I really count on you guys for help! Don't let me down!

For some time now, i have noticed that my car idles like crap. It searches for the right idle speed... I start it up, and RPMs vary from 1200 to 500. It drives fine though. I took off the throttle body and IAC valve and cleaned things up, thinking that this was the problem. It seems to have improved, but only marginally.
One thing i noticed was that when I took the throttle body off, i smelled gasoline coming from the intake. Is this normal? I didnt think it was.

Please tell me what I need to do to investigate this problem, and if it is related to why the idle is crappy.

Thanks,

Joe



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86 IROC TPI 305
700-R4 with Trans-go shift kit
K&N Air filters
Dyno-Max cat-back
Summit tranny cooler
CEI throttle enhancer chip
Gutted MAF

 

Is it a dead miss on a cylinder??
Mine had a bad injector and it seemed to run fine around town but come up to a stop and it would almost die then surge up to 1200 and then almost die. Might check the ohms on the injectors. If they all ohm at the right resistance doesn't necessarily mean that they are good but if one registers out of the correct range you know that one is bad.

 

Thanks for the response, but tell me...

Do I need to disconnect the injectors to do this? I would also imagine that the car needs to be off? (meaning that the electricity is turned off)

Do you know how I would look for a leaky injector? I was wondering if maybe that caused the gasoline smell when I took the throttle body off.


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86 IROC TPI 305
700-R4 with Trans-go shift kit
K&N Air filters
Dyno-Max cat-back
Summit tranny cooler
CEI throttle enhancer chip
Gutted MAF

 

Mine had that smell...made the whole garage reek after I let it sit for several weeks. I drained the oil and found close to a quart of gas in my oil from a leaky injector on cylinder #1. This can cause all the symptoms you describe. First of all, check your oil and if it smells like gas change it immediately before you drive it again. Next, check the fuel pressure after priming the pump and watch for it to fall. If it doesn't drop within an hour you probably have other troubles. If it drops I'd suspect a leaking injector or pressure regulator. To rule the PR out, pull the little vacuum hose off of it and prime the pump. If fuel squirts out of the reg. then this would also cause your symptoms just like a leaky injector.

Now to isolate the individual injectors that are leaking do one of three things:

1.) Pull the injector clips one at a time with the car idling and listen for a change in the idle. If one is pulled and the idle doesn't change, there's your problem.

2.) Pull the spark plugs about an hour after the last time you ran it and smell each one. The ones in a cyl. with a leaking injector will likely reek of gas (mine did).

3.) The hardest and the best...pull the fuel rail and leave the lines connected, put towels below the injectors with the rail propped up above the intake manifold, prime the fuel pump and watch to see which ones are dripping.

Either an injector problem or a FPR problem can destroy driveability.

I would recommend replacing them all as a set if you find any leaking, although I can't recommend Accel injectors as I'm chasing my SECOND leaking one right now . Hope this helps.

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1990 IROC 350
Mods: Too busy trying to make it run right to mod it.
Airfoil, Dynomax cat-back, MSD coil, 180 t-stat, Bald Eagle tires,
Hypertech fan switch, Accel 23# injectors, Holley module, ported plenum,
Ported Daytona Yellow stock base, Moroso valve covers, other stuff,
Streetdampr, Ruger P95DC, hot wife, new oil filter, !cats, !TB.
18.0 @ 85MPH since I'm one big-a$$ MF
"It's better to have and not need than to need and not have."

 

Wow, that was exactly what I needed to know. I'll be out there first thing in the morning! I have to go buy a fuel pressure gauge first.

I'll let you guys know how it goes...

Joe


------------------
86 IROC TPI 305
700-R4 with Trans-go shift kit
K&N Air filters
Dyno-Max cat-back
Summit tranny cooler
CEI throttle enhancer chip
Gutted MAF

[This message has been edited by JoeIROC (edited September 02, 2001).]

 

Ok... here's what I got:

Pressure with the pump primed: 38 PSI
Road test: Pressure went up when I accelerated, well into the 40's/50's.

I pulled the injector clips and noticed a similar drop in power on each.

I checked the resistance of each injector and got 16.5 - 16.7 Ohms on each one.

I whacked the MAF sensor while the car was running, and this did not cause any idle speed changes.

Pulled the oil dipstick and took a whiff -- it only smelled like oil... I dint notice any gasoline smell.

Now what???

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86 IROC TPI 305
700-R4 with Trans-go shift kit
K&N Air filters
Dyno-Max cat-back
Summit tranny cooler
CEI throttle enhancer chip
Gutted MAF

[This message has been edited by JoeIROC (edited September 03, 2001).]

 

The evaporative emissions system would be the next place I look, grab a service manual and check the operation of the purge solenoid. Also, make sure not to keep filling your gas tank after the pump clicks once.

Did you check for gas leaking back through the regulator vacuum line?

Also, a leaky injector can sometimes be an intermittent problem .

 

yeah, i'm figuring its a leaky injector. The oil DOES smell like gas. Also, I hooked up the fuel pressure gauge and paid a little more attention than before. Turns out that the pressure is initally 42 PSI, and then quickly drops to 38-40 PSI. The wierd thing is that it holds there. I would expect a leaky injector to keep leaking until the pressure is 0 PSI.

I can't make heads or tails of this!

Any more ideas?

Joe


------------------
86 IROC TPI 305
700-R4 with Trans-go shift kit
K&N Air filters
Dyno-Max cat-back
Summit tranny cooler
CEI throttle enhancer chip
Gutted MAF

 

Check the fuel pressure regulator. pull off the vacumme line and if it is wet then you need a new diaphram. I would check this out soon because i saw what happened to a 98 buick park ave. It back fired through the intake and blew it apart. Hope this helps.

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89 Iroc 350 TPI,
Forged pistions
Comp roller Cam .510 lift 230dur
Flowmaster exhaust
Dart Iron Eagle heads 200cc runners 64cc chambers
MINI RAM SOON!!!!!
stock TPI for now 24# inj
87 Trans Am GTA 350 TPI
had engine fire
SHE NOW RUNS!!!! GREAT!!
Flowmaster exhaust
LT1 Injectors