2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

low idle issue

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Old Aug 2, 2008 | 11:01 AM
  #1  
bealzubub88's Avatar
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From: knoxville
low idle issue

hey guys gotta ask about it. ive tried everything adj the tps to run without bucking made it worse which makes me think my leaking injector is cause it to run so rich that it pulls the idle down some how. ive adjusted the vr and the top air screw. another thing is if i hold the pedal at at certain rpm steady its bounces like im revving it. anybody got any ideas??? sure my efan isnt helping it to much either
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Old Aug 2, 2008 | 11:17 AM
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From: marietta
Try replacing your leaky injector. No two symptoms are identical with leaky injectors.
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Old Aug 2, 2008 | 11:47 AM
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your AFM might be shot. what year/model is the car?
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Old Aug 2, 2008 | 11:58 AM
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HAILERS
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From: FORT WORTH, TEXAS,USA
Get a digital meter and timing light. Set your timing with the rpms well under 900 rpm. Then follow the FSM, FUEL AND EMISSIONS SECTION, for setting the idle speed i.e. initial set coupler installed and adjust the screw on top of the dynamic chamber and possible the variable resistor to get a idle of 750rpm.

You might want to see if your BAC is functioning or not. You say your present idle is LOW. So with a HOT engine, idle the engine and while idling pull the plug off the BAC. Some change in idle speed should be noted it it's actually working. A lower idle speed should be noted IF the present idle speed is under 750rpm.

I'd surely check the timing with a timing light if I were you. Don't just go out and twist and shake the CAS willey nilley in one direction then the other. Get/use a timing light.
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Old Aug 3, 2008 | 03:31 AM
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From: Maryville, TN
Hey, I'm a friend of this loser so I figured I'd post some info...

His car is an 88 N/A. BAC is removed, so no help there. We checked the CAS and the timing still lined up with TDC so I don't think it's ever been screwed with. He also tried adjusting both the variable resistor and the dynamic chamber screw.

It ran really good for about a day after that TPS adjustment! What'd you do, Cody? And I gotta agree with specialop... replace those injectors. Or better yet, put that spare turbo motor to good use.
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Old Aug 3, 2008 | 10:50 AM
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From: Austin
It might be worth doing the resistance check on the TPS as described in the FSM.
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Old Aug 3, 2008 | 11:21 AM
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Originally Posted by vrracing
It might be worth doing the resistance check on the TPS as described in the FSM.
1khm at idle, sweeps smooth to 5.5khm WOT.
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Old Aug 3, 2008 | 02:34 PM
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From: knoxville
so i believe liz was right on his theory about the throttle plates sticking cause i cleaned the throttle body and it ran well at 1k rpms for about 15 seconds then the idle started bouncing like crazy. turned it off and it started up at 1500 rpms and wont really move if i adjust the vr or dc screw. ive put vaccum cap on it not too long ago but i havent checked to see if some of the block off plates might be leaking. anybody go ideas???
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Old Aug 3, 2008 | 02:37 PM
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From: knoxville
also i have another afm and tried it and nothing changed but it is possible that both are shot. oh and liz id do it by now but i want this one running right before i put it in the base
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Old Aug 3, 2008 | 03:02 PM
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From: Maryville, TN
Oh yeah, I guess that makes sense. Would be good to have a running motor to drop into that car.
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Old Aug 3, 2008 | 03:20 PM
  #11  
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From: Knoxville
TIMING GUN!!!!!

No MAMES WAY!!!!
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