Lol, thats the first time in my life, I heard Mopar and cheap in the same sentence. Congrats on the vette, as a mopar guy aswell, I like the c4 corvettes
Nice tutorial. I actually did everything you mentioned to my '94 Polo Green 6sp 19yrs ago which I still own and has been trouble free to this day. I also ran a vacuum intake line into my cabin to insure I had clean dry air going into the OptiSpark. Replaced it with the updated vented one and modified it as you have. My upper radiator hose blew out and the coolant shorted out the OptiSpark, so replace that hose if it hasn't been done recently! Replacing an OptiSpark is no fun, believe me.
The reason for two make up hoses on the bottom of the Optispark is that the "general rule" is the make up air flow capacity has to be greater than the vacuum hose flow rate. That ensures that no vacuum is created inside the Optispark unit. If you develop a vacuum inside the Optispark, oil from the shaft seal and/or moisture might be drawn into the Optispark. Not sure if the Optispark shaft oil seal would work under vacuum. If you look at any vehicle, the make up air hose is always bigger than the PCV hose.
You know what would be significantly easier and a far better option? Buy the MSD cap and rotor set for the spline drive distributor, it includes the correct check valves in the venting hoses, and has the vacuum fittings in the correct spots. No need to re-invent the wheel, and if you're going in there you want a new cap and rotor. More importantly, while you have it all apart, you need to do something with that bearing. That is what often causes issues on these older OEM units.
A true genius is a talented man who has the ability to pass on his knowledge to others without insulting them and the student can duplicate the task. Thank you for sharing your time and knowledge.
Had thoughts of doing the same things to the dizzi and water pump on my Corvette in Australia. Parts aren't readily available in Aus. Very good explanation, and no rambling on like other videos!! Just straight to the point, with explanations of why and how. . Excellent
Parts are easy to get in Australia, Summit and Rock Auto ship here and it usually takes 5-7 days to get what you order. Also much cheaper than any of the outrageously over priced parts places that are in Australia charging around 2-3 times the price you can get it delivered to your door from Summit or Rock.
I couldn't watch past 210. Chevy did use a vented opti in the later model c4s. And I'm not a mechanic but I wouldn't pull the opti without running the dtcs first. Looking gor the dreaded H16 code. I fixed mine by running some silicone around the opti where it mates with the water pump. I also run a tube from the weep hole in the bottom of WP around the opti in case of failure.
Buick Roadmaster and Cadillac Fleetwoods (of which I have owned or still own quite a few) have the vented style. I never had a problem with them. I think most people who have problems own Camaros or Corvettes.
1994 Firebird Trans am - terrible problems with opti. 54,000miles water pump failure, replaced opti distributor with (lifetime) Autozone part and then 2500 miles later failed again. 😢 Going to modify the new replacement with this and pray for the best. Autozone unit has a double gasket to keep it dry but by not venting I heard they build up ozone and that causes corrosion. I've also heard the optical sensors are what go bad.
Thank you for this excellent demonstration video. Very nicely done. Just started having the opti-spark problem on my 92 convertible with 27K miles on it. I’m going to flow this procedure to the T. 👍
The vacuum source i use is on the left side of the intake manifold. It uses a vacuum tee but i no longer use EGE and secondary air . Since i have the MSD cap and rotor i have the check valves and vent hose. I run an electric water pump to so i no longer use the weep hole on the water pump.
Nothing new. I did this 5yrs ago. I used the center hole to run a line up to the intake tube and the other 2 I ran lines up to a hand made box 3 inch square filer. Issue solved. I used a tap and die set and threaded the tubes into the opti Where the electronic connection goes in the top I sealed with epoxy to keep water from getting in.
I have a 94. I did this same exact mod to mine before i seen your video. I like a few different ideas you presented. My next opti will get a couple of these tips. My only question is why two hoses on the bottom? Flow is not so critical i would think. Instead of tapping for vacuum behind the IAC is to tap in front of the throttle blades. I cant beleive how clean your engine bay is for the year of car. I like the color of your car as well. Nice job on video. Clear and to the point.
I too have a '94, Polo Green with a clean engine bay. Simple Green and a small brush, then spraying all the plastic parts with a non greasy preservative. Just keep water away from that OptiSpark!
