86iroctpi

I have had problems with trying to get my car to idle correctly. When it is cold idles really rough ond dies if you don't keep giving it gas. After it warms up alittle it won't die, but it still idles rough. I have changed the evap canister and checked the canister purge valve, but that didn't help any. I also took the tb off and cleaned it thoroughly. That didn't help either. If i disconnect the vacume line that runs from the canister purge valve to the tb the the car idles and runs fine, but I don't want to leave it this way, because pressure stays built up in the fuel tank. I am also not getting any codes from the ecm.

Any suggestions?

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86 iroc, tpi, auto, compucam, headers, pace-setter cat-back, stageII chip, afpr, air foil, filters, maf screens removed, gutted air cleaner box, 160* stat.

[This message has been edited by 86iroctpi (edited December 04, 2001).]

snakeskinner

check the coolant temp sensor with a scanner when the engine is cold. if it were off a lot, it will affect the injector pulse-width.

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Kyle Osterholt
Okarche, Oklahoma
ASE Master Certified
86 T/A 383 TPI
89 TTA #1002 T-top/Leather
89 TTA #1358 Hardtop/Leather
80 T/A Pace Car
73 Opel GT
73 bronco
2000 Ducati 996 Monoposto
83 MSE #52

88camaro

im guessing here, so dont take it as facts , but i'll sujest ckecking the hoses u disconnect for cracks if u didn't already do that , and maybe checking your AIC and TPS, that what solved my problem , i had a similar one...
and a question for u , how much did u get the EVAP canister and purge valve for?

86iroctpi

The evap canister was $70 at an OE parts house. The purge valve was $16 at Advanced Auto. Advanced also has the canister for about $78.

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86 iroc, tpi, auto, compucam, headers, pace-setter cat-back, stageII chip, afpr, air foil, filters, maf screens removed, gutted air cleaner box, 160* stat.

86iroctpi

The engine has less than 14,000 miles on it. That includes the heads and fuel injectors. The coil, cap, rotor, plugs, and wires have less than 2000 miles on them. The reason why I had the vacum line off, was when I cleaned the tb, I forgot to hook it back up. Upon restarting the engine after cleaning the tb, I noticed that the vacum line wasn't hooked up. It ran fine while the vacum line was unhooked, but when I reconnected the line, it started idleing rough again. That is how I Know it runs fine while the line is unhooked.

It ran great up until about a month ago and within the span of about a week, it developed this problem.

I have good fuel pressure at idle; 42 psi. I have tried adjusting the idle; that didn't help. None of the plug wires are touching the headers. I have tried adjusting the tps. I clear the ecm every time I try something new. Nothing so far seems to help.

The problem is only at idle (all engine temperatures)and cruising, at less than about 1500 rpm's. After it reaches a higher engine speed it runs fine. The engine idles at 750 rpm.

The evap canister has been replaced. So I don't think that is the problem. The vacum line that goes to the tb only opens the purge valves associated with the canister, it does'nt actually suck air or fuel vapors from the canister. It is a very small hose and only goes from the canister, to the tb, and to the egr solenoid.

I have tried everything that I can think of.

RedFirebird

A bad purge solenoid can be the problem. The purge solenoid is controlled by the ecm not the vacuum source.

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'87 Red Formula Firebird
-mostly stock LG4 w/cowl induction setup borrowed from '83 TA and T5 tranny

'85 Corvette
-stock L98/4+3 manual tranny
-z51 package