white91formula

iTrader: (4)

first off its a 91 305 tbi, 5peed swap

i have a very high idle when my car starts at anypoint, its worse when its cold, but thats because its still in closed loop. when its cold it idles at about 2000-2100 RPMS until it warms up and then it drops down to about 1400-1700 depending on what mood its in... and i cant for hte life of me figure out what the problem is

ive checked and cleaned my IAC, as well as set the idle a FEW times... it will set the idle fine with the pins A&B jumped on the ALDL, turn it off plug everything back in the right way and start it up... runs fine, take it for a ride around the block, bring it back and shut it off.... start it up a few minutes later and the problem is back. and the thottle linkage stop is not touching the idle set screw stop on the TB itself... even though the IAC is cleaned, could it still be bad, anyway to test if it is bad or not ?

i checked the TPS, seems to be normal

sprayed down the engine back with carb cleaner to look for any vacum leaks and coudlnt find anything at all

the only other thing that i can think of would be my timing....

the car used to be a auto... now its swapped to a manual, should i have reset my timing when i swapped it over ? is the computer still looking for the torque converter and causing the engine to idle high because its not there to slow it down ?

8492bird

We just had a chevy suburban at work (305 TBI) that did the same thing. Mechanic at work tried everything until he gave up and sent it to the shop. It WAS a vacuum leak. I'll try to find out where it was tomorrow.

joe350

If the throttle linkage stop isn't touching the screw at closed throttle, then your throttle is sticking open. If your problem was a vacuum leak, you would not be able to set the minimum idle RPM at all. It just would not go any lower.

Toehead

Good point. Did you try manually closing the throttle to see if you ccan get the stop to touch? It could also be that somebody backed off the idle screw to the point where it can't touch.

Matthew91-Z28

I assume you changed ecm's, right?

white91formula

iTrader: (4)

it isnt touching when the car is running... but when it is off it does


i can push it back to the screw... but it just goes back to where it was after i let go



no, and that was my first though but i have talked to a few people who have done this swap and not changed ECMs and not had any problems....








I tried a new IAC valve today and that didnt work, so now im thinking it is vacum, even tho i went through a whole can of carb cleaner in the engine bay looking for a vacum leak