Converting TBI to Carburetor, tips and tricks
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- Опубликовано: 13 сен 2019
- Converting Your TBI to a carbuator isn't that difficult as long as you know what you are getting into. This is a short vid explaining what you need to know before you start this project.
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After 15 years of nonstop issues...throttle body electrical, sensor, regulator, etc., ...I'm done with TBI. I love my old truck , a 94 chevy 454, but hate TBI with a passion. When I was young I had a 79 ford f150. Just a plain old 4 barrel carb, on an edlebrock manifold and that motor always ran...no issues. Thanks for the video Brother. I'm changing back to carb.👍
We have been chasing our problem for 5 days on this pickup and would like to say thanks for the help!
I've been on the forums gathering information for a carb swap I'm doing on an 84 vette this is the first time I've seen a clear straight forward answer on this fuel pump wiring thanks so much for making this video!
Same here
Glad I found this. Not running a carburetor on my 88 but I just bought a 94 for parts because it has the tow package and better brakes to put on my 88. I needed this information because I plan on dropping the 94 350 into my 66 Belair while I rebuild my 283
This was exactly what I needed. My k1500 has something wrong in the knock sensor circuit/wiring and after replacing nearly all the sensors its time to go back to a simple, reliable, mechanical solution. Thanks again, awesome video, especially about the fuel pump wiring.
Been have'n trouble with run'n out of fuel,, the purple wire I hope is my problem,,,, will give that a shot tomorrow,, went out n found the 4 pin connector with the purple wire w/white stripe,,, Thank God He Led me To your video,,,, Thanks for the info,, hope it works tomorrow,, God Bless
Works like a charm,, thank You for the video,,
No ur problem is u listen to a stupid mfker. Go get a mechanical pump. And problem solved. All 350s pre vortech. Can have a mech pump bolted to the block they just put a plate over it. Fun fact the tbi cams HAVE THE FUEL PUMP LOBE. ALL U NEED IS THE SHAFT. PUMP AND GASKET. PROBLEMS SOLVED FOR EVER. NOT ONLY THAT. But your fuckin factory pump pushes way to much fuel pressure to a carb thats ment to get 5psi really of pressure. Ur gonna ruin ur carb and constantly have issues. I dont care if u go put a inline regualator u can set fuel pressure. Dont work.
Rusty just seen your video. I’m in the tree business and my Son and I have a 1997 gmc top kick with a 366 gas engine with a throttle body. It is our main bucket truck we use in our business. It starts but idles very roughly for 5 minutes or so then it smoothes out enough for us to drive to the job site to do our work. We have a pony motor that operates the hydraulics to run the boom. We have been having issues with it for around 6 months now. We’ve spent $3 to $4,000 on it so far changing out everything there was to change out. All the sensors, new throttle body gasket, tune up of plugs, wires, distributor, fuel pump, coil and everything else we could think of.
We have someone who done this on a truck like ours and he said it runs great. He is going to do this to our truck. I’m glad I seen your video p, it was very encouraging to me. We are hoping to get our motor running great again. The only has about 105,000 miles on it. Thanks for your video, Steve Miller
Thanks for the information about the fuel wire to tack side of dist. I was thinking it would work off the fuel pump relay! I really like your video, it has helped me. Thank you.
What kind of issue were having?Im asking to see if yours is similar to mine
Once again I really like this video. I thought that all I needed to do was hook up the purple wire to tack side of dist. and all will be good to go.Wrong, you still need the fuel pump relay hooked up at least this is the only way my fuel pump would work. And the car is running great, all finished. 1986 corvette, and only using it for drags at the 1/4 mile race track. I hope this may help someone on the fuel pump! Thanks.
@@mikepolk3361 Hello mike, I just wrote a about the wire to dist. for fuel pump and in my comment I said that I also hooked back up the fuel pump relay and this is working great now! With out the relay I was not getting any fuel only a prime for 2 seconds. Hope this helps!
