So I took the car for it's first proper test drive after the turbo's have been done. I was driving it home, everything was running fine. Then on the motorway I noticed that the car wasn't feeling right, like it's missing on one of the cylinders.

 

So I got it home gently, parked on the drive and popped the bonnet. I thought I'd find out which cylinder it was by removing the coil pack connector one by one to see when one made no difference. I got them all off and they all were working, as i went to put the last one back on the engine died.

 

And now will not re-start. When I go to start it it turns over, I can smell fuel after doing it for a little while, so I'm guessing its a spark issue. But all the sparks at the same time? Surely that would be a PTU fault? I am still running the series 1.

 

Has anyone else had these symptoms or a PTU failure of similar consequence?

 

When I get time, ill get a coilpack and sparkplug out to check it's actually not sparking, or is there an easier way?

On most occasions when a Series 1 PTU is failing, waiting for it to cool down (or pouring some cold water over it) usually gets it going again for a while.

Yes that's what I'd read.

 

So I got Mr Green Flag man down, he had a good look and I have air, I have fuel, I don't have spark . . . from any of the cylinders.

 

So if one cylinder was not firing I'd say coilpack has died, but as no cylinders are sparking surely that is a blown PTU?

 

Does the PTU come up on the ECU diagnostic tests?

I had a misfire that was PTU related, however the misfire was always there and I tracked it down to corroded connections on the PTU loom. It was so bad I had to chop it off and solder a new connector on. Worked fine after that. As far as I know I'm still on the original ptu.

Well i've ordered a 2nd hand one off ebay, so I'll fit that when it arrives and see if it starts :blink:

well ideally you need to start from the front backwards. cleaning or at least inspecting the ptu is a good start, then the cas connection. as this is where the spark signal is sent from. then working further back.

Ok, I've checked the PTU connections, they look good, no corrosion at all. I've cleaned all the coil pack connectors already, so I don't think it would be that. If the PTU comes up as a dead end. I'll move to the CAS unit. But I'll check the connections now. Thanks.

Ok, I put my hands up, I made a mistake, I have found the cause, but not the problem. The cause was there are two earth points in the efi harness that connect near the #6 cylinder that were not connected. They were probably resting against the plenum, hence the car starting ok, but when I came round to removing the #6 plug of the coil pack I must have disturbed them they lost the connection and the car stalled.

 

They are now connected correctly but the car does not start. I am assuming with a blunder like that I probably have blown a fuse or damaged a unit. Any idea what fuse it is likely to be and where it is located on the car? Or what unit may be affected by those earth points.

The grounding point is F11, this earth 3 devices:

 

1) Air Regulator (F7)

2) ECCS (F1)

3) Air flow meter (F29)

 

Ive checked all the fuses and nothing is blown. I believe that the MAF and the AR wouldn't effect the ignition so have I taken out my ECCS. If so would that stop fueling as well? Because I have air and fuel just no spark. Also swapped the PTU over with no luck.

 

Is there a way of testing components with a multimeter to see functionality, like how would I test to see if my CAS is working correctly?

I did a ECU diag and I got error 21 (ignition signal circuit).

 

Apparently if the Earths are not done up or are poorly connected it can fry a PTU and this error is thrown up.

 

My replacement PTU I tried before discovering the earth problem so maybe I fried a 2nd PTU?

Just to sum this up for everyone, because lots of Error 21 codes are not resolved on previous forum posts:

 

I received my 2nd replacement PTU, fitted it and it didn't start.

 

I then disconnected the battery overnight to reset the ECU. Then I got some contact cleaner in the morning and scrubbed the PTU/Harness, CAS/Harness, TPS/Harness and it started on the first crank. :laugh:

 

I haven't as yet checked my error codes.

Good to hear you got it sorted.

 

Nice to hear what you did to resolve it also.