I have changed out the Ignition Coil, Ignition Module, Electric Fuel Pump, Fuel filter, Fuel pressure regulator, Map sensor, Idel air sensor and the Fuel positioning sensor and the internet says that All these part should be replaced after 75,000 miles so i did just that.... my C4 just turned over 100,000 miles and just started running bad... rough Idel and making a popping and pinging backfiring sound so yesterday I changed all Spark plugs and wires the old factory wires were numbered from the factory... however there was no change in the way it ran.. I've been told that the OBD1 Scan Reader will not tell you if the Optispark is bad or good... so what's the point...? Just keep changing parts until you fix it or what...? The C4 Vette with the LT1 is an amazing car but the idea of the Optispark was STUPID...! THANKS FOR NOTHING GM.... If anyone reading this has any ideas concerning my problem I'm open to any ideas... Thanks Happy New Year
I agree with your assessment of stupid!! It truly is stupid. To read the codes from the ALDL. To recover ECM codes from the 1984 through 1993 Corvette, place a jumper between pins "A" and "B" on the ALDL (Assembly Line Diagnostic Link) connector. This connector is located under the dash just to the right of the steering column and has space for 12 pins although not all of the cavities will be populated. Turn the ignition switch to "On" but do not start the engine. Depending on the model year, either the "Check Engine Light" or the "Service Engine Soon" will begin to flash. As the code display sequence begins, you will see a flash followed by a pause and then two flashes. This is the indication for the number "12". The number 12 is a delimiter intended to show where the ECM code display starts and stops. Code 12 will flash three times and then any stored codes will flash. When all codes have been displayed or if there are no stored codes, the number 12 will again flash three times. For example, a problem with the EGR system (code 32) will be shown as 12, 12, 12, 32, 32, 32, 12, 12, 12. This would be displayed on the Check Engine/Service Engine Soon light like this: 12: flash (pause), flash, flash, (long pause) 12: flash (pause), flash, flash, (long pause) 12: flash (pause), flash, flash, (long pause) 32: flash, flash, flash (pause) flash, flash (long pause) 32: flash, flash, flash (pause), flash, flash (long pause) 32: flash, flash, flash (pause), flash, flash (long pause) 12: flash (pause), flash, flash, (long pause) 12: flash (pause), flash, flash, (long pause) 12: flash (pause), flash, flash (long pause) On the 1990 and 1991 model shorting pin "H" to pin "A" will cause the ABS light to flash ABS codes. (Beginning in 1992, there is another technique. Not all codes are displayed using this technique. There are four codes that will not display without a scan tool. The 1986 through 1989 Corvettes will not display any ABS codes. A special test fixture is required for those models. With the interior redesign in 1990, Chevrolet added additional computer capability. The CCM (Central Control Module) was added and a method was provided to display codes on the speedometer of the Corvette. From 1990 through 1993, you shorted ALDL pin "G" to "A" and turned the ignition to "On" without starting the engine. The codes will display on the speedometer. If there are no codes, the speedometer will show three dashes (---) and if the CCM cannot communicate with the other computers, the letters "ERR" will show up on the display. The module number associated with the codes will be displayed on the odometer and will show which computer's codes is being displayed. For the 1990 and 1991 Corvette, the modules are Module "1", the CCM computer and module "4", the ECM module. For 1992 and 1993, an additional module, module "7", the ABS (Anti-Lock Brake System) and ASR (Automatic Slip Regulation System) codes will be displayed. The codes will show up for three seconds each and once all codes have been displayed, the speedometer will show three dashes. You can either turn the ignition off for five seconds and then back on to repeat the process or turn the ignition off and remove the jumper to restore normal operation. Sequenced Code Recovery - 1994 through 1996: In 1994, Chevrolet went to a 16 pin ALDL connector in preparation for the federally mandated change to the much more capable OBD-II (On Board Diagnostics - Version 2) system. As with the 1990-1993 model, you can display codes on the speedometer but the pins to be shorted are different. Beginning in 1994, you short pin "12" to pin "4" and once again turn the ignition switch to "On" without starting the engine. The speedometer will display any codes using the same protocol as the 1990-1993 model but there are some changes in the designation for the modules plus additional modules are added: Module "1" is still the CCM module. Module "4" is now called the PCM module (Powertrain Control Module) because automatic transmission computer control was added to Engine Control Module in 1994. Module 7 (on the 1996 model only) is the RTD module. (This is the Real Time Dampening module which replaced the Selective Ride Control module in 1996). Module 9 is the ABS/ASR module number from 1994 through 1996. Finally, Module "A", the DERM (Dynamic Energy Control Module --- the air bag control module) will be requested to show any codes. Just like the 1990-1993 display, you read the codes on the speedometer and read the module number on the trip odometer. Again, you can cause the codes to repeat by turning the ignition off for five seconds and then back on. Turn the ignition off and remove the jumper to restore normal operation.
@Dan Dilts that's alot of great information... 👍🏻 I got my 95 C4 running yesterday and just like you said.. it was the Optispark (FLUX CAPACITOR)... purs like a big kitty...
Also the Torkhead system doesn't support all the 92-93 corvette's dash functions, I investigated a year ago for my 93, the only work around they considered was to update the harness to 94-96 which also converts to mass air from batch firing , But im cheap so did basically what you did. great video
Batch fire refers to injector firing, where pre 94 all fired the injectors one whole bank at a time, 94+ has sequential firing. Nothing to do with the MAF, that device reads incoming air volume only, and a 94+ it is used in conjunction with the MAP to help the PCM determine load on the engine.
I bought a replacement Optispark unit from O'Reilly's Auto Parts. They have a lifetime warranty! So far the car has been flawless. Runs perfect with no issues.
Hi what Optispark did you use for a replacement. Thank you for the very informative video. I am going to need to do mine soon and this will be something to consider when I do it.
