Wh statesman idle problem, tried a lot of things, please help.

[Damothedevo]

I have a wh 02 statesman spercharged v6 and have replaced plugs, leads, coil packs+controller, cam angle sensor, iac valve, tps sensor, o2 sensors, fuel pump, injector clean, intake and head gaskets, compression 155-165, runs much better but little or no change in idle miss, not on one cylinder, every few seconds a few misses in a row, pretty much disappears when hot, any idea will be much appreciated, pretty lost and spent a bit so got to keep going now.

 

[harrop.senator]

Were any of the valves burnt when heads were off? Have you checked codes? Checked for vac leaks? Checked fuel pressure? Running out of simple options. Fact its only when cold could be something like temp sensor and its running a bad mixture when its cold because pcm thinks its already warm or colder then it is.

 

[Damothedevo]

Were any of the valves burnt when heads were off? Have you checked codes? Checked for vac leaks? Checked fuel pressure? Running out of simple options. Fact its only when cold could be something like temp sensor and its running a bad mixture when its cold because pcm thinks its already warm or colder then it is.

Thanks for reply, valves looked ok, did the stem seals as they came in kit, springs ok, unless weak, but problem would probably continue when warm from weak spring(guess). Checked for vacuum leaks with propane, chanced some hoses when had intake off, also crimped booster hose, with no effect, going to have a look at vacuum hoses under dash, but isolated feed line and seems like thats not it. Checked fuel pressure was reading 300, tolerance said 290-400, so changed fuel pump for brand new. Also when had intake off, snaped the sensor inback of manifold so changed that for a second hand one hopefully not same issue on two. Like i said everything ive done has made it run heaps better plus better fuel economy, but idle problem persists.

 

[Damothedevo]

Were any of the valves burnt when heads were off? Have you checked codes? Checked for vac leaks? Checked fuel pressure? Running out of simple options. Fact its only when cold could be something like temp sensor and its running a bad mixture when its cold because pcm thinks its already warm or colder then it is.

Which temp sensor should i replace? Are they linked to the gauge as this works good.

 

[Not_An_Abba_Fan]

I'd also look at the fuel pressure regulator.

If it goes away when warm, it sounds like a vacuum leak, particularly intake manifold or SC base plate. As it warms up, everything expands and the leak stops.

 

[devilly]

egr gasket may be leaking. was the iac and tps replacement genuine holden's or aftermarket ? when cars is idling just hold your hand like high five and move it around you might pick up a vacuum leak.

or i'm also thinking i was chasing a miss for years as soon as i went genuine on iac and tps the miss went away.

looks for something small or basic as you have done all the hard work.so think simple is all that's left to do.

 

[Damothedevo]

I'd also look at the fuel pressure regulator.

If it goes away when warm, it sounds like a vacuum leak, particularly intake manifold or SC base plate. As it warms up, everything expands and the leak stops.

Thanks for reply, i did sc gasket when i did the head gaskets, highly recomended as mine was in pieces, car went heaps better, just doing sc gasket not hard job.

 

[Damothedevo]

egr gasket may be leaking. was the iac and tps replacement genuine holden's or aftermarket ? when cars is idling just hold your hand like high five and move it around you might pick up a vacuum leak.

or i'm also thinking i was chasing a miss for years as soon as i went genuine on iac and tps the miss went away.

looks for something small or basic as you have done all the hard work.so think simple is all that's left to do.

I don't think sc modles have an egr, and yeah both iac and tps were genuine delphi units about 3 x the price, but if it fixed itwould have stayed fixed, auto is changing much better since tps change, so prob needed doing. I pulled iac to check/clean it, i turned the ignitionon with it out to see if it moved and plunger shot out somewhere haha. Looked everywhere, finally replaced valve without plunger to see if i could get away with it (you can't), started car and found plunger had fallen into serpentine belt, destroyed brand new belt and plunger so had to get new one. Haha just a little anecdote, still spewing on the belt, could have happened to old one haha.

 

[devilly]

bugger i just test mine this way dunno if it's right or wrong.i just disconnect the power to it start the car for a few seconds then turn off and plug back in do you still have the problem has anything changed ? i also noticed that when you turn your car off you hear the noise of the iac stepping back kind of like wrrrring noise.this is what you want to hear which means its working properly to my understanding

 

[Damothedevo]

bugger i just test mine this way dunno if it's right or wrong.i just disconnect the power to it start the car for a few seconds then turn off and plug back in do you still have the problem has anything changed ? i also noticed that when you turn your car off you hear the noise of the iac stepping back kind of like wrrrring noise.this is what you want to hear which means its working properly to my understanding

Yeah still have problem, out of ideas, car doesn't stall and goes good otherwise but really rough when cold. I'm going to go back to iac because everything points to it. Is brand new but going to check seat and see if something wrong there.