Very Rough Running when cold - Mechanic and Auto electrician can't diagnose

[wrx884]

how r they testing the CAS? on the bench or in the car? should b tested on the bench as even new parts can fail.

 

[Tsunamix]

PCV Valve, Fuel pressure regulator, dodgy ignition module (i have had that happen myself), Vac hose from under throttlebody to Purge control solenoid. Can even be spark plug leads (if you have leads with the shields on them - take the shields OFF).

 

[lout]

might be time to get a new mechanic

 

[Longman]

Hi mate,

I noticed it hasn't been mensioned as yet. Did your mechanic/sparky check the Engine Collant Temperature sensor (ECT)? A faulty sensor can cause issues when cold and hot. It's located just below and to the right of the thermostat housing on V6 models.

 

[FstStig]

Any updates on this, be interesting to know what was wrong if its been fixed.

 

[db_notso]

for those codes
if WIRING HARNESS and SENSOR (CAS) are OK
PROVEN OKAY BY TESTING OUTPUT OF CAS WITH A OSCILLOSCOPE (auto elecies job)
i would try/think about fitting another ECU if you can find one thats been reset or ask the auto elecie to hunt it for you~!

have to check if wires from CAS to ECM are shorted to ground/power, or open circuit
if all is okay im leaning towards the ecm being dead

im not able to acess the net atm for another month so soz but good luck!~

 

[vsd]

Hi Guys

Sorry about the long time gap since last post. It has taken a while and also needed a new auto-sparky on the job but the guys did find the solution. Actually many of you guys found the solution way back :-( It was (as some of you suggested) a faulty Crank Angle Sensor.

The real curve ball in this whole process is that it was a brand new sensor that was causing the issue. The mechanic and auto-electrician did some tests on it - but probably only while in-car etc.

There was a secondary issue of a blocked catalytic converter also. This became evident when they put the car under load on the dyno.

So a big thank you to you guys for the advice, and suggestions. The mechanics and auto sparky felt bad about the time it took to diagnose and fix and as such have only charged for parts at cost and virtually no labour. So other than having no car for three months it has worked out well.

Cheers Guys!

 

[Brett_jjj]

Ive seen some cheap ass brand CAS's like some of the ones seen on ebay, cause problems before.I always buy genuine holden parts because of this,especially engine sensors,genuine parts are more expensive,but they usually work out cheaper in the long run as they last longer and usually dont fail from new.We once fitted a new cheapie CAS to a mates car,it still wouldnt start, and it took ages for us to work out that the new CAS was the problem,Grr.We only found out that it was faulty after removing the "new" CAS and fitting another second hand one,she fired straight up after that..

 

[vsd]

Thanks Brett_JJJ yeah it seems like that would have avoided the major hassles we had.
Cheers

 

[aveugotone]

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