me420

Ok so Ive been reading posts for about 3 weeks now about an intermitent problem my 87 iroc has.

It stalls on cold and or warm conditions. It gets me to work still but between this random problem combined with a burnt power steering pump my car is a death trap. Since I work at night, when I actualy get time to just check it out its fine, making it harder to diagnose.

If it wont start I have to pump the gas like a carb. When running if I let off the throttle it shoots to zero rpms almost instantly. I gotta pump the throttle a few times a second to keep it running but sometimes after driving it idles fine. Until I restart the engine later it sometimes doesnt wanna fire up without help.

As far as parts, I have installed both power and burnoff relays for MAF(from Chevy), installed IAC today, and checked TPS voltage .5 @ idle 4.3 @ WOT.

I disconnected the timing wire and the iac and the car ran extremely rough with a strobing check engine light. Still wouldnt idle. Did the paper clip, 30 sec wait, disconnect iac, fire engine.

Also tried disconnecting the MAF sensor and it wont idle.

Since last weekend when I touched it last, I went this whole week without the problem until just after I removed the airlid and MAF plug to installl the IAC. Im almost convinced its either the MAF plug or MAF itself. Anyone have any suggestions? 3rd owner 79k-166k

me420

Guess ill buy MAF and sensor connector, was hoping to avoid buying the MAF

Vertigo107

iTrader: (3)

Did you check the IAC valve? I had your issue years ago on my 87, and it was a simple IAC replacement. Worth checking.

vetteoz

iTrader: (13)

Have you tested the whole MAF system as per the factory diagnostics?
http://www.chevythunder.com/maf_code_33.htm
http://www.chevythunder.com/maf_code_34.htm

That would indicate it has too much fuel. Having your foot on the gas while cranking the engine over shuts off the fuel supply.
How good are your fuel injectors? Have you tested them? May be leaking.

FWIW,
you can't " pump gas " on a EFI engine like you can on a carb engine ;
There is nothing to squirt the fuel in on a TB like there is a carb does so hitting the pedal does the opposite to what it does
with a carby; it lets more air in , not more fuel.

me420

yeah I put a new IAC in. Thanks for diagram Im going to get a voltmeter I didnt test the MAF.

btw sorry next time ill say pump the air pedal, lol jk

Tuned Performance

iTrader: (92)

pump the air pedal ? while cranking or running rapidly pumping the throttle will result in a accelerator pump shot.

nothingbutagthn

iTrader: (2)

ck fuel pressure

nothingbutagthn

iTrader: (2)

Also have you performed any recent work on the engine and what do the plugs look like is this tpi or throttle body

me420

Tpi as listed in profile. Previous owner put new injectors in 85000+ miles ago. No mods.
Ill check the fuel presssure and look into checking the injectors.

me420

Put new iridium plugs not too long ago ill check them tho

camarofvr

If it's stalling randomly check your minimum idle adjustment since you installed a new iac. I had the same problem after installing a new iac and whoever owned my car before had adjusted it all wrong. Also check all your vacuum lines for leaks and make sure your spark plugs aren't fouled.

BLACK92B4C

My car was a little different because it was in police service for over 10 years, but I had the exact same problem. For me it was the pickup in the distributor. When I tried to remove it, it just crumbled into dust...all the hours of idling in heat had really worn it out. I just got a replacement distributor and it has ran perfect ever since.

nothingbutagthn

iTrader: (2)

any ck engine lights? I should have suggested getting it ran for codes first thing.

me420

forgot to add intermittent code 34.

been a week since i believe i fixed it. visualy looked at maf + screen few times looked fine but i used MAF cleaner on sensor and i think that was the problem. i also noticed sludge behind the butterflies for the throttle body. took the 4 bolts off and cleand the tb's backside.

now car idles, just high.

i installed a new iac but also broke it so i put the old one back in so im thinking the bad idle now is bc of IAC.

by the way parts installed have been attempts to cure the problem.

rgarcia63

i assume you followed a procedure for setting the IAC.