HELP HELP HELP

I have an idle fault on my99 impreza, its fine when cold but when its warm the idle hunts up to 1500rpm then drops low and nearly stalls, it does this about 5-6 times then seems to clear and idles fine until i drive it again and then when brought back to idle it happens again.

I have fitted a genuine subaru MAF sensor, spark plugs, new intake hose, as the one i had on the car started breaking up on the turbo inlet, new inlet manifold gaskets and all new vac pipes incase it was sucking in air, tested the lambda sensor which is fine and reset the ECU but still no joy.

i was told to take the ICV out and clean it which i have done, while it was out of the engine i connected it up and put the ignition on and off and the plunger was moving in and out and seemed free and not sticking. I cleaned it with WD40 and refitted with a new o ring seal, but the fault is still there. The only thing i wasnt sure about is at the end of the plunger there seems to be a rubber bung which when i checked had gone hard like plastic????? is this how it is ment to be

I really dont know what to do next, there are no faults in the ecu the only thing that happens when this fault comes in is the boost pressure goes from be 18 - 20psi down to 8psi but when i check faults on the ecu there doesnt seem to be any there.

 

What dump valve?

 

Fitted the factory recerc valve today to see of that help but no joy, I even sprayed the engine with easy start while it was running to see if it was sucking air but it's not. This fault is doing my head in now lol

 

QUOTE "The only thing i wasnt sure about is at the end of the plunger there seems to be a rubber bung which when i checked had gone hard like plastic?????"

With the engine running, undo the the locking screws on the icv half a turn (mark the original position first) Rotate it 1mm either way, one way will make it worse, one way will stop it hunting. Tighten the pinch screws, stop the engine and re start to check.

 

Had a look this morning my idle control valve can't be adjusted is just screw straight to the throttle body, the throttle position sensor can be adjusted but that hasn't been touched, and the fault isn't all the time it's intermittent.

 

hmmm i knw somewith that fault too

 

Have you checked the ecu for error codes?

 

No fault codes present on there plugged it into the computer today, going to order a new idle control valve and hope that fixes it.

 

Ah, i see you're on a MY99, changed over to stepper motor type icv with no adjusment. Keep us informed if the new one sorts it?

 

Hi

Have you manged to resolve the idle issue m8, i've got the same issue on MY00

Stew

 

Classic MAF failure symptoms...........

 

With him when he fitted the main dealer maf sensor no change he also changed lambda no difference icv only other possibility