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MG MGF Technical - Revs Sticking Occasionally Hot and Cold

I have read all the threads but I just cant work out the problem.
Car - MGF NON VVC 1996 Bought 18months ago
75,000 miles, Head Gasket replaced 14 months ago (70K.
New plugs, service at about 3months ago.

Occasionally I am unable to start the car in the morning - smells of petrol when turning it over. It also sticks at about 2,500 rpm when driving. You have to gradually accelerate to avoid it missing or stalling. (Very embarrassing!!) If you stop the car whilst it is revving high you are unable to start it again. It doesnít matter what the temperature of the car or outdoor weather.

**The RAC were called and he advised me to keep my accelerator to the floor and turn it over for 15 seconds at a time. The car does finally start - And stinks of petrol!**

He said to clean my stepper motor. (The black plastic cylinder (Same size as 35mm Camera film) with two wings for the screws which has wire coming off the rear located at the top of the engine between the injector and the head) Simply terms for simply people like myself.

I removed the stepper motor, cleaned the soot and replaced. Car worked fine. (Very pleased, as Iím useless with cars!!)

That was 2 weeks ago. Yesterday the car started playing up again! And this time the temperature gauge rose above the half way line. I stopped the car immediately as I thought the head gasket had gone again. Left it for 1/2 and hour it was fine. Head gasket is fine no water loss etc.

I went to MG and asked for a stepper motor and the service engineer said It is very unlikely to be that book it in and we will find the problem. (Rubbing his hands together with pound signs in his eyes!)

Any suggestions??? Do I pay £78 +Vat for a new stepper motor and find that its not that??
I hate keeping it in the garage in this fine British weather. (Whilst it lasts)

GJ

>>That was 2 weeks ago. Yesterday the car started playing up again! And this time the temperature gauge rose above the half way line. I stopped the car immediately as I thought the head gasket had gone again. Left it for 1/2 and hour it was fine. Head gasket is fine no water loss etc.<<

Not really sure what is going on here. It does sound rather like the idle control has gone to pot - and that was cured by simple cleaning of the stepper motor. Assuming that the same thing has recurred, the question is why? When was the last time the air filter was cleaned/replaced GJ?

The overheating may be a sign of another problem - but clearly should not be occuring here :o( Is the radiator fan working as it should? (Check fuses and the MEMS water temperature sensor function - http://www.mgf.ultimatemg.com/hgf_pages/related_problems_overheating.htm)

There is a possibility that the head gasket is failing again - but exclude other causes of the problems first...
Rob Bell

Many Thanks for your Reply.
I had a new air filter fitted a few months ago. But I will clean it for curiosity sake.

Is there any need to change the throttle body?
I see that they make a metal one?

Where would I find the idle control?

Is there such thing as a fuel filter in the petrol? I remember on a cavalier I had to change the fuel filter (Little plastic cylinder with paper in fitted on middle of a petrol pipe)?

I am not 100% sure what the stepper motor does?
Can you explain?

I am hoping that the high revving caused the overheating.
Touchwood I havenít had any water loss and it hasnít happened since.
My fan works but I am going to double check all the fuses, as it is the cheapest option - thanks for the link.

Thanks Again
GJ

This thread was discussed between 14/08/2003 and 15/08/2003

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