C5 A6 2.5tdi cut out and won't restart

[brad25uk]

Hi,

I have been lurking on here a while, just reading on common issues and mods etc. I now need some help with the below issue...

I have a 1998 manual C5 A6 2.5tdi FWD 150 AFB model, approx 120,000 miles (hope that covers it) that has happily been working fine until last Friday.

It started fine and moved about 2-300m, then attempting to move off it just cut out and would not restart. It doesn't even attempt to crank.

I scanned for faults and got:

00550 - Start of Injection Regulation
08-10 - Control Limit Surpassed - Intermittent

I since cleared the error and it now shows no errors when the ignition is on.

Battery power is fine. I have been running a chipped ECU, but I have swapped back to my original ECU (exact same model no.) and there is no difference.

I have tried researching the problem on here and other forums, but with the different models it is hard to pinpoint. My gut feeling from reading the posts is that it's the injection pump, rather than something simple and cheap!

I have vagcom, so if there are any readings or measurements I can take then please do let me know.

If it is the injection pump, are used pumps an option? As I know there are possible coding issues.

Thanks in advance for any help.

Brad

[zollaf]

just confirm, it desn't actually crank over ? do the dash lights dim when you try ? can you hear anything, like the starter trying to engage or spinning.

[brad25uk]

just confirm, it desn't actually crank over ? do the dash lights dim when you try ? can you hear anything, like the starter trying to engage or spinning.

Hi,

The lights don't dim, it's not the battery, as it's still got 12v when trying to start it.

The key won't turn to allow it to start. A mechanic friend mentioned after a brief description that it might be immobiliser related. Is this easy to diagnose?

Thanks

[Peter D]

"The key won't turn to allow it to start." Really. That is an ignition barrel failure. Regards Peter

[brad25uk]

"The key won't turn to allow it to start." Really. That is an ignition barrel failure. Regards Peter

It's most likely I'm describing this poorly, I'll try and get a video of it this evening.

Thanks

[Lukenkarl]

I am guessing immobiliser, but if key wont turn, as Peter says ignition barrel, or steering lock is holding against the key mechanism. Try wiggle the steering wheel whilst turning the key.....

[bluezie]

If the key won't turn it's the ignition switch
If the key turns, but the starter doesn't crank the engine, it's wiring or the starter motor.
If the engine cranks, but doesn't start, it's engine mechanicals or fuelling.
If the engine starts, but cuts out after 2 seconds, it's the immobaliser

[brad25uk]

Hi All,

Thanks for the suggestions. I have an update on the car...

Following a visit from the RAC (as i'd given up diagnosing) the battery was deemed unhealthy (most likely due to all the attempted starting). This was swapped over and a temporary extra earth added, it still didn't want to start, but did now attempt to crank.
Eventually it fired into life, made a loud noise and then smoke came from down low at the front (near the alternator location), so it was switched off.

The RAC chap diagnosed it as a seized alternator that had then freed with a new battery. It was then towed to a friend's garage last night.

We then got it up on the ramp last night and removed the belt covers, it quickly became apparent that the drive belt had snapped. Once the front end was off and the covers removed it showed that the failure was the drive belt tensioner that has a bolt in a dual threaded sleeve had sheared a bolt. This had then ground through the crank pulley and destroyed the drive belt.

The cambelt is still intact, so replacement pulleys and belts are due to arrive tomorrow and hopefully it'll fire up ok once back together