Hi

I have a problem with my 89 RS conv. L03, bone stock engine.
The only way the engine can start is, if I press the gas when the engine is cranking. Can it be a IAC problem ?

Sometimes it also suddenly stalls when the engine is idleing, can that be the same problem ?

Any advise will be thankfull received.

There are not to many TBI/chevrolet experts here in Denmark

 

Sounds like you might have a loose or worn out throttle position sensor. Are you getting any codes or SES lighting up? It should give a code 21 or 22 for a bad sensor. Good luck!

 

No, I am not getting SES light or any stored codes.

 

isnt that the way you're supposed to start older GM's?

before cranking, step on the gas 1-3 times, then start..
if it doesn't go repeat, and then as it's cranking step on the gas...

that's how i've started my cars for long time..

the manual also mentions a procedure very similar to this

 

Yes, it is the way with older CARB cars, but not with EFI cars like this one .

 

That's wierd! I think auto comp. are like people, when they get old they get forgetful! I have a start-up problem with my 88 pontiac Formula, L03 and never get any codes that help identify the problem. I've been trying to find it for a couple of years now and I'm about ready to shoot it!!! I would still look for your TPS to be loose or bad connection wire, might even replace it since your engine won't start till it recieves a wide open throttle signal. and quits sometimes at idle.

 

Could be the IAC. Try cleaning it with some kind of spray cleaner or something.

 

lots of these tbi cars seem to do that same thing. Catch and then promptly stall/flood out when the engine is really cold. Sluggish IAC is definatly something to look at. You can take the pintle out of the IAC, from what I hear, by gently rocking it back and forth while lightly pulling. You can also get the ecm to eject the pintle by putting the computer in diagnostic mode. After you have it out you can use some gentle solvents like gasoline, naphtha, or zippo lighter fluid to get all teh carbon off the pintle shaft and surrounding area of the IAC. Lubricate with a light grease and reassemble. I did this for mine and it helped but it didnt really fix teh starting problem since the pintle wouldnt fully retract. I ended up just replacing it.

 

Hi Guys

Thanks for the tips, I will try to find a new IAC and take a look at the TPS wiring.


Other tips are still welcome.

 

Just an update :

After I changed the IAC, the problems was gone.

Thanks for the tips.

 

Hey dimented, Does that IAC valve screw up when warm too? My Lo3 starts and surges a couple of times and then dies! If you keep restarting it, it keeps doing it unless you masterbate the dam throttle to get the rpm up to about 2000-2500 rpm for about 10 sec. and then it soothes out and will Idle. I suspected the IAC valve, so I took it out, dissasembled and cleaned it then reinstalled it and reset acording to manual instructions. Well, It still did it I then started it through the drivers window and jumped under the hood, kept it running as best I could pushing the throttle linkage and looking down the top of the TB into the passage hole to observe the pintle movement to see if it was closing. Here's what was happening.
Turn key on pintle is retracted (open)?
Start engine and it wants to die
Continuoisly pump TB linkage to keep running
During that process the pintle slowly closes about 10-15 sec.
After it finally closes the engine will Idle ok.
If you shut the engine off and then try to restart it the pintle is fully retracted and the whole Process starts all over again to get it to Idle ok. It usually starts ok when it's cold though. Should the IAC valve close at a faster rate than that? seems if it did it would Idle ok after start up I noticed in your last post you mentioned SLUGGISH OPERATION and thought this might be my problem but I would like a little more feed-back before I spend all my wife's MONEY that I earn! Thanks