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IAC dirty?


RangeStang

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So the wifes car it is a92 lumina 3.1L when you start it up it will die 1or2 times before it will stay running. What is this I cleaned out the throttle body thinking that it was just dirty. I cleaned it twice each time it stops for about a mounth every time I clean it out. Is it a dirty IAC? Oh yeah when it is cold sometimes it will sound like it's cammed. :lol: Any ideas? If you need more info let me know I will try to explain it better. Thanks

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I know the sound you are talking about. Maybe replace the O2 sensor? It made a world of difference with me

 

But wouldn't that kick a code? I hooked it up to the scanner and it is not complaining of anything and it is running with a A/F ratio of 13.2 stupid obd1

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my guess is a vac leak!

 

It only does it every once in a while but it is getting progressively worse. It just does not sound like a vac leak to me but I will check it out though.

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You'd be surprised at how many things don't throw a code in these cars that definitely should.

 

Couldn't hurt to take the IAC off and clean it. Run some Seafoam through the topend to clean it out, too. After you fool with the IAC you're probably going to have to do an idle relearn (proceedure is somewhere in the FAQ forum).

 

Definitely could be a vac leak too, maybe somewhere in the manifolds that seals up once the motor is warm.

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Sounds like a typically MPFI engine in these cars... It's 90% likely it's a fuel system issue. I.e. Injectors, FPR, clogged fuel filter, weak fuel pump, or fuel pump on it's way out...

 

I can't tell you how many times I have replaced injectors, FPRs, and fuel pumps in cars with these engines...

 

Seeming the TB is getting dirty wayyyy too soon (you TB shouldn't get dirty to the point of causing an issue within 100K of each cleaning)

 

Good chance the FPR diaphram is slowly getting worse and possibly dumping some fuel into the intake through the vacuum line which will cause the TB to get pretty dirty pretty damn quick.

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Sounds like a typically MPFI engine in these cars... It's 90% likely it's a fuel system issue. I.e. Injectors, FPR, clogged fuel filter, weak fuel pump, or fuel pump on it's way out...

 

I can't tell you how many times I have replaced injectors, FPRs, and fuel pumps in cars with these engines...

 

Seeming the TB is getting dirty wayyyy too soon (you TB shouldn't get dirty to the point of causing an issue within 100K of each cleaning)

 

Good chance the FPR diaphram is slowly getting worse and possibly dumping some fuel into the intake through the vacuum line which will cause the TB to get pretty dirty pretty damn quick.

 

See the weird thing is when I pull the intake tube off the throttle body it has a ton of oil siting in it. The car does not have very many miles on it either for being a 92 (103,000) broken oil ring maybe? P.S. it has a thrust bearing going out too what the hell!

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I know the sound you are talking about. Maybe replace the O2 sensor? It made a world of difference with me

 

But wouldn't that kick a code? I hooked it up to the scanner and it is not complaining of anything and it is running with a A/F ratio of 13.2 stupid obd1

 

mine didnt. I had the original sensor until a couple months ago too!

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Sounds like a typically MPFI engine in these cars... It's 90% likely it's a fuel system issue. I.e. Injectors, FPR, clogged fuel filter, weak fuel pump, or fuel pump on it's way out...

 

I can't tell you how many times I have replaced injectors, FPRs, and fuel pumps in cars with these engines...

 

Seeming the TB is getting dirty wayyyy too soon (you TB shouldn't get dirty to the point of causing an issue within 100K of each cleaning)

 

Good chance the FPR diaphram is slowly getting worse and possibly dumping some fuel into the intake through the vacuum line which will cause the TB to get pretty dirty pretty damn quick.

 

See the weird thing is when I pull the intake tube off the throttle body it has a ton of oil siting in it. The car does not have very many miles on it either for being a 92 (103,000) broken oil ring maybe? P.S. it has a thrust bearing going out too what the hell!

 

It has a thrust bearing going out, you know the thrust portion in intregal to the main bearings unlike some japanese engines. The most common failure of a 3.1L is the thrust portion wearing and voial, rod know. Just replace the engine and worry about the startup issue later, as it may not be a problem then...

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Sounds like a typically MPFI engine in these cars... It's 90% likely it's a fuel system issue. I.e. Injectors, FPR, clogged fuel filter, weak fuel pump, or fuel pump on it's way out...

 

I can't tell you how many times I have replaced injectors, FPRs, and fuel pumps in cars with these engines...

 

Seeming the TB is getting dirty wayyyy too soon (you TB shouldn't get dirty to the point of causing an issue within 100K of each cleaning)

 

Good chance the FPR diaphram is slowly getting worse and possibly dumping some fuel into the intake through the vacuum line which will cause the TB to get pretty dirty pretty damn quick.

 

See the weird thing is when I pull the intake tube off the throttle body it has a ton of oil siting in it. The car does not have very many miles on it either for being a 92 (103,000) broken oil ring maybe? P.S. it has a thrust bearing going out too what the hell!

 

It has a thrust bearing going out, you know the thrust portion in intregal to the main bearings unlike some japanese engines. The most common failure of a 3.1L is the thrust portion wearing and voial, rod know. Just replace the engine and worry about the startup issue later, as it may not be a problem then...

 

 

Yep! sure does,I did not know that I am using 20-50 oil just to keep it quiet.I have never been farther than the top end on these engines. But oh well I have a short block 3400 out of a 02 Grand Am and a complete 3400 out of a 98 van.;) I am going to put the top end of the 3.1 on the 3400 short block Talk about a torque maker.

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I wouldn't even waste one more breath worrying about a startup issue when the bottom end is junk. It's just a ticking time bomb.

 

True, I will let you guys know how long it takes for it to go boom! ;)

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I wouldn't even waste one more breath worrying about a startup issue when the bottom end is junk. It's just a ticking time bomb.

 

True, I will let you guys know how long it takes for it to go boom! ;)

 

 

Please, put a brick on the pedal and get a vid of it for us :lol: :lol:

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I wouldn't even waste one more breath worrying about a startup issue when the bottom end is junk. It's just a ticking time bomb.

 

True, I will let you guys know how long it takes for it to go boom! ;)

 

 

Please, put a brick on the pedal and get a vid of it for us :lol: :lol:

 

 

NOOO!, it is the only reliable DD for us right now lol but after that changes I just might! That is why I am trying to get the 95 GP running.

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