bad idle or overheating after stopping?

[LeRoiDeLaRue]

Hmmm.... I had a problem on acceleration twice on return home the other day. I spoke to chap who supplied a replacement engine to a former owner and he identified a possible dodgy fuel pressure switch as maybe not responding swiftly enough on demand ... maybe it is linked?

[Herman]

Hmmm.... I had a problem on acceleration twice on return home the other day. I spoke to chap who supplied a replacement engine to a former owner and he identified a possible dodgy fuel pressure switch as maybe not responding swiftly enough on demand ... maybe it is linked?

If it is something else (or also happens when cold) it might be pump, sensor, dodgy COP or plug.

If they're all OK and it still happens it is most likely vapour in the fuel line due to heat build up. TADTS

[WNJ516]

Would be interesting to know what fuel pressure the rail is at, and what temp the fuel rail is when this rough idle occurs. What temp does petrol boil at, to cause this vapourisation. I don't presently suffer with it but should it occur will try and take those measurements.

[Cribbit]

Suffered quite badly from this today. Did an hours drive, stopped for an hour and then had really lumpy idle. Drove for 20 mins, stopped for 20 and same again. Then drove for an hour again and stopped for 10 mins and it was fine. Whilst I do quite like the car's shake and the lumpy low idle noise it makes and the burbling when you bring the revs up with no load it's probably not generally good for the car. It does seem quite random as to when it does it, and it's more frequent since I had the kenne bell heater bolted to the top of the engine. I have no insulation under the bonnet, and plan to fit some vents if I ever get round to having some body work mods done, so will be interesting to see if this helps.

[AndyG]

Try running without the under engine plastic tray.

I removed mine years ago mainly to aid the view of any liquid leaks.

I understand it was fitted for something to do with high speed running. As I rarely exceed the NLS by much for any length of time I have not had any problems.

Without it it would allow the air from the rads escape.

[Herman]

Try running without the under engine plastic tray.

I removed mine years ago mainly to aid the view of any liquid leaks.

I understand it was fitted for something to do with high speed running. As I rarely exceed the NLS by much for any length of time I have not had any problems.

Without it it would allow the air from the rads escape.

Problem is that hot air rises. So when the car is parked, hot air will always travel to the bonnet and not to the underneath of the engine bay,
You may get a little more cooler air depending whether it's windy outside when parked up.

[AndyG]

Problem is that hot air rises. So when the car is parked, hot air will always travel to the bonnet and not to the underneath of the engine bay,
.

But it would help to draw in more cool air from below and reduce the air temp above the engine.