Awesome video. I am forwarding it to my son who I gave my 92 to a few years ago. He has it in pretty good shape with the exception of the Optispark and digital dash. Have you done any work with your dash? Thanks, Bruce
The Corvette has been flawless since I converted it to a vented Optispark. Absolutely no issues. As for the digital dash, I haven't had any problems, so I'm just going to leave it alone. I'm kind of new to this Corvette......is there a common failure with the digital dash display?
I have a 92 LT1 and I vented my opti-spark with the help of Petris. As part of this project I did the "while I was in there" other mods that also help protect the opti-spark. I upgraded to an electric water pump which eliminates the weep hole leaking onto the opti problem because you plug the weep hole up. you also eliminate an oil leak possibility as you close up one of the seal holes where the water pump drive comes through the timing cover. If the electric pump fails (which mine is still working after 7 years or so) it only takes a few minutes to replace. Your idea about the filter used for the inflow of clean air is interesting. I just made a hole in the air intake rubber tube and put in a plastic hose connector for the intake air to the opti. How did you clean all the rust out of your opti? Nice video.
The only way to get rid of the rust and corrosion was to replace the entire Optispark distributor. It's been a year since I did the modifications and the car still runs flawlessly!
My next opispark is going to be a Petris. I like the idea of using the air intake for the source of vacuum. I will be adding a electric water pump. What kind did you use?
Wow! I have an 88' which doesn't come with the Optispark but man wanted to understand the issues surrounding it. Gotta tell you this was a very good idea. But, how would it work with a closed system to collect the moisture. Maybe install a small catch-can with a drying agent in it? Maybe silica beads? Or maybe, just leave the third (top) line off, using only the bottom lines and route the lines from a vacuum source and dump it into the plenum? Thoughts?
The two make up air hoses are completely separate. You want double the amount of "make up" air going to the Opti-Spark. That way you don't create a high level of vacuum int the Opti-Spark unit. The trick is to have high air flow going through the Opti-Spark not high vacuum.
you have to notch both rings 1 on cap and 1 on plastic spacer with ring on it otherwise electrodes are are air tite and bad gas will corode them. on new virson 1 vac in back and 1 in top cap both were dead ended once cap was installed the cap was never changed with upgrade two notches one on main cap one on bottom mid cap and then vac flows through caps and back of distributor the 2 rings are to keep cap from getting sucked in and rubbing on rotor
I bought my Optispark from O'Reillys Auto Parts. The price was good and it has a lifetime warranty. So far, I've had no issues with the ignition system. The car runs great!
Where did you get the check valve. I am assuming the two hoses pointed down are connected to the filters. The hole drilled in the cap is the source for the vacuum. Holy cow, a Mopar Guy fixing an issue on a Chevy. 😂 Also what did you adjust to make up for the vacuum loss?
That was a survivor car. 100% original car I bought new in March 0f 1985. It was a 1985 GLH turbo without air conditioning. Ended up selling it o a collector for a good price about two years ago.
Dump the Optispark and get the TorqHead 24x system, it's a coil over ignition system. I did 4 years ago and it's the best thing I ever did. Optispark is still a disturber with a rotor with pins on the cap. As soon as you install it starts deteriorating the minute you start the car. If the Optispark was a normal access disturber on the top of the motor it would be fine, but it's buried on the front of the motor requiring you to remove the water pump and crank damper to get to it. I installed the water pump weep hole rerouting when I did the swap, it's a weep hole and subject to weeping and GM screw up not routing it away. With the TorqHead 24x system you also get a OB11 PCM.
I agree with you that the Torqhead system is a more modern system, but it also costs thousands of dollars to make the conversion. You can buy a lifetime warranty complete Optispark unit from O'Reilly's Auto Parts and do the modification I outlined in my video for about $250 bucks. So, if you have the mechanical abilities to install a Torqhead system, then replacing the Optispark for free (lifetime warranty) every 10 years is no big deal. There is no guarantee that the Torqhead system won’t fail sometime in the future and if it does hopefully that company that makes the Torqhead system is still in business. Since I’ve converted my Optispart to a vented system, my Corvette has run flawlessly. There have been many reports of Buicks and Pontiacs with vented Optispark systems that have gone over 100,000 miles without any issues.
@@Arizonaperfect It cost me $1,730.00. I'm the original owner of a 94 Z28, it doesn't owe me a dime, the car is in perfect shape. Over the years I've done all the maintenance and up grades. To me the money is well spent.
I have a 93 40th anniversary with 32K on the clock . Its running OK. I plan on venting mine and replacing the cap and rotor and keeping my optispark original. Trying to be proactive before problems set in . How many miles are on you Vette. I'm hoping my opti is not a rusty
My Corvette has 69,000 miles and spent most of its life in San Diego Ca. They have perfect weather and the inside of the distributor was filled with rust. I don't know how the car was treated before I bought it, but it ran ruff until I replaced the Opti-Spark.
For those vacuum lines, aren't the 2 fiiting joined together with T hose fitting and 3rd part of the T goes to manifold. There's no need for that long line with a fuel filter, that's hacky!😳
The whole thing is, you can simply buy a full kit from MSD or Petris, and both are significantly better than just doing this. Neither are expensive, and both include everything you need.