Thank you sir. You just saved my rear end. I was about to give up
This video is sure helpful thank you ive been trying to figure out the fuel pump wiring because i have a 1992 gmc c3500hd that im changeing over to to carb because the tbi is failing so bad the truck would run so lean that it doesn't have the power to go up hills
Sweet thank you you're my hero 😂 but fr lol I did a bunch of work engine wise heads intake like that and I was trying really hard to use my throttle body but I don't think it's going to work so this is helpful thank you very much
thanks for the vidieo, been trying for two days to figure out why fuel pump was not working after swap.
Rusty really liked your video you explained it clearly and very comprehendible. I'm going to change the manifold to carbetsted on my 93 gmc 4x4. Z71 with 350 but I changed the 700r4. Like you said chasing phantom problems to have any tips for a manual trany manifold switch? I subscribed to your channel. Thank. You again.
Thank you so much I fully converted my truck and I love it now it peels the tires off do this conversion
I have one question do I disconnect the old timing advance wire as it does impact the initial timing to your hei
Good clean job, any year update vids to your build?
The purple with white stripe to dist. was all I did and with no luck hooked up the fuel pump relay and it works great!
I hooked purple wire up and when I turned key on I get nothing. No sound just cruckets.... thinking of just running to toggle
Good vid and info..
Im pretty much decided to do the swap on my 91 camaro and ive watched a few videos already and it seems like they all say thr same thing,, that theyve kept the factory computer to operate the temp switch for the cooling fan.
So my question is.. If ive already run the cooling fan to a toggle switch, is there any other reason for keeping the ecm? Cuz this thing is a wiring nightmare and im ready to just rip it all out 😂
Excellent video. Ty
Just the video I was looking for...got the same truck with a stalling issue at stop signs ...I've been fighting it for months..im an ok mechanic but am done replacing stuff..took it to a reputable shop and they are scratching there heads..gonna save up and go with your setup.
I did the same thing to my 94. Ill say if youre doing to swap from scratch, it'll run you around $1500 all said and done. Thats a good aluminum intake, 4bbl carb, HEI distributor, tps set up, regulator, brass fittings, etc. You won't regret it though. You'll gain probably 30hp and tons of torque and it will run SO smooth. My truck runs like new and has more power. And with electric choke, it starts very easy. Just 2 pats on the throttle and ZOOM. Paint the valve covers, keep it clean and it'll look like you dropped a $5k crate engine down and this also opens up a lot of possibilities for aftermarket exhaust since you have no emissions to worry about.
@@ericchapman8956 what do you mean by tps setup? Thanks
@@mainerj Throttle Position Sensor. This only applies if you have the 4l80E as it uses the TPS to control its shifting. If you jave a mechanical kickdown or a manual transmission you wont have to worry about it. I used a Holley carb and a special bracket sold by Holley that can be used with the factory Throttle Position Sensor. Without it, a 4L60E/4L80E transmission wont shift right. Sorry im not very good at explaining things.
@@ericchapman8956 thank you, ya makes sense I have a 700r4 so just wanted to make sure I wasn’t missing anything 👍🏼
@@mainerj then you can skip that step entirely!
Good video. Friend can you tell me where I should connect the distributor coil cables so that after starting the engine I can also turn it off by the switch.
doesnt the c in c1500 mean its 2wd? you probably meant k1500
Building a carbed engine for my 91 k1500. Great video! Thanks for the tips!
@Dawnstriker I'm trying to do one on the same year and truck as you, any tips or things you learned/problems you ran into?
@@realWideOpenThrottle actually I haven't even gotten to it yet. Setback after setback.
@@Electrains No problem, I've been looking around on forums and other places to see what others have come up with. Thanks for the reply.
@@realWideOpenThrottle I did a carburetor swap on mines I have a 1990 K1500 350 how far did you get on yours?
@@road2richz_q266 I actually finished it. Truck has been running for a good while now, has the occasional rough idle most likely due to the 87 octane gas I keep throwing at it. Too cheap to buy the good gas. Otherwise it runs perfect.
Great tips thanks sir
I really like your video. Clear and straight forward. I am planning on doing a similar swap on my 1988 Chevy blazer 350 5.7L. Watching your video and comments I had a couple of doubts. Did you use the 2101 or 2104 intake from edelbrock? What carb did you use? and did you change to a melinized gear on the distributor to protect the camshaft? THANKS FOR SHARING.
