High idle on start up.

[scorpio]

Hi folks,

Just wondering if anyone has had a problem with idle having a mind of it's own sometimes.
It is most noticeable on startup as it revs up twice to three times as high as it should.
It also sometimes does it while warm. It usually revs back down slowly after about ten seconds.
If the car is stationary, the high revs can be brought down by turning the steering wheel back and forth.

i'm guessing it is something to do with the accelerator cable sticking. Maybe something to do with the throttle body. Something sticking in there or sensor needs cleaning. had a new MAF sensor a year ago.
I don't know if it is just due to it needing a service but the car does feel a bit sluggish to drive in general. It is a 2001 1Liter Micra S.

Many thanks for looking and any ideas.

 

[richardwbb]

In EF & EC-2.pdf from k11 fsm on pdf page 83 (EF & EC 7201), there is some information about the IACV. This technical information might be hard to digest. If this valve is not operating properly all sorts of revving may occur. I'm not sure on how easy it is to remove and clean but that is a good start.

Be aware that I did not read the whole EF & EC chapter but there might be more and maybe also easier things to check.

For IACV cleaning you will need besides a cleaner, RTV, a scraper, some tools that also will fit in there and some moderate mechanic skills. The important part is that you need to reinstall it without leaks.

It would be nice to read fault codes from ecu with Nissan Datascan, do you have this?

Be aware that removing and reinstalling this sensor will require to put your Micra engine in timing mode and adjust idle. If you have never done this, this task is simple but can be hard the first time.

 

[scorpio]

In EF & EC-2.pdf from k11 fsm on pdf page 83 (EF & EC 7201), there is some information about the IACV. This technical information might be hard to digest. If this valve is not operating properly all sorts of revving may occur. I'm not sure on how easy it is to remove and clean but that is a good start.

Be aware that I did not read the whole EF & EC chapter but there might be more and maybe also easier things to check.

For IACV cleaning you will need besides a cleaner, RTV, a scraper, some tools that also will fit in there and some moderate mechanic skills. The important part is that you need to reinstall it without leaks.

It would be nice to read fault codes from ecu with Nissan Datascan, do you have this?

Be aware that removing and reinstalling this sensor will require to put your Micra engine in timing mode and adjust idle. If you have never done this, this task is simple but can be hard the first time.

hi Richard,
Sorry for the delay and thanks for replying.

Just checked the cable and where the nipple meets the foot peddle, it looks like it has broken and the inner cable has stretched. I just lengthened the outer cable at the throttle body to make up for the inner cable being slack and causing a high tickover, as a temporary measure till I get another cable.

Thanks again for all your help.

 

[richardwbb]

Good guessing you did there. If it runs right and it cycles nicely to warmed engine and there are no driveabillity issues there is no real need to get the IACV off. And you need to be in timing mode after reinstalling which I recommend to anyone though to get Datascan.