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MG MGB Technical - facet fuel pump problem

Car was running fine with newly installed facet solid state fuel pump.

Then the pump stopped working. I could not hear it when the ignition was turned on.

I ran a new wire from the ignition directly to the pump and it now workd.

But ...

the car tries to start then dies immediately.

Any ideas?


PS I'm a novice.
L vanderfeen

There are only two thing that will keep a Facet pump from chattering away - power and ground. You have run a new power lead to the pump, now try a new ground lead. See the article Electrical Connection Preparation in the Other Tech Articles section of my web site at:
Note: a clogged inlet or outlet side of a Facet pump will not stop it from running. Cheers - Dave
David DuBois

Thanks for the quick reply David. I shall certainly check the ground lead. However, I also ran the pump using an emergency car starting battery pack but had the same problem.

When I first checked the pump, it had less than 10V, so I changed the supply. It now has 12V or more.

Tomorrow IŽll also disconnect the outlet fuel pipe to see if it is pumping fuel. Though I donŽt really know the rate it should pump at.

The documentation that came with the US pump said to connect it to the oil pressure guage, but I connectged it to the ignition directly, as per the 197 Haynes manual wiring diagram.

Thanks for your help.
L vanderfeen

The OE Su fuel pump would pump 18 gallons per hour or 2.4 pints per minute. Cheers - Dave
David DuBois

I disconnected the fuel pipe to the carbs and ran the pump. Seemed to pump fast, around the 2.4 pints per minute mark.

So it looks like the pump is fine.

Car revs to around 3000 on ignition with accelerator and medium choke, then immediately dies.

Must be a coincidental problem I imagine.

Air is in the fuel filter but I think that might be normal.

Car was running fine before the pump problem.
L vanderfeen

Air in the filter is normal - it will completely fill with fuel after running somewhere around 24 hours straight. If the pump is actually dying - no clicking at all, I would say that you have a defective pump. I call the Facet pumps, little square, run all the time, make a lot of noise pumps. Unlike the SU pumps, the Facet pumps have an internal bypass valve, so the chatter away all the time - it they aren't doing that (and have good power and ground) then they are defective. The Facet pump is an electromechanical device like all electric/electronic pumps and as such can die anytime, anywhere and usually at the most inopportune time. This is not to say that they are not a good pump, they usually last for a good long time - up to 100,000 miles. Cheers - Dave
David DuBois

Thanks for your help David. I am pretty sure the pump is OK after testing the outlet and comparing it with your flow rate.

I supposse I need to start another thread to try to sort out the other problem.

On another website I saw that the choke not closing can cause the engine to die immediately after ignition but it looks OK. I don't want to mess around with twin carbs so I'll probably have to call out the garage.
L vanderfeen

"then immediately dies"

What does the tach do? Drop to zero immediately the engine starts to slow down? Or drop slowly with the revs? A sudden and complete dying sounds more like ignition to me, unless the pump has completely failed, the carbs are empty and it won't restart. That's one of the beauties of the SU pump, if you get a fault like this, turn off the ignition, then turn it on again subsequently and the pump chatters away like billy-oh you know the carbs were empty, for what ever reason. If it only clicks a couple of times the carbs are full so the cutting-out was for some reason other than no fuel in the carbs.
PaulH Solihull

This thread was discussed between 27/05/2012 and 29/05/2012

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