C6 Z06 cam angle sensor

[jagsy]

Hi all
Post for info.

Our 2008 C6 Z06 has had some sporadic starting issues over the last few weeks.

The initial symptoms was engine cranking but not firing which is common for a faulty crank angle sensor.   I have a great mechanic and the crank angle sensor was changed. Note the symptoms never showed for the mechanic after I had a towie take the car to the workshop!

And no fault codes!!

Soon after the crank angle sensor was changed the starting problem symptoms changed to engine firing but then just stalling,  no response to revs - nothing. This was still sporadic and after a few attempts the car would start and run fine.

Again I couldn't get the symptoms to show the mechanics, the car started fine every time I saw him!!!

We did have a couple of non firing again but the mechanic suggested to change the cam angle senor.

Yes it was the cam angle senor. A serious problem was that it was seized in the mounting point (front of engine).  After a big effort and fingers crossed we have solved the problem.

An info post.

[jagsy]

Update - car won't start again. Must ne more than just th3 sensor!!

[Shane Finn]

Have your mechanic check the the throttle body behind the blade and the back of the throttle blade for accumulated gunk. If gunk is present, open the throttle blade manually and liberally spray the back of the blade and the area behind the blade with carb cleaner.

When I first got my C5 Z06 20 years ago I had an issue where intermittantly it wouldn't start. It would crank but not fire. Or sometimes would start but surge around below idle speed until it died. At the times this happened I could leave the car for 20 minutes or so, try again and it started. Once started and idling the car always ran great. It did this maybe 5 times in the first year of owning the car.

After cleaning the throttle and blade the issue never re-occurred in 20+ years of owning the car. My theory was that the throttle blade was sticking shut.

[jagsy]

Thanks Shane. Symptoms sound similar. We'll check that next week.

[bfit]

Two things to check.
Check go pedal is returning all the way up!!!!  Ie hook foot under pedal & lift /  NOT TO aggressively.

Next         multi meter on battery,
Floor the go pedal ( engine no start position) engine should not start with go pedal all the way down.
Partner push  start and check what the voltage drop is.  It would be handy to know what the engine cranking speed as well
Let us know how you go.
Bfit
 Ps ps ps
Can you hear the fuel pump running

[Vettech]

I think your opening post indicates what is needed.

The car fails at your house, but works perfectly at the mechanics.

Your house is located on a Serpentinite Lens in the Rocky Beach Metamorphic Melange.
This melange is know to draw the Southern Diplex Magnetic fields into these Lens Vortex's.
This then interferes with electromagnetic radiations, esp where angelization are concerned.

There is nothing you can do except - get the mechanic to make space in his garage and store your car there between uses.

Where would we be without modern electronics !?....
 

[bfit]

Ahhh yes the Putin triangle,

[jagsy]

Update
My mechanic brought his scanner to the car yesterday and it was the first time he has experienced the non starting issue for a prolonged time and was able to scan and see what was happening!!

All sensors, voltage, fuel, throttle blade working correctly  :(

He checked the relays and fuses. All ok   :(

He then checked for spark and injector firing. Good spark but no injector firing signal. AHA we have what's causing it but why?

Tried starting again and the car started. Had the mechanic moved the injector/coil wiring harness - he wasn't sure.

The injector/coil wiring harness feels hard and brittle as though it's been subject to heat. Moving the harness is hard and can almost hear cracking whenmoving it!!!!

We are now going to test the harness and replace it to see if that eliminates the issue.  Further testing of the main harness back to the ECU may ne needed. We don't think it's the ECU as when it does run all is OK.

With the engine running I took the car to the mechanics workshop, but needed some fuel on the way.  After fuelling, at the garage, the car wouldn't start again!!!!  I tried 3 times.  Opened the bonnet, took the engine cover off, wiggled the wire harness and the car started!!

We have an area now to look at to see if that is the problem.

[Vettech]

C6 has sequential Injector firing, not like the C4's with TPI, firing all left bank then all right bank.

It would be unusual for wiring to effect all injectors, a wire to one injector would not cause failure to start - more likely a miss whilst running. So I dont have a cct dia, but would be inclined to look for a common wire - say a common earth return etc.

In the C4 the injectors have power via 2 dedicated fuses to all, whilst ever in the run position.

The other side of All Injectors go to two outputs on the ECM - these are basically electronic transistor (SCR) switches, which switch earth on and off as required. I use my daughters stephiscope to listen to the injectors firing, some cars are noisey enough to hear without it.

If you loose All injectors I'd be looking for a common denominator - and the ECM or computor or what ever a C6 has, could still be in the running for culprit. I hope not.

Best of Brittish - sorry Best of Welsh.

[jagsy]

Update and hopefully problem found.
The wiring I talked about last had a bad connector with one spade badly corroded and burnt. That has been replaced and other spades checked. All.gopd so far but will need to do local testing to be confident all.is well.