Fuel pump won't stop

[V1DL3R]

Strange one. Came to the car, the battery was flat and when I charged it the pump was not priming. I went and fiddled with the relays but no joy. I went and got all new relays to be on the safe side. Put them in this evening and the fuel pump just buzzes, no ignition on, no nothing.

What is going on? I'm assuming that the pump is somehow just taking power straight from the battery. Where could this possibly be a break? Any ideas, I'm getting really stuck on this one.

[Evo2aGTO]

May be that the Fuel pump relay is stuck (contacts welded) closed.

[Green3R]

First thing to verify is that you have replaced like for like relays. Sounds like the fuel pump relay is always on (or at least passing some current to the pump).
Put one of the old relays back in the pump position?

[Adrian W]

I reckon you fitted a change over relay rather than a normally open one , either cut the middle pin off or buy the right type of relay

[andygtt]

Adrian W said:

I reckon you fitted a change over relay rather than a normally open one , either cut the middle pin off or buy the right type of relay

probably this^^^, or some other relay fault... a week ago I had a relay fail and replaced it, I then found another relay was feeding back power to the ignition so that the car ran even after the key was removed, turn the heater off and the engine stopped!

the relays are a mix of different types but all have the same pin design and some switch rather than turn on/off... also be aware the fuel pump relay is in the engine bay.

[TuxMan]

Definitely the WRONG relay !!!!

[V1DL3R]

Hi All, thanks for all your help as always!

Through sheer determination it now worked (singular, I haven't tried it again yet this morning). I swapped out the new fuel pump relay for one of the old ones. Initially it didn't work but I think additionally there was some water trapped in the connector block as after being left upside down for an hour or so it seemed to be okay. My conclusions so far was a faulty relay and water in the connector - the water is what I assume was causing the drain?

I looked up the part numbers printed on the side of the old relays and bought like for like. The other new relays seem to work for the other three relays, or are they not and i'm haven't noticed the impending issues? Does anyone know if all four should be the same?

[SwankBaton]

V1DL3R said:

Initially it didn't work but I think additionally there was some water trapped in the connector block as after being left upside down for an hour or so it seemed to be okay. My conclusions so far was a faulty relay and water in the connector - the water is what I assume was causing the drain?

A few people have rotated the Relay block 180 degrees so they dont collect water in them

V1DL3R said:

I looked up the part numbers printed on the side of the old relays and bought like for like.

Have you checked its not an 87 vs 87a relay?
I found the aircon relay works well in the fuel pump position !

[TuxMan]

The fuel pump relay is different to the other 3 , I made a little alloy cover to keep the water out .

[anonymous-user]

You can generally "pop the cap" off most std square 20A automotive relays and take a look at and sometime "clean" the contacts inside. Can be done in-extremis on the side of the road........ ;-)