Fuel Pump Relay

[Steve20]

2.0 Zetec on TBs, understand I need a relay for the fuel pump but cannot find any description within the build manual.

What do I need please and if possible names of suppliers

Thanks

Steve

[Peter M]

With the loom westfield supply that goes to ecu from the engine the fuel pump relay is part of the loom.

[Steve20]

I am not using the standard engine loom from the factory as I went for a Emerald ECU so need to buy the relay seperately, appreciate any advice

Steve

[Peter M]

Sorry cannot help hopefully someone will come along who maybe able to help.

[scruffythefirst]

Any 4 pin 20amp plus relay will be fine.  Easily found on any car in a scrappy.

Alternatively places like Polevolt or Vehicle wiring products etc should be able to help you.

[Steve20]

Good web site, many thanks

[nikpro]

Sorry for being dense; I know the fuel pump has a relay but why do fuel pumps need one and can't they just be run from a switched live?

[scruffythefirst]

Sorry for being dense; I know the fuel pump has a relay but why do fuel pumps need one and can't they just be run from a switched live?

Depends on what is doing the switching.  F pumps draw upto 20amps (cossie one draws 18ish IIRC) and if an ecu was controlling its unlikely it's going to take the current.  Also it makes wiring the heavy duty cable required to transmit 15-20 amps the length of the car shorter and more convenient - it can take the shortest route from the battery to the F-pump resulting in less voltage drop and a pump that actually works properly.

If you run it from the main switched live feed the pump will always run when the ign is on, not always the best idea.

[Dave Eastwood (Gadgetman) - Club Chairman]

The fuel pump's are usually "controlled" by the ecu these days, which presumably can't supply the current to actually power the pump.

Not typing fast enough again; wot Scruffy said  

[Lurksalot]

I went to start mine this morning and .....  

with a tester I have checked for voltage at the fuel pump and with the engine cranking we have 0.15v  

the fuses are ok but .....where do I locate the relay ?

ther is ablock of wiring under the dash but only 1 relay and this appears to be the indicators.

does anyone have any ideas or are there any common likely problems  

sorry for the hijack but the topic fits  

kev

[Dave Eastwood (Gadgetman) - Club Chairman]

I don't know whether there's anything like a standard position for the fuel pump relay. But normally being part of the ecu loom, I'd start at the ecu and follow the cable back. I mounted my ecu inside the car under the scuttle and there wasn't that much length of loom to the relays - about half a metre or so, so I mounted mine on top of the transmission tunnel as far forward as they'd go.

[Lurksalot]

the loom comes in through the tunnel and there is semingly a group of what look like relay terminals bolted to the cockpit side of the scuttle , but only an indicator relay fitted into the top one  

[deano.1]

Normally the fuel pump would be fed by a fused +30 (constant live) through a relay. The relay coil would then be fed with a +15 (ign live) and a switched negative from the ECU. I would think that 80% of fuel pump relays on Westfields will be located somewhere behind the dash. If you have low voltage at the pump it could be caused by poor connections onto the fuel pump fuse, relay, crash switch or pump itself, relay or crash switch could be faulty or you could have a poor earth to your pump (test the voltage to a known good earth)

HTH Dean

[Lurksalot]

Dean

I think I love you

traced ithe fault to a dodgy connection at a switch at the rear which Ippresume to be the crash switch .

Istill dont'know where the relay is though

but it works so I dont' need to look any more

cheers  kev

[deano.1]

Pleased to help