MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - Fuel Pump Problem?

My TD usually starts right up (with a little choke) when cold, and after that starts and runs fine without choke after it is warm. The past several days I noted the fuel pimp clicking excessively fast on the initial start, but no problems on start. Today, after running a few miles while warmed up, it wouldn't start cleanly after being shut down 10 -15 minutes, without adding some choke. I drove it home, shut it down, and same thing on re-start. Starts and dies without choke, and misses and runs rough when pedal is applied with the choke off. In about 30 seconds all seems fine. Also, the idle does not seem as smooth as before when warm. Does this sound like a fuel pump issue, or something else? Any input appreciated.

Larry
L Karpman

Larry, see if you have any fuel running overboard from the carburetors. The float valve may be stuck. YOu might have to pull the lids off the bowls to check the valves.
Jim Merz

Larry, how warm is it out? Having to choke the carbs slightly is commmon on restart when the fuel is warmed from engine heat and on the verge of vapor lock. If the mixtures are set correctly (as opposed to being rich) this problem is more pronounced. Solutions I've used in the past is to park with my LH bonnet open to dissapate heat. Once restarted, cool fuel running into the float bowls takes care of the problem. You may have a slight exhaust leak between the manifold and the down pipe. The most typical leak is a blown exhaust pipe gasket. Make sure you have bronze nuts on the manifold studs for easy removal in the future.

On my rebuild I installed a jet-hot treated exhaust manifold to reduce under bonnet temperatures.

warmly,
dave
Dave Braun

OK, thanks guys. Temps today in the mid 70's (F) so it may be some sort of a VooDoo spell the "Northerners" have cast upon me for being able to drive the TD in such fine weather :-). I made one more check, and so far the problem seems like this:

Shut down for 30 mins or more. No issues on start.

Shut down for 5 mins or less. No issues on start.

Shut down 10 -20 mins. Need to use choke, and an application of pedal leads to rough running. All OK in less than 1 minute.

I see no fuel overflow, so Dave's "on the verge of vapor lock" suggestion seems quite popssible.

Larry
L Karpman

That makes it sound just like mine... 10 minutes seems to be the culprit!
gblawson - TD#27667

Larry - Sounds very much like a vapor lock problem in the channel between the float bowl and the carburetor (the usual place for a vapor lock). If you still have the tickler pins in your float bowl lids, try pushing the pins after the 10 - 20 minute soak period and see if you get a little spurt of gas out beside the pin, if so you have cleared the vapor lock, although if you are just at the inseption of vapor lock as Dave B. suggests, that may not happen. I will send you an article I wrote some time ago on how to modify a heat shield ffor a Mini to fit the TD. The other thing to check is the angle of the slats in your radiator grill. They should be angled such that one can see the radiator quite easily through the grill. This wil keep the engine compartment much cooler. Cheers - Dave
David DuBois

Thanks Dave! And thanks for send the neat templates for the heat shields too. I'll give the tickler pins a try the next time it happens to see if they spurt fuel.

As for engine temps, the engine runs quite cool. The grille slats look Ok to me, and I can see the radiator, but I'm afraid I don't know what the "correct" angle is supposed to look like, other than mine look pretty much like all the other TD pics I've seen, but certainly not as open as a TF. At operating temp it stays right about the 82-85C mark as I have an 82C thermostat in there now. Of course when Summer arrives, that will be the real test.

As I said earlier, this just started to happen. But then again, I've only owned the car 6 months, and I can't say with a certainty that I have only left it shut down for 10 - 15 minutes before in anything other than cool weather. Could be just a coincidence that I've just noted it now.

BTW, can you explain the fule pump clicks to me? Obviously, after an overnight shutdown, or other long period, it clicks like crazy. After a 5 - 10 minute shut down, no clicks. After 30 minitues, just a few clicks. To click, or not to click, that is the question :-)

Larry
L Karpman

Larry,

Your fuel pump clicks sound like the normal operation to me.

warmly,
dave b
Dave Braun

Thanks Dave. I assumed so too. Just wanted to confirm that the clicks are related to required fuel for start the longer the car sits.

Larry
L Karpman

Larry - Sitting overnight a certain amount of fuel will evaporate out of the float bowls and some of the fuel will drain out of the fuel pump. Therefor the rapid ticking when the ignition is first turned on. This is perfectly normal as long as the ticking come to a stop in a short time. If it coutinues ticking at a rapid rate, you are either out of gas, have a stuck needle valve and are dumping gas on to the ground, or you have developed an air leak on the inlet side of the pump or line. Cheers - Dave
David DuBois

Hi Larry - lot of sound info. above - check out the archives for overheating reasons. Most important of all in my opinion is timing - with modern hot burning fuel the standard static T.D.C. timing as per. the Manual is much too retarded and leads to classic overheating. About 4mm. in advance on the crankshaft pulley from the existing notch seems to work well for me but if still a problem check out the bobweight springs in the distributor to ensure you're getting proper advance at speed. This can be checked with a strobe or a diagnostic machine at a garage around - 25degrees advance at 3000revs.is about right - again lots of info. in the Archives under 'distributor'.

