Chevy 350 TBI help

[clintbailey]

Long story short, I have 2 1995 Chevy pickups now, both with 350 TBI/auotmatics, bought the latest one a couple weeks ago. I was told it had a "cold start issue" when buying it, and he wasn't kidding. Have to give it gas with the pedal to get it started after it sits overnight/more than a few hours, and it idles real low, like 3-500 RPM until I drive it some, then it idles around 900-1000 and will start fine until it sits a while. We swapped the throttle bodies today, and the problem seems to have followed to my older one. Any ideas? I'm wondering about the injectors or the idle air sensor that screws in on pass side of throttle body? Thanks for any help, Clint

 

[Pokinfun]

check the fuel pump pressure

 

[O4L]

Found this online...

http://www.chevytalk.org/fusionbb/showtopic.php?tid/176155

More here...

https://www.google.com/search?q=che...print-mvno-us&sourceid=chrome-mobile&ie=UTF-8

 

[clintbailey]

Thanks Old Phart, will dig around in there some...

 

[NightShade]

First thing I would do is hose down the TBI passages with some carb/intake cleaner. May take a few runs of doing it but eventually it should clear out a lot of crud. My Dakota 4.7l intake had a bunch of buildup and didn't want to idle right until I clear out the Idle Air Control passages and some other stuff.

 

[Okie4570]

Pretty common swap in the early Ford bronco world for guys to put these TBI on their 302 and 351. Most issues are usually throttle position sensors, fuel pressure regulator, or relay. I'm not a Chevy TBI guy, but have seen a few fail over the years and it was always one of those three. Good luck!

 

[sh00ter]

The pressure on these is regulated by some springs in the TBI itself if I recall, these can fatigue and they sell kits at O'reilly to rebuild the TBI fairly cheap...but I had a buddy with a similar issue and it turned out to be something with a fuel hose back under the bed somewhere...apparently a common issue with these trucks. I will try to find out the specifics but I remember he chased the issue forever and then figured out the line thing.

EDIT: he said there is a 3inch piece of rubber hose between fuel pump and fuel sending unit that corrodes and caused it to run rough. Might not be your issue but figured I'd let you know. However, the idle air control is prob cheap enough at parts store to try it too.