VL Commodore Rough Idle

[guidos]

hehe. i tried a few different computers too, no difference.

it NEVER stalls or misses a start. just when warm the idle is a bit 'hairy' i guess you could say. nothing too bad.

[FastEHHolden]

It's not the cam timing..it happened at stock timing and at 1 tooth advanced....I will replace the CAS eventually because it is logging the CAS fault code but until it fails to start I'm just going to drive it.

[timmeh]

guidos, although mine runs well, at warm temp it has a slight miss every now and then... i was a bit worried at first but admitted to myself that it is a 15 year old car with 200thou on the clock.. i then sat in my brothers VT and it has a rougher idle then mine, so ill just put up with the fact it aint brand new (noticebly diff idle characteristics if im using regular unleaded or the exxy stuff).

also, have u tried temp sensors, its not sending the wrong signal making your car run rich or lean is it?

[guidos]

i've tried swapping just about everything with a working car.

yeah the motor is old but its got a reco head and the compression is 180psi across all cyls so the internals seem ok really.

when the motor is cold you can barely feel its running, when its warm theres a bit of a shake. not as hards as dropping a cyl, but also more random.

[tandy ass]

I had that same problem on my Skyline although it would do it only on petrol (was fine on LPG), would idle well when cold but when it warms up (and the injector pulse width is shortened to near minimum) then it would start doing the minor splutter every 10 or so seconds. You can hear it splutter out of the exhaust too, although quite minor.

Poured a bottle of Wynns through the tank and it did nothing. Blew the engine up about 12 months later and then I pulled the injectors out and sent them off to be ultrasonically cleaned (20 bucks each) and after that she was perfect.

[guidos]

injectors were ultrasonically cleaned about 2 years ago so rule that one out!

if i unplug the coolant temp sensor when the motor is warm, the idle goes up etc but still misses the same, so i dont think thats the problem

its not a minor splutter every 10 seconds or so like you said bozz, kinda hard to explain, but its more constant while still being quite uneven and random.

[tandy ass]

Hmm I dont know then... 2 years still is a bit of time and an injector could have failed perhaps.

Other than that if everything else is right such as fuel pressure etc then I'm at a loss to explain

[guidos]

its always been like this.
i may try another set of injectors but it doesnt bother me that much any more and i dont plan on keeping the car much longer. getting a turbo around easter time hopefully.

[tandy ass]

Now you're talking

[guidos]

:D