Cold Idle Problem

[temo_shay]

Hi there, i have previously posted about my idle problem on my mk2 rev 2 mr2 non-turbo but i would like to make the situation abit clearer. My idle sits at about 900-1000 when first started, when cold and when warm. the idle never changes except when revved obviously lol. I've adjusted the tps properly now but still no change. throttle body and idle control valve have all been cleaned. The air flow meter screw is all the way down and has been since i bought the car. If loosened the revs just rise. Any help will be appreciated. thanks in advance!

[stuMR2lee]

Have a read of this: http://www.mr2oc.co.uk/know-your-2-know ... bartid=270

Not had a Rev2 myself but it seems like a place to start.

Edit: ignore this link as OP doesn't actually have an Air Flow Meter (AFM)!

[_Al_]

For me it has to be the ECU coolant temp sensor. Look for the coolant filler neck then follow the rubber pipe down to the engine. There are two sensors IIRC - one grey one green. I think it's the grey one you're interested in, you can check by unplugging them in turn. One will stop the temp gauge working, the other is the one you're interested in.

Check that it's connected, if so then you need to get a multimeter and measure it when cold then again when warm.


Have you checked that the idle speed rises and falls when you unplug the ISCV by the way? Just because it's clean doesn't mean it works...

[littlemisstubby]

The green sensor is the ecu temp sensor, the gray one next to it (if fitted) is the cold start injector time switch and the coolant sensor for the gauge is the other side of the coolant elbow Al.
The engine should stall with the ecu temp sensor wiring disconnected and it won't with the gray csi time switch connector.

[littlemisstubby]

The air flow meter screw is all the way down and has been since i bought the car. If loosened the revs just rise. Any help will be appreciated. thanks in advance!

I take it you mean the throttle body screw as the 3sge doesn't have an afm? Only the fe and turbo engines had afms.

Edit: Ahem, oh and also the V6.

[temo_shay]

Thanks for the info, really appreciate it. I will play about with the sensors tommorow. And oops yes i mean the throttle body screw lol the revs dont change much when i unplug the iscv?

[temo_shay]

And regarding that link, i had a look and it dont add up as my screw will not go any lower however my measurement is meant to be 17.4mm?

[littlemisstubby]

And regarding that link, i had a look and it dont add up as my screw will not go any lower however my measurement is meant to be 17.4mm?

Your car doesn't have an afm mate so that guide doesn't apply.

[temo_shay]

Oh i see, is the screw meant to be all the way down?

[littlemisstubby]

The screw is usually about 1 to 1-1/2 turns out but it can vary.

As well as checking the sensors try swapping the airbox sensor (IAT sensor) with the one on the engine bay lid. Also check all the vac pipes for leaks/cracks/splits and secureness.

[temo_shay]

Ok thanks, ill try that too

[temo_shay]

Right.. Ive just messed about with the sensors and now i'm even more confused as no matter what sensor i unplug the car stays the same just keeps idleing at around 950, revs don't change and car don't die. I unplugged the ecu temp sensor - no change atall aswell. Its really starting to bug me now lol anyone got any idea whats going on?

[_Al_]

Was the temp gauge at half? And nothing changed when you unplugged them?

Confusing!

[temo_shay]

Nope i unplugged them when it was cold as the cold idle is the problem, should i have waited until it was warm?