Welcome to our resource for MG Car Information.



MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - Fuel pump upgrade transistor, or diode?

To extend the life of the (double) fuel pump points, which is better? To transistorize, or a diode, with the stepped cover? I have found 3 upgrades listed on the net one with this site,; one with Jag lovers . org. by our own Mr. DuBois, & one in this archive (TD TF archive). 2 advise transistors, 1 describes the O.E.M. diode as in the MGB. (Positive ground TD} Len
Len Fanelli

Len - I have to vote against the transistorization as described on the Jag Lovers site. That is an article I wrote some 25 years ago and it has a problem with it, in that the resistor in the base circuit will cause the pump to operate very slowleyor not at all. If you wnat to go with a transistor, replace the resistor with a straight piece of wire. You will probably get just as good service from the diode as you will from the transistor as long as the swamping resistor in the coil housing is intact (they usually are in the LP pumps). The transistor circuit works well except that there is not enough current through the base circuit to keep the film that develops on the contacts of the points burned off. This is expecially true on a car that is not driven frequently or one that is laid up over winter. If you haven't seen the write up on what I am now doing with the pumps when I restore them, you can see it at:
This is a generic article on SU fuel pumps as a whole and at the end is a link to the write up of my SU fuel pump services, in which I describe the use of a magnetic reed switch and magnet to trigger the transistor, thus doing away with the open points and the problem of the contacts filming over.

If you decide to go with the diode, drop me a e-mail as I have several of the positive ground diodes that I have salvaged out of MGB pumps that I have convertred to solid state. I will send you one to do your mod. Cheers - Dave
David DuBois

This thread was discussed on 11/05/2005

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.