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MG TD TF 1500 - Just cuts out...

OK...here are the symptoms...TD runs like a champ then just cuts out...coast to a stop, won't restart...eventually restarted and drove home running strong as if nothing happened. Took it out today for a quick run around the neighborhood, ran 10 minutes fine then conked out pulling into the garage. Checked fuel & pump both times...float bowls full & pump operating correctly. This leads me to ignition...I have a pertronixs which I've run for 4 years...I am assuming that since it is electronic, it is either working or not working and will not be intermittent, so I dont think that is the problem. Rotor & cap are newish, been in the car for about 3000 miles. Checking the achieves I found a similar symptom caused by the coilcoil is about 5 years old (flamethrower)Is my next step replace the coil?
Bob Dougherty

Does is 'cough, sputter, etc' to a stop... quit with the ignition light just coming right on... miss a little bit, then more, then stop.... or just stop running like you turned off the ign switch????
gblawson(gordon)

Change the rotor
George Butz

I remember there were some reports of bad rotors and caps back a bit. As I remember the caps had an issue with internal shorting.

It does sound like an issue with something getting warm and then not working, then working again when it cools off.
Bruce-C

Just stops like you turned it off...I'll start with the rotor...
Bob Dougherty

Why is it always so damn hard to do the simplest things??? Change the rotor...easy, just unclip the hold downs, take off old rotor, install new... bring up the hold down clips....where is the back hold down clip??? Yup...fell out of the distributor body!!! Can't get it back in sooo...pull the dizzy...housing is broken and will not hold the pin...JB Weld should do the trick...letting it harden right now...why do we love these cars so...are we masochists??
Bob Dougherty

Gee Bob.. i don't know????

http://www.youtube.com/watch?v=x7wc55oXWf8
gblawson(gordon)

Bob

Many good places to look here. Two of us in our club have had similar problems in the past. In two cases when the car stopped, the bonnet was raised and everything looked OK until a hand rested on the coil and it was really hot. The car would start and run fine once the coil cooled off, the fix was to replace the coil. If it is going South on you it will get really hot to the touch. The same type of thing happened in my TD and it was the fuel pump overheating, again once cooled it would work fine for about and hour. The final diagnosis was that the diaphragm has a pin hole and when you drove in situations that created a demand on the pump, it would overheat and fail. This lead to the body of the pump weakening and thus a spiral downhill. The pump has now been rebuilt by Dave Dubois and is like new again.

Anyway, these are two places to look, the coil will stop you dead the fuel pump will sputter to a stop.

Brian
Brian Smith

I had the same problem with my TD years ago. Took a while to find it too. It was an internal break in the low tension wire to the distributer, impossible to see from outside appearance.

Another cause can be the tacho reduction box if it is not tight. It can move and short out the low tension terminal on the dizzy.

Cheers,

Paul.
Paul van Gool

It happens to me even today. 20 years ago, I twisted the key, and it sprang back to life - bad contact in the ignition switxh - just too lazy to change it.

Gord Clark
Rockburn, Qué.
Gordon A. Clark

OK…riddle me this Batman! I swapped the rotor and no change…car will start and run 1-2 minutes then just cut out like I turned the key off. Thinking that just maybe it is the Pertronix ignitor (my assumption is it is either good or bad, but maybe they do get intermittent) I pulled out my spare ignitor and prepared to install…that is when I made a startling discovery! I installed the original ignitor 5 years ago (the car is positive ground)…haven’t touched it since…tune-ups consist of new plugs & set timing…every 3rd tune up gets new rotor, cap & wires…car has about 20,000 miles on it in 5 years, including two 3000+ cross-country trips…the startling discovery…according to the instructions that came with the new ignitor and the info on T-Talk, the ignitor was hooked up backwards! I had the black & white wire hooked to the + side of the coil and the ground wire from the chassis to the – side of the coil…Now…how could the car have run (and run well!) for 5 years with the ignitor hooked up backwards? I’m SURE I have not touched any of the wires from the ignitor…shouldn’t the ignitor have burned up or something? Even more perplexing…on a whim, I reversed the wires to the correct positions on the original ignitor that had been installed for the last five years and…car started right up, idles @ 800rpm and runs like a top…I’m scratching my head…but…I think I found the problem!! Don’t understand it…but the car is running strong again…I’d love to hear any theories…
Bob Dougherty

You didn't mention if you can hear the fuel pump. If you have an old or original wiring harness you may have had the problem I did, which took a long time to track down.

The bullet connector going to or coming from the ignition key and the connector was badly corroded, and when the car ran for a while, this joint heated up, expanded and didn't conduct.

The big clue was that I lost both power to the fuel pump AND power to the ignition system. I replaced the connector with one from moss, and cleaned the bullets.

A year later, with no further failures, I replaced the wiring loom.

Larry
Larry Ayres

Bob, reversing the coil primary terminals would have only negligible effect. My guess is that your reconnecting various wires corrected a bad connection. Had you reversed the polarity of the connections to the Ignitor it would probably be kaput. 'Simply' reversing the coil direction wouldn't affect the Ignitor, just the polarity of the high voltage pulse.
Bud Krueger

Bud,
I guess that makes sense! I'll monitor this and see how it works...
Bob Dougherty

I had the same symptoms when I got my TD about ten years ago. The P.O. promised that the car would be running well when I picked it up. Being cautious, I rented a trailer to bring it from the D.C. area to Long Island...and it was a good thing! I drove it around the block and ended up rounding up his neighbors to help push it onto the trailer. When I took it out for a ride at home it did the same thing-ran for a few blocks and cut out. I pushed it home and after a few hours or the next day it would repeat. The previous owner had tried-he brought it to an expert in Virginia and they rebuilt the carbs to make it right. On his way home, he got stuck and had to get towed back to the shop. They then replaced the fuel pump. He spent about $1500.00 for nothing. I subsequently replace the points, plugs, wires and dist cap. I reset the floats, played with the mixture and still no help. I was really getting fed up having to push the car home constantly (but I did lose some weight). I finally replaced the coil for about $16.00 and it has been totally reliable since. I've replaced the plugs a couple of times in the last 10 years and 11,000 miles, but thats been it! I redid the bottom end -reground the crank and new bearings along with a rebuild on the oil pump and reground rockers and new rocker shaft to cure low oil pressure about 8000 miles ago, but never even changed the points-just checked the timing when it was all back together. I did end up replacing the fuel pump a couple of years ago because the crap in the bottom of the tank would foul it up and I could never get the tension on the membrane quite right when I put it back together. When it got hot it would stop ticking. That is another thing to check. When the car craps out push the tickler pins down and see if the pump sends fuel.
Steve Tobias

This thread was discussed between 14/09/2008 and 17/09/2008

MG TD TF 1500 index

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