8 replies to this topic

[Fast Ivan]

Hi all,
My MPI won't idle below 1500 and at times goes right up to 3000 when driving, tried all sorts - air leaks, temp sensor, map sensor.....
the question I have is will a faulty idle air control valve show up on a diagnostics reader? I have removed and cleaned, and replaced the housing as the original was cracked, (also tried a different IACV, not new though).
I have plugged it in to a diagnostics a few times over the last couple of days and its showing no errors.
Any thoughts?

[icklemini]

am thinking an air leak...

warped throttle body perhaps holding the butterfly open...

[Fast Ivan]

throttle body replaced, not new but from a freinds running mpi. cant find an air leak, all good there i think.
it points to the iacv, but this isnt showing as a fault on the diagnostics, im not sure if it should?

[Fast Ivan]

anyone?

[icklemini]

in my experience it wont show a 'fault'

[charie t]

Hi all,
My MPI won't idle below 1500 and at times goes right up to 3000 when driving, tried all sorts - air leaks, temp sensor, map sensor.....
the question I have is will a faulty idle air control valve show up on a diagnostics reader? I have removed and cleaned, and replaced the housing as the original was cracked, (also tried a different IACV, not new though).
I have plugged it in to a diagnostics a few times over the last couple of days and its showing no errors.
Any thoughts?

I have one doing exactly the same,
if it is not working iacv will show up, if its sticking it won't show up

[liam_italian]

Try cleaing the IACV. Also I would look for a vacuum leak around the throttle body, especially where the inlet meets the cylinder head. Best way is to spray a little carb cleaner over the areas when the engine is running. If there is a leak you'll hear a slight change in the revs.

[Fast Ivan]

Thanks guys. I tried another used IACV today, from an MGF (they are the same) this made the idle a lot better, still a little high though. I'll check for leaks again.

[liam_italian]

Is your throttle cable correctly adjusted?