While driving yesterday 4x4 saph Cos just died suddenly. Turned out to be no power to the fuel pump. I need to fault find this after work today and just want to know if Power to the pump and/or pump relay should be there with just the ignition on or do I need to be cranking the engine to check for these voltages. Thanks David

 

Comon problem m8, you can buy after market looms on ebay and a few other places.

Edited: just looked on Ebay and theyre Ł50 posted

 

As regards to the power being there, i think its only there when the fuel pump is pumping.

 

fuel pump relay at a guess tho its worth rewiring them anyway as the old wiring causes a voltage drop on the pump

 

Have you checked the fuel cut-off inertia switch? It's in the spare wheel well on earlier models or above the kick panel in the driver's footwell on the later ones.

 

Thanks for the replies. Yes I did check the cutoff and I actually got home by bodging up a feed before the cutoff so that and the pump are definately O.K. Have just got home from work and about to go and have a look at it. My main question was does the computer wait for pulses from the CPS before energising the fuel pump relay (meaning I would have to crank the motor to check voltages etc) or does it energise the relay as soon as ignition is turned on. Also will be looking to rewire system but need to get it going first. Can you buy the fuel pump connectors over there. (I am in New Zealand) They have a couple of little catches that you have to push to get them off (although I have so far only managed to get one off) Thanks again David

 

The Fuse attached to the actual fuel pump relay had gone. Any ideas why this should happen while just cruising along. Also would still like questions asked in my post above this one answered if anyone knows. Thanks

 

Just the ignition on to energise the pump. And then check the voltage whilst the engine is running.
Most use these relays running of the original black an red stripped wire to trigger the new relay then run a braided wire down the boot floor gromet to the pump.

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If you did buy another loom they come with everything you need.

It could just be the fuse rather than a problem, if it goes again then the pump or the wiring are likely to be the problem.

Re your first question the pump primes when the ignition is switched on, and at terminal 30 and 85 of the relay you will have power WITH the ignition switched on with the latter.

Martin

 

You can't check at idle.

The problem is when under load, more fuel is required, thus the fuel pump draws more currect, which it can not always do via the old wiring, hence the voltage should be checked under load!

Martin

 

Fair one.
Thought he was asking if you needed more than just position 2 on the ignition to get the pump priming etc etc before cranking over lol. But yes The test is under full load

 

Thanks again for the replies. As said the car is now running after changing the fuse mounted on the relay. Interestingly I have the proper ford '90 wiring diagrams which I bought when I got the car 12 years ago and I can not see this fuse or the Inertia switch on the drawings anywhere. I am assuming the switch is just in series before the pump and the fuse in the feed to the relay. I have not actually driven the car yet so I guess it is possible the fuse will blow again when the pump comes on load. Either way I would like to rewire the pump now. I realise I would get everything by buying a loom but I am quite capable of making one myself and would rather go this way if possible. I would rather use the proper connectors for the pump if I could get them. Another option would be to rewire to a relay in the boot as normal and feed this into the input to the inertia switch thus using the short bit of original wiring from the switch to the pump (including the connectors.) Would this solve the voltage drop problem or is this pump wiring- particularly the connectors half the problem. (incidentily I seem to have only 11.5v at the inertia switch at the moment - on idle - so who knows how low it will drop under load) I see in the photos above standard eye terminals used on the pump. Can this be done on the standard pump or is this a "bosch 044" type. Cheers David

 

It's a standard pump there mate

 

Any answer to the use of the end bit of the original loom (see above) or where to buy the original connectors for the pump. Thanks

 

The connectors you need are just circled crimp connectors. And I'd use a whole new pump loom. I'll look up the crimp connection size.

 

It's blue ring loop crimp connections.

 

You could, but then if that section of wiring, or your joint is bad then it defeats the point of rewiring!

If you do reuse it be sure to check the power in the matter I described above.

Martin

 

I will thanks. I think I will rewire the whole thing and just use the loop connectors and hopefully get some rubber boots (as on my XR4i) to go over the terminals to protect them from the environment.
David