LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Car Idling ROUGH

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Old Apr 13, 2008 | 04:45 PM
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97formulakid's Avatar
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Car Idling ROUGH

So right after I got the car I had a check engine light that ended up going away. Awhile back ago I got it again and went to have it scanned. It was showing up as a bad MAF sensor. They cleared it and it ran great.

Today I pulled my car out to paint the rear end and when I pulled it back in it started idling VERY rough and would not stay running. The wideband said I was running a little rich and if I gave it gas I would stutter bad and barely rev.

Everytime I seem to unplug my MAF this starts to happen. I just got done installing a bunch of stuff on the car including a Mallory ignition box. The box is mounted in my back seat and I know the ground is a little loose but I am going to tighten that up right now.

Could my MAF be going bad or maybe just need a good cleaning?? The car has a LE2 kit with LE ported intake manifold and 36 lb injectors.
Old Apr 13, 2008 | 04:57 PM
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THIS is what I found when I took the intake tract off. There is a black carbony looking substance that is all over the TB and the MAF. It smells VERY strong of fuel. The only thing I have done to the fuel system is tap into the Schrader valve for the nitrous kit.

Anyone have ANY idea what the hell is wrong with the car?
Old Apr 13, 2008 | 05:51 PM
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wow that dont look too good, i would check the fuel injectors out, how is your fuel pressure?
Old Apr 13, 2008 | 06:24 PM
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Fuel pressure is great. Pumps up to around 38 psi. Then at idle it is around 41-42.
Old Apr 13, 2008 | 06:25 PM
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FYI I cleaned everything up and cleaned the MAF and it started right up and idled great. The check engine light is still on though.
Old Apr 13, 2008 | 06:58 PM
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have any way to scan it?
Old Apr 13, 2008 | 07:10 PM
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Haynes manual says if you tap it with a screw driver handle when its running, if the engine studders or dies, its a bad MAF
Old Apr 13, 2008 | 07:18 PM
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i am having a similar problem, the car starts for 2-3 seconds and then dies. i dont mean to jack your thread but what type of fuel pump are you running
Old Apr 13, 2008 | 11:07 PM
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running a racetronix 255 lph pump.

reamo04 - I plan on getting scanmaster but for now I can get someone to scan it with a regular scanner.
Old Apr 14, 2008 | 10:52 AM
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Check the hose from the passenger valve cover to the TB for oil. Pull the cover plate off the top of the TB and look for a puddle of oil? Looks like it may be blowing oil out of the valve cover and into the TB. It ends up in front of the blades.

You don't list nitrous as a mod, but you mention tapping into the Schrader valve for the fuel for a nitrous kit. What kind of kit do you have? Sounds like its a wet kit. Where is the nozzle located?
Old Apr 14, 2008 | 11:02 AM
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leaky fuel solinoid
Old Apr 14, 2008 | 02:48 PM
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I have a Nitrous Works plate wet kit. After I cleaned it up I have started it a few times since then and don't have any more residue on the TB orthe MAF. It seems like it just happened this once and hasn't done it since. And the plate is located AFTER the TB so if it was leaking fuel it would have just sprayed it into my intake tract, wouldn't it?
Old Apr 14, 2008 | 05:12 PM
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A leaking fuel solenoid would explain the fuel smell and rough idle. It wouldn't account for the grime on the inlet of the throttle body, and I wasn't suggesting that was the cause. Did you check for oil in the hose from the valve cover? That's what the mess in the TB looks like.
Old Apr 16, 2008 | 08:50 AM
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Originally Posted by Injuneer
A leaking fuel solenoid would explain the fuel smell and rough idle. It wouldn't account for the grime on the inlet of the throttle body, and I wasn't suggesting that was the cause. Did you check for oil in the hose from the valve cover? That's what the mess in the TB looks like.
I haven't checked for oil in the hose, but I have a catch can and that thing is still almost empty. I can check it again today at lunch.
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