Hi Jorge, I used the 2101. The only reason to change distributor gear is if you have a roller cam setup, then you would need to use a bronze gear. I used a Holly 600 cfm with electric choke. Had to use adapter to make intake square bore.
@@tlariscy do you remember what adapter? And where to get one? About to attempt on my 88
@@tlariscy hey man I got a 1989 with a rod knocking in my 350. I've got a 78 with a beast of a 350. Can I just set the whole engine in there sir?
@@wildestcowboy2668 shouobe an issue. Just got to provide fuel and spark to be good to go. Not sure on the motor mount match up, but that’s not too hard to adapt if there are any difference.
Thank you for pointing out the tac wire. Just did mine 87 chevy 454, used original intake with carb spacer.runs 90%better.everybody talks about the tbi to carb , but don't tell you about the wire hook up thanks.
Yup,, I just ran across this video point'n out the purple wire,, went out n found it,, gonna try it tomorrow,,, them forums aint all they crack'd up to be are they,,
@@bigpigslapperoinktoo4953 I hooked purple and white wire to the tach port and the pump did not come on i stuck my test light in the wire and it came on strong for just a few secounds and quit, if i pull the test light out and stick it back in it does it again, any thoughts??
@@michaelbraun8074 I have none,, mine is still goin,, when I spliced it in,, it aint stop'd,, I have no clue,, I was gonna drop the tank,, mess with the wire'n and possibly put a Holley red pump on it before I saw that dudes video,,, I almost went mechanical fuel pump if the Holly red didn't work bein it's so old,, I pray ya get it figured out,,
@@bigpigslapperoinktoo4953 I just hooked it up to a hot wire by itself and it still came on the same
Question, I'm learning as I go, I have a jasper 350 engine out of a 95k1500 I'm putting in my 85k 20, do I just need to swap all the fan,water pump, power steering off my old engine for belts and would a Edelbrock 2104 be the correct intake to use to go carb?? Since everyone is telling me the intake that's on it won't work?
"You got a good motor, but your electronics suck", classic truth.
I was wondering if u can do a better video on the wiring for the the distributor and for the fuel pump to stay running
Do u figure out wiring it’s were im stuck at..
4l60e has that cable under the throttle cable as well. If that cable goes to a box on the firewall it controls the cruise control.. just so nobody gets confused after watching this video when they go look and the cables there on a newer trans truck 👍
95 and after has a 4l60e I believe, My 91 has a 700r4
There's a special detent cable corrector that goes on the throttle linkage. It keeps the line pressure right through 3 4 gear. If you don't have that adapter, you will burn up that 700r4 within 1000 miles. You will be lucky to even get 400 miles out of that 700r4 without that part. Cool video
Hi Jeremy, you are right I do have my detent connected to the carb. It took a little adjusting with the bracket to get the proper adjustment from it. Still running strong. Thanks for the comment.
What do you do if you have a granny low 3 speed manual? Would that effect anything with the detent cable?
@@tlariscy hey I did the purple wire what u said but when I’m driving the fuel pump will shut off
@Romeo Weeks did you ever get that issue fixed?
I found out I have to get a inline pump hopefully that will work I’ll let you know if it worked in a couple weeks because I keep bending all my push rods so it’s in the shop tired of fuc*ing with it lol but everything else is perfect transmission shifts smoothly and I found out I have to get a throttle position sensor is from usshift bolts on the passenger side of the carburetor look up nick connors I believe his RUclips name u will see what I’m talking about
Thanks for the video! It was really informative. I have a 1984 Ford LTD Crown Victoria with a 5.0L engine. Do you know if you can convert a Ford the same way as a GM? Any tips are appreciated. :)
Do you unplug the old computer,do you’ve the part number for the fuel pump regulator?
Oil pressure switch sees pressure and keeps the fuel pump running after the initial prime. Needs to be plugged in on the back by the dizzy,,, if your motor has one.
Hi, i have a question. I have a 89 Chevy Extended Cab Silverado C1500 with a 350 and I'm in process of doing the same carb swap.
