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MG TD TF 1500 - MGTD Dies While Idling

About 4 months ago I started having trouble with my car dying at intersections. The California lights are long and sometime before the light turns green the idle will decline rapidly and the car will die. If I rev the engine while idling it seems to make it die faster. It seems to happen more often when it's hot outside and when I have a passenger. It seems to happen soon after going to a store, then coming out and leaving the parking lot, it can happen before I get out of the lot or at the first intersection. When it dies it will start in a few minutes, but it will not want to accelerate until it seems to clear, then it will run normal again until I have to idle again. I have changed the points and plugs which made the car run better but the dying while idling is still happening. Tonight it did it in my garage soon after starting, so it's not just from the car being at high temperature. When I felt around the core and the electrical connection it seemed to make it worse but it was not hot as the engine had just started. Can anyone help? Thank you.
F W Abel

Next time when you idle it at home and it dies, shut the key off and pull a float bowl and see if there is fuel. If not I would be checking the filters to see if debris is trapped in them. then I would get a can and turn the pump/s on and see the flow rate. Maybe a diaphragm in the pump is bad ? a vacuum leak on the suction side from the tank to the pump, especially if rubber lines are spliced in anywhere? I'm new to these cars and don't even have one together yet but that's where I would be looking...Good luck


W. A. Chasser Jr

FW - Sounds like an intermittent capacitor (condenser) or coil. There is a rash of bad capacitors recently, so if you changed out the capacitor in your distributor recently, I would suggest going back to the old one (if you saved it). A coil can also act up this way, particularly in higher temperatures. Since coils are easier to change than capacitors, I would suggest trying a new coil as your first step.

The fuel pump could also be acting up as Bill suggests, but it this were the problem, I would think that it would be worse at speed rather than at idle. You can use the procedure in the article, Fuel Delivery Troubleshooting Guide in the SU Fuel Pump Articles section of my Homepage at: Cheers - Dave
D W DuBois

F. W.,
If your carbies have tickler pins, watch them as the car is ideling,, if there is a fuel delivery problem, the pins will go down until it stalls from lack of fuel.
ALSO, listen to the fuel pump as it is ideling,, it should periodicaly tick as it pumps fuel, I have seen a pump not operate at idle, but work fine as the car was moving. This was because the points needed to be reset, and all it took was the extra vibration of the moving car to make the pump work! Once the car stopped moving, the pump also stopped.

Steve Wincze

Thank you all for all the great advice. When I changed the points, the capaciter looked like it may be somewhat damaged but I'm not sure what a good capacitor looks like. Dave, what is the difficulty in changing the capacitor, I've never changed it and not sure what's involved. I only know where the band fits in with the band for the points. Again, thank you all, and I will keep you posted on following your recommendations.
fwa Fred Abel

I'm with Mr DuBois - I suspect either coil or condenser. Also, depending on how hot it is, you could be experiencing heat-related issues with your fuel system. Do you have a heat shield for your carbs? If not you may have some boiling of fuel in your bowls and/or jet assembly. Also there's a potential you may be getting vapor lock. Either could cause stalling on idle.
Kevin McLemore

Way back in the beginning F. W. indicated;
>>Tonight it did it in my garage soon after starting, so it's not just from the car being at high temperature. <<

I think that would rule out Vapor Lock,,

Steve Wincze

The original capacitor is soldered to backing plate, with a strap going over it. I have not tried replacing the capacitor in our TD for the simple reason that it has never given me any problem in the last 40 years. Your best bet would be to try and find another backing plate with the capacitor already attached to it. I think that I would try replacing the coil first as it is easier to change out. E-mail me at and I'll see if I have a spare backing plate or a capacitor that could be swapped onto your plate. Cheers - Dave
D W DuBois

Very easy to use the later style capacitor- remove the old one from the plate (unsolder, cut, whatever), locate the new one, mark the hole, drill a new hole and either tap and use machine screw or use sheet metal screw. "Tonight it did it in my garage soon after starting, so it's not just from the car being at high temperature". So not vapor lock. There was a recent thread about vapor lock/stalling, try to find that- lots of good diagnostic tips in there. You are missing either spark or fuel. When quits (better/safer if cold), pull the float bowl lids and see if there is fuel in the bowls and the floats are bobbing. If they are dry and the floats on the bottom, it is fuel delivery issue. If plenty of gas, then it is ignition. Condensors and rotors seem to be lousy, change the rotor if black/brown to one of the red ones. See:
George Butz

Not necessarily saying that your problem is the condenser.

I struggled with my condenser for a while and read a lot of posts about the problem. I learned that just about any condenser will probably work. The difficulty is in mounting it to the MG breaker plate.

Here is a not-so-brief description of the solder-in breaker plate that Dave DuBois described and the drilled breaker plate that George Butz described.

