Idling problems with a JDM 12AT engine

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myatt1972
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Re: Idling problems with a JDM 12AT engine

Post by myatt1972 » Wed Nov 02, 2016 8:29 pm

If this were a piston engined car I would be diving for the auxilary air valve, I have no idea about your turbo / fuel injection system but if it has such a thing I would be looking at it and its control, also with a fuel injection system there will be a temperature sender for the ecu, worth checking.
Keith...

KiwiDave
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Re: Idling problems with a JDM 12AT engine

Post by KiwiDave » Wed Nov 02, 2016 9:42 pm

Sticking throttle shaft or throttle position sensor?
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Traxnada
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Re: Idling problems with a JDM 12AT engine

Post by Traxnada » Thu Nov 03, 2016 9:26 am

Hum, OK I'll try and take a look at a possible sensor failing... Seems like I'll struggle a little for that lol.
Logically, where would one be positioned?
And I don't think it has to do with a throw problem. Idling being high only, it could be. But here it's fluctuating like a cammed v8 so I doubt it has much to do with that.

KiwiDave
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Re: Idling problems with a JDM 12AT engine

Post by KiwiDave » Thu Nov 03, 2016 9:56 am

I've asked around. Showed the video to Efi technician. He suggests fault with idle air control valve or vac leak at inlet manifold.
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Traxnada
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Re: Idling problems with a JDM 12AT engine

Post by Traxnada » Thu Nov 03, 2016 10:36 am

Awesome, thanks man! I'll go look at it a bit deeply this week end. I'll keep this thread updated with my progress!
I can only hope it's not a vacuum leak. Those 80's engines are a bit of a mess with vacuum hoses lol

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DKWW2000
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Re: Idling problems with a JDM 12AT engine

Post by DKWW2000 » Thu Nov 03, 2016 5:44 pm

You can check for a Vacuum leak by spraying a solvent based spray eg WD 40 around the hoses, you will hear the revs change if there is.
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Th0m4s
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Re: Idling problems with a JDM 12AT engine

Post by Th0m4s » Sat Nov 12, 2016 10:24 am

It could be that the thottle position sensor is out of adjustment or simply worn because of the high age or it might be a vacuum leak. I don't think the idle control valve is the cause because it looks like it is working but it's trying to adjust to something which shouldn't be there.
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Traxnada
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Re: Idling problems with a JDM 12AT engine

Post by Traxnada » Tue May 30, 2017 12:30 am

Noticed I never updated this... I found the culprit!
Believe it or not, but my A/C was responsible for that haha... The relay of the solenoid that raises the idling when the AC is on. No more problems now and it idles very smoothly :)

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