My question is...there's a hose with like a nut type piece where you can put a wrench on to and it attaches to some short of a fitting that im assuming goes into the intake area of the block. would i have to remove the fitting in order to do the carb and intake swap?
Thank you very much Sir. I hate the computers and I know that I will make my 89 K5 Blazer run like it should with the tried and true method of a distributor and carburetor. 🙂
Your video is exactly what I was looking for. Thank you so much. So, I got all the parts but I have a question as to what hei distributor did you use...do you by any chance have the brand and number? I thank you in advance. Thank you again for the informative video. 🙏
Any HEI distributor for a 350 should work
Been looking for diagrams and videos on how to wire the fuel pump the right way verse just wire it to a switched hot or a toggle switch. Does that bypass you're fuel pump relay? You're fuel gauge works?
Which fuel pressure regulator did you use?
good video my brother
Thanks
GM rocks try to do a conversion to a Ford it’s complicated as for Chevys can swap clear back to 1955 Im not picking on Fords but they are a pain to try to swap out things unless you have the specific year sometimes. Those engineers have too many ideas keep it simple.. tried and true great video long live the HEI and Carb👍🏻
“Gm rocks” that’s why everyone is here trying to get them to run, or be reliable or both. 😅
If you haven’t converted a 5.7 tbi to carb yet they won’t take the ignition timing a conventional carb engine will because of the combustion chamber shape. They rock alright, 1/2 the motor is rocking the scrap bin to make them proper unlike the fords.
Thank you!
Was yours an automatic transmission? I have a 4 speed manual and mine and was wondering if anyone knows what kind of linkage I need for it? I haven’t put it together yet but it will be on an Edelbrock AVS2 carb
Like your vid! You didn't have to mess with the fuel relay at all? So you just connected the purple and white cable to the tach port right? So this way it will run the fuel pump like normal? Thanks.
Yes, straight to the tach port. Keeps fuel pump running. No issues
How much did everything cost for conversion and where did you get it
I have a 95 K1500, did you leave the stock full pump in the tank? I assume you did based on the regulator.
How much did this project run you, great video by the way, answered most of my questions, also would it be fine with a 5 speed ?
Thanks for the how to vid
How did you hook up the Regulator Just a feed on the left and return on the right? And is the a vent on the bottom does that go to the intake or the carb im using my stock intake 1987 4.3l V6 switching over to carburetor.
This is for the Holley fuel regulator documents.holley.com/99-39_30-1900_by-pass_regulator.pdf
Thanks for the video, it was very helpful. But need help. I completed the efi to carb conversion on my 96 silverado and am utilizing the 4l60e. I used the holley tps. Tried to set tps to .5 at idle and can't get the wot higher than 3.8 and doing so changes the idle to 1.8. It goes without saying g the trans starts out in second gear. I can not find the purple with white stripe wire in the plug which went to stock dist. Or for that matter anywhere else in the engine wiring harness. I even had an additional wiring harness from a 96 and couldn't find the wire in it. The engine I installed does not have crank sensor. Can you please help?
I have a 1988 Chevy 1 ton that had tbi I put a 350 out of a 1994 in it and want to go carbureted I have put a Edelbrock intake and a quadrajet 750 from 1987 that has a plug shaped like a trailer light plug built into it and my wiring harness always had a green plug that never had something to plug into and it matches and fits the one in carb I have new fuel pump in tank but my question is do you think I will need a fuel pressure regulator like yours to run properly?
I'm doing a 454 swap on my 83 c10. The 454 has tbi buy I'm buying a new harness and going back to carb. Do I still need the tbi harness or can I use a universal harness from painless performance that does not support tbi?
I have the same setup same carb I just did my swap carb yesterday I ran purple and white to tach and battery side to key turn on also directly to hot truck cranks when given gas but the pump cuts off
My biggest question with this swap is if this will affect any of the gauges on the dash, im considering a carb swap for tuning reasons, but i have a fully functional gauge cluster and id like to keep it fully functioning
You can disconnect your fuel lines just below the cab and you can get to metric fittings and you won't have to cut the line
Could you go into more detail?
@@andreschavez3373 what detail are you wanting to know ?
What initial timing do you run with this setup?
