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MG TD TF 1500 - sputtering to a stop - still

... a continuation of the same problem discussed a few weeks ago.

When running normally, the engine runs GREAT.

Symptom:
After running 5 - 20 miles I'm getting (at first) a few minor misses. The missing and skipping gets worse over the course of a minute until the engine runs so poorly it just sputters to a complete stop.

After sitting 5 to 10 minutes it starts and runs perfectly for 2 to 3 minutes, then the symptoms reoccur. I have had it stall 5 times while limping home.

In getting the car up to 'driver' status, the following has been performed:

Carbs professionally re-jetted, adjusted and balanced. Cleaned filters.
Timing has been professionally set.
New coil, condenser, points, wires, plugs.
fuel pump replaced with borrowed working replacement.
Fuel lines blown out, checked for flow.
Tank filter cleaned, line to pump tested for free-flow.
Water temp gauge is showing between 80 and 90c, days have been between 65 and 75F.
The fuel line runs on the frame and is not overheating.
The see-through in-line filter is as clean as a whistle.


While sitting at the side of the road, I've taken the top off a float chamber and the level is at it's proper level. The chambers do not overflow. Immediately upon stalling, the fuel line is disconnected and gas pumps freely. Pulled a plug - it's dry and a healthy grey.

Something is happening at temperature that self-corrects, then reoccurs.

None of the members of my British car club has this problem, so it isn't the altitude (2,400 ft) or ethanol fuel. Many use it with no problems.

Except to add spacers and a heat plate under the carbs, I'm at a loss as to what to try next.

MAndrus

Did you replace the rotor with a new red one? Good cap? I would install a spark plug test light on one of the spark plugs, look for a spark when it happens. Just for fun, try to replicate with the gas cap open. There is not too much to go wrong on these little cars.
David
D. Sander

New red rotor and cap. This happens with the old cap too. Hard to imagine the temp of the rotor or cap will change much in 5 minutes. The gas cap gasket is almost non-existent.

...
MAndrus

Are you sure your generator is charging?
What you described fits into the symptoms of running the battery down. When the voltage is too low, ignition quits. You may have enough amperage to roll over, but not enough voltage for good spark. After setting a while, the voltage comes back up enough to fire back up, for a while, until the voltage dips too low, again.

I installed a voltmeter to keep an eye on it. Running in the rain with wipers, at night with headlights on, plus the heater fan spinning, in stop and go traffic for miles, has me worried sometimes, waiting at lights down at 10V. The HID headlights can go out under extreme conditions.

I just bumped my regulator voltage up a week ago for just such situations. Now, under the opposite conditions with no draw, voltage can get up to 15V. Now I'll have to keep an eye on bulbs to make sure they're not burning out.

Are you running points or electronic ignition? I'd expect points to sputter whereas the electronic ignition might just quit all at once.
JRN JIM

Check all the connections on that new stuff to make sure they are tight and your grounds are good.

Another possibility, depending on how your fuel system was put together, is there is trash accumulating on a filter or screen somewhere in the system. It starves the vehicle of fuel after awhile, then when the fuel flow is turned off, it falls away again, leaving the screen/filter looking clean. This a notorious problem for racers as fuel cell foam deteriorates and gathers on a fuel pickup, clogging it, but floats away when the pressure is no longer pulling it against pickup.
David Littlefield

Could be a Crack in the head or block, opening when hot
G Mills

Does the fuel line go anywhere Near the exhaust, could be boiling the fuel.
Td29330
M Lees

If the fuel line or the filter in the tank were becoming clogged, the float bowls would not show the correct levels. In addition to checking the rotor and capacitor (condenser), also check the ignition coil for any output. Cheers - Dave
D.W. DuBois

Again, which plugs are you using?
mog

When it heats and stops, spray starting fluid into the carbs and see if it cranks and runs. If so, it is ignition. There have been several threads about bad condensers lately, coils also. Just because new does not mean any good. George
George Butz

I see that you haven't replaced the coil. As Dave DB points out, it could be the culprit. I would definitely replace it with a known good one. Bud
Bud Krueger

Since so much has been done to resolve your problem, here's a little check easy to do. We used to do this on antique cars years ago. Disconnect the condenser wire from the points, tape the end or even pull the condenser out all together. Make sure the nut on the points has been tightened again and start the engine. Doing that only increases a little more heat to the points and is ok for a temporary test. Run the engine for a period of time and see if it quits as before, if it doesn't, then you have a bad condenser, if it quits as before, you more than likely have a bad coil. I would imagine you have the coil wires on the correct terminals also. PJ
Paul S Jennings

About the only thing that hasn't been suggested is vapour lock. Could this possibly be your problem? Cheers
Peter TD 5801
P Hehir

Had the same problem with an MGA that I just finished restoring. It had sat for 15 yrs. without being run. Would run good for 8 miles then start to sputter. One overflow pipe was plugged with a mud dobber. Scroll down to 05 May. Paul Jennings post. L.M. Cook has some list of S.U. problems. One by Jim Taylor on a Jaguare site list some quirks on S.U. problems. I would never Have found the plugged pipe on my own .The A runs fine now.
Dave
DL Rezin

Take your timing light with you and when she croaks hook it up and see if you have fire. My first suspicion is a crap condenser.The new replacements are total junk.
MG LaVerne

Wow. I love all of the responses, I hope once we get this cleared up this thread helps someone else too.

