Engine died!
 

Cruising on the M5 yesterday, I suddenly felt the car stop pulling (no vibration or loud noise, although my wife and I both noticed a faint ticking sound). Put it from D into 4th, no change, the engine had died. Managed to get it onto the hard shoulder and stop safely; several warning lights had come on (I think it was Engine Management, Oil and Battery) but I was a bit busy so I didn't make notes! While my family were getting out of the car, I turned off the ignition and tried to start it again, but no joy (turned over but wouldn't catch). The first recovery guy who turned up checked all the usual things and reckons it's the crankshaft sensor; sounds reasonable, but I'm no mechanic and the hard shoulder isn't the place for trying my very limited diagnostic skills anyway. The recovery home turned into an epic faff, and I was in work first thing this morning, so I haven't had a proper chance to look under the bonnet.

Basically, does the diagnosis sound plausible, or is it as likely to be something else? If that is the problem, the Haynes manual suggests that the sensor can be cleaned and refitted without much difficulty (it's a V6), but is that alone likely to cure it, or should I aim to replace it?

Can't offer any advice for the KV6, but if you need help Terry at TS Autos is only 40 miles away, near Ludlow, and what he doesn't know about Rover 75s isn't worth knowing. ;)

Have you tried a restart today - failing Crank sensors do tend to fail when hot and start working again when cooled down. When you turn her over does the rev counter move at all - if not then that points to a failed crank sensor.:shrug:

My understanding is the cam sensor is only operative to start the engine and as far as I know will not cause it to stop if it fails but it will stop it from starting. The crank sensor however will cause the engine to stop if it fails

Do you remember if the rev counter died instantly when the engine stopped pulling ?
My understanding is that if the crankshaft sensor failed, the rev counter would die immediately, but I could be wrong....

Yes Charlie it does, but you can verify that quite simply.

Lift the rear seat cushion on the driver's side to listen to the fuel pump. When the ignition is turned on you should hear a buzz for two seconds only. When the starter motor is turned that same buzz should be continuous. If you don't hear it at all, suspect the crankshaft sensor.
It's always sensible to inspect and clean first, including the connector. You have everything to gain and nothing to lose!

Don't forget to let us know how you get on. :}

Simon

Check the engine management fuses in the under bonnet fuse box first

Sincere thanks for all the replies. I didn't have a chance to do anything with the car yesterday evening as there were other crocodiles circling the canoe, but I'll follow up on the suggestions later today. I don't think it's the fuses - the recovery guy checked those. Will be interesting to see if it starts now that the engine is cold! Would be fantastic if I could get the car under its own power to a car club I belong to - much better place to attempt a fix than my drive.

Thanks again all, fingers crossed with your advice I can get the car moving again!

No further on
 

Unfortunately, I haven't made any progress. It seems that it's not the crank sensor - fuel pump works as advertised, and the sensor and connection have been cleaned, with no improvement. A friend who has infinitely more knowledge of cars than me came round with some tools, and basically there's no spark when the engine turns over (but the rev counter does twitch). There's a local mechanic who has a good reputation for fault finding, but the earliest he can see the car is a week today. Anything else I could try in the meantime?

It's a long shot but maybe take a look at the lambda sensor, the wiring can chaff and cause your trouble? it chaff on the heat shield.

https://i.imgur.com/ROiodCtl.jpg1

https://i.imgur.com/8cZfzHtl.jpg2