I have a 1988 Chevrolet k 1500. Rebuilt motor and doing the TBI to carb swap. Brand new HEI distributor. 12-volt to battery on distributor
Purple and white wire to takw Port. Fuel pump not running it was before
Do you have video on your vacuum lines on carb and from the booster to carb?
Hi, Thanks for the video!!! Did you or do you have to run a throttle position sensor or does the transmission lock up still work without it. I have a 700R4 in my 89 caprice and I’ve been wanting to do this conversion for the last four years but was just a little scared
Hi the easy way to do this is to put a manual switch to activate the lock up from the dash of your vehicle. here is a link that explains it, itstillruns.com/wire-switch-lock-up-torque-converter-700r-transmission-11372151.html hope this helps
@@tlariscy do you leave the hole on driver side valve cover open? I also have the same motor in my 86 GMC Sierra 1500 along with the Holley 600 carb and was wondering what lines you have connected to the carb
Carlos Hendrix I used a threaded pipe Niple in rubber groumet on valve cover and attached rubber hose to vacuum source.
What is the transmission lock up and do you have to do this?
@mr_brooks_2 i have a 89 caprice switched from tbi to carb and i have some questions if you don’t mind
I'm having the exact issues you described near the end of this video, put a brand new engine in and it has ran like shit since, changed every sensor there is and have come to the conclusion there's wiring issues in the tbi system, idle is erratic all over the place and I can't get it to stabilize so now I'm weighing out switching to carb setup or tracing the wiring issue...
Did you ever figure out why it’s doing this? Mine has been doing it for 1 year but seems it only does it when it wants too. Like one week it’s running like shit and the next it’s perfect.. I’ve tried locating naked wires I’ve changed throttle bodies, distributor +(cap wires and spark plugs), coil, every sensor on the damn thing, fuel pump and filter, and have looked over the ecu wiring behind the glove box and still acts up sometimes.. it was my grandpas truck. Had it every since I was 5 and he gave it to me when I was 16 and I would do anything for it to run right .. please let me know if someone has solved this! Thanks.
@@daltongrayson8513 my 99 is the exact same way,I've figured out outside air temperature effects it.At first when it's cold runs like ass.ten minutes of driving and it's mostly normal.Just not the best setup
@@brandonvansel3716 have you changed the temp sensor on the intake?
@@daltongrayson8513 yes.Ive changed pretty much everything at this point.The other thing that does this is to much air at the maf
@@brandonvansel3716 I’ll try to figure out how to post a video of what my truck is doing on here and tell me if yours is doing the same thing
Do did you not have to run a hot wire to the battery or take the green and white wire hook it up to your ignition wire ?
Hello Mr. Lariscy. I have to ask you another question. I will be sending quite far from the US the parts that I will order for my conversion so I need to make sure that what I buy is what I need. In the case of the Intake manifold the edelbrock 2104 is the one that goes well with the cast iron heads on my 1988 350 5.7 L engine? Thank you again.
The four center holes on intake are straight up and down on the TBI heads that’s the only difference as far as I know. Not sure if your heads have the older style center holes that are the same angle as the others.
Lots of questions! What carb? I know the flow of the heads is crap.
Have 1989 C1500. Motor was rebuilt with Comp cam (5000rpm)and roller valve train. Suddenly have no high end. What linkage kit? (I have 700R4). Where is the timing? Does yours have more power over the TBI?
Thanks
Very good illustration.Does your Truck have the L98 aluminum heads. I 'm doing a 89 Vette.Going to use 2102 Edelbrock.so the distributor is no computer Hei.purple wire goes to the tach side of the new distributor
Thanks Robbie
Cast iron heads
L98 aluminum
Which wire do I use to put on bat side of the distributor and which cable to I use for the electric choke ?
What do you do about the electrical wiring for the rest of the truck? How does that change with a carb?
Hi Steven, you will still use all the engine sensors like water temp , oil pressure Ext. All the plugs for throttle position , map sensor ect will not be used. I cut mine off. Be sure before cutting anything that everything works like it is supposed to. Better safe than sorry.
