VX V6 not starting

[Holden202T]

as long as the cas signal is detected it shouldn't log a code.

im not sure if you know how it works, but the fuel pump relay normally primes the pump for 2 seconds on key on, then after the engine starts cranking it goes again, now if the fuel pump relay is shagged it wont prime, and also it wont start running until the motor has wound over long enough to get oil pressure and then the oil pressure switch allows the pump to run.....

after what you said about the key and the key reader on the column im wondering if its related to that or not, but disabling vats should rule that out!

[hsv08]

as long as the cas signal is detected it shouldn't log a code.

im not sure if you know how it works, but the fuel pump relay normally primes the pump for 2 seconds on key on, then after the engine starts cranking it goes again, now if the fuel pump relay is shagged it wont prime, and also it wont start running until the motor has wound over long enough to get oil pressure and then the oil pressure switch allows the pump to run.....

after what you said about the key and the key reader on the column im wondering if its related to that or not, but disabling vats should rule that out!

Yeah thats whats strange, it registered it being there then after 2 or so seconds on the started motor it throws the CAS fault, what does the ecu use the cam angle sensor for? i thought it was to register the motor turning over in order to pulse the injectors? If so whats The ecu use the Crank angle trigger for? i always thought it just used a cam angle not crank angle?

New it primed but wasnt aware it uses oil pressure to signal pump on again. so thanks for that, the afaia the VATS will stop the starter and injection right?

[antus]

Cam angle sensor is so it knows engine position for sequential injection - which injector to fire when it gets the signal from the crank. I would say it would be technically possible to run off the cam sensor alone, but it makes the system more reliable having a fallback option. It also depends where the notches are etc. Im not sure if the cam just signals when cyl 1 is at TDC and crank says now now now now for the cylinders and the pcm starts at 1 and counts... It will be something along those lines.

I see what you mean about the injection ms, it shows some but its there before you even start cranking, and it doesnt change. Im not sure if thats normal, but I would assume it is, and its updated after you get an rpm signal. You definately dont have the rpm signal, so thats what you need to figure out. you've checked fuses and relays, so check wiring, bad connections in the loom, and the CAS itself. Ive also heard bad things about after market cas, I suggest going genuine if they are still available from holden.

Dont worry about checking for a DTC straight up, you should see something like 100 to 300 rpm when its cranking off the starter. If you cant see that, it wont be firing.

[delcowizzid]

crank angle sensor or dfi would be a good start and making sure theres power to the dfi

[Holden202T]

yeah the cam sensor just sees a single trigger once per rotation so it know where home is. (TDC)

[hsv08]

well the cam angle sensor is apparently getting replaced tomorrow now. any way to check the dfi module? I have a vs v6, is it worth throwing my unit on too see if it works?

[delcowizzid]

yeah just fit a known good dfi for a test.does it have spark at all if not it can only be power to the dfi the dfi itself or the cas.even if it has spark dont discount the cas.aftermarket ones can last an hour or a week or a year they can be hit or miss depending on where it was made LOL

[hsv08]

Ok ill bring my tools with me to work tomorrow and swap mine out for his to see if it works. I should never have offered to have a look at it cause its doing my head in!. he is my supervisor so brownie points if I cant sort it but then again it could go opposite if I cant haha

[Holden202T]

also if your DFI doesn't work on his car check that his works on yours!! can at least rule another item off the list!

I agree with delcowizzid, also seen CAS work fine when cold then fail when hot too.

[vs ss]

Yep had two aftermarket ones fail,one lasted two weeks the other started within the same day!
So I just pay the bit xtra and buy genuine ones now.