Volvo 850 GL 1996. Was all good suddenly the engine cuts out without warning. Electricals remain working. If you try to restart there are NO dash lights, the starter turns over but won't fire up. Wait 5 minutes or less and dash lights come on again and it starts, runs for a few minutes then cuts again.

This happened out of nowhere, but it is now completely reproducible. Must be electrical related due to the dash lights symptoms. I notice when it does cut, one hears a click.

SOLVED. Was one of the relays must have some dodgy contacts. Changed and all good.

 

a common engine cut out issue with 850s is the fuel pump relay which can over heat due to a worn out pump that's drawing too much current - but if as you noted you have no dash lights, then I'd suspect another relay or the ignition switch itself. Here's a few things to try: jumper the fuel pump relay (google for how to's) to see if that allows the car to restart without waiting. If no change there, next try wiggling the key in the igntion switch to see if that helps make contact and gets the lights to come on. Finally, check out Volvotips.com for a wiring diagram and check for relays, connection points and ground points for the dash lights. One last thought - there's also the injector relay (up front by the radiator - if I recall its a gray relay) - try tapping on that to see if that helps the car to restart.

 

Hi, thanks. Luckily it was just one of the two 80A relays, that must have a bad contact that was reacting to current in a way that caused the cut off. We swapped the two relays to get home then verified the bad one and changed it. All good now. I was alarmed that such a small fault could result in a sudden engine cut without warning, in my case I was in busy city traffic when it happened but managed to roll over to the roadside before the steering went stiff. Anyway I still love my old girl.

 

thanks for the update. Over 25 years or so, relays can develop pitting that makes for resistance and that heats the relay to the point that the solenoid doesn't have enough grip to keep good contact. the old school remedy was to pop the cover off the relay and clean the contacts with some emery cloth.

 

Interesting! Thanks very much for the support. I'll get some emery cloth for the toolkit!