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z34 goes straight to 3 grand(rpm)
right after start motor revs to 3000 and doesnt let up. disconnecting elec. doesnt resolve problem, no service engine code light. replaced lower manifold gaskt 2 yrs ago. disconecting iac, tcs, maf, results in no significant change other than maf making it erratic after disc. WTF
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94 Z 34 165000 on the ticker, 3" cat back into dual Flowmasters,air box MIA, K&N sucking it up, auto -
a 3K idle and no SES light? you may have a junked ECU.... not sure if the crank sensor could cause this though... -
I wonder if one or both of the rear vapor canister lines has rusted through and broke? Our cars are known for the hard lines in the rear to rot through. Brake lines known for it too @ the rear. Had a 90 grand prix 3.1 that had every one of them brake back there while I owned it. Or maybe one of the hard plastic lines to the canister is rubbed through and leaking vac..Last edited by Smittro; 08-24-2009, 08:08 PM.Comment
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this is what happened to me when i took my UIM off and pinched off the vacuum for the FPR. removed UIM and re routed vacuum, car ran like a top.Comment
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i'd definitely invest in some starting fluid or maybe some propane to start looking for vacuum issues...
but the lack of an SES light doesn't make sense.Comment
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Thought crossed my mind aswell. But mine did'nt even throw a code when the purge soloniod vac lines where disconnected either. Only when I unpluged the power sorce did it code. Man did it run bad and dropping her in gear @ 3000 rpm is bad mo jo..Originally posted by robertisaar View Post
Last edited by Smittro; 08-24-2009, 08:28 PM.Comment
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mine wasnt leaking though, just pinched off... i just had to un squish it. then the car ran good. but when it was squished as soon as it started, it was hittin the rev limmiter like crazy, i shut it down and started it a few times, the best i got was a really rough high idle and tried to drive it, drove ok... i guess. but man it hit hard puttin it in gear 2KComment
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Electric problems aside it sounds like a vacuum leak. The most common fail parts would be the upper and lower intake gaskets. I don't think OBD I is smart enough to trip the service light for something like - I've had bad intake gaskets cause a similar problem and it never had a check engine light, heck I can pull my brake booster hose off and start the motor and it'll just rev really high without a check engine light.
Could also be something like a bad IAC, stuck throttle body/cruise cable, deteriorated or missing vacuum hose, etc etc etc.1991 Grand Prix GTP LX9swap/Getrag 284 --- SOLD =(
1994 Corvette LT1/ZF6
2006 Dodge Dakota 4x4 3.7/42RLEComment
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it should set codes... i've actually got the hack on my laptop and can tell you the exact conditions for codes to get set....
but off the top of my head: IAC, MAP High should be set.
EDIT: possibly idle speed error as well. not sure if its tied in with the IAC code...Comment
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My 91 threw a code for the IAC when the intake gaskets went on it.-60v6's 2nd Jon M.
91 Black Lumina Z34-5 speed
92 Black Lumina Z34 5 speed (getting there, slowly... follow the progress here)
94 Red Ford Ranger 2WD-5 speed
Originally posted by Jay Leno
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I think the conditions for the IAC is supposed to trip its service code is something like idle speed +/- 300 rpm from desired for x seconds?
But, in my experience my 91 has never thrown a code from even a severe vacuum leak (like a disconnected brake booster hose, ask me how I know!) so at least we know it is possible to not have a code. When my intake gaskets were bad it would idle at around 2500 rpm on startup and this would last for several minutes until things expanded/sealed - even then no codes.1991 Grand Prix GTP LX9swap/Getrag 284 --- SOLD =(
1994 Corvette LT1/ZF6
2006 Dodge Dakota 4x4 3.7/42RLEComment
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When the gaskets went on my 91, it would bounce off the limiter @3k on startup, then eventually as seals and metal expanded from heat it would idle normally. Also when it was idling high it took everything I had to stop the car since 1. it was idling high, and 2. i had no vacuum for the booster for the brakes.-60v6's 2nd Jon M.
91 Black Lumina Z34-5 speed
92 Black Lumina Z34 5 speed (getting there, slowly... follow the progress here)
94 Red Ford Ranger 2WD-5 speed
Originally posted by Jay LenoComment
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when mine was pinched off there was no code for it...Comment
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starter fluid didn't locate leak. sprayed it about anywhere i could get into. still taching 3g, smokin and its fuel and not oil. what could cause it to dump so much fuel, and not throw a code?94 Z 34 165000 on the ticker, 3" cat back into dual Flowmasters,air box MIA, K&N sucking it up, autoComment
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MAF? really bad O2? so you're seeing black smoke not blue? might be due to going apeshit insane and idling at 3K...
but its definitely not a Vacuum leak...
ever check the FPR?Comment
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