Fuel Pump problems

[Schuey9]

I have a fuel pump problem, this has given rise for some questions from the learned masses. I can hear the pump priming but do not get any fuel at the fuel rail. I have checked this by depressing the Schrader valve and no fuel comes out when cranking?

I have the pump off the car and cleaned the debris of rubber from a collapsed feed pipe from the tank! When connected to a battery it runs quite nicely but I cant get it to pump any fuel, any ideas why?


Connected to the fuel pump bracket is a small electrical component, on the yellow wire. What is this?

[Belle427]

That device is a suppressor, i think its used for both noise suppression and to reduce any arcing on the motor.
are you sure the filter isnt now blocked with debris?

[Schuey9]

Good point, although the pump has a fine mesh on the inlet.

Will take a look at the post pump filter though as a precaution.

Thank you for your reply

[Belle427]

You could also try pumping into a clean bucket see what the flow is like.

[Belle427]

The outcome of this may be of some interest too.

https://www.pistonheads.com/gassing/topic.asp?h=0&...

[Steve_D]

Schuey9 said:

...........I have the pump off the car and cleaned the debris of rubber from a collapsed feed pipe from the tank! When connected to a battery it runs quite nicely but I cant get it to pump any fuel, any ideas why?..............

Is this test while still on the bench?
If so then quite likely the pump is FUBAR.
The pump rotor has blades in slots so when running the blades are flung out against the pump housing forming a seal.
Two things can happen.

• The blades jam in rusted slots and fail to make a seal.
• Debris jams them in the slots.
• Debris gets between the blade and the pump housing.

In all of this the pump makes all the right noises whilst trying to fool you into thinking all is well.

It is not possible to strip the pump but sometimes they can be brought back to life by running them backwards. or giving them a bit of a clout whilst running.
Having said that would you really want to rely on something that has failed once.

Steve

[QBee]

I have a spare, known working, used TVR fuel pump you can try if you want.
It has done 95,000+ miles, but was working fine when I upgraded to a Bosch 044 pump.
My reason for an upgrade was to be able to handle the necessary flow for 400 bhp.
Let me know.....

[Schuey9]

Thanks all.
Pump is definitely FUBAR. I am guessing some of the rubber hose has lodged itself in there as it is now seized again. I have had it running off the car but it does not pump fluid.

I stripped my original Lucas pump apart to see the workings and now understand. The pump mechanism is fairly small with most of the aluminium tube taken up with the rotor and stator of the electric motor.


I have a new pump now and am going to fit it but am wondering if any of the rubber may have got past the pump and into the filter?


Schuey

[Steve_D]

It will take only one tiny piece to jam a pump. It will take quite a lot of ste to block a large fuel filter.

Steve

[Schuey9]

OK Guys,

Thanks again for all the help and steerage.

The new pump has been fitted and...……………………………….Vroom all is good. Now to do quick test drive and MOT.

Happy days are here again

Schuey