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MG TD TF 1500 - TD missfire

Just readNorm Tuckers' missfire.I have a similer fault,my TD starts perfectly runs superbly,I can drive for many miles and never misses a beat,but if I stop at a red light or similer just for a few seconds I drop down to 2/3 cylinders the more I put my foot down the worse it gets the only way i can keep going is to accelarate very gently and after a couple of miles it clears and runs perfectly until I have to stop again then the miss is there again.I have changed all the ignition Componants to no avail,I am now looking at the carbies, all clean all levels correct, has any one tried to keep the fuel lines cool by insulating them,this fault occurs at any ambient temperature.
Any suggestions would be appreciated. Adrian Wells.
Adrian Wells

Wonder if it is an advanced stage of boiling fuel in the carbs...don't know why it might do it on your car, but maybe a heat shield could be tried to see if it makes a difference?
gordon lawson

Here in the hot wilds on Minnesota <grin>, we have often made up insulator block to insert between the carb bodies and the intake manifold. This helps a lot. They're not as think as those found on an MGA, but similar. Lots of other suggestions, no doubt, in the archives. But I agree that it is likely vapor lock. A sure test is to pull the choke out when you experience the problem. If the symptoms go away, it is vapor lock.

Cheers,
Lew Palmer
Lew Palmer

Just a thought - have you cleaned the fuel pump filter and the filter at the tank... I know that would be a constant issue - but just a thought.

Also - does the car do this in cool weather?
J Delk

Adrian -- Sounds like a problem I had at one of the British Marque Triathilons(sp) the TD sputtered and I stopped by the side of the road, waited a minute and went on. At the last check point of the rally it quit. I replaced the ignition system and it still didn't work! Then I replaced the rotor and it has worked ever since. Put the original rotor back in and it won't run! Yet the rotor looks OK, no tracks, ohmmeter checks OK but it won't run in the car!! Obviously an internal high voltage short inside the rotor.

Before that, I had a problem every time I came to a stop light. The engine would run on 3 cylinders for a 1/4 mile before it would get going on 4, then I could run away from the other cars in the caravan. After I replaced the rotor no more problems at the stop lights. Somehow we have to find a way to check the system.
Cheers,
Bob
R. K. (Bob) Jeffers

Thanks for the replies guys,Gordon,I have tried a heat shield but no improvement,Lew, I tried the choke ,no improvement.j.Deck,I checked the filters, all clear,the problem is there at all temperatures but not as bad when cooler.Bob,stangly enough I had the same experience with the rotor but found a tiny exit mark inside the rotor,I have replaced the rotor again.seem like the same symptoms as you describe as if tracking under the extra load of starting from standstill.I am now leaning to the fuel but why only when stating off?
Thanks to all.Adrian.
Adrian WELLS

I had a similar problem, except it would also occur after running at roadspeed for about 20 minutes. After eliminating all the ignition items, everyone was convinced it was "vapor lock". I tried a heat shield, heat sinks on the fuel line, etc, no success. Finally succumbed to a fuel pump test which required a temporary tube into a bucket for a timed delivery amount. I happened to use a clear plastic lab type tubing, and immediately saw a steady stream of tiny bubbles, which didn't clear up. This was my "vapor lock" which would accumulate to the point of insufficient fuel supply. The fuel pump diaphragm had a pin hole and was pumping some air. Another pump solved the problem. May not be your problem but a clear tube on the discharge of the pump will tell you.

Dallas
Dallas Congleton

This thread was discussed between 07/08/2006 and 08/08/2006

MG TD TF 1500 index

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