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R107 350 SLC no signal to the fuel pump relay

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Old Oct 26, 2021 | 01:34 PM
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R107 350 SLC
R107 350 SLC no signal to the fuel pump relay

Hi Guys

I've got a 350 SLC manual that's a non starter. I put direct power onto the fuel pump and it runs 100%. I checked through the relays and found the fuel pump relay. Swopped the relay with another to test and no joy. I then bridged the relay so direct power from 12v goes directly to the pump and the car starts then cuts after a second or 2. I have ground to the relay so the only thing left is the signal to activate the relay.

I cant seem to find a thread or a wiring diagram that tells me where the signal comes from. Some posts say there's a ballast, some say from the ignition, some say a sensor from the fuel distributor (of which my car does not have). I also read one that the relay gets its signal from a safety plate which i would assume is in an auto box. I however have a manual.

The car was standing for a few months and didn't start. I had a look at the relays 2 weeks ago, charged the battery up and the car started first time. Took it for a drive and everything was fine. Fast forward to the following weekend for another drive and the fuel pump isn't getting power again, this time I cant get it to run. This leads me to think there's a loose connection somewhere or a sensor of sorts that is intermittently playing up.

If there's anyone here that could point me in some sort of direction then I can stop pulling my hair out. Much appreciated
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