914-6 fuel pump conversion

[velomann]

okay, i know this has been discussed, however, i am unable to locate the preivous thread or determine what was the actual conclusion for correct 'pin' placement on this. in order to utilize the exisiting relay position on a '73 relay board, to make your fuel pump work after disconnecting your FI computer, what pins do you put a jumper wire into, without frying your board?! there was a couple of solutions posted, however it seemed to go in circles based on how you were looking at the diagram. which of the two pins do you connect?!

[Dave at Pelican Parts]

Do you need to use the original wiring, or do you want to run a new pump power wire?

Refer to the diagram here.

If you run a new wire, you can hook it to pin "I" (right-front) of the four-pin connector at the left-rear of the board.

If you want to use the existing wire, then you want to jumper the output of the FI Power Supply relay (this relay goes "hot" all the time the ignition is on) to the output of the Fuel Pump relay.

The output of the FI power relay is pin #87 on that relay--but notice that it also connects to pin #85 on the fuel pump relay itself. The output of the fuel pump relay is pin #87 on the pump relay. So, if you hook together pin #85 on the fuel pump relay to pin #87 on the fuel pump relay, you will use the FI power relay to send power to the fuel pump power wire any time the ignition is on.

Note that the fuel pump power relay doesn't actually have to be there for this--you can just hook a wire between those two holes in the relay socket if you want.

Let's see, what else? You could use the white wire that used to go to the AAR (it's pin #12 in the 12-pin connector at the right-rear of the board) and plug that into pin "I" in the four-pin connector. That would also hook together the fuel pump power circuit and the FI power circuit the same way. And it might be a little simpler, at least if you are going to have that 12-pin connector still plugged in. Pull the white wire out of that harness, cut it (leave enough length!), crimp on a 1/4" female spade connector, and plug it into pin "I".

...There are probably other ways you can do this; but those two are the first two that jump to mind.

--DD

[velomann]

Hey Dave,
Thanks! The answer that I was looking for was to use the jumper wire from the fuel pump relay on the relay board, so that I could utilize the original wiring without having to run another, and make a mess of the original set up. This is advantageous to me, because it really does just make a simple adjustment while removing a bunch of unnecessary parts!! Thanks again.