Horrible idle when warm

[justice4all3000]

Hey this has really got me stuck, my car idles horribly when its warm it has even got to the point when it conks out when I pull up to the lights sometimes! I have fully cleaned out the throttle body, replaced the throttle position sensor, idle air control valve changed spark plugs tested the coil pack and leads and also checked for errors any ideas???

[vp_commo]

Well the old crank angle sensor comes to mind, I know I am no mechanic and the CAS is mentioned every time a car farts, but this time it sounds like the CAS might be worth an inspection.

Mainly because you said it only does it when warm, this is typical of a CAS.

One way to test if it is the CAS is carry a 5 litre container of water in the boot, when it stalls in the heat get out and pour water on the front of the engine, behind the main pully where the CAS is lodcated.

If the car starts again easily then you know the CAS is on the way out.

BTW. If it is on the way out then it will eventually die completely and you will have to get towed.

Also the CAS will not show up as an error if it is failing intermitantly (only now and then).

Just an idea

Cheers

Dan

[justice4all3000]

Hey thanks for the help! is there another way to test the cas? (e.g. with a multimeter)

Cheers

[vp_commo]

yes It is in the gregorys, it involves wiring up a test lamp or good multimeter that can read pulses and battery terminal with the coil pack plug where the CAS wire goes in then manually cranking the engine with a ratchet.

It is in the gregories manual.
The only issue is that if the problem is intermitant then it may work fine on inspection then die out on the road.

There may be a way to test the sensors resistance (ohms with a multi meter), to check for wear but I do not know how to do this.


Cheers

Dan

[justice4all3000]

Ok I have tested the crank angle sensor and it appears to be working fine any other ideas anyone?

[D3V14NT]

Some possible causes may be the oxy sensor, coolant temp sensor (to ECU not gauge), dodgy ECU, fuel regulator, dodgy injectors and maybe even the fuel pump.

Oxy sensors are the cause of quite a few problems and most people don't know about them to change them. They're simple enough to replace, just a bit of pain to get to. The sensor is down the end of the LH exhaust manifold. Check how many wires it has before you go replacing at it as there are different types. How's your fuel consumption? A crappy o2 sensor more often than not causes poor fuel efficiency too.

[v6lux]

I had a problem where the car, when hot, would stop completely for 5 or 6 years before I was told it could be the power pin to the DF Module. A guy at Holden told me to scrap the corrosion off the pins and it worked. It's the red or pink wire or the pin closest to front. You will need a 7mm socket to undo the connector bolt. Take a socket with you and when it happens, loosen the bolt and wiggle the connector, then re-tighten it and see if it fixes the issue.

Also try borrowing and completely replacing replacing the DF Module and see if this changes things after the pin scrape.

[justice4all3000]

yeah I also had a feeling it was the DF module I have already tryed swaping it for another

[wortus]

as well as the CAS check the fuel pressure, fuel filter, corrosion on any electrical connectors, loose electrical connections and vacuum hoses that are cracked and maybe look at the PCB on the ECU for any dry joints or damaged tracks?

[justice4all3000]

well the fuel filter was replaced about a week ago all of the vacume hoses look secure and in good condition what would be the best way to check for vacume leaks?

cheers

[justice4all3000]

well I took my car to the mechanic today all he did was tell me to come back when the problem is worse lol

[edals]

Well i replaced the coolent Temp sensor in the VR to the ECU today cause it was a bit rough when cold. MUCH MUCH better now. only 16$ from holden. WOuld give it ago.

[justice4all3000]

yeah I tryed that, didnt realy notice anything though