We are just now completing a similar conversion on my son's 91 Silverado. We went with carburetor heads, because our valve seals were bad and different intake but similar distributor and carburetor. Was just now fighting trying to figure out how to power the fuel pump, our only hurdle before starting this motor. If I understand correctly, and its great information, all I need to do is run that wire from the distributor plug to the tac wire from the coil And the fuel pump will operate normally?
Yes, the computer uses that wire to sense engine speed so that the voltage to the fuel pump is regulated to supply appropriate pressure from the pump.
@@tlariscy Thank you so much for the very valuable information. We took the info in your video and were able to finish up the minor wiring for the distributor and the fuel pump in just a few minutes. We did get the engine fired but are having a bit of a vacuum leak issue we are working on. One thing we have different, another post had referenced the part number for a mechanical fuel pump that they used in tandem with the electric. The tandem fuel pump has a return and according to the poster it automatically regulated the fuel down to the 5 psi needed for the carburetor. We have everything hooked up, it appears to be working but at this point I believe I'm going to add a regulator between the mechanical pump and the carburetor for safety.
Have 1994 converted 350 to carb. Only now have 2nd gear and reverse only. What do i do without going to older trany?
How do you get the trans to go into overdrive once you have removed all the sensors and electronics? Is there an easy way to do this or do you have to install a kit ?
Overdrive is accomplished through the lock up of the torque converter. This can be achieved through a TPS and a kit or through wiring a switch to the harness coming out of the xmsn. I do not know which wires they are you would have to do some research.
To Get The In Tank Pump To Work other than just prime! cut grey wire from fuel pump relay on passenger firewall and connect it to new relay which will be your fuel pump hot with constant 12v, switched 12v & ground wahla fuel pump comes on with ignition switch and works properly! Remember to use a bypass regulator!
What year did you do this on?
I got a 90 c2500 with a L98 that I carbed. I have the 3l80/th400 trans. What do I need to make it work right? It's not quite driveable yet but I'm just trying to figure out what else to do
Can you please tell me if they make an adapter kit to where I don't have to change my intake manifold
If you leave the tbi wiring harness in place and guve it the tach signal, hook the map sensor to the new manifold, and fit a throttle position sensor to the carburetor the 4l60E should shift fine
Does changing from injection to carb affect the spark plugs performance? Seems to me a hotter plug may be necessary? Anyone have thoughts?
Can you put a old mechanical fuel pump on the block or did they remove that provision on the block??
Should work
I am about to do exactly what you did. Had my 350 in my 89 C1500 rebuilt to a 355 and roller cam. Wont idle worth crap. Has ALL new sensors, yadda yadda. The old TBI has to go. Endless surging and uncontrollable idle. Looking for part numbers for manifold, carb and kickdown linkage adaptor. Also, did you use anybold HEI distributor? Thanks
Edelbrock 2101 performer Spectre Performance 24283 Throttle Cable Bracket and yes the standard HEI will work, you will have to change to a bronze distributor gear for the roller cam.
What do you set your timing to after the HEI distributor and club swap I did this a month or so ago putting that motor out of that truck 93 1500 extended cab in my little square body S10 Blazer and it's running really good but I was wondering what did you say your timing too on the balancer with a light you can go on my RUclips channel 1lowz and see my build
So basically you could put that intake on an older carbureted engine with hei already and it'd work in tbi truck?
hey im doing the same thing i got 1990 k5 blazer 5.7 700r4 trans ..did u have to get a convert lock up controller for it..i heard once you eliminate the tbi that you need that or u would burn your tranns out..let me no
Did you have issues with the side intake bolts with the angle of bolts
Do I. Need to hook up the electronic kick down on my 1988 gmc it was to and someone made it carburetor but never hooked up the electronic kick down I have the 700r4 transmission mine also has a another kick down cable on it that’s on the passenger side of transmission
What are the color of wires that go to the starter. I removed my whole engine to rebuild inside out and forgot to add name tags to the wires
do I lose the factory tach doing this or does the relay/tach wire keep stock tach?
Can you provide brand of carb and distrib you went with? Also, assumably you got more power, how was your mpg (increase/decrease?