@@TheCorvettedez it is if I don't have to do it 2 or 3 times ..using and then having to modify cheap Chinese parts 2 or 3 times is not cheaper than buying a quality product only once
@@TheCorvettedez no one makes OEM parts anymore....every OptiSpark available on the market today is made in the same factory in China unless you purchace one from MSD or Petris ...you are 100% garanteed to do this 2 or 3 times if you buy any other Optispark
I understand about the vents for optispark but the water pump if it’s leaking and you just installed a hose to avoid coolant going on the optispark wouldn’t you still get coolant on if you replace the water pump . I believed they did that on purpose to make you pay for two jobs after warranty expired and there’s really nothing to avoid a optispark problem when the water pump leaks because it’s really directly right next to it. This is just my thoughts nothing negative towards anyone who adds a hose to the water pump just that why did gm do this and when the ls came out back to belt drive water pump these water pumps can out last the 100k mark just change the coolant every 5 yrs or 2 yrs that’s the main problem when the water pump leaks the coolant degrades after so many yrs and if you add the green coolant to orange coolant it foams and gels up the whole coolant system.
I purchased my Optispark from O'Reilly's Auto Parts. It comes with a lifetime warranty. It's been over a year since I did the modifications and the car runs perfect. No issues from the Optispark system. GM was so close to getting it right, unfortunately they came up a little short!
Great video and very informative 👍🏻.. I have 95 c4 corvette has rough idel and makes a pinging popping sound... I have changed 02 SENSORS, EGR, TPS, IAC, MAP SENSOR and the sensor that screws into the front of the waterpump... but it still runs the same.... any ideas? Please don't say it's the Optispark... Lol
Okay, I won't tell you it's the Optispark...........but it's probably the Optispark. Changing the Optispark is labor intense, but not that difficult to do. There are a lot of good videos that show how to do the job. Since I did the modification shown in my video I've had no issue with the car. It is rock solid and very reliable.
Which direction did you run the drain hose from your waterpump... I'm getting ready to go back with new Optispark and waterpump... oh and I was able to find the 5/16 brass inserts on ebay... I must say the drain hose from the waterpump and air to the Optispark is a great idea 💡 😀 👍🏻 good job..!
I ran the water pump drain tube down the right (passenger) side of the engine. The accessory drive belt is on the left {drivers} side. This minimizes the chance of the drain tube getting tangled in the accessory drive belt. Certainly don't want your drain tube to get tangled up in the drive belt.
Had to get the garbage off the parts shelf fkn all us till theres a few if any left. Shocking to watch a mechanic thats above a fkn parts changer smdh.
![ian - Fit Check (Feat. VonOff1700) [Official Music Video]](http://i.ytimg.com/vi/sDGWDBg45Dw/mqdefault.jpg)
This is honestly the most American thing I have ever seen. It’s guys in their garages and shops that solve problems, not engineers in Detroit.
He didn't solve anything 😂🤣😅
@geneyus6411
Actually, he did. Moreover, he did it on a small budget.
Lol, thats the first time in my life, I heard Mopar and cheap in the same sentence. Congrats on the vette, as a mopar guy aswell, I like the c4 corvettes
Nice tutorial. I actually did everything you mentioned to my '94 Polo Green 6sp 19yrs ago which I still own and has been trouble free to this day. I also ran a vacuum intake line into my cabin to insure I had clean dry air going into the OptiSpark. Replaced it with the updated vented one and modified it as you have. My upper radiator hose blew out and the coolant shorted out the OptiSpark, so replace that hose if it hasn't been done recently! Replacing an OptiSpark is no fun, believe me.
I watched a 35 minute video on replacing one on a 4th gen z28. What took that man slightly over a half hour on video took me 15 hours over 2 days 😂😭
I’m also working on a kit to relocate the water pump (electric ).
Excellent demonstration. Thanks for taking the time to put together a straight forward video.
The reason for two make up hoses on the bottom of the Optispark is that the "general rule" is the make up air flow capacity has to be greater than the vacuum hose flow rate. That ensures that no vacuum is created inside the Optispark unit. If you develop a vacuum inside the Optispark, oil from the shaft seal and/or moisture might be drawn into the Optispark. Not sure if the Optispark shaft oil seal would work under vacuum. If you look at any vehicle, the make up air hose is always bigger than the PCV hose.
You know what would be significantly easier and a far better option?
Buy the MSD cap and rotor set for the spline drive distributor, it includes the correct check valves in the venting hoses, and has the vacuum fittings in the correct spots. No need to re-invent the wheel, and if you're going in there you want a new cap and rotor.
More importantly, while you have it all apart, you need to do something with that bearing. That is what often causes issues on these older OEM units.
Excellent explanations and thorough! The vette is gonna be happy being yours! A beauty.
A true genius is a talented man who has the ability to pass on his knowledge to others without insulting them and the student can duplicate the task.
Thank you for sharing your time and knowledge.
Nice video,hadn’t thought about that weep hole trick. Wife’s car is 95’ Z28 T56 conv with 12K on the clock.
