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MG MGF Technical - MGf refuses to start


I have what will seem a common tale of woe.
My 1999 MGf was running quite well, despite cooling problems which were steadily cured by replacing pipes and hoses. I drove it home from the garage, who were waiting for the final new hose to arrive, stopped the car, removed the shopping from the boot. Shut the lid and left it overnight. In the night the snow came, and ice. Next morning, entirely out of character, it would simply not start. Remembering the last thing I had moved, I checked the boot wiring, and sure enough that was broken near the boot hinge. We rewired it but still no start. The boot light still doesn't come on - are their fuses somewhere I have missed? Still, we persevered, charging the battery - which checks out OK - and spraying WD40 around the HT leads to dispel damp.... Days passed, repeated attempts failed.

The local garage took the car in last night and changed the plugs - dried out the flooded cylinders, cleaner the Distributor cap and HT leads, checked the fuel feed.... boosted the battery etc. and they have managed to start the engine...but not keep it running.

Now, it was working well enough before the snow and the broken boot wiring. I have missed something. But what ? Any ideas?

Anthony Luckcuck

Do they have a fault code reader? This may be a sensor failure, maybe its not seeing the engine is cold? I would also change the dissi cap and HT leads to ensure that area is solid.
Stan Best

Hmm. Thank you for responding.
The garage have a fault code reader but cannot access ones so old as mine. When they get the car back to me, I will try changing the leads and Distrib.cap; it seems so common a cause of such difficulty it has to be worth doing. But what sensor might be faulty - where is it located, do you know?
Anthony Luckcuck

If the coolant temperature sensor wasn't giving a reading the car would still start ok but run on full choke even when warm, i.e. high idle & rich.

With a spark plug removed and earthed to the cyinder head, does the spark look red/orange or a bright blueish? If not bright and blueish, that suggests a weak spark is the cause of the problem. The boot wiring loom is beyond the engine circuits so unlikely to be a factor in the non-starting, however if the garage have been changing coolant hoses then the possibility of some water having sprayed around shouldn't be ruled out. unscrewing the distributor cap and checking for moisture evidence there would be my first step, and if there's any doubt of its condition then as Stan says renewing it and the rotor arm is a wise investment. Many starting problems have historically been cured by fitting new HT leads, and upgrading to Magnecor type leads seems well worth the extra cost in the long term.

Failing that, pull off all the plug connectors you can find and check for moisture, and a squirt of electrical contact spray before re-connecting can work wonders.

Good luck, it's usually something simple ;o)


After the simple electricals above which are the first things to look at, when the garage say they can't keep it running; is that using the throttle or just at tickover? You might find the IACV a bit grubby if it is only at tickover? Also the recent extremes of temperature may have done for an O ring seal anywhere. Cold as well as work around the engine might have disturbed any of the sensor connections. Are you familiar with Dieter's site :
If you search the LH index for 'Sensoren' you get a brilliant check list of locations and tests.

Most garages dont have a diagnostic machine that will 'talk' to the MGF or TF... I've found most Land Rover main dealers are most obliging and they have the correct machine to tell you what if any problems you may have.

M T Boldry

This thread was discussed between 10/12/2010 and 22/12/2010

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