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annoying issue


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Hi all.


Recently started having a problem occuring and not sure how to go about sorting it.


I changed when my aux fans kick in from 90 to 88 as was trying to get car to run cooler in traffic.

Ive also changed my overrun fuel cut as it was set far too high up in revs making car run on.


This is set to 1400rpm at ect of 80 across to 110 and a delay of 0.7 sec


The recent problem altho i am not sure if these are corrilated is that after engine has warmed up and ive been for a bit of a drive the idle doesnt settle. It bounces from 1k to 1500rpm and eventually settles but at a higher level (1100-1200)


On cold start the car will start and stay a lovley 850rpm steady.

After warm up idle is 1k sometimes higher seems to vary unsure why.

Also another note to put it after car is warm and turned off....the next time i turn car on it instantly revs to 3k...holds for a second.....then drops to idle then 3k then settles again.

I was told that this was done to clear any excess fuel in cylinders due to the large injectors. 


I dont really know all the terminoligy to start tinkering with idle settings so if someone could help or point me in the right direction that would be great....


Thanks jon

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Hi Jon,

It sounds like a you have a couple of problems going on. Is the throttle mechanical or electronic? If you could reply and attach your base-map we may be able to help identify the cause of the problems. Also if possible, can you record a log file of the problem occurring and attach it.


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Hi Jon,

Thanks for your base-map. I have had a look and can see some reasons why the problems may be occurring.

In your 'idle base position table' your stepper motor is asked to do 278 steps at 60 degrees and then 208 steps  at 70 degrees. This is quite a big step difference over 10 degrees. I would suggest making the steps more progressive. This is likely the reason your engine is hunting at idle. To confirm this is the case you could set the whole table to one value (perhaps 278) and see if the problem still occurs.

The reason your engine does a rev up to 3k when started is because your idle stepper motor is configured to reset it's position upon the ignition switch being switched to on. The normal way to reset a stepper motor is to do it when the ignition key is turned off, but this involves some extra wiring, a relay and a diode.

To see more about this take a look at:

PCLink Help > Wiring Information > Power and Ground Wiring > ECU Hold Power Wiring

PCLink Help > G4 ECU Tuning Functions > Idle Speed Cotnrol > Stepper Reset

One other thing I noticed is that your 'Startup Step Table' has 150 steps for the whole table. Normally you would have the stepper motor open more at a cold engine temp, and less at a warm engine temp.

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