bad idle or overheating after stopping?

[Julianp]

This sounds like fuel vaporization, which affects the fuel/air mixture and can cause the engine to misfire and idle roughly. I used to get this periodically with my (standard) 260 in heavy traffic in Paris during hot weather. On a couple of occasions it triggered the check engine warning light and I had to reset the codes, but it always fixed itself once the car had cooled down.
Julian.

[LeRoiDeLaRue]

Oooh ... any links to the kind of bonnet vents that might suit our motors? Anyone know any good specialists doing such work in the north of UK?

[Nich]

When you go Green Jim you will be able to see where this link leads to:

https://www.two-sixties.co.uk/mgoc26...ghlight=bonnet

Nich.

[Nich]

What about this:

Magical Snap - 2014.03.15 20.09 - 002.jpg

connected to this:

Magical Snap - 2014.03.15 20.07 - 001.jpg

Using the wireless remote to activate the fan when necessary.

Just have to work out where to mount the fan.

Nich.

[LeRoiDeLaRue]

Thing is, I dont actually see the engine overheat ... the needle stays where it stays.

The flattening on acceleration needs sorting though - at 3500 yesterday in second it happened and two scallies in a standard ford focus flew past me

... i actually felt myself blushing ...

backing the foot off a smidgeon and then immediately back on cures it though

not the blush ... the fuel supply thing

[Nich]

It's not necessarily the engine that overheats but the fuel rails that get too hot. This vapourises the fuel in the rails and causes flat spots in acceleration. It might also be the fuel supply system i.e. the pump, have you checked for separation? Have you got the orange clip mod? Is it a COP breaking down? Lots of things to check but you need to get it sorted you can't carry on being overtaken by scallies.

Nich.

[LeRoiDeLaRue]

It's not necessarily the engine that overheats but the fuel rails that get too hot. This vapourises the fuel in the rails and causes flat spots in acceleration. It might also be the fuel supply system i.e. the pump, have you checked for separation? Have you got the orange clip mod? Is it a COP breaking down? Lots of things to check but you need to get it sorted you can't carry on being overtaken by scallies.

Nich.

Cheers Nich - indeed i cant It is also about the old MG motto - safety fast

Mark Sibley of GT Racing in Honiton was very helpful when I rang him to confirm the replacement engine was indeed supplied by him back in 2010.
He suggested it may be the fuel pressure switch on the fuel rail that might need replacing, as a first fix - can these be checked on a diagnostic? Throttle position sensor was also mentioned as a possible, along with a microweep on fuel line.

Yes the fuel filter has had the clip has been put on under previous owner.

[NOCTURNAL]

What about this:

[ATTACH=CONFIG] see above[/ATTACH]

connected to this:

[ATTACH=CONFIG] see above [/ATTACH]

Using the wireless remote to activate the fan when necessary.

Just have to work out where to mount the fan.

Nich.

whilst I would rather get to the bottom of the issue, if this would cure the symptoms, I'd consider it..... can we have an expert opinion on how long a solution like this might take to cool the fuel rail once applied? Lets assume some form of ducting to ensure cooling of the actual rail area as well...
what I am saying is once it had reached this 'faulty' state is that too late to turn on the fan?? or would it need to be running permanently?

still interested in the 'why' when it hasn't done it for many previous years of identical driving patterns..

Nick

[Herman]

Vapour in the fuel rails is not uncommon on cars with a non-return system.
It can also be rather random. I have noticed it on mine in 7 years of ownership probably twice.
Both times the symptoms went away after a few miles of normal driving

As the problem is with heat soak from the engine, getting the heat out is the best option.
Bonnet vents will prevent heat build-up and allow hot air to escape, reducing the chance of vapour lock.
It could create another problem though with regards to water ingress and the electronics (injectors, COPs etc)

If the symptoms are caused by a failing COP it would gradually get worse until the COP fails consistently under load.

Any issues with the fuel supply (pump, pressure sensor, pump module or filter separation) would most likely be noticed on every run.

I don't think an additional fan will cure the problem because the radiator fan will be running most of the time when stationary anyway

[peterv8]

Maybe this or something simular is a solution?

Open the hood electrical to let the heat out when staionary.


http://www.youtube.com/watch?v=3MTN82KqHRc