Poor idle quality - Help & advice please.

[Thecrispynoodle]

check coolant temp sensor on back of the head too....distant memory of mine causing grief resulting in poor idle G62 IIRC

Maf and ISV contact pins clean?

Its a pain when its not obvious for sure

Temp sensor was replaced 3 years ago when head rebuilt (professionally). MAF & ISV contacts cleaned with contact cleaner and look good.

[Rusty]

I've checked values for IAT (30-35 degC @ idle), coolant (90-95 degC), throttle angle (8-96 deg), atmospheric pressure (1025mbar) and they all look normal.

I've just cleaned up the MAF and ISV plugs too.

Got to get the injectors swapped for a spare set and then cleaned and a compression test done.

Where is good to get the injectors cleaned? I'm in Bristol.

[Rusty]

Another thing I've just thought of is that I have an RS2 spec ECU running ABY cams and cam pulley, so both the cam timing and overlap is different... AFAIK, there is no overlap on the cams but the RS2 exhaust cam opens later than the ABY and closes earlier, so could this make a difference?

[stocious]

Throttle body cleaning time?

Just out of curiosity, was it clean ?

[Rusty]

Not checked the TB as yet but will have a peek when i take it all off to fit the new lifters

I do keep wondering if I'm being a bit precious about a 172k car with non-standard parts etc. but then I think it should be better. I think it's a little worse than the 172 Clio that the missus now owns and that's pretty poor in the idle department... wait and see what shows up. If it's nothing, then I'll chalk it up to age and the fact that it's a bit worn.

[stocious]

Not checked the TB as yet but will have a peek when i take it all off to fit the new lifters

Ah ok!! I took mine of and used carb cleaner! The area for air to squeeze past when closed throttle is tiny and almost none if dirty, hold it up to a light before and after cleaning, I was glad I looked

[s2driveruk]

http://www.injectorcleaning.co.uk/index.htm

i used these guys - easy and quick

[Rusty]

Cheers David, I'll get some spares to try and get mine cleaned up

[Greg_S]

worth checking the ISV again too, mine was intermittently sticking causing rough idle

[Rusty]

I've done a little more work on this.

Swapped my injectors for known working ones. No change. I will get my injectors cleaned though, as a matter of course.

Swapped to stock RS2 chips. No change.

I need to get a proper boost leak test done off a compressor rather than vigorous hand pumping

I've also got a slight blow on a V band on the exhaust to look in to at some point, as that certainly will not be helping, as it's pre lambda! I'm not sure what amout it's blowing but there is a bit of soot on the underside of my turbo heat shield, so something's amiss