The coil is new, the symptoms occurred with the old Lucas script original too. I replaced the original coil because it became too hot to touch. The new one stays cool-ish.

The condenser is new, I've put the old one back with the same results.

I LOVE the low volts in the battery thought. I'm going to work on this one. The ammeter shows a charge of about +2 to +5 amps, daytime driving.

Carb overflow pipes are open and have never had gas coming out of them.

Running on new points.

My next step will be to hotwire around the original wiring - hotwire the ign. just in case there's a weak spot in a wire.... I seriously doubt this though.

The entire fuel system has been cleaned and the tank sealed. At the side of the road I've cracked the fitting and gas dribbles out. Not clogged, and the pump produces more than the engine could ever need.

The fuel line is tucked tightly into the flange in the frame and the frame would act as a heat sink keeping the line cool. I'm thinking if it was vapor lock, it would take more than 5 miles and I wouldn't get gas from the line feeding the carbs. The days are not hot. I've driven up to 30 miles with no problems.

This happens with either fuel pump, the new one that came with the car and a borrowed one.

I have a pertronix points replacement, not installed yet. I'll assume if I replace the points ONLY with a solid-state unit and the system is having an electrical problem it will just die altogether instead of sputtering....??? Worth installing as a diagnostic aid perhaps?

I'm going to go for a run with the lights on to see if I can get the volts down. I'll also test for spark if we quit running.

After this, I'll make a heat baffle and install it behind the carbs on the chance I'm boiling fuel in the jets.

....
MAndrus

I had this EXACT same problem on my TD. Went through all the electrical etc.

Ended up being the inline fuel filter. It wasn't big enough. I had some fine sediment in the gas tank and it would plug the filter until the engine would stop. Shut off for a bit and enough of the sediment would slough off the filter element to allow it to start and go another mile then stop again. Rinse repeat.

It took a long time and a lot of pushing to figure that one out.

Finally put a larger clear filter in place so that I can change it easily and frequently.
L Rutt

Water in the gas? How long has it been sitting?
D. Sander

As a young broke teenager I had a battery that could spin the starter motor but not strong enough to turn the crankshaft. With only the ignition as a load the car always started with the hand crank. You have to have very low voltage to have an ignition failure.

Jim Haskins 1953 TD (Then and now, 56 years off and on)
J. M. Haskins

MAndrus,,
You said
>>Immediately upon stalling, the fuel line is disconnected and gas pumps freely. Pulled a plug - it's dry and a healthy grey.<<

If it is a spark issue, wouldn't the plugs be moist ??? Rather than dry and grey?? The fuel would still be drawn into the cylinder, but not fire off??

SPW

Steve Wincze

Are you saying that you have a Pertronix Igniter installed right now?? If so - take it out and reinstall the points. Is yours a negative ground system? Bud
Bud Krueger

Steve, yea. If I'm loosing spark the plugs should be wet and I should smell gas at the pipe. They aren't .

Bud, no. Pertronix not installed yet.

D. S. No water in tank or the carb. bowls. The tank was cleaned and sealed, it's been drained and filled twice to check on the mesh filter.

L. Rutt, the first few times this happened there was no in line filter. I installed one so I could catch any crap and see the fuel. So far... no crap, no water.

I've driven 30 miles without a hiccup, and 4 miles to a dead stick stop.

I just took 2 drives, 12 and 8 miles close to home, no problem. Now I'm DISAPPOINTED that it didn't fail 'cause I know it's going to.

.....

MAndrus

By any chance did you put a new seal on the gas cap. If so you may have plugged the only way air can get into the fuel tank. Just try running it with the cap not snapped shut.
Sandy
SANDY

Take the inline filter out and run straight from the tank to the pump. My inline filter looked clean as a whistle but was blocking fuel after about 5-8 miles. See my thread "Ominous Engine Rattle. Damned invisibly clogged inline filter costs me a complete head job. Jud
J K Chapin

Gas cap seal...HA! If I put too much fuel in the tank, it pours out on hard corners. Not a worry.