Hi Dan, the carb was a Holly 600 cfm vacuum secondary with electric choke. The distributor was a OEM GM HEI distributor. Much more power due to adjustability. Gas mileage isn’t going to be as good as the fuel injection, but most do this swap because of the TBI system being in a state that is not repairable.
I have a tbi 350 and plan on using a 2barrel carb and adaptor to bolt up to the tbi intake but my question is will a hei carbureted distributor work on the tbi intake?
Hi Sam, as far as I know it should. But you might want to float that question around to other sources just to be sure.
Walt Lariscy who should I ask?
Can you by pass the knock sensor when you do the conversion?
Can you assist on instruction for how to attach the linkage to my Rochester 4 bbl on my new 2104 Intake?
So you can't use the tbi distribution when doing the swap?
That is correct, the Tbi distributor is totally controlled by the ECM, based on signals from all the sensors. It needs to be stand alone and to function properly. That is why the HEI works excellent for this swap.
What did you do for the egr valve?
I blocked off the EGR port on the intake and deleted the system
(Really hoping you reply).... Is the purple wire to the tach to reroute power due to you removing the ECU? Or did you leave the ECU wired in place? Thanks!
The ECU is still in and functioning partially,the wire to tach port is to send signal to ECU to control the fuel pump based on engine rpm and fuel demand. Hope this helps
@@tlariscy We're getting there... So I'm guessing you ran the purple/white from the old distributor plug to the tach terminal of an HEI? I suppose the HEI tach signal must ba a 5VDC square wave?
When you hooked up the purple and white wire to the tach port did you still have a functional tach?
Hi this truck did not have a tach, so I’m not sure on this.
I was able to hook up both the white factory tach wire and the purple/white-stripe fuel pump wire to the tach port on the HEI and everything works to include factory tach. 1992 1500 Z71
Went from tbi to carb in 89 chevy k2500 its showing a MAP sensor code but the Carb runs fine without it. Is there a way to bypass that? The computer is throwing the engine off in some aspects like harder start. This just recently started happening.
Hi Robert, if you changed to a carb and switched to a HEI distributor, the computer has no control over your engine any more. There could be some other issue causing the hard start. Are you using an electric choke on your carb? With a carb in colder weather you need a choke for better starting. As far as your computer throwing codes … you can ignore these as they are irrelevant. Your computer does not know that it isn’t controlling the engine, as a matter of fact the only thing it is controlling is the fuel pump if you are using the in tank fuel pump. I would double check the easy stuff first like… timing, plugs, and fuel/air mixture of carb. Good luck, let me know what you find.
I have a question and need a little help I just did this conversion to my 92 suburban, but I swapped in a 385 stroker motor with a 750 Holley carb with electric choke and I also have a Holley 12-841 fuel pressure regulator.
the other day Saturday the 27th I got my first start I started it then turned it off and then started it again and let it run for a min or 2 then it had cut off
on its own and since then I tried to get it running again but it fires and just shuts off.
So I am thinking I got an fuel issue I got the purple and white wire hooked up to the tach port but I dont think the pump is staying on maybe.
I want to ask do I suppose to also have that white wire from the coil hooked up to the tach port also?
Tomorrow morning I am thinking of proving my theory that the pump not running after the initial prime after turning the key by hooking a keyed 12 volts source to the pump green and white wire but if it still dont run any ideas to why it want stay running maybe I need to tune down the fuel regulator cause I did turn it up the other day or maybe an issue with my carb which I hope not!
I'm currently doing this on a 87 and you need the oil pressure switch that's on the back of the engine hooked up because it needs to see oil pressure
I am using that oil switch and an after market oil pressure gauge and for the short time it ran I was watching the after market gauge and I had good oil pressure but I didn't pay attention to the dash gauge.
But this morning I bypassed the purple and white wire and ran a red wire from the fuel pump relay to the green and white wire on the relay so when I put the ignition switch in on position the pump turns on but I still couldn't get it to stay running it would just fire and stall so I guess tomorrow I will be trouble shooting the carb to see if I'm getting fuel in the bowls and make some set up adjustments
@@roddavis5494 Good sir, dump some fuel into the vent tube, or try and keep it going with starting fluid or even brakleen, the HEI module is renowned for ignition issues, if it stays running you have a fuel problem. Or if it still stalls, I guarantee its your HEI module under the distributor cap its worth it to keep a spare as these things age.
