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MG MGB Technical - Which Fuel Pump?

I'm helping a colleague get their 1969 MGB GT back on the road and having tried unsuccessfully to start it, we have come to the conclusion that the fuel pump is dead.

Engine's turning, getting a spark, but it doesn't look as there is any fuel going in.

Firstly what is the best way to check whether a fuel pump works or not and secondly,which pump will it need?

Cheers

DJ
DJ

The fuel pump is located near the driver's side rear wheel (UK), passenger's side (North America) in front of the battery box. A silent SU fuel pump is a bad thing, assuming you still have the original style pump. Check that there's power to the pump; you should have 2 wires going to it. If there is power, but no audible clicking with the ignition turned on, give it a good smack with a big screwdriver. Sometimes that is enough to free the points, especially if the car has been sitting for awhile. If that doesn't make it click, then you have a few options; replace the points or diode, purchase a new SU fuel pump (solid state model or points/diode model) which are available and reasonably priced, or purchase one of the small box type electric fuel pumps. Since SU fuel pumps are only supposed to deliver between 1.5 - 3.0 psi, not all pumps will work properly. My preference would be a new solid state SU pump. The small box types are readily available, but they are noisy and click all the time.
Check your fuel filter(s). If totally blocked, they can stop the fuel for getting through. If your are getting lots of clicking, but little or no fuel, then the diaphragm might be ripped or torn, hence not providing adequate pressure.
That should be a good start to diagnosing your troubles. I'm sure I've missed a couple of things to check, but others will add to this as required.
SteveO

Steve

Thanks for that, the lack of clicking made us reach this conclusion, so thanks for confirming it, we'll try the smack with a screw driver and see what happens otherwise its a new one then.

DJ
DJ

It's dead easy to see if the pump is working. Disconnect the petrol feed to the rear carb and put the pipe end into a jar. Briefly switch on the ignition. Fuel should pour out of the open pipe. If it doesn't, pump not pumping (likely) or totally blocked filter (unlikely), if there is a filter. My '71 has no fuel filter. Before you bin the pump, check the earthing wire and use a multimeter to check the power feed. It could be that simple.
Mike
Mike Howlett

If you can't get your existing pump to go and have to replace it, I wouldn't bother with the SU pumps unless you're going for originality. Personally I'd save some cash and obtain the compatible "Moprod" object. It's cheap, it's plastic (waterproof, corrosion proof), it's sealed-for-life, it's solid-state, it's a perfect fit and it won't go wrong. I've had one of these for some years now and I'm amazed that more people don't use them given how much cheaper and more reliable than the SU they are. Oh, it even makes the right "ticking" noise as well. If you want the "Moprod" part no. let me know. I've still got the box on a shelf somewhere, full of U/S SU.
Tim Cuthill

Tim,, tell me more about the Moprod fuel pump. Will it work in a 67 pos earth GT converted to neg earth. Cheap is what I am after rather than original along with reliability. Mine is working fine but want a spare for that moment it stops ticking. And is it available in the states?
Curt

The problem with the Moprod pumps is that, being plastic, they will eventually start cracking around the inlet/outlet fittings. Until then, they work quite well, but once the cracks show up, the only thing to do with them is throw them away. You should also check the output pressure. One that a friend got for a T series car had an output pressure about 3 times the rated pressure.
Good luck - Dave
David DuBois

Moprod pumps break down and leak fuel quite quickly - don't waste your money on them or the Facet pumps either - just go and buy a new SU pump and it will give years of good service.
Chris Betson

Hi chaps, I've just mograted over from the "Help my car died" thread. Have worked out that it was the fuel pump after reading this thread. A sharp tap and it worked again, then died again. Another sharp tap or two and it worked again. Clearly on the way out.

Question - how long can it be expected to last? I need to get the car back to the UK as I have no proper garage facilities, and I have no idea where to find parts here. However, something tells me that getting a new one may be wise before the 500 mile trip home from Belgium...
S R Ellawala

Can't say I've had a problem with mine and my father has had one on his midget for 10 years plus with no issues. Maybe somebody's been unlucky.
In answer to an earlier query, the Moprod pumps, being plastic, do no earth through the pump body. Instead they have two leads emerging from the end, a live feed and an earth. As a result they will work on both +ve and -ve earth cars. I've no idea whether they're available "across the pond", although Moss stock them, so it's entirely possible.
Tim Cuthill

This thread was discussed between 31/07/2002 and 02/08/2002

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