Let me say that this is the best tbi, and tpi site on the net and after searching the forums I still cant find a solution. So here it is

My 350 tbi has a problem that has me stumped. First I am getting no ses light (no codes). What it is doing is when I go to start it (cold) like after it has sat overnight or all day at work the truck wont start unless I put the gas pedal to the floor (acts like it flooded). It will briefly fire then nothing. Hold the pedal to the floor and it will start but run rough and put out lots of black smoke. Its acting like whatever controls the increase in air flow during open loop is not functioning. After it has warmed up (closed loop) it runs great and will start every time. I guess what I need to know is what controls the increase in airflow during open loop operation and what to look for as a solution? Its getting plenty of fuel on cold start but not enough air.

 

Someone check this theroy, I had the tbi off about 2 months ago and nuked it w/ carb cleaner in the parts washer w/out taking the Iac or the TPS off. I have a feeling that the carb cleaner has fubared the IAC motor causing it to be inoperative. I have also noticed that when the ac is turned on I get no idle increase. So this leads me to believe that the IAC needs replaced.
If i am not getting any codes it could mean that the electronic part of the IAC is working but the motor is not,
Any takers?

 

Well I do know that carb cleaner will fry the crap out of electronic components, but if the computer wasn't getting a signal from the IAC or the TPS (not likely), I would think it would throw a code.

 

Carb cleaner will not hurt your IAC as long as you put a drop of clean oil on it before you put the TBI unit back on. It helps it work properly and avoid sticking. You may have fried your TPS or bumped it out of wack. Check the IAC and TPS adjustments tech article.

 

Could be the other way around... Too much fuel with the air that comes in. Having the IAC closed/malfunctioning may act as a choke if the VEs arnt quite sync'd up with the motor in the car. Is it all stock?

I had a similar problem with mine. Even stock it would always flood out. Mostly a tuning issue and taking out fuel during crank would help keep it from flooding when it finally fired. Flooring the accelerator pedal will put the ECM into flood clear and will reduce the AFRs to 20:1 to help clear out a flood. Check to make sure your car/truck/whatever doesnt have any issues and if that doesnt work, a little trick that can prevent stalls is to slightly open the throttle on cold starts. Did it for awhile after I got my car and it helped prevent it from stalling when cold.

 

Replaced IAC and all is well now except for a intermittant code 43. Which is either my knock sensor or Tps. Goint to check voatage then bump up timing.