Had thoughts of doing the same things to the dizzi and water pump on my Corvette in Australia. Parts aren't readily available in Aus. Very good explanation, and no rambling on like other videos!! Just straight to the point, with explanations of why and how. . Excellent
Parts are easy to get in Australia, Summit and Rock Auto ship here and it usually takes 5-7 days to get what you order. Also much cheaper than any of the outrageously over priced parts places that are in Australia charging around 2-3 times the price you can get it delivered to your door from Summit or Rock.
Great idea. MSD does sell a updated cap and rotor with a vent hose for the non vented distributors.
I couldn't watch past 210. Chevy did use a vented opti in the later model c4s. And I'm not a mechanic but I wouldn't pull the opti without running the dtcs first. Looking gor the dreaded H16 code. I fixed mine by running some silicone around the opti where it mates with the water pump. I also run a tube from the weep hole in the bottom of WP around the opti in case of failure.
He did both in his video.
Very well explained. Beautiful car too!
beautiful garage and Corvette! Ty for the tips
Nice video! Car looks great!
Buick Roadmaster and Cadillac Fleetwoods (of which I have owned or still own quite a few) have the vented style. I never had a problem with them. I think most people who have problems own Camaros or Corvettes.
1994 Firebird Trans am - terrible problems with opti. 54,000miles water pump failure, replaced opti distributor with (lifetime) Autozone part and then 2500 miles later failed again. 😢 Going to modify the new replacement with this and pray for the best. Autozone unit has a double gasket to keep it dry but by not venting I heard they build up ozone and that causes corrosion. I've also heard the optical sensors are what go bad.
@@americanmotorsam-caz524 Only OEM Mitsubishi modules are reliable. Aftermarket sucks. Yes Firebird has the same faults as Camaro and Corvette.
Beautiful garage. Can't wait to get mine
I did this mod to my 94 this week. Hope to get some long life out of it. Thanks!
Did your opti fail? I have a 94 and I think my opti is going out
@@kylestolfo4695 yes, died, wouldn't start again and gave a code for optispark. Check your codes.
Well done mate , enjoyed your comments , cheers Trevor in Australia
Thank you for this excellent demonstration video. Very nicely done. Just started having the opti-spark problem on my 92 convertible with 27K miles on it. I’m going to flow this procedure to the T. 👍
What results did you get?
The vacuum source i use is on the left side of the intake manifold. It uses a vacuum tee but i no longer use EGE and secondary air . Since i have the MSD cap and rotor i have the check valves and vent hose. I run an electric water pump to so i no longer use the weep hole on the water pump.
👍👍👍👍👍👍👍👍👍I am absolutely going to do that to My Corvette I have a part right now
Very good know how and K&N filter --oh no !! I goofed .I like the fittings for air and silicone to cover the seams thanks
Outstanding video
Thank You for teaching us.. Good Job
I recomend a vacuum restriction orifice to reduce the amount of vaccum pulling thru the cap
Nothing new. I did this 5yrs ago. I used the center hole to run a line up to the intake tube and the other 2 I ran lines up to a hand made box 3 inch square filer. Issue solved. I used a tap and die set and threaded the tubes into the opti Where the electronic connection goes in the top I sealed with epoxy to keep water from getting in.
Thanks for the information
Thanks for sharing!
I have a 94. I did this same exact mod to mine before i seen your video. I like a few different ideas you presented. My next opti will get a couple of these tips. My only question is why two hoses on the bottom? Flow is not so critical i would think. Instead of tapping for vacuum behind the IAC is to tap in front of the throttle blades.
I cant beleive how clean your engine bay is for the year of car. I like the color of your car as well.
Nice job on video. Clear and to the point.
I too have a '94, Polo Green with a clean engine bay. Simple Green and a small brush, then spraying all the plastic parts with a non greasy preservative. Just keep water away from that OptiSpark!
Your system creates a vacuum leak. Mine rellies on the a negative pressure from the intake before the throttle body.
Great video, thank you for sharing.
Is there a better source for vacuum that wouldn't require drilling? Also, what size check valve did you use?
I have changed out the Ignition Coil, Ignition Module, Electric Fuel Pump, Fuel filter, Fuel pressure regulator, Map sensor, Idel air sensor and the Fuel positioning sensor and the internet says that All these part should be replaced after 75,000 miles so i did just that.... my C4 just turned over 100,000 miles and just started running bad... rough Idel and making a popping and pinging backfiring sound so yesterday I changed all Spark plugs and wires the old factory wires were numbered from the factory... however there was no change in the way it ran.. I've been told that the OBD1 Scan Reader will not tell you if the Optispark is bad or good... so what's the point...?
Just keep changing parts until you fix it or what...? The C4 Vette with the LT1 is an amazing car but the idea of the Optispark was STUPID...!
THANKS FOR NOTHING GM....
If anyone reading this has any ideas concerning my problem I'm open to any ideas...
Thanks
Happy New Year
I agree with your assessment of stupid!! It truly is stupid.
