TBI 350 barely runs after tbi rebuild

[iamtherealJayy]

It ran fine before I took the tb off and replaced the gaskets and cleaned all the caked up grime off of it

 

[squaredeal91]

Its pretty odd because it ran fine before but it's possible something else has failed and waited to show up. How long was it down for? Couple days? Couple months?

 

[iamtherealJayy]

Was running that morning, decided to show the truck some love because the injectors or the regulator or was leaking because you could see fuelpooling around the regulator if it idled for a while. Took tb off cleaned it regasketed assembled and it fired right up, jumped a and b ign on 10 sec unplug iac then I had the issue. I didn’t have the truck running long after the rebuild

 

[gmbellew]

Was running that morning, decided to show the truck some love because the injectors or the regulator or was leaking because you could see fuelpooling around the regulator if it idled for a while. Took tb off cleaned it regasketed assembled and it fired right up, jumped a and b ign on 10 sec unplug iac then I had the issue. I didn’t have the truck running long after the rebuild

probably not the issue, but I think 10sec may be a touch short to fully seat the IAC. you may try resetting it to full close for 30 sec and see if that makes a difference. the ECM doesn't actually know where the IAC is, just where it is commanding it to be assuming it knows where it is.

 

[iamtherealJayy]

Alright, I’ve never had any issue with the truck idling too low so I’ve never had a reason to mess with the idle screw. I’d rather leave it capped than start trying to bandaid a problem

 

[squaredeal91]

So if you disconnect iac it stays running and won't die?? Do you have another iac you can try on there from another engine?

 

[iamtherealJayy]

No when I disconnected the iac and tried to start the truck it wouldn’t start or stay running without throttle

 

[gmbellew]

No when I disconnected the iac and tried to start the truck it wouldn’t start or stay running without throttle

I am guessing the throttle blade shaft bushings are worn or the shaft bent that is allowing the blades to close all the way, when the throttle stop screw should prevent the engine from dying with IAC closed off and unplugged

 

[iamtherealJayy]

So I 100% need to turn the idle up slightly

 

[Bextreme04]

No when I disconnected the iac and tried to start the truck it wouldn’t start or stay running without throttle

You are killing me with this. This is another thread that is going to go 30 pages because you are going to circle around the actual problem because you refuse to do the ENTIRE procedure that is called out the first time. The throttle body idle is set at the factory when the engine was assembled(god knows how long ago) and then they put the plug in over it. If it was a replacement TBI at some point, it might have NEVER been adjusted. Any time you do maintenance or change anything on the system(or have a problem with idle) you are supposed to do a full IAC reset procedure. You took the whole thing apart and now it won't idle correctly without you using throttle. This is because you didn't do the proper adjustment. I'm not sure why you are so dead set on removing that plug, but you need to remove the plug and properly adjust your idle. Use the service manual or any of the readily available instructions all over the internet. Short the IAC closed. Unplug it. Start the truck and then set idle manually to 650 rpm. Turn it off. Plug IAC back in. Magically find you no longer have a problem.

 

[squaredeal91]

Copy that, I don't know if this is helpful but I had a tbi s10 and wanted it to idle low so I manually adjusted it by hand and left it unplugged and it ran great. On a different rig I had an iac act up and killed my engine allot in parking lots and stuff the wiring was good so I replaced it and problem solved. I guess it forgot where it thought it was or something lol.

 

[iamtherealJayy]

I’ll break the cap n adjust it

 

[gmbellew]

I’ll break the cap n adjust it

also check out the throttle blade shaft for play.

the cap should punch out easy with a small screw driver and a light tap from a hammer.

 

[JACK34]

I have a 1994 that does the same thing. I replaced everything but the TBI and took it to a local mechanic and still can't figure it out. I'm going to either set it on fire or part it out it's no good to me or anyone else. That whole TBI thing is junk in my opinion. Good luck.

 

[iamtherealJayy]

Finally got the cap off, probably turned the screw half a turn to get idle between 650/700 with iac closed and unplugged. Pedal is somewhat softer, I’ve got a new cable just incase. Truck idles fine but cranked for forever and alternator isn’t happy, it appears to be charging but not past 13 on the gauge where it normally is