Another high idle thread...zzzzzzzzzzzzzzz

[jimbom30cab]

But this one might have been seen before so bare with me...

flashed up the car, idle perfect at 800 revs, went for a drive, about 10 mins, got back, car idles at 1500 revs. Its also very slow to reduce revs when the clutch is dipped.

turn it off, went in for tea for 30mins, came out and flashed it up, idles fine at 800

WTF !!

All hoses and gaskets are new, everything is tight, changed the ICV and TPS is all set up fine. CPS gap correct. Am convinced there are no vacuum problems. Changed AFM made no difference.

There is a BBTB fitted. Throttle cable is slack, throttle closes fine.

But, the fact its high one minute, I turn it off and re-start and its back to normal is odd.

It's an m30b35

I might fit a new blue sensor and change the ECU next but any other ideas would be most appreciated.

ta

[Brianmoooore]

If it's revving higher than it should, then more air is getting into the engine than there should be.
There are only three ways that can happen, and that's the throttle butterfly isn't on its stop, the ICV is wider open than it should be, or there's an air leak into the inlet plenum, which may not be direct, but can be via a pipe from the crankcase, brake servo, etc.
You need to do checks to see which is the problem.

[jimbom30cab]

Ok, will do, I put my ££ on the ICV

[jimbom30cab]

did a bit of testing today and the high idle is only when the engine is hot

on cold start up its perfect at 800 and then gradually gets higher as the lump warms up

i'm suspecting the blue temp sensor now, am guessing the resistance isn't falling as the temp increases so the ECU still pumps loads of fuel in thinking the coolant is cold

would explain why its running rich on the exhaust analyser and also I have used a LOT of fuel recently !!

anyone agree?

i'll check it's earthed ok to the housing and take the readings as recommended in the WIKI - que instant orgasm by Mr Grrrrrrrrrrrrrrr or whatever his name is that plugs the WIKI a lot

[Brianmoooore]

It can pump in all the fuel it likes. If it can't get the air to go with it, it won't rev.

[jimbom30cab]

Ar

Well just to keep me busy tonight I changed the following for known good ones:

Blue sensor
CPS
ICV

And it made.....

No difference

It's just like driving a car with the choke out

Next swap will be the TPS

Then TB

Then ECU

There simply can't be any air ingress, I have checked every connection and all the hoses are new.

Still very odd as it is consistently 800 when cold and the idle gradually increases as the engine warms up to about 1500

[gromgsxr]

Is the tps still clicking as you just start to open it when the engine is warm?

[jimbom30cab]

Yup

[gromgsxr]

OK that kills that idea.

[jimbom30cab]

Thanks any way mate

[hongkongfuey]

Is your afm knackered ?mine had probs with that before

[jimbom30cab]

Mmmm, thanks rob, I have a spare so might change that also, 2 min job

[Rav335uk]

ICV.
That was my problem on mine when it rev'd high

[jimbom30cab]

Ok so far I have changed the following

ICV for known good one
Blue temp sensor
CPS
ECU
TPS
Inlet boot
AFM

Changed TB to the non-BBTB one, no change but changing them did cure the issue for a while.

New TPS connector as the old was a bit damaged

Nothing changed, in fact it's almost worse! When hot the engine is steady at 1800 revs.

No vacuum leaks found and when it idles cold its perfect and smooth at 800 revs, 10 mins driving later and it's back up to 1800 ish.

Not much more else to change

I've triple checked for loose hoses or connections but vacuum is good.

[gromgsxr]

Has it got a o2 sensor think I came across something about those when I was googeling about

[jimbom30cab]

Nar, not got one mate, thanks anyway

I managed to sort it, the new plug I fitted on the TPS needed a wiggle and the TPS was a little to turned opening the butterfly valve slightly, now she purrs like a happy cat