Fuel Pump Wiring

[dooley1414]

Hi all.... I have a Series 3 V12 2+2.... I am re commissioning and the fuel pump in the boot space was all unplugged and not wired up.... I was just wondering if anybody know which way the wires went. Many Thanks In Advance.... Des.

[MarekH]

Dear Des,

The white wires go to the spade terminals on the end of each pump and the pump body is earthed.

I am currently making an electronic upgrade for these pumps to stop them suffering from points corrosion. I'll post a picture once I am done.

kind regards
Marek

[dooley1414]

Thanks Marek.... that will be most useful.

Des.

[baganz.sven@web.de]

Hi,

do you want to know the Routing of the wires or the wiring of the pump itself?
The wiring is quite easy (I used an autosparks harness) and is quite well shown in the wiring diagram.
(41 is the pump, white + wires). There is no fuse! so I will ad a fuse by myself.
Sven

[MLBS3V12]

Hi,
adding a fuse sounds a good improvment to protect the wiring loom to fuse itself.
What about incorporating an inertia switch? It is an impact switch which would turn the pump off in the event you had an accident ...

Michel

[baganz.sven@web.de]

Hi,

J‘aime le comment:

Le chemin sera long!...

Ce vraiment correct pour un E V12

Sven

[MarekH]

I am making these now.
Price is £20 plus postage.

If your points are getting corroded due to arcing then this should halt that. What it does is use the points only to turn the transistor on and off so the high current switching is electronic.

To fit it, no soldering is required - you simply have to disconnect all of the wiring and reconnect it onto different terminal posts as per the instructions.

For the v12, you'd need two as it has back to back fuel pumps.

kind regards
Marek

[dooley1414]

Cheers thank you Marek but mine is working now at the moment but I will keep that in mind and may converts it later. Des.

[Gfhug]

Marek, will that fit an S2 pump? The pumps are different S3 vs S2, but would it do the same job?

Thanks

Geoff

[MarekH]

It'll fit any SU pump that has the long rounded tapered points blade. The cutout in the middle of the pcb in the picture fits over that blade.

kind regards
Marek

[dooley1414]

Cheers thank you Marek but mine is working now at the moment but I will keep that in mind and may converts it later. Des.

Hi Marek 

I'm interested in buying two of your fuel pump conversion kits for my double-ended su pump how do I go about buying them off you?

I don't think my click click the fuel pump is giving enough fuel to the carburettors I had a problem Saturday afternoon going up a hill like it was going to run out of petrol it then stopped completely on the Hill I turned ignition off gave it a couple of seconds turn the ignition on not to start the car over just to prime the pump and carburettors again then it started as it should just don't think the fuel pump is man enough anymore! do you think this will solve the problem with your conversion kits?

Kind Regards

Des.

[MarekH]

Dear Des,

The circuit boards have nothing to do with fuel delivery. All they do is keep the high electrical currents away from the frigile points by interposing a transistor betwen them, thus saving wear and tear and increasing long term reliability. f for some reason, your fuel pump persistently draws too much current then they might act as a very cheap safety fuse as a simply 50p component fails ahead of an expensive pump coil.

If you think you have a fuel delivery problem, I'd first check that both pumps are working, then I'd check that fuel is returning to the tank each time.

The pumps' only purpose is to refill the four float bowls. They do this at low pressure and the excess fuel returns to the tank via a spring loaded valve. There has to be enough low pressure flow to refill the float bowls even at 6000rpm and still return fuel to the tank.

Your probably need to start by checking whether the fuel filter is blocked or whether the fuel cap or expansion tank (if fitted) allows the tank to vent as air has to take the place of fuel used up in the tank.

kind regards
Marek

[dooley1414]

Hi Marek

I have s expansion tank on my Series 3 and also I think a Charcoal filter in the engine bay belowe the battery tray.... will this charcole filter be a good thing to look at 1st.... I have just put a new fuel filter in the glass bowl and had my petrol tank professionally cleaned.
Also how would check if the air in tank is replacing the fuel as It's being used?

Thanks for your help so far....

Des.