Fuel Pump Relay

[dave_clutterbuck]

I am experiencing an annoying intermittent problem with the external fuel pump. On the way to MOT the car cut out due to fuel starvation I have found the pump is not priming this appears to be due an electrical supply problem as the pump primes when I bench tested.

Before I start searching, can anyone point me to where the fuel pump relay may be hidden ?

Regards
Dave

[cameronfurnival]

Re: Fuel Pump Relay

short answer is...it could be anywhere Dave! One of the Cabrio owner/builders will be along soon to point you in the general direction. Is yours the Ford setup?

[dave_clutterbuck]

Re: Fuel Pump Relay

Thanks Cameron as I half suspected.
It is a Hunte,r Ford Sierra based with EFI engine.
Regards
Dave

[djj_engineer]

Re: Fuel Pump Relay

Are you sure there is a relay?
FMB has an appetite for fuel pumps I think it is on it's 4th. I've had so much trouble I have fitted a fuel pressure gauge so at least I can see that I have fuel.
The SDI layout had a fuel pump that was wired through the oil pressure gauge. No Oil pressure - No fuel, thus saving the engine from expensive rebuilds.
I don't think they persisted with this feature on other V8's
Derek

[philcoyle]

Re: Fuel Pump Relay

Hi David,

I take it that you didn't have time to read all about EFis through the winter, on my EFi set up the ECU relay is next to the fuel pump relay (yellow). The ECU connects to the fuel pump relay when the ignition is switched on. This is the noise you hear for a few seconds as the pump primes the system. When the engine is turned over that is when the ECU takes charge of everything. If the ECU relay is faulty it will not energise the fuel pump relay, so this may be something to look at, there is nothing special about the relays and your usual parts supplier will do. Get someone to turn on the ignition only while you touch the ECU relay for the click, and like wise for the fuel pump relay. This should keep you occupied for a while.

[dave_clutterbuck]

Re: Fuel Pump Relay

Thanks Phil
This is exactly what is happening, where are the ECU & ECU relay located ?
I am sure the pump is not being energised which rather points to the relay.
Unfortunately I cannot pop out to my garage and look as the car is at the MOT garage.
When working correctly I hear the pump prime for a few seconds then the engine starts and off we go accompanied by the rather pleasant constant noise of the pump working.
I have to admit I neglected reading about EFi during the long winter months.
Regards
Dave
Regards
Dave

[philcoyle]

Re: Fuel Pump Relay

Hi David,

I don't know if you can remember a long time back when we were discussing something similar, but ! the ECU relay has to get a signal from the signal return wire from the injectors.
In line from the injectors is a diode, these become brittle with age and break. No injector return signal means no activated ECU relay, and no pump relay activation. Take it one step at a time and it will probably be something silly like a broken connection or a duff relay.
Sorry I can't help with the location of your relays as it will depend on the builder and where they put them, but as a rough guide, somewhere between the injector wiring and the ECU, they can't be far away.

Forgot to mention that the diode is in a rubberised case and looks like a Ripault connection, and cost pennies from Maplins. If it is this I can look up which one it was that I bought.

[dogoncrazy]

Re: Fuel Pump Relay

Hi David
I had a similar problem on my Cabrio [BMW based] Drive for weeks/months no problem then out of the blue would lose power and stop. Removing and refitting fuel injection relay would bring it back to life. I found one of the wires into the relay holder was insecure or to be more precise the female terminal of the sort that once fitted to the relay holder wasn't 'locked' into the holder so installing the relay was pushing the female spade out resulting in an intermittent contact. Once the connection was broken the relay was unable to operate the injectors.

[DAS_Cabrio]

Re: Fuel Pump Relay

There is a Fuel Pump Relay on the LH side wall of the Passenger footwell on some Hunters

[dave_clutterbuck]

Re: Fuel Pump Relay

Thanks I now have clearer idea what and where to look.
Will pop to the garage later and look on passenger footwell I know there is something there.
Regards
Dave

[dave_clutterbuck]

Re: Fuel Pump Relay

All up and running fuel pump had burnt out caused by defective fuel pipes which were collapsing under pressure, thus restricting the flow of petrol to the pump.
Fuel pump relay and ECU was located to the passenger footwell.
Took it for MOT today passed with flying colours without any reflectors. The tester did an emission test although it was not required, found to be well within the limits.
Should be onward to Donington.
Dave

[dogoncrazy]

Re: Fuel Pump Relay

Great stuff!! See you there.

[dave_clutterbuck]

Re: Fuel Pump Relay

Hi Alan
Presumably you will be crawling underneath to inspect the work done.
Regards
Dave

[dogoncrazy]

Re: Fuel Pump Relay

Hi David
Its probably better than new so I'll be wearing my sunglasses . Will be at Tatton on Saturday if you're there.
Regards
Alan

[dave_clutterbuck]

Re: Fuel Pump Relay

No need to go to that extent, I am am happy to have peace of mind knowing that everything is as it should be.
Unfortunately I am unable to attend Tatton a pity as it is very close to me.
Regards
Dave