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Fuel pump only starting when turning key off??


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FYI Car is 89 RS Legacy

And typically this only happened the day I went to put in on trademe!

So, I replaced the pump for a Walbro about 6 months ago, and have done several drives with the fuel pump going fine. Then went to start it a couple of days ago and it would crank but not fire. I noticed something was missing and I realised it was the absense of the fuel pump priming noise. I checked the relay (the green plug one right?) and it wasn\'t clicking when I turn the key to \'ON\'. I noted that the main relay was though. I swapped the fuel pump relay from my other RS but no different (although I can\'t \'guarantee\' that it was working beforehand). I swapped the main relay too but still no improvement. I tried a couple of other things, as I noticed that the check engine light wasn\'t coming on either when the key was held in the ON position. So, I swapped the ECU, and same result with the other ECU - no check engine light, no fuel pump priming.

It gets stranger though - although the pump is not priming when I go to \'ON\' when I switch the key back from \'ON\' to \'ACC\' I can hear the fuel pump prime for about .5 - 1 seconds??

I\'ve confirmed when attempting to start the car there is no voltage getting to the fuel pump.

Any ideas what\'s going on? Only thing I haven\'t really tried yet is either a brand new relay or checking the ECU grounding. I dont have access to a multimeter currently but can get one from work tomorrow

Thanks in advance.

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Solid B_____ Fuse?

yea I\'m lost too on that one

contacts in the ignition switch? bit of a mish\' to get at but douche\' it in electrical cleaner maybe?

fact it activates when going back to "ACC" makes me think this, and apart from checking the pump it self (connections) you seem to have eliminated everything else

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Something I discovered when putting my external fuel pump in recently... the fuel pump has it\'s own control unit somewhere, which I believe is just a fancy relay.

This control unit (or the fuel pump) has constant power. The fuel pump control unit is itself controlled via the ECU. The ECU controls it via a ground switch...

i.e. when the ECU outputs 0 volts, the fuel pump will run, when it outputs 12v, the fuel pump will stop. A weird side effect of all this is that when

the car is totally off, and the keys not even in... if you apply 12v to the ECU fuel pump control wire, the fuel pump will run. So... maybe the fuel pump control unit

is toast. That\'s all I can add.

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89RS wont have fuel pump controller

Its a ecu controlled relay which is the powerfeed for the pump

green replay next to the brown ignition relay

ignition relays gave plenty of problems early on. if the relay has a 000 as the last digits of the part # - replace it first before you do anything

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