To read the codes from the ALDL. To recover ECM codes from the 1984 through 1993 Corvette, place a jumper between pins "A" and "B" on the ALDL (Assembly Line Diagnostic Link) connector. This connector is located under the dash just to the right of the steering column and has space for 12 pins although not all of the cavities will be populated.
Turn the ignition switch to "On" but do not start the engine.
Depending on the model year, either the "Check Engine Light" or the "Service Engine Soon" will begin to flash.
As the code display sequence begins, you will see a flash followed by a pause and then two flashes. This is the indication for the number "12". The number 12 is a delimiter intended to show where the ECM code display starts and stops.
Code 12 will flash three times and then any stored codes will flash. When all codes have been displayed or if there are no stored codes, the number 12 will again flash three times.
For example, a problem with the EGR system (code 32) will be shown as 12, 12, 12, 32, 32, 32, 12, 12, 12.
This would be displayed on the Check Engine/Service Engine Soon light like this:
12: flash (pause), flash, flash, (long pause)
12: flash (pause), flash, flash, (long pause)
12: flash (pause), flash, flash, (long pause)
32: flash, flash, flash (pause) flash, flash (long pause) 32: flash, flash, flash (pause), flash, flash (long pause)
32: flash, flash, flash (pause), flash, flash (long pause) 12: flash (pause), flash, flash, (long pause)
12: flash (pause), flash, flash, (long pause)
12: flash (pause), flash, flash (long pause)
On the 1990 and 1991 model shorting pin "H" to pin "A" will cause the ABS light to flash ABS codes. (Beginning in 1992, there is another technique.
Not all codes are displayed using this technique. There are four codes that will not display without a scan tool. The 1986 through 1989 Corvettes will not display any ABS codes. A special test fixture is required for those models.
With the interior redesign in 1990, Chevrolet added additional computer capability. The CCM (Central Control Module) was added and a method was provided to display codes on the speedometer of the Corvette.
From 1990 through 1993, you shorted ALDL pin "G" to "A" and turned the ignition to "On" without starting the engine.
The codes will display on the speedometer. If there are no codes, the speedometer will show three dashes (---) and if the CCM cannot communicate with the other computers, the letters "ERR" will show up on the display.
The module number associated with the codes will be displayed on the odometer and will show which computer's codes is being displayed.
For the 1990 and 1991 Corvette, the modules are Module "1", the CCM computer and module "4", the ECM module.
For 1992 and 1993, an additional module, module "7", the ABS (Anti-Lock Brake System) and ASR (Automatic Slip Regulation System) codes will be displayed.
The codes will show up for three seconds each and once all codes have been displayed, the speedometer will show three dashes. You can either turn the ignition off for five seconds and then back on to repeat the process or turn the ignition off and remove the jumper to restore normal operation.
Sequenced Code Recovery - 1994 through 1996:
In 1994, Chevrolet went to a 16 pin ALDL connector in preparation for the federally mandated change to the much more capable OBD-II (On Board Diagnostics - Version 2) system.
As with the 1990-1993 model, you can display codes on the speedometer but the pins to be shorted are different.
Beginning in 1994, you short pin "12" to pin "4" and once again turn the ignition switch to "On" without starting the engine.
The speedometer will display any codes using the same protocol as the 1990-1993 model but there are some changes in the designation for the modules plus additional modules are added:
Module "1" is still the CCM module.
Module "4" is now called the PCM module (Powertrain Control Module) because automatic transmission computer control was added to Engine Control Module in 1994.
Module 7 (on the 1996 model only) is the RTD module. (This is the Real Time Dampening module which replaced the Selective Ride Control module in 1996).
Module 9 is the ABS/ASR module number from 1994 through 1996.
Finally, Module "A", the DERM (Dynamic Energy Control Module --- the air bag control module) will be requested to show any codes.
Just like the 1990-1993 display, you read the codes on the speedometer and read the module number on the trip odometer.
Again, you can cause the codes to repeat by turning the ignition off for five seconds and then back on. Turn the ignition off and remove the jumper to restore normal operation.
@Dan Dilts that's alot of great information... 👍🏻 I got my 95 C4 running yesterday and just like you said.. it was the Optispark (FLUX CAPACITOR)... purs like a big kitty...
I would use a cap and rotor with brass contacts. They last a lot longer.
My 1995 Caprice still as that same system optispark, mine is the vented one.
Also the Torkhead system doesn't support all the 92-93 corvette's dash functions, I investigated a year ago for my 93, the only work around they considered was to update the harness to 94-96 which also converts to mass air from batch firing , But im cheap so did basically what you did. great video
Thanks for sharing that information about the Torkhead engine management system. That is a serious consideration to make when purchasing that system.
Batch fire refers to injector firing, where pre 94 all fired the injectors one whole bank at a time, 94+ has sequential firing. Nothing to do with the MAF, that device reads incoming air volume only, and a 94+ it is used in conjunction with the MAP to help the PCM determine load on the engine.
Leaned a good bit..thanks
Thanks.
