iac gurus, is mine bad?

86turbo

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Apr 8, 2006

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Sep 27, 2008

#1

• Sep 27, 2008

• #1

hey guys ill make it quick...

horrible cold start, tries to die. ect and act resistances are good. I also have a slow surge that travels from 750 to 1200 and back again. I unplugged my iac and it limited the surging to only 100 or so rpm. Stays under 1k rpm now at idle. Voltage across the iac leads show 1.5v+.2v and never varies to anythig different even when the car is stone cold. btw no codes being thrown for the iac...

thanks

Drew

 

93 LX

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Jun 2, 2000

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Norwalk, CA.

Sep 27, 2008

#2

• Sep 27, 2008

• #2

http://forums.stangnet.com/698148-help-me-create-surging-idle-checklist.html

 

86turbo

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Apr 8, 2006

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Sep 27, 2008

#3

• Sep 27, 2008

• #3

yeah man i know about the list, ive seen you post that same link in 3 threads tonight. I already did all of the checks for the iac and i need some advice form someone who has diagnosed a bad iac. The voltage across the leads never changes, when its cold Or hot and the idle doesnt seem to change when i unplug it.

Anyone?

Drew

 

jrichker

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Sep 28, 2008

#4

• Sep 28, 2008

• #4

If it surges without the IAC being connected, the IAC is not the problem. A working IAC can amplify a surge caused by other faults. Using a DC voltmeter across the IAC will not give a correct measurement of what is really happening..

IAC operation:

 

86turbo

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Sep 28, 2008

#5

• Sep 28, 2008

• #5

thanks again for the reply!!

"""I unplugged my iac and it limited the surging to only 100 or so rpm."""

i forgot to mention i have a stage 1 cam, typical h/c/i setup .....

You dont think the iac could be causing the majority of the surging and another small problem could be contributing?? It only surges like 100 rpm with the iac unplugged and its a slow surge..

 

N

noslow1986

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Mar 25, 2006

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oswego Il

Sep 28, 2008

#6

• Sep 28, 2008

• #6

i bought mine new at autozone and my car still had cold idle issues i turn the iac upside down and it runs alot better no more cold idle issues. dont know why but it works maybe somebody can explain that to me

 

86turbo

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Sep 28, 2008

#7

• Sep 28, 2008

• #7

thanks again for the reply!!

"""I unplugged my iac and it limited the surging to only 100 or so rpm."""

i forgot to mention i have a stage 1 cam, typical h/c/i setup .....

You dont think the iac could be causing the majority of the surging and another small problem could be contributing?? It only surges like 100 rpm with the iac unplugged and its a slow surge..

 

jrichker

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#8

• Sep 28, 2008

• #8

Fix the problem with your MAF, and the idle surge will probably go away.

 

86turbo

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Sep 28, 2008

#9

• Sep 28, 2008

• #9

first off i really appreciate you giving me advice...

I installed a known good iac (other car) and the idle is a lot better now.

I'm trying to figure out if my maf voltage is good or not, i assume you're saying its not