave me stranded, the points had closed up. Plus, I always thought the transistor on the box was cool looking.
I recognized that part as soon as I saw the thumbnail. In 2005, I bought a '91 Cadillac DeVille with the 4.9 and 200,000 miles on it when I needed a cheap cash car (I paid $995!). It needed some mechanical attention, and there were several instances when it would just die, and then a while later (usually after getting a tow - I ended up paying AAA a surcharge for having so many service calls), the car would start right up and run fine until the next time where it would die without warning. Took a long time to figure out what was wrong, but when I replaced that HEI module, the problem was solved. I probably replaced it twice in the five years I owned the car, and Adam's video is the first time I've heard about adding a heat sink grease. What failed more often was the Hall effect switch, also in the distributor assembly. I probably replaced that four or five times, and it got to the point where I could swap it out in 30 minutes - and I'm about as good a mechanic as Elmer Fudd is a hunter. After I dealt with the neglected maintenance items, however, the car became very reliable and lasted another 70,000 miles.
I had a 1980 Bonneville Brougham coupe where this issue with the faulty module reared it’s ugly head a few times. I was 17 at the time and had no idea what the issue was. I called my father, told him what was happening. It took him all of 3 seconds to nail down what the problem was. Fond memories now.
I've learned to just carry a spare in the glove box... or at least in my ignition toolbox. And in all the cars I rode in or drove that had it, I've only had one ever fail... but that was on a car I added a cheap tachometer to.
The HEI module in my Pontiac is from 1989. Installed with a good heat sink compound on the back. Works perfect. No spark scatter below 6500 RPM. It’s 34 years old.
Had an 85 Bonneville with the Chevy 305, and Turbo 200 (I wanted the T350, but the dealer said it wasn't available). And yes, the HEI was a single point failure in those cars. I never thought to pack one in the glove box. Similar to Ford Fairlane/Falcon upper ball joints. They would wear prematurely, as they carried all the weight of the front end.
Thanks for the tip!
I had one problem with that module. It was in a late 1970s Chevy 305. I replaced it and it ran to being disposed of because the rings were shot. The HEI ignition was wonderful. I never understood why the spec was 35 thou for the plugs. I increased it to 55 thou and that increased the power dramatically. An old mechanic suggested 55 thou. All of my other cars and friends cars I did that to and everyone was happy about it. That car went from 15 MPG to 18 consistently.
Points - love them while you have them. Friends that I know that still use points tell me that the quality of them are going to crap. One guy does racing in a Porsche. He had to break down and switch to electronic because he couldn't buy points that would work anymore. They're dying out. The only place that I know still uses them are prop aircraft. They have self contained magnetos. Two of them. Some old tractors have Bendix mags as well.