Page 13 in the 1954 Lucas Equipment and Spare Parts shows that breaker plate #409613 with a solder-in condenser was used on TCs and TDs through 1952. Screw-mount condenser #418113 was used on TDs and TFs starting in 1953. See photo below.

Moss sells a shorter version of condenser #418113 with the "ear" in the right place, but a number of people, including myself, have reported that the condenser is defective. BWD part #G635 has the correct mounting "ear" and states that it is for an MGB. I bought one but didn't install it. Looks pretty small. It is not the same condenser that Moss sells. Click on Compatibility ...

Moss sells a breaker plate that accepts the screw-mount condenser. Possibly as acknowledgement that the condenser is defective, Moss states that they can drill the plate to accept an MGB condenser with a mounting ear on the bottom - Moss #154-000, or Beck/Arnly 172-5829.

> Moss Breaker Plate

> Beck/Arnly Condenser (click on "Fitment")

I have seen pics of a Chevy condenser with the mounting clip moved to the bottom (away from the lead) and the clip attached to the screw mounting hole in the breaker plate. The lead was routed around the other direction in the distributor. I'm not comfortable with the lead rubbing against the breaker point mount.

Right now I have a BA 172-5829 in my distributor with a cobbled together mounting clip. I'll probably drill and tap my breaker plate to mount it correctly.


LM Cook

I was going to order a coil, but I read Dave's Fuel Delivery Troubleshooting Guide and went out to the garage tonight and started the engine and let it run for about 5 minutes. I then reved the engine a bit and when I took my finger off the throttle cable it immediately died rapidly. The car started right up again and I reved it off and on for 3-4 more minutes and it again died after a rev. The third time when it started dying I tried to rev it and it sputtered a bit but soon died. This experience makes me think it is a fuel issue.

I felt around the car, the carburetors, the fuel pump, the coil and distributor cap, and nothing felt hot. The car definitely has acceleration problems along with the intermittant dying while idling. I also tried to tap the fuel pump when the car was dying but it died too quickly to get to it. I changed the fuel pump once when the one on the car stopped working a long time ago and the current pump says it was made in New Zealand.

I have a couple of questions, what are tickler pins, and how do you pull a float bowl, does it come off by removing the cap nut?

fwa Fred Abel

Fred - Disconnect the fuel line from the rear carburetor (the line coming from the pump). stick it in a quart jar that has a mark on it at the 1 pint level. Turn the ignition on (remove one of the primary wires from the coil while doing this so that the coil doesn't get hot) and time how long it take for the fuel pump to deliver 1 pint of fuel - should be around 55 seconds. If it is significantly longer than 55 seconds, it is time to look at your fuel system. See the article, Fuel Delivery Troubleshooting Guide in the SU Fuel Pump Articles section of my Homepage at: If the fuel being pumped into the jar has a lot of bubbles in the stream, you will need to read the article Air Leak Troubleshooting in the same section of my Homepage. Cheers - Dave
D W DuBois

Thank you, Dave, I'll do it tomorrow night.
fwa Fred Abel

Fred, where in CA are you? Perhaps one of us is close enough to lend a hand.
Steve S

I have attached a pic of the Tickler Pins,, They should be about 1/4 to 3/8 inch above the top of the bowl lid at normal running,,, If you don't have fuel delivery to the bowl, (as in a failed fuel pump or failed fuel pump points)they will go down as the fuel is used in the bowl and nothing is being replaced by the pump, there for starving the carbies.

NOT ALL SU's have these pins


Steve Wincze

Dave Du, thanks for the link to your helpful page (ballroom dancing is one of the few joint ventures that my wife and I enjoy). I want to follow up on the tickler pins but to avoid hijacking I'm going to start a new thread. In the mean time, given the amount of air bupples I see going through the soon-to-be-gone clear fuel filter ahead of the fuel pump I'm thinking that I should replace the entire fuel line from tank to pump. I hope to have my four foot lift installed soon (it's been sitting in the shop for nearly a year and needs attention) but messing with gasoline in any form (in or out of a container, liquid, atomized or vapor) scares the Bejeezus out of me. I'm terrified about unscrewing the tank drain plug because (1) it may be so froze that twisting it damages the tank and (2) it's not leaking now but the gasket is so old and probably brittle that I may not be able to reinstall it leak free. The same fears apply to the tank outlet connection to the fuel line. Hopefully another investment in Moss or LBC (376-665, 328-040 & 370-650) will partially alleviate those fears. Do y'all recommend that I also get a complete new fuel line (454-080)?


J K Chapin

Fred, Sounds so much like a partially plugged fuel line or filter screen at the tank. I would check the filter screen in the pump and the carbs as well.