'Water wetter' in the coolant also worked for me although I was sceptical to begin with. We had a hot summer in the UK last year with shade temps. regularly in the mid 80's F and I had no overheating with the car.

Best of luck - just deal with one aspect at a time is my advice but get the static timing right first !

Cheers John.
J.C Mitchell

Dave: Just checked the pump action after sitting all night and it only clicks for about 2 seconds then stops. Car starts fine, so I don't think there's an issue there. I'm going to try the tickler pins later today if it does the vapor lock thing again, and see. Temps today outside should be about the same as yesterday (75F).

JC: thanks for the advice. I don't have an overheating problem, as I said the temps never got over 85C (except for occassional excursions to 90C or so stopped in traffic on a warm day or after a long highway run). This, of course, since I put a new thermostat in 3 months ago. That said, you are correct about timing affecting running temperatures. Of course the real test will come this Summer :-)

As for Water Wetter, I have used in all my Jaguars with good results here in the Texas heat, and have it in the TD.

Larry
L Karpman

Larry,
Do check the archives from this BBS on Vapor Lock and Operating Temperature.
I had quite a problem with this on my TF years ago and got some excellent advise from the board on the subject.
In a nutshell ...couple things I learned:
Until you get it figured out...go the the drug store and get a couple of "cold packs" ...next time she won't start "snap" one of these and hold it against the carbs for a few mins. If the car fires right up after you do this, good chance you do have a vapor lock problem! (this is much cheaper that the method I was using...i.e. call for roll-back, only to have the car start right up once I got it home because it had cooled down by then!)
Now ...here I go on my little soap box again!!! (the disclaimer) I do not work for Jet-Hot....but still feel it is the smartest $100. I ever spent on the TF ...as well as several other cars that were notorious for overheating!
http://www.ttalk.info/picture_this.htm#JetHot%20coated%20manifold
Cheers,
David 55 TF1500 #7427
David Sheward

Thanks Dave. Never head of that one before :-) Guess I'll store that one away in my files. I may have a vapor lock issue, but really don't feel the car is overheating in the traditional sense. No other signs that it is doing so. Now the manifold heat, as you mention, is another issue and one I'll need to look into.

The car "will" start in the "mystical" 10-20 minute shut down period, but I do have to use a bit of choke and tickling of the pedal. All clears up in 30 seconds or less. As I said, any shut down longer than 20 mins or less than 10 mins seems to be just dandy. Of course that's right now. Only time and waming spring and summer outside temps will tell me for sure I guess :-)

Larry
L Karpman

Larry,
The "cold pack" is a modern version of a little trick I remember my Dad using on his TF (and others). Dad hated doing Parades...but people were always asking because we had "unusual convertibles" and he was a business man selling them. He would buy dry ice back then and pack it in under the bonnet to keep the temp down driving at these slow speeds in the parades! He would also put some in the foot-well to keep us cool! I can remember having cold toes on July 4th when everyone else was sweating bullets!
My did the same that you describe ...as far as bizarre "time slots" that it would or would not start up! I never showed what one would call "classic overheating" (on the gauge), but the car did get to a point where it would lose power as well.
For me to say for sure what "fixed" my problem is hard ..I got so much advise from the BBS, (and was so frustrated), that I did EVERYTHING! The deeper I dug, the more things I found wrong!
My Carbs were a mess, I changed from rubber to stainless fuel hose, I put on larger spacers (between carbs & manifold), I went to pertronix Ignition, I repaired crack I found in exhaust manifold and sent to Jet-Hot, I fixed the broken spring I found on the dizzy advance.
After looking at all that was wrong ...came to the conclusion that those that say these cars are "unreliable" should have seen what I did! I was amazed it ran at all! (see my post in archives for details)
Just looking at the "engineering" of XPAG XPEG engines though the Jet-Hot treatment really made a lot of sense to me. Get the "hot air" out quicker could certainly not hurt...lower operating temp ...a good thing!....added performance welcome.
I know this is a "dirty word" here ...but we also own a TR7 (notorious for overheating & blown head gaskets) and this helped that one and our Opel GT (also known for running "hot")
Cheers,
David 55 TF1500 #7427
David Sheward

This thread was discussed between 25/02/2007 and 26/02/2007

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.