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Hey guys, my 7afe AE112 has a very high idle (1600-1800) and i don't know why.

I have already cleaned the IAC and not seen a difference. Is there anything else i should be looking at to get my idle down?

Thanks

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Hi Lewis,

                1600 - 1800 rpm idling, is a bit high alright.  Few questions.

1.    Did this happen suddenly, after it had been OK for a long time ?

2.    Did  anything else happen to the car just before this became apparent ?  (had you been working on the engine)

3.    Is it a steady high idle, or "wavering around" between 1600-1800 rpm ?

High idling, is usually caused by too much air. That could be caused by an air leak into the induction system, on the engine side of the throttle box butterfly. (failed gasket ?)

It could also be that the bottom stop of the butterfly movement is set too high.  It is usually set so the butterfly 'edge" does not bang up against the inner wall of the dicast throttle body. However, I came across one recently, which was set a bit too wide, & therefore stopped the IAC valve from controlling properly, & doing it's thing.

P.S.  Do you have an aftermarket ECU fitted to this engine ?

Trust this starts us off, in ultimately helping you solve this issue.

Cheers Banjo

 

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Sorry it took me so long reply 

It came on a while ago but got progressively worse.

I didnt do any work on the engine or anything like that.

It will start off at 1600 and when the car heats up it will drop to about 1200 briefly. But when i then drive it, it will stay at 1800.

I don't have an aftermarket ECU either. 

Thanks Banjo

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Hi Lewis,

                Build up of carbon in an IAC valve will stop it working properly. Even a small bit of carbon, will stop it.

Have a look at this video, & see if your valve is like this one.

https://www.youtube.com/watch?v=VOUB1UiDkKc

If your IAC has severe carbon build up, you may have to replace the whole IAC valve assembly. You would be surprised how a little bit of hard carbon, inside the IAC, on the vanes, can prevent them from working properly.

There is also the possibility that the actuator is faulty.

I still wouldn't write off, the possibility of a leaking gasket somewhere of the inlet manifold, between the throttle body & the head, if the IAC works well. 

Let us know how you go.

Cheers Banjo

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On 12/12/2020 at 12:08 AM, Banjo said:

Hi Lewis,

                Build up of carbon in an IAC valve will stop it working properly. Even a small bit of carbon, will stop it.

Have a look at this video, & see if your valve is like this one.

https://www.youtube.com/watch?v=VOUB1UiDkKc

If your IAC has severe carbon build up, you may have to replace the whole IAC valve assembly. You would be surprised how a little bit of hard carbon, inside the IAC, on the vanes, can prevent them from working properly.

There is also the possibility that the actuator is faulty.

I still wouldn't write off, the possibility of a leaking gasket somewhere of the inlet manifold, between the throttle body & the head, if the IAC works well. 

Let us know how you go.

Cheers Banjo

Have to get round to checking it out when it is not so bloody hot outside.

Also just asking if there is a possibility of a faulty MAP sensor or something? 

Cheers

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Hi Lewis,

                 I've not come across this before, so can't offer much help.

However, if you Google your query, Google offers the following . . . .

Quote

5. Your car surges and dies out: A faulty MAP sensor can cause engine RPM to fluctuate or surge, primarily at idle or low speeds. If you turn on the air conditioning or use the power steering when the happens, the engine can die out.Apr 6, 2018

Hope that helps.

Cheers Banjo

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7 hours ago, Banjo said:

Hi Lewis,

                 I've not come across this before, so can't offer much help.

However, if you Google your query, Google offers the following . . . .

Hope that helps.

Cheers Banjo

Appreciate the help mate. At least i know where i should be looking now.

Thank you

 

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