Power fc help

[bolton]

Hi all had my mr2 mapped (power fc) and all was great, drove her home and put her away for the winter in my garage with battery disconnected.

Today woke her up! Lol! Started fine but the revs were hunting on idle! Was told that the ecu might have to relearn idle as the battery has been disconnected for months so did the idle learn again.

She now idles fine but if you press the accelrator it will start to hunt again at idle for about a minute then idle fine again?

What could this be?

[2mad]

Water temperature sensor faulty seen this happen to a few people .



Edit.. I did actually have this happen to me running a hks vpc .. I increased fueling 2% or so under 1500rpm and the problem went away


Hope you sort it it is rather annoying.

[bolton]

Is there anyway i can test the sensor?
Would it throw a fault code?

[2mad]

Bgb multimeter resistance test from what i understand .


Might be easier to take it to where it was mapped and have them plugin and look for the error ... not cheap but could get your answer quicker.

[bolton]

Yeah ryan mapped it in surrey and i live in worcester its about a 3 hr drive. Ill see what i can do myself.
The sensor was replaced when the car was rebuilt 1000 miles ago.
Could it be the idle control valve?

[2mad]

I can only advise you from stuff thats happened to me .. "could it be the idle control valve" yes absolutely.. while it was off the road somethings gone out of tune. if plugging it ins not an option , its process of elimination time

Check everything from vac hoses to sensors .. such a pain i know .. been there



Dont forget to look at the o2 sensor .. the ecu looks at that for idle .. only saying that because a fuel tweak cured my hunting idle.

[bolton]

Ok took the throttle asembly off today and cleaned the idle control valve and checked it was working also cleaned inside the throttle body and butterfly. Loads of carbon in there!

I then adjusted the screw which dictates where the butterfly sits at idle. I could wind it in so the butterfly was closed more.
It now seems a lot better!

Should the butterfly be fully closed at idle?

[2mad]

On mine the throttle body butterfly was closed fully .. dont have any experience with the idle control valve, one of the few things that actually worked on my car


Sorry for the late reply , hoped someone with more experience than me would chime in .