[Solved] Fuel pump doesn't start

[paydase]

Winter is coming, my fuel pump refuses to start, maybe because of a bad electrical contact somewhere due to oxidation.
Il already had shown some signs of weakness, not always starting at each request.
Electrical supply seems to be OK otherwise, the battery is fully charged and the starter revs when switched on, so apparently the earth is OK.

I first thought of a worn fuel pump and was prepared to change it (I have a spare C19919R which seems to be an electronic model, my car is a 3.8 with positive earth).



Before changing it however, I checked the voltage between leads in the small electrical box inside the trunk when the ignition key is on: there seems to be some unstable voltage, neither 0 nor a good 12-13 volts.
Do you think the issue would be the pump itself or something else in the electrical supply of the pump?

Additionally, I am wondering how fuel leak tight will be the penetration of the electrical cable through the steel plate on the tank when I see the type of rubbers on each side of the plate of the new one compared to the screwing system of the current one. Should the current nut(s) be transferred on the new pump?



I have also observed that I shall empty at least partially the tank, because the plate seems to be positioned at a level under the current level of fuel in the tank: it started to leak when I unscrewed some bolts.
Should I also change the seal(s) of the steel plate or can I keep the current ones? Aalready the current seals seem to be not totally leak proof.

[cactusman]

If there is not a steady 12 volts or so in the trunk connection ( or boot as we would say in the uk :D ) then I would check the wiring to the boot before condeming your pulp.

Check the fuse no 4 is OK and the fuse box terminals are clean. From memory there are a bunch of bullet connectors on the left hand side just by the glove box ( RHD car) or by the head/dip switch on a LHD car where the harness to the rear of the car connects to the main harness behind the dash. The fuel pump wire is white with a purple stripe according to the wiring diagram. Check the bullet is not loose. Happy hunting. J

[ralphr1780]

Serge,
It could be the ground connection which is poor.
You could try hooking a parallel ground, and even a totally independent direct power supply to check whether the pump is functional or not.

[paydase]

Thanks, Julian and Ralph,
Good advices.
I will have a closer look on the electrical wirings and on the quality of the ground next WE before considering changing the pump

[paydase]

Feedback on my fuel pump.

Problem solved.

After having checked once more that the electrical engine of the fuel pump did not start on ignition I checked the fuses behinhd the dash.
Fuse n?4 was apparently still good but no voltage on the wires of the fuel pump when the key was turned for ignition.
However, after having closely inspected the fuse, I noticed that one of the connecting ends seemed to be loose.
Tilting it a bit finally ressurected the fuel pump on ignition!
So a bad electrical connection of the fuse was the culprit and my antique pump is still good....

Nevertheless, as I was prepared to change it, I decided to check that pump.
I first disconnected the battery and emptied 10L from the full fuel tank to be able to unbolt the plate on top of the reservoir.
The pic below shows the current electro-mechanical pump removed and the spare electronic one, substantially smaller.



Two questions:
- the overall length of the new pump seems substantially shorter, so for those already having made the change, is the new pump able to suck the fuel close to the bottom of the tank?
- the electrical wiring of the new pump in the tank seems much simpler, with no shielding as for the old one. And the sealing system to avoid fuel leaks at the level of the plate of the old pump does not seem to be easily transferrable to the new pump. Any trick or tip to do it?

[cactusman]

Looking at your new pump it can be slid up and down by releasing the two screws on the vertical bracket. You need to release them a bit and adjust the pump body location so it matches your old Lucas pump. As to the sealing I can't really comment but there must be a seal or else fuel will leak when the tank is filled.

If I were you I would get the new one ready and carry around as a spare and use your old one. Do NOT bin the old one as they are worth ????? even if they don't work....and yours does.

[paydase]

Thanks, Julian, you are right for sliding the pump on the vertical bracket.
I must confess I did not look closely, I was more concerned by the possible fuel leaks.

I have indeed put back in place the old pump as it works but also because I did not see how to ensure no fuel leaks around the electrical cable at the plate of the new pump.

And for sure, I will keep that nice antique :D

Any more tip from those having the electronic one to ensure fuel sealing?

[cactusman]

I presume you are worried about the wire inlet. Certainly what is there looks pretty useless. I would replace it with some sort of compression gland. You will need to get one that is resistant to petrol. You might be able to get one from a somewhere that does race car bits or try a marine chandlers. They will sell bulk head compression glands.

[paydase]

Thank you again Julian.
I think you are right.
I am however surprised to see that such a pump was sold by one of the usuals in a sealed pack with the C19919R reference number as if it were ready for use...

Certainly others here have replaced their fuel pump with this new one.
Was it delivered as such and if so how did they adapt it?

[Heuer]

That cable gland is indeed useless if not downright dangerous! More info here: viewtopic.php?t=4855&highlight=leaking+pump

[cactusman]

Try something like these maybe? They will certainly be better than the useless grommet you appear to have on your pump.

http://www.ebay.co.uk/itm/Pkt5-16mm-25m ... DaS327hxig

[paydase]

Thank you for the very useful link, David.

When I see the new pump that I have (and that was given to me as a spare by the PO from whom I bought the car), I realise that this pump is useless and that it is probably one of the very early designs.
It does not even have a gland around the cable!

I will try to contact SNGB to get a replacement as this pump is completely unsuitable for purpose

[cactusman]

I agree...what you have looks very dodgy. Fuel fire equals lost E type so better be safe than sorry. SNG do sell modern type replacements.... Last time I looked which was a while back...they said low stock.