.....
MAndrus

Before I put my TD away for the winter it was showing what seem to be almost exactly the same symptoms that yours is having. I never got it sorted out, but will be taking it out of hibernation in the next week or two and then the hunt is on! Last year I replaced the coil with a new one and no change. Replaced the condenser with new...no change. I bought new points and they'll be next in. One thing that I did notice,that may be a lead, is that one time after I made an aggressive turn into a parking lot so not to stall out while on the road it seemed to improve for a minute or so before it again started to sputter.
I will be checking for debris in the fuel that could be temporarily plugging the filter and also checking the tank for vacuum build up.
Not much help for you but perhaps it's good to know you're not the only one this is happening to. It is very frustrating!
Needless to say this is a very interesting thread for me.
One question I do have is what are the chances of a new condenser, or coil, failing in exactly the same way as the ones that were replaced? There is certainly lots of talk about faulty new condensers out there.
Good Luck. Tim
Tim Mayor

OK. Most people know that the distributor body can come loose on the shaft and give major misfire problems. Many of them don't know that, in some cases, this only happens when it gets hot. Mine was tight cold and had to be heated before it loosened up. Now the expert heats all the distributors he gets in to check for this, and he's found a few.

Anyway, that's my thought for the week - the symptoms fit. Maybe, if it happens again, you could leap out immediately and try wobbling the distributor top. If you do it with the cap off, you may actually see the point gap changing markedly.

Good luck, David
David Provan

David, good thought. But it would have to then self-correct 5 minutes later. I've always limped home and run for another 5 to 30 miles on the next trip out.

I re-installed the old diz cap.

.....
MAndrus

How about a loose ground wire or badly corroded one?
Eric Brown

An update that may help others:
I was trying to get my TD running after its winter hibernation. On start up it would run for a few seconds but would not keep running. It would sputter to a stop. Eventually it would not fire at all. I pulled the plugs and they smelled of gas. Changed out the points and cap thinking it must be electrical. That didn't work...same symptoms, so decided to switch out the condenser,the brand new one I put in in the fall, with an old one that was in a spare distributor, one that has likely not been used for at least 40 years. It started right up and kept running! Go figure. Now I don't know if this was the cause of the original problem described above but I am hopeful. Need to wait for a warmer, less rainy day to find out. Don't trust new condensers!
Tim Mayor

Not wanting to bad mouth anyone's product, but a while back, I had a hard starting problem with my TD. The Champion spark plugs were not firing. Replaced them with Bosch and have had no problems since. Same thing with the auxillary generator in my truck. Through the years I have had notorious bad luck with Champion spark plugs. Much better luck with Bosch, AC or Motorcraft / Autolite.
John Masters

My 2 cents. I had similar problem. Also check the dizzy shaft for radial "wiggle". Doesn't take much.
Peter Dahlquist

"decided to switch out the condenser,the brand new one I put in in the fall, with an old one that was in a spare distributor, one that has likely not been used for at least 40 years. It started right up and kept running! Go figure. Now I don't know if this was the cause of the original problem described above but I am hopeful. Need to wait for a warmer, less rainy day to find out. Don't trust new condensers!"

That is what I have been preaching for some time. The ignition capacitors (condensers) available today are junk (to use a more acceptable word) and quite frankly something to be expected in today's automotive world. With every single new car on the market for the past decade (at least) have electronic ignition and most do not even have a distributor in them. The result of this is a precipitous drop in the demand for ignition capacitors. This, coupled with today's stamped to have every item produced off shore, has left us with junk parts.

The very best thing to do when doing a tune up on any car with an old fashion points style distributor is to leave the existing capacitor in place - They very seldom wear out! I repeat, DO NOT REPLACE THE EXISTING CAPACITOR when doing a tune up. If the existing capacitor isn't failing, leave it in the circuit. If you are dead set on replacing the capacitor, purchase a dozen of them - you just might find one in the batch that will not fail in the first few days of installing it.

I have an article written by Steve Maas (a frequent contributor here) detailing a series of tests he has done on a series of present day ignition capacitors, why new, out of the box ones purchased today are failing, what the symptoms are choosing a non automotive capacitor and how to attach it in place of the existing capacitor. I will see if Steve will agree with my putting his article on Bud's T Talk for all to read. Cheers - Dave
DW DuBois

I be happy to host it. Bud
Bud Krueger

Comments from MAY 11th,
You said
>>Immediately upon stalling, the fuel line is disconnected and gas pumps freely. Pulled a plug - it's dry and a healthy grey.<<

If it is a spark issue, wouldn't the plugs be moist ??? Rather than dry and grey?? The fuel would still be drawn into the cylinder, but not fire off??

My comment today June 18th

Are you sure that all of the linkage and the throttle disk are tight and in place? Would it be possible for the throttle disk to be closing for some reason, stopping air/fuel flow to the cylinders?
I believe this would result in "dry and healthy grey plugs", but the engine won't run.

Steve
SPW Wincze

See http://www.ttalk.info/CondenserFailure.html for a link to Steve Maas' excellent article on the subject. Thanks to Dave DuBois for setting it up. Bud
Bud Krueger

Dave, I do not replace cap & rotor either, unless absolutely needed. The condenser should only be replaced when there is a mountain on one of the points & a crater on the other side of the points. Then look for the Blue Streak Premium condenser.
Len Fanelli

This thread was discussed between 11/05/2015 and 19/06/2015

MG TD TF 1500 index

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