dr_jekyll Posted August 9, 2011 Share Posted August 9, 2011 hi, im fitting a twin pump set up on my car using 2 30a relays from a 12v power source . can anybody tell me what wire from the fuel pump ecu should be used to trigger the relays in order to not run the pumps when the engine is off. i have searched but found nothing. cheers, craig Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted August 9, 2011 Share Posted August 9, 2011 Just wire the relay energising coils up to the stock fuel pump feed wires? Then they'll only run for the standard priming time and close down. Quote Link to comment Share on other sites More sharing options...
dr_jekyll Posted August 11, 2011 Author Share Posted August 11, 2011 hi chris , i tryed this just now but the car wont start using the blue wire fron the stock pump plug. i also tryed it with the thin purple wire from the pump ecu but this will not switch the relays even though it emits a small voltage when the key is turned . the only way i can get it to ruin is on the 12v ignitin to the pump ecu but it then runs the pumps with just the ignition on and i dont like that. Quote Link to comment Share on other sites More sharing options...
Andy Blyth Posted August 11, 2011 Share Posted August 11, 2011 I use the blue with red stripe wire coming out of pin 2 of the fuel pump ECU to power a relay. This is the wire that normally goes to the stock fuel pump. Works a treat. However, this is on a TT, I'm not sure which wire it would be on a N/A. Quote Link to comment Share on other sites More sharing options...
dr_jekyll Posted August 11, 2011 Author Share Posted August 11, 2011 the problem withthis wire is that it runs the pumps with key turned to accesory so the pums keep running with the engine dead , so in the event of a track crash i could end up in a big ball of flames Quote Link to comment Share on other sites More sharing options...
Andy Blyth Posted August 11, 2011 Share Posted August 11, 2011 Again, I'm not sure how it works with the systems on the N/A; on the TT, the fuel pump is powered only when the engine is turning or for a few seconds after the key is moved to the ignition position to prime the pump / rail. I agree that it's potentially dangerous to run the pump at any other time so I checked this behaviour when adding the relay on my car. Cheers Andy Quote Link to comment Share on other sites More sharing options...
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