If you disconnect the fuel line at the pump intake, you may be able to use compressed air at 3-5 psi to blow back to the tank. Open the filler lid to the tank and you should hear a free flow of bubbles in the tank, and air should move freely. If there is any resistance , then I would think the line may be partially plugged. This is a short term fix, as if there is "crud" blocking the screens , it will block again.

If you find any of the other filter screens filled with "crud" you will most likely have to purge and clean the entire system. If the filter screens are clean, you may still have a partially plugged line as fine particles can settle in the line from the tank. ( usually near the tank, just before it rises to the frame )

I had the same problem. The fuel pump worked fine, but didn't deliver enough fuel. I thought it was the pump, but in reality it was a plug of fine rust from the fuel tank that partially plugged the fuel line. I removed the line and ran a wire down it and found the plug approx. 12" from the tank. I blew out the line and got about an inch of rusty crud out of the line.

Once the line was clear... no more problem. Before that I could run the car for about 5 min. then wait a few minutes to have it run again... til it died again. And so on.

The dirt had restricted the fuel flow enough that the pump could not deliver, but not enough to stall the pump completely.
C.R. Tyrell

Jud - Bubbles in a clear fuel filter is not necessarily indicative of air getting into the fuel line. If you pump fuel through them for about 24 hours straight, you can usually get rid of that bubble, in the meantime the bubble doesn't hurt anything - it is just the nature of that kind of a filter (I have yet come across anybody who can explain the physics behind the phenomenon). The only way to check for an air leak on the inlet side of the pump, is to use the method I stated in my posting to Fred. Air leaks between the tank and the pump will not necessarily show up as a wet spot along the line.
I am glad to see the "soon-to-be-gone" statement about the filter ahead of the pump - put it after the pump and you will be fine.

As for removing the drain plug from the fuel tank, pump all the fuel out of the tank first (you can pump it out with the fuel pump - just monitor the pump for over heating). Removing the plug should not be a problem, it is a brass plug into brass threads in the tank - same with the pickup outlet. If the tank has not been cleaned out, that would be a good idea to drain it and check for debris and any bad rust spots.

"Do y'all recommend that I also get a complete new fuel line"

Unless the fuel line is showing signs of deterioration, I would just blow air through it to see if there is any debris in it.

Cheers (and keep dancing), Dave
D W DuBois

Drain the tank by using the fuel pump - I never think of the simple solutions! I'd been wracking my po' little brain trying to figure out an easy way to do that. Drain the tank and test the fuel pump throughput at the same time - two birds and all that.


J K Chapin

RE: Tickler Pins -

Just curious - Do the carbs on TDs (H-2 or H-4) not have a spring on the tickler to keep it up against the float bowl lid? The ticklers on the SU H-4 carbs on my '55 TF-1500 are spring loaded so they don't rise and fall with the float. They only touch the float when I push them down which pushes against the float and lowers it to open the needle and allow fuel into the bowl.

Joe Curto's carb pics:


Dave Dubois tickler w/spring, circlip, washer, and gasket ...

LM Cook

Lonnie, see my new thread "Tickler Pin." I think the lack of a spring (or a weak spring) to do exactly what you say is why PO pushed on the piece of rubber tubing on the rear flaot bowl tickler pin. Jud

J K Chapin

When working with gasoline, be careful. Years ago, someone in the Orlando(?) club was using an SU pump to drain something and the points sparking started a nasty fire. If you use the pump, do it in a well ventilated area, and even better, find someone to help you that is well versed in safety precautions dealing with gasoline to avoid explosion/fire.
George Butz

I thank every one so much for your help. I live in Orange County. I checked the fuel going to the back carburetor and it delivered a pint of fuel in 45-50 seconds. I have an early TD and my car does not have tickler pins. However, I have some good news.

I took my car out on the freeway tonight and when I got off I barely made it home. It nearly died on every stop and struggled accelerating afterward. When I got home I remembered one area I wanted to check, the air filter. My unit is a solid unit consisting of the cover, the body, and a wire mesh filter inside, all in one piece. There has always been fluid dripping from it and at the bottom of the unit it screws onto.

I took the air filter off and went for a drive and it ran great. I took it to a course I like where there are areas where the car always dies or has trouble accelerating and it ran fine all the way. True it was a little cooler later in the evening but it was a huge change only a few minutes after having a lot of trouble. Is there a way to clean this model of air cleaner?
fwa Fred Abel

If it is a standard TD air cleaner it is an oil bath type made by AC and the mesh section can be cleaned with some carb cleaner, brake cleaner, solvent etc. There should be a round trough of engine oil in the lower section. This might be overfilled and restricting the air flow. There is a mark on the body of the cleaner for the correct level. I think sometimes they over fill themselves from what comes out the crankcase breather tube.
John Quilter (TD8986)

Besides overfilling, the top/lid can get bent and squeezed downward over time, choking off the air supply. I think (been a long time) there are support legs on the bottom that can also get bent, causing the whole top to be too low, also choking off air. The top should be convex/rounded, except for the recess where the wingnut goes. George
George Butz