Great video, I need to do this on my 94 also, which opti did you purchase to modify
I bought a replacement Optispark unit from O'Reilly's Auto Parts. They have a lifetime warranty! So far the car has been flawless. Runs perfect with no issues.
Hi what Optispark did you use for a replacement.
Thank you for the very informative video. I am going to need to do mine soon and this will be something to consider when I do it.
I bought a stock aftermarket replacement from O'Reilly's Auto parts. They give the part a lifetime warranty.
Awesome video. I am forwarding it to my son who I gave my 92 to a few years ago. He has it in pretty good shape with the exception of the Optispark and digital dash. Have you done any work with your dash? Thanks, Bruce
The Corvette has been flawless since I converted it to a vented Optispark. Absolutely no issues. As for the digital dash, I haven't had any problems, so I'm just going to leave it alone. I'm kind of new to this Corvette......is there a common failure with the digital dash display?
I have a 92 LT1 and I vented my opti-spark with the help of Petris. As part of this project I did the "while I was in there" other mods that also help protect the opti-spark. I upgraded to an electric water pump which eliminates the weep hole leaking onto the opti problem because you plug the weep hole up. you also eliminate an oil leak possibility as you close up one of the seal holes where the water pump drive comes through the timing cover. If the electric pump fails (which mine is still working after 7 years or so) it only takes a few minutes to replace. Your idea about the filter used for the inflow of clean air is interesting. I just made a hole in the air intake rubber tube and put in a plastic hose connector for the intake air to the opti. How did you clean all the rust out of your opti? Nice video.
The only way to get rid of the rust and corrosion was to replace the entire Optispark distributor. It's been a year since I did the modifications and the car still runs flawlessly!
My next opispark is going to be a Petris. I like the idea of using the air intake for the source of vacuum. I will be adding a electric water pump. What kind did you use?
Wow! I have an 88' which doesn't come with the Optispark but man wanted to understand the issues surrounding it. Gotta tell you this was a very good idea. But, how would it work with a closed system to collect the moisture. Maybe install a small catch-can with a drying agent in it? Maybe silica beads? Or maybe, just leave the third (top) line off, using only the bottom lines and route the lines from a vacuum source and dump it into the plenum? Thoughts?
Do the 2 bottom vent hoses join up to a T piece then to the modified fuel filter or is it 2 hoses for 2 modified fuel filters? Great video
The two make up air hoses are completely separate. You want double the amount of "make up" air going to the Opti-Spark. That way you don't create a high level of vacuum int the Opti-Spark unit. The trick is to have high air flow going through the Opti-Spark not high vacuum.
@@Arizonaperfect thanks for getting back to me, it's much appreciated.
you have to notch both rings 1 on cap and 1 on plastic spacer with ring on it
otherwise electrodes are are air tite and bad gas will corode them.
on new virson 1 vac in back and 1 in top cap both were dead ended once cap was installed
the cap was never changed with upgrade
two notches one on main cap one on bottom mid cap and then vac flows through caps
and back of distributor the 2 rings are to keep cap from getting sucked in and rubbing on rotor
Great Video !What brand of Optispark did you use ?
I bought my Optispark from O'Reillys Auto Parts. The price was good and it has a lifetime warranty. So far, I've had no issues with the ignition system. The car runs great!
Where did you get the check valve. I am assuming the two hoses pointed down are connected to the filters. The hole drilled in the cap is the source for the vacuum.
Holy cow, a Mopar Guy fixing an issue on a Chevy. 😂
Also what did you adjust to make up for the vacuum loss?
I had that check valve in my drawer full of Mopar junk. I believe NAPA auto parts sells that check valve.
1995 CHEVY AND UP USE VENTED OPTISPARK.
How about a video of that red Omni GLH in the background? I used to have a black 1985 GLH and I miss that sleeper.
That was a survivor car. 100% original car I bought new in March 0f 1985. It was a 1985 GLH turbo without air conditioning. Ended up selling it o a collector for a good price about two years ago.
Dump the Optispark and get the TorqHead 24x system, it's a coil over ignition system. I did 4 years ago and it's the best thing I ever did. Optispark is still a disturber with a rotor with pins on the cap. As soon as you install it starts deteriorating the minute you start the car. If the Optispark was a normal access disturber on the top of the motor it would be fine, but it's buried on the front of the motor requiring you to remove the water pump and crank damper to get to it. I installed the water pump weep hole rerouting when I did the swap, it's a weep hole and subject to weeping and GM screw up not routing it away. With the TorqHead 24x system you also get a OB11 PCM.
I agree with you that the Torqhead system is a more modern system, but it also costs thousands of dollars to make the conversion. You can buy a lifetime warranty complete Optispark unit from O'Reilly's Auto Parts and do the modification I outlined in my video for about $250 bucks. So, if you have the mechanical abilities to install a Torqhead system, then replacing the Optispark for free (lifetime warranty) every 10 years is no big deal. There is no guarantee that the Torqhead system won’t fail sometime in the future and if it does hopefully that company that makes the Torqhead system is still in business. Since I’ve converted my Optispart to a vented system, my Corvette has run flawlessly. There have been many reports of Buicks and Pontiacs with vented Optispark systems that have gone over 100,000 miles without any issues.
