2 replies to this topic

[philip663]

Hey all, Iv been having a werl of a time trying to sort out why my fuel pump wasn't working. Turns out it was two problems in the end. Poor connections in the tank, and a faulty fuel pump relay!

Iv fixed the tank and have worked out the problem with the relay. Easy eh! Well anyway the fuel pump relay receives the 12v from the ecu on turning the ignition on breifly before returning to 0v as its received no signal from the crank sensor. Iv traced continuity right through the relay pack and back out. Everything is fine with virtually no resistance. The coil pack on the relay its self has a higher resistance than usual though,at around 450ohm's. With the other 3 resistors coming in at 66ohm's. Iv read somewhere that the 66ohms is correct. Problem is, I'm presuming the higher resistance is effecting the functionality of the relay which isn't making it work.

Now the problem is the car worked fine when I last drive it, but this was 10 months ago and it's been sat outside through winter which I'm presuming damp has gotten to it. I'm quite happy with a soldering iron so I'd happily try and change the relay... Although I wouldn't no where to buy one if anyone does? The circuit board is in good shape spit would be a shame to just bin it as such.

Has anyone done this before?

Thanks!

[FlyingScot]

Try re soldering the pins. The info on the MFU is pinned on here, and if it reading 450 ohms when disconnected it's an issue I measured the coils with the shunt resistor at 66ohms ( that's where you read it :winking:)

The relays are difficult to find and I have changed them but only with parts gathered from scrap MFUs.

FS

Edited by FlyingScot, 13 September 2015 - 09:39 PM.

[philip663]

Good shout, I tried re soldering the contacts on the coil but it didn't change anything, resistance still the same. The problem must be down in the coil somewhere, sigh. I'll try and get hold of a knackered one and rob a relay from that! Thanks