Was the mesh filter element totally blocked with "crud" ???? How deep was the oil in the bottom??
John is correct about being overfilled,, seems like that would be the only reason for it to drip out of the bottom.
Steve Wincze

I found a good drawing of an air filter showing the correct level of oil in the bottom,,

Steve Wincze

Steve's cutaway shows what the top is supposed to look like, you can see if it is flattened/squashed it closes off the air supply. This would make it run very rich, which would be worse when hot. George
George Butz

The gap is supposed to be 1/2". See Malcolm Green's book. The legs can be easily straightened, as George suggests, thus increasing the gap & airflow. Cheers
Peter TD 5801
P Hehir

I cleaned and serviced the air filter. All the work has made my car run pretty good now but I still have the problem that if I have to idle through a long stop light the car will die. If I do make it through the light, it will sputter a bit until the car gets going again. I suspect this is vaper locking.

I've always had trouble after driving in the heat, then stopping say at the grocery store, trying to restart the car to drive home. Any time trying to restart after driving in the heat has always been a problem. However, this problem of dying while idling just started in the last year. My mechanic, who has now retired, told me he adjusted the carburetors in one of my last services but I don't know if this is related.

In a Yahoo search I saw an archived thread on carburator shields and saw this picture by Dave Braun. I felt behind my carburetors and the forward carburetor seems almost against the exhaust manifold. The following was the comment... "Heat shields are fine, and they work,,,BUT IMHO, first, make sure that your float bowls are rotated enough so that there is distance between the bowls and the exhaust manifold as shown in the picture below."

My question is what is involved in rotating the float bowls. Thanks.

fwa Fred Abel

I would suggest a tune up,,,,It is not going to get vapor lock as long as it is running,,, the dieing at idle is not vapor lock! It must be in the carbie tune up that you had done at some unknown mileage ago,, maybe it is just set too low,, maybe it is set too rich or too lean,, but it is not vapor lock when the car is running and then dies,,,,,
Have you tried to raise the idle speed???? What is it set at now??
Steve Wincze

Thank you Steve, and everyone else. I will make adjustments on the carburetors and post the results. I have thought the mixture is too rich. I also just noticed the cover on my voltage regulator is cracked in half.
F W Abel

Fred it's very simple to "rotate the float bowl". Just loosen the bolt that secures the bowl to the body, reposiition it & retighten the bolt. I've also read that keeping the bowls near to vertical is desirable but looking at Dave's pic it's difficult to see how that could be achieved. Both Horst Schach & Malcolm Green discuss heat shields (though from what you say in your first post vapour lock does not seem to be your problem.) Their restoration guides are well worth getting. Cheers
Peter TD 5801.
P Hehir

So far I have cleaned and serviced the air cleaner, and changed the points and plugs. The last time the choke was adjusted the knob was about an inch back from the dash so I loosened the nut and let all the slack out of the cable hoping it was holding the choke open. This made the car run very rough and I barely made it home. I reduced the idle on the carburetors and it made the car run better.

Next I cleaned the plugs (they were very black) and changed the spark plug wires. I went for a drive and the spark plug wires made a huge difference, but when I would stop and idle (on a hill to roll start), I would eventually start smelling gas and the engine would start to falter and die.

Does the fact there is the smell of gas before the car dies indicate anything. I don't know at this point if a new coil might be a next step or if I should look for help with the timing and carburetors. My mechanic retired a few months ago or I would have gone to him for help already. Thanks.
fwa Fred Abel

Two things I would consider:

1) as a test, on your carbs, remove washer #33 (Moss diagram). Many of these washers sold with rebuild kits over the years were too thick and result in an overrich condition (seeing your plugs are black suggests this possibility).

Here's the Moss diagram

If running without #33 solves the problem, you can either just continue doing that (which is what I am doing) or order a new washer and have it measured; it should be 0.016 thick; some apparently were sold that were twice this thickness.

This suggestion by my local MG expert solved my rich running problems and the car has been fine ever since.

2) replace your air intake with twin pancake filters, they will let the engine breathe much better

Here's a cutnpaste provided by LM Cook from an article about the washers:
I found information about the copper washers, plus some other related information on the Jaguar Clubs of North America web site. "SU Carburetor Tips" By Jim Taylor.

Selected portions of the article. Read the complete section in the link for details.

On the H series carbs the upper jet bearing copper washer is supposed to be 0.016" thick. Many after market kits have this washer 0.025" or even 0.033" thick. This holds the complete jet assembly down farther away from the needle than intended and defeats about 1/2 turn of the mixture adjustment nut (ability to lean out).
Geoffrey M Baker

This thread was discussed between 01/08/2014 and 14/08/2014

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