SU fuel pump

[Dave-MI]

Hi everyone. The SU fuel pump in my 1955 series one is only about 6 years old, and was working fine till I parked it about 10 months ago due to a recent move. Yesterday when I went to fire it up the usual "tap tap tap" was not there but instead it went "tap (10 seconds of silence) tap (10 more seconds of silence) etc. etc. etc. I removed the fuel lines from it and everything is dry. There's plenty of fuel (blew through and heard bubbles in tank), and plenty of good voltage. (12.4v) any thoughts? I did do some searching but everything is for the most part about completely dead (no tapping) pumps.

Thanks!

Dave


Sent from my iPad using Tapatalk HD

[bugeye88]

Dave,

If the SU pump is not "tapping" either the pump is junk (which happens with SU pumps, I have first hand experience) or the fuel line, pick up in the tank or the fuel filter is clogged. Try taking the fuel line off the output side of the SU pump and turn it on to see if it is pumping at the outlet of the fuel pump. No output = the above problem. If you replace the pump, I would go with a low pressure solid state pump. There are several to choose from. I use a Facet pump. Good Luck and let us know how you are coming along.
Rob
68 Bugeye88

[leafsprung]

These are a points style pump. Try dressing the points . . . . Should fix you right up.


Dave,

If the SU pump is not "tapping" either the pump is junk (which happens with SU pumps, I have first hand experience) or the fuel line, pick up in the tank or the fuel filter is clogged. Try taking the fuel line off the output side of the SU pump and turn it on to see if it is pumping at the outlet of the fuel pump. No output = the above problem. If you replace the pump, I would go with a low pressure solid state pump. There are several to choose from. I use a Facet pump. Good Luck and let us know how you are coming along.
Rob
68 Bugeye88

[bugeye88]

Hope it does, but I'm still not a big SU pump fan. I've had too many of them give up the ghost in several Brit mobiles, usually at inopportune moments. For this reason I carry an extra in any car still with an SU pump. I'll be curious if "dressing the points" fixes it up.

Cheers,
Rob

[leafsprung]

My su pumps have been wonderful. I have at least three in regular service that are 50 years or older and are still running strong. I pulled a rover out of the brush a few weeks ago that sat for 20 years. Dressed the points and the 64 year old pump is still working well. It's now in daily service and the pump is performing great! They are quiet, reliable, completely rebuild able and they are still being made to this day.

[bugeye88]

To quote George Bush "It's a mirror-kill" I,ve gone through twice that many in 35 years in various British cars. . Just found more modern pumps more reliable. Glad you've had such good luck. As with any pump, it's a good idea to carry a spare, especially on long back country trips. The good thing with a manual/electrical pump combo with Land Rovers is you have a spare already attached.

Cheers,
Rob

[leafsprung]

You can now get the SU in a solid state now from Burlen Fuel Systems if you dont like the points. Im a fan of the points style though. You needn't carry a spare pump, a diapham and a set of points will do. New pumps like facets are not serviceable so when they pack it in they are trash. SU is also nice because you can use all the original hard fuel lines and fittings, no rubber lines and hose clamps or custom hoses and fittings - just plug and play. The newer aftermarket pumps are all negative ground too so unless you insulate the body of the pump, you have to change your polarity. The SU pumps will work positive or negative. I honestly have never had an SU strand me in hundreds of thousands of miles of driving series ones.

[bugeye88]

Whatever fuel pump strikes your fancy..... Always carry a spare(or repair parts) , especially if you do serious off roading. Just common sense. And if you have a mechanical pump with electric pump installed AFTER the mechanical pump, with a on/off in the cab, that is even better as you have a back up available quickly.

Rob
Bugeye88

[Apis Mellifera]

If you've had gas sitting in the pump for many months, it is possible that the diaphragm is gummed up or debris has settled in preventing it from moving. Or if the gas evaporated, the diaphragm might be dried out or otherwise less flexible than it normally should be. Both of these would prevent the pump from cycling properly. Dirty points will cause intermittent loss of continuity. The pump is acting like it's deadheaded, so I'd connect the inlet, prime the pump, and disconnect the outlet side fuel line to see if it is actually pumping.

Finally, while I've had the same SU pump on my MGA for nearing 60 years, I've recently started buying AC Delco pumps spec'ed for an 84 Honda Accord. They click, click,,, click,,, stop just like the SU, are the correct pressure/volume, and are well made.