Hi guys. i've got a 90 mk4 xr3i e.f.i and the fuel pump has stopped pressurizing the system on ignition. you can't hear the loud noise it makes anymore. i've got a feeling it's one of the relays. does anyone know where the relay is for the fuel pump and what colour it is??? i think there's two. one of them is under the dash, it's grey and is still clicking when you turn on the ignition so i figure its ok but as for the other one?????????

 

I think they have a fuse and 1 relay under the dash altho i don't know for certain... Have u checked the fuse? Also check the inertia switch in the boot under the spare wheel, that kills the fuel pump in the event of a crash etc. Just have to push a button on it bk in if its popped out...

 

I checked one relay under the dash which seems to be working as you can hear it click when you turn on the ignition. As for the other one i'm not quite sure of it or where it is..The inertia switch is also in the right position. I did a lamp test on the two wires going into this and there doesn't seem to be any power.

 

from this explanation, i gather it doesnt run at all then.

 

The relay should be standard SPST relay (Yellow), this is tripped by the ECU and so the pump primes, however it won't do so until it receives input from the CPS.

The reason you haven't got any power at the live is because you would have to test it while someone else turns the ignition on as it will only be live for the duration of the prime.

If you have the right relay you should hear it click and then it will open again.

You could also bypass the relay temporarily as well if it is the problem, which it quite possibly is.

Martin

 

Just jump from 30(battery) to 87(output) and see if it then works, then do as said.
tabetha

 

" The relay should be standard SPST relay (Yellow), this is tripped by the ECU and so the pump primes, however it won't do so until it receives input from the CPS "

what is the " cps " ? im having a similar problem, cheers

 

CPS = crank position sensor.
tabetha