My 4 pin plug has black/white strip, white/black stripe, white, pink(or orange)
Hello, and you just left your factory tbi ecu plugged in? No issues?
That is correct
My 1988 W100 i just sold a couple months ago had a TBI rooted gremlin i just couldnt iron out.
I loved the truck but i had to make a decision to either keeo dumping money into it or use that money for fishing, and i chose option B.
Thanks for the sub BTW 😊
got question for you ....i just rebuild my chevy 350 1990 k5 blazer i converted it over from tbi to carb ..i did a few up grade on the engine high performance intake headers 3' pipes all way back up graded the cam to a howard rattler cam 525 intake lift 535 exhaust duration 227/235 lobe separation 109 center line 103 i still the same factory heads on there i believe they the swirl port heads ..i no i should have went with some better heads but the engine was already done. i put a brand new 1406 edelbrock car on it right out the box every sence i put that carb on there i been using alot of fuel i set the carb best as posible ..im using a awful lot of fuel just with it iding..i have my pressure regulator set at 5psi..dont no why im losing so mush fuel
Not sure. I use a vacuum gauge to adjust carb. Maybe dialing your carb in will help
I have an "88 with a TH400 trans. Any idea what has to be done for that trans?
i have been considering going to carb and hei on my 95 gmc van. it has vortec heads, marine cam .431/.451 lift, headers, and of course, aftermarket intake. only thing stopping me is the 4l60e. any sugestions? it is starving for fuel
Same here have you found any answers
@@brendentaylor8976 i installed a holley 650 and hei, now running really rich. hard to adjust the fuel pressure. either buy a quality bypass regulator or delete the in tank pump and run a mechanical pump. just hook up the power wire and ecu wire to distributor and you need the throttle position sensor. without the tps, it shifts at about 2000 rpm no matter what. if you want to keep your tbi set up, there is a regulator set up you can install, but i dont know much about it. i scratched that project and am working on an s10 now. www.amazon.com/JEGS-159050-Adjustable-Pressure-Regulator/dp/B078WHVJHX
@@chrystalpaugh9458 thank you for the info
Not sure if you're going to see this Walt, but I am swapping a 1997 Chevy Tahoe 5.7 to carbureted. The only thing I can't figure out is if I have vortec heads. It says vortec above the intake boot, but it has TBI.. for some reason I keep reading that TBI motors are different from the vortec
during 1997 was the 5.7 L 5700 L31 engine, which was produced from 1996 to 2002. The V-8 engine had an overhead valve configuration, with two valves per cylinder. The truck engine was rated at 255 horsepower and 330 foot-pounds of torque. The 5700 engine appeared in the 1997 Chevrolet Express, Chevrolet Suburban, Chevrolet Tahoe, Chevrolet/GMC full-size trucks and the Cadillac Escalade. This engine was replaced in 2002 by the 5.3 5300.
Yes you should have vortec heads
I have 96 silverado that I completed the conversion and could not find the purple wire with white stripe anywhere that everyone runs to the tach port. Did you find the wire?
Im going to do the conversion on my 92 camaro i allready have the hei distributer hiw and what wire would i use to run the pump thank u
Hi. Im also doing a 91 camaro 3.1 to 2.8 mani/carb swap. Did you find a distributor? What part#
I see some other wires going to the distributor. Don’t know anything about wiring so what would those be?
Do the service engine lights come on after the swap out
What bracket did you use for the cables?
It was a generic one from the local parts store. Had to drill two new holes for TV cable bracket to get adequate adjustment. I just don’t remember the brand.
What is the part number for the flueI pressure regulator
We did everything you said and the motor runs fine ,but when you put it in gear it stalls out. It has the detention cable for a 700R . IT'S a1990 CHEVY c 2500 with a 5.7 motor. Thanks! ED
Hi Ed, my guess would be fuel supply, however the lock up torque converter may be locking up when you put it in gear. Try disconnecting the wiring harness on side of transmission and see if problems still there. This should rule out transmission problems. Hard to troubleshoot when not on site. Good luck