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MG MGB Technical - New fuel pump; no ticking, no pumping

I installed a brand new SU fuel pump in my 67 MGB today and it doesn't work! It's a pump that I bought about 4 years ago as a spare and kept in the car. I removed the existing pump to work on it and keep that one as a spare. I checked that I had power and ground to the new pump which it has. I tapped it a couple of times in case the contacts were frozen but no life at all. It's the correct pump for the car with the outlets that are side by side.

Any ideas where to start with the checking.

Many thanks again,

Andy
Andrew Preston

Once again, Dave's website. The points oxidise when not used and need to be cleaned. New points are easy, I use a 1/4" wide strip of 600 wet or dry silicon carbide paper, then plain paper with Brakleen or lacquer thinner to remove any debris.

FRM
FR Millmore

Andy - Following Fletcher's recommendation should get the pump going (unless it is an all electronic pump). I am going to add one thing - DO NOT use a points style pump as a backup. Points style pumps do not like to sit idle for long periods of time and will usually not work when you need them to. See the article, Backup Fuel Pump in the SU Fuel Pump Articles section of my web site at: http://homepages.donobi.net/sufuelpumps/ This article tells how to put a permanently installed back up pump in the car, using a cheap Facet pump and controlling the two pumps with a single pole double through switch. This installation, besides installing a non points style pump that can be switched in without having to so much as get out of the car if the primary pump fails. Cheers - Dave
David DuBois

A sleepy SU fuel pump can often be awakened doing this:

Get yourself a length of 1/2" wooden dowel or broom handle
(8" - 12")

Butt one end of the dowel up against the metal body of the fuel
pump (- NOT the plastic cap! NOT the aluminum casting where
the fuel unions connect! ) .

Switch the fuel pump on.

Get a light hammer (I use an auto body hammer) - and tap the
other end of the dowel VERY sharply. Don't be bashful or shy
about this - but don't be brutal or damaging, either.

It takes anywhere from 2, to a dozen or so hits to get things
going. Basically, you want to rattle the points loose from their
frozen state.

Listen for the points ticking/pumping.

If this doesn't work, then an inspection of the points is in order.
Daniel Wong

David Dubois, What a great site you have, where I procured the back-up-fuel pump story. Right I am off to get a spare, Facet you say? I have never embarked on a really long trip for fear of something going wrong, and as the fuel pump is the only item that is probably still original , ( could it be 38 years old? )Your back up plan sounds great what a great weekend project. Thanks Mike
J.M. Doust

Mike,

Also make sure your license plate it tight. At least on the US models, that is where the pump gets the ground. Experience tells me that it can ground enough to light a test lamp but not enough to run the pump reliably.

Charley
C R Huff

Dave many thanks for you help off line. The first time I cleaned the points I used 400 wet/dry and thought they were clean enough. They weren't and after contacting you scrubbed them shinning bright by removing them from the pump and also cleaned the points in the housing as you suggested. The pump started working immediately and now is in the car and ready for another 40 years.

Thanks to everyone who helped and the points need to be shinning silver clean.

Andy
Andrew Preston

For others and future reference if it is a license plate earth that is the problem (or a bad connection in the 12v circuit) testing the voltage between the 12v and earth terminals of the pump with the ignition on will show zero volts, showing you it is a supply problem, not a pump problem.
PaulH Solihull

I must admit, finding out about the earth/ground at the license plate was a bit of a surprise. I never would have guessed on using the license plate or the bumper for a ground. As I recall I have a ground wire going to the right rear bumper guard too. A loose bumper guard = a loose ground.

When I replaced my fuel pump (pointless - all electric) I grounded it near the pump. But then I'm definetly not trying to maintain an authentic MG, just a daily driver.

P.S. I originally had one of those little brass block fuel pumps, mounted next to heater motor; so it was prone to heat issues. I bought an after market pump and moved it back by tank where it can push instead of pull fuel. I kept the brass block in my parts bag in trunk, as back up for others more than for myself, right there with the other stuff for others like points (I went pointless), cap, rotors, thermostat, wires, tape, wire clothes hangers, etc.
R.W Anderson

This thread was discussed between 22/08/2011 and 25/08/2011

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