Idle Fluctuating Wierdly

olliecast

olliecast

Active Member
Aup everyone,
was driving around tonight an pulled up at a junction. Noticed my idle was really high. Like 3000k high!!

I blipped the throttle and the car revs starting going up and down. It keeps doing this now and i`m not sure why its happening. Between 2000 and 1000.

I tried a different maf earlier but it was goosed. Put my standard one back on and it was fine for half an hour then this problem began. Mentioned this as its the only thing that has ben changed tonight, however it might still be a red herring

Below is a screen shot showing the fluctuating.
Any idea what it could be? is there some sort of idle valve that could be broken?


cheers,
ollie
 

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GTIR-LOZ

GTIR-LOZ

New Member
mine sort of does this at the mo, im using power fc but i have a fcuked distributor cap remove and check that its only 2 8mm bolts
 
F

Fubawu

Guest
I have the samething when the car gets up to temp it pulses from 1k to 2k. Makes me look like a fool at red lights :) I also have a power FC though I think it might have something to do with the ITB cable being stuck slightly???
 
stumo

stumo

Active Member
mine used to do this, even with 2 different ecu's. It stopped when i plugged in the PFC8)
 
stevepudney

stevepudney

GTiROC CHAIRMAN
Staff member
despite the fact I agree with Ed, like I said to you, the idle speed needs adjusting mechanically, did you check for the vac/boost leak we suspected as well
 
Fusion Ed

Fusion Ed

Active Member
Its simple a case of elimination.

The bottom line is only one thing will make an engine idle too high and thats too much air entering by which ever way exists. An engine cannot run with out air (obviously) so somewhere, something is not right and more air is entering the engine than you want at idle. It could be by many means leaks, or even the AAC valve etc..

That bit you're going to need to find.
 
F

Fubawu

Guest
His engine revs are not staying high, they are pulsing? I think a vac or boost leak would hold the revs high no??
 
Fusion Ed

Fusion Ed

Active Member
No,

ECU is seeing TPS = closed. Therfore it will enter over-run if RPM approx <1800 rpm. This will cause pulsing. If you unplug the TPS sensor the RPM will stay high and the pulsing will stop.

Its a physical issue, pipe etc that has caused the RPM to go high.

I have seen this many times before.
 
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