Not start after getting hot
 

Hi,

My Volvo starts well when it's cold. However, after it runs in low gear for a while and runs in idle for an half hour, it does not start. If I allow it cool down while bonnet is open for roughly ten or fifteen minutes, gets start immediately without hesitation. My battery and spark plugs are in good condition. What could be the reason?

Thanks

Lack of fuel pressure?
Read elsewhere on here that fuel can return past a worn non-return valve and starve the engine when restarting?

My 940 Turbo used to struggle to restart after stalling (my fault, not the engine's - mainly when parking) when up to temperature.
But a quick blip of the throttle as I turned the key made it start with no issues :)

Cheers

Is your fusebox behind the ashtray? I think some early 940s had them there. If so, check the fuseholder for the fuel pumps fuse. On some of the 740s i had, this had got hot in the past and melted, causing burning of the contacts where the fuse fits in.

This could be a possible cause of your trouble, also have you access to an exhaust gas analyser and where does the temperature gauge sit once it has run for half an hour?

Thanks for the replies.

jonnyf90, do you refer fuel pressure regulator?

Laird Scooby, yes, it's behind the ashtray. I checked but couldn't find anything wrong.

Does it cut out whilst driving or does it only have trouble starting after you turn it off?

Common problem when the crankshaft position sensor is defective

Also a common problem if the Coolant Temperature Sensor is defective - they fail in a high resistance/open circuit state which tells the ECU the engine/car is in Siberia so consequently over-fuels.

It could be anything, at this moment in time we only have an FTP situation when hot. Need more clues and/or tests to get to the bottom of this. ;) :D

No, it runs flawlessly whilst driving, having trouble after turning it off...

Just to get this right, the car doesn't cut out, you switch it off and then have trouble restarting?

Have you ever put any injector cleaner into the fuel tank? I'm thinking one or more injectors are dirty and not closing properly, while it's off the extra fuel is leaking through and flooding it. This would have gradually got worse over time and has probably effected the fuel economy as well, and general performance.

That may or may not be the problem, for the cost of some injector cleaner it would be worth adding some to your tank to see if the symptoms improve or disappear.

Yes, the car does not cut out, having trouble restarting after engine compartment getting real hot.

No, I have not ever used injector cleaner. However, couple months ago, all 0-rings on injectors were replaced.

I will try injector cleaner and report back. Thanks