@@Arizonaperfect It cost me $1,730.00. I'm the original owner of a 94 Z28, it doesn't owe me a dime, the car is in perfect shape. Over the years I've done all the maintenance and up grades. To me the money is well spent.
I have a 93 40th anniversary with 32K on the clock . Its running OK.
I plan on venting mine and replacing the cap and rotor and keeping my optispark original.
Trying to be proactive before problems set in .
How many miles are on you Vette.
I'm hoping my opti is not a rusty
My Corvette has 69,000 miles and spent most of its life in San Diego Ca. They have perfect weather and the inside of the distributor was filled with rust. I don't know how the car was treated before I bought it, but it ran ruff until I replaced the Opti-Spark.
@@Arizonaperfect Thanks for the reply
Msd sells a vented conversion Cap & rotor for 92 to 94
MSD is $250. This mod is $20. I'll give this a try.
For those vacuum lines, aren't the 2 fiiting joined together with T hose fitting and 3rd part of the T goes to manifold. There's no need for that long line with a fuel filter, that's hacky!😳
The whole thing is, you can simply buy a full kit from MSD or Petris, and both are significantly better than just doing this. Neither are expensive, and both include everything you need.
@CaseTheCorvetteMan
$20 or $250+. I guess expensive is a matter of opinion, but numbers always speak to me.
MSD already makes a wayerproof optispark
Petris Enterprises makes a vacuum conversion with the spline drive
Is it less expensive than this?
@@TheCorvettedez it is if I don't have to do it 2 or 3 times ..using and then having to modify cheap Chinese parts 2 or 3 times is not cheaper than buying a quality product only once
@johnperales5431
Not at all, because he started with a quality (lifetime warranty) OEM part that he then modified.
@@TheCorvettedez no one makes OEM parts anymore....every OptiSpark available on the market today is made in the same factory in China unless you purchace one from MSD or Petris ...you are 100% garanteed to do this 2 or 3 times if you buy any other Optispark
Вентиляция оптиспарк1 👍🖐️🇷🇺
I understand about the vents for optispark but the water pump if it’s leaking and you just installed a hose to avoid coolant going on the optispark wouldn’t you still get coolant on if you replace the water pump . I believed they did that on purpose to make you pay for two jobs after warranty expired and there’s really nothing to avoid a optispark problem when the water pump leaks because it’s really directly right next to it. This is just my thoughts nothing negative towards anyone who adds a hose to the water pump just that why did gm do this and when the ls came out back to belt drive water pump these water pumps can out last the 100k mark just change the coolant every 5 yrs or 2 yrs that’s the main problem when the water pump leaks the coolant degrades after so many yrs and if you add the green coolant to orange coolant it foams and gels up the whole coolant system.
Better off just getting a 4 Way easy out for Brake bleeder and making threads and putting in a hallowed out bleeder
I wonder what opti he used for replacement.
I purchased my Optispark from O'Reilly's Auto Parts. It comes with a lifetime warranty. It's been over a year since I did the modifications and the car runs perfect. No issues from the Optispark system. GM was so close to getting it right, unfortunately they came up a little short!
Great video and very informative 👍🏻.. I have 95 c4 corvette has rough idel and makes a pinging popping sound... I have changed 02 SENSORS, EGR, TPS, IAC, MAP SENSOR and the sensor that screws into the front of the waterpump... but it still runs the same.... any ideas? Please don't say it's the Optispark... Lol
Okay, I won't tell you it's the Optispark...........but it's probably the Optispark. Changing the Optispark is labor intense, but not that difficult to do. There are a lot of good videos that show how to do the job. Since I did the modification shown in my video I've had no issue with the car. It is rock solid and very reliable.
@@Arizonaperfect OK Thanks..
Which direction did you run the drain hose from your waterpump... I'm getting ready to go back with new Optispark and waterpump... oh and I was able to find the 5/16 brass inserts on ebay... I must say the drain hose from the waterpump and air to the Optispark is a great idea 💡 😀 👍🏻 good job..!
I ran the water pump drain tube down the right (passenger) side of the engine. The accessory drive belt is on the left {drivers} side. This minimizes the chance of the drain tube getting tangled in the accessory drive belt. Certainly don't want your drain tube to get tangled up in the drive belt.
@@Arizonaperfect Awesome.. and Thank you for the information..
Can I buy the boom box😁
Seems to me your introducing a vacuum leak by doing this.
Mopar guys cheap?!? Haha you should see my homies SRT8 300 🤣😂
5/16" compression tube fitting.. for those wondering. That's what they are.
It's really 5/16" Compression "inserts". Not fitting.
Holedrilled one n done
Those are fkn wire ferrels check car audio or slamazon sells kits 10 or so diff sizes
Had to get the garbage off the parts shelf fkn all us till theres a few if any left.
Shocking to watch a mechanic thats above a fkn parts changer smdh.
Lmfao just watched a guy thinking their not clockable lmfao oh n of course he didnt mark one thing nit even tdc on cyl 1
Its been a trash design from mile 1