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MG TD TF 1500 - Fuel pump...tap,tap,tap

Driving last night, my car coughed to a stop...opened the bonnet and tapped the fuel pump with my hand.... click, click, click, etc. All was well for the rest of the drive.
The pump was a new rebuilt (?) from ebay last summer. Is this something that can be fixed by cleaning the points, or is it deeper?
gordon lawson - TD 27667

Gord,
It could be some grit or corrosion on the points,, a bit of cleaning might help,,, My brand new pump didn't work, and it was caused by just a little bit corosion on the points from sitting on the shelf,,,,
SPW

Steve Wincze

Hi Gordon,

I have been very fortunate all my life with hardly any fuel pump problems.

When they did occur I just fitted an Burlen Service overhaul kit which is easy to do. After that no more trouble.
Bas

Gordon - A real good cleaning of the points is in order. One of the big problems with the pumps that have points is that, left unused for long periods of time, the tungsten contacts will develop a film that is insulating and will stop the pump from running. Cleaning the points with fine (400 grit) sand paper and solvent should get the pump running properly. The other problem that arrises occasionally is that the points stick together due to excessive wear and arcing. If this is the problem, the best approach is replacement of the points. I would not suspect this as the problem if the pump was recently rebuilt. Finally, if the diaphragm and points were not properly adjusted the toggle may not be throwing over the way it should. To adjust the points, the uper adjustment tang should be bent one way or the other until the upper points are raised 0.035" (measured just under the end of the spring blade) above the pedestal when the points close. With the toggle in the same raised position, the lower adjustment tank should be 0.070 - 0.090" above the top of the coil housing. After these adjustments are made, and if there is still a problem of the toggle not throwing over, the coil housing will have to be removed fromt he pump body (messy, with fuel spilling out all over your nicely painted firewall) and with stationary points either removed or propped up so they don't touch the lower points, the diaphragm is screwed in until the lower points will no longer throw over when the diahragm is pressed all the way in. The diaphragm is then unscrewed, one screw hole at a time until the points just throw over, then a further 4 screw holes. Reinstall the upper points or remove the toothpick propping the up and reassemble the pump (don't worry about streatching the diaphragm as the book says, that is no longer done). Your pump should work fine at that point. If not, sen it to me. Good luck - Dave
David DuBois

In my experience the actions mentioned by David are best done with the pump removed and taken to a comfortable clean workbench. Not on the car.
Bas

Bas is correct, everything is easier on the bench than it is on the car. Dave
David DuBois

Tap. Tap..... . With key on engine off how long of an interval is recomended between tap, tap. What are the items to check after the float neelde/ seat is ok? I can think of the check valves, & base gasket, any other areas to check? I,m helping a friend when time permits, his taps about every 5-8 sec. Mine is > 2 minutes
Len Fanelli

Gordon
I always carry a piece of emery cloth in the tool box, for just this occasion. You can even use it on the distributor points to get you home. To Baz very few of the fuel pumps break down on the work bench, it is usually on the road and needs immediate attention. So carry a little piece of emery cloth, you never know when you will need it. John
John C. Hambleton III

Thanks all... just finished 120 mile run yesterday in the pouring rain ( http://www.niagarabritishcarclub.org/events.html ) and have not had a problem since i "tapped" it that one time. Have my emery cloth and paper match book at the ready.... (a paper match book cover is the right gap for the points, so cleans them nicely....)
gordon lawson - TD 27667

Len - Check your e-mail. Dave
David DuBois

David DB - As my tap......tap..... tap..... is the same as Lens's friend (once every 5 or so seconds) I would also be interested in your reply.
No obvious leaks, all seals (cork) replaced. Perhaps grose jets are the answer? Has.

HJ Oldham

One must differentiate between the 'tap, tap' of someone tapping upon the pump to get it going, as happened to gordon to begin this thread, and the resultant 'tick, tick, tick' when it's running. I'm in Len's group with the (engine not running) 'tick, tick' being timed via the minute hand, rather than the second hand. I've been led to believe that quick ticks are apt to be from leaky fuel pump valves if the carburetor needle valves are good.
Bud Krueger

Thanks Bud... i was going to post the "tick" vs "tap" difference. Mine wasn't "ticking" so i "tapped" it. Think mine goes "tick" about once a minute...not sure if i can hear it that well with my muffler as loud as it is......?
gordon lawson - TD 27667

Rapid ticking when the engine is not running can be caused by 1) a leak on the lutlet side of the pump or the carbs, including a needle valve not shutting properly or a flooded float; 2) an air leak on the inlet side of the pump at any one of the joints from the gas tank to the pump; 3) valve disks in the pump that are excessively worn or the seats that are damaged; 4) leaky diaphragm or a leaky gasket between the diaphragm and the sandwich plate or the gasket between the sandwich plate and the pump body. Normally, if you don't see any gas leaking anywhere and the pump has a lot of miles on it, the problem is going to be the valve disks.

For those of you whose pumps tick once a minute without the engine running, congratulations, that is about as good as it gets. Gordon, if your pump only ticks once a minute with the engine idling, you car is eligable for an environmental award, it is using less gas than a hybrid.

For those of you whose pumps are ticking once every 5 seconds with the enngine off, if everything is running well, I probably wouldn't worry about it. You probably have worn valve disks in the pump, but if everything is working, don't fix what aint broke bad. Just be aware that your pump will probably need to be overhauled sometime in the not too distant future. Has - If you don't see gas leaking from the carbs, then the needle valve is ok and you just have worn valve disks.
Cheers - Dave
David DuBois

I was a novice mechanic at a BMC dealer in the '60's & as i remembered 5 sec or so was ok but not the best, not to worry until it worsened, (as long as the needle & seat were not leaking). I did not get reinvolved with LBC'S again till '98 0r so. At this time my pump was at the 5 or so second engine off tick, tick, i inspected the needles, seats, & check valves , to no avail. Car ran fine, then one day it would not start, found a internal leak at the fuel pump body gasket, #377-100 in the Moss book. This is what prompted my query, as i was wondering if i was overlooking something. My tick . tick key on engine off is now over 2 minutes, i did not wait longer as i was afraid to damage the pertronix ignition, ( key on, engine off). Tomorrow i will check engine running time between ticks, with a stop watch. (Again the issue is with a friends car). Thanks again to Dave & the others on this BBS.
Len Fanelli

Len,
You won't hurt the Pertronix, or any other electronic trigger system - they depend on movement of the dist cam to trigger the spark. Points will run power through the coil if they happen to be closed when the engine is OFF w/ key ON.
FRM
FR Millmore

Just a comment to Len and some others ------ The ammeter
will show a tick--tick deflection for each pulse of the fuel pump. In fact that is one of the complaints about the Lucas regulator, it does not smooth these out ( the needle gets to swinging back and forth so much that it's hard to tell what's happening).

Bob
R. K. (Bob) Jeffers

This thread was discussed between 16/07/2005 and 20/07/2005

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