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MG TD TF 1500 - fuel pump

The BBS has been such a great source of help and experience that I hope I can now get some more advice. My fuel pump is ticking over about once a second on idle speed. I rebuilt it with a new diaphram and points and a than adjusted it according to the shop manual. I was suspicious that I had an air lock in it since I've never had more than a gallon of gas in the tank. I assumed that the unprimed pump was stuggling to lift the fuel the needed 2-3 feet. The valves don't look particularly worn and I did lap them. The voltage at the terminal is 12 and the ground is good. Yesterday I filled up the tank and it still clicks rapidly. Unfortunately the sender unit leaked severely so I had to empty the gas tank quickly. I've sealed that up with gasket sealer but have not filled the tank again yet. Before I pull the pump apart again or give up and buy a new one, do you have any advice?
Russ Oakley

Russ,

I think 1 pulse per second is about OK.

However your diagnosis doesn't necessarily point to the fuel pump as the likely problem.

It sounds to me like you have may have put a new seal in the gas cap. Many folks look at the puny cork seal in it, and replace that with "something better" like Buna N, Viton or some other material less impervious to gasoline.

But the "puny cork seal" has a purpose. It SHOULD leak, otherwise you'll build up a vacuum in the fuel tank and the pump will not be able to pump (actually draw) against it, resilting in starvation. Its also damn hard on the pump.

Air enters the system ONLY via the gas cap, so don't seal it up!

Gord Clark
Rockburn, Qué.
Gordon A. Clark

Gordon, I didn't mess with the cap. I have what seems to be a more common problem, a leaking sender unit. The archives are full of expletives with trying to get this thing to seal. Yesterday I milled the surfaces flat. Replaced the gaskets with new Moss neoprene gaskets and sealed it with gas resistant permatex hard gasket maker and it still leaks like a seive. I an going to try to tighten the screws but I am pessimistic that will work. Any ideas.
Russ Oakley

I use GASIOLA and have had NO problem atoll. I think that's the name of it. I'm on restricte OXY reight now so will have to wait till tomorow to check.
Greg & Grimm
G.J. Cenzer

Russ...I had to remove my sender when I had the tank sealed...had read tons in the archives about leaks. I got a sheet of gasket material from an auto supply and cut it to fit...used a gasket sealer, then went around and around tightening up the screws a very little at a time...had read that it was easy to warp. I must have tightened each bolt a dozen times...could hardly feel any resistance with each turn, but that (or my luck) seemed to have done it...haven't seen any leaks.
gordon lawson - TD 27667

I agree with C.J. Cenzer...use Gasoila as the gasket sealer. It's used in the underground fuel tanks as a pipe sealant.

http://www.gsasupplyco.com/liquidsealants.html
Gene Gillam

Hi Russ, what happens when you switch the ignition on with the engine not running?

The pump should fill the carbies and then stop. If it keeps ticking there is a problem with the pump.

Cheers,

Paul.
Paul van Gool

The pump clicks with the engine off.
Russ Oakley

Where can you buy gasiola?
Russ Oakley

Abingdon Spares has correct,precision-fitting, non-dissolving sender gaskets for the sender to tank, sender back plate to sender, and the terminal stud. They are stiff and green, and don't leak. My last experience with the Moss rubber ones was that they would turn into Jello in a few weeks- that was a couple years ago. Contact David DuBois about your pump/and/or search archives for his info. I don't think the shop manual adjustment proceedure is just right. Also, make sure the flange is not warped on the sender (the screws spring it in at the screw holes) George
George Butz

I have had all kind of problems with leaking pumps and Dave Dubois sent me some Burlen fuel gaskets and cured the problem. I had major trouble with the MM gaskets which disintergrated into gooey mess. 3 times!
Did you give the pump the old "suck and blow" test to see if the valves were sealing. If not the pump will run very erratic.
I am convinced that most of the leak problems are related to the summer formula additives or the use of Stabil.
Colin Stafford

Russ, this is one of those subjects with lots of threads in the archives. Search for 'fuel pump tap..tap', or something like that. With the engine not running, the time between ticks should be almost measured with your watch's minute hand.
Bud Krueger

I bought one of those packages of assorted and used the one marked for "oil and gas"... black rubber type stuff.
(Noticed at idle that my fuel pump ticks every 3 or 4 seconds).
gordon lawson - TD 27667

This thread was discussed between 01/06/2006 and 02/06/2006

MG TD TF 1500 index

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