THETANK

My fuel pump relay on the drivers side firewall is wired directly to a switched source in my fuseblock. The green and white wire coming from the relay is cut and a wire is spliced on and wired directly (it has a 20 amp inline fuse )to an ignition source in the fuseblock. Of course anytime my key is on the fuel pump is running. I wanted to wire a switch so I could shut it off. I have an unused fused toggle switch. What would be the easiset and safest way to run it? I would like to be able to have my car in the ACC position when the key is turned and be able to shutoff the pump.

camaronewbie

If it were me ....

I'd get the fuel pump wiring back under the hood, and out of the car interior. I hate having more wires than necessary run between inside and outside - makes a mess and more potential for fire on the wrong side of the 'firewall'.

Originally, your car had a Oil Pressure Sending Unit (OPSU) on the driver side block just above the oil filter. Is it still there? Or at least, are the wires still there? It should have had a 3 wire connector, one black, one gray, one orange. The black wire is for the oil pressure gauge. The grey and orange are for the fuel pump. Here's what I did ...

I reused the factory fuel pump relay. The black is already grounded. I connected a hot-in-run wire (from under the hood, any wire will do that only gets voltage when the key is ON) to the green/white stripe wire - this activates the relay. I then used the gray and orange wires from the OPSU on the other two relay contacts. This way, all my fuel pump wiring is under the hood, and on the right side of the firewall.

But - until you get to rewire it like that (if you want) ...

In the fuse box, there are single slots (a fuse won't insert b/c a fuse has 2 tabs). These slots are marked IGN, BAT, LPS, and RADIO.

BAT = 12v+ always - direct battery current
IGN = 12v+ ONLY when key is ON
LPS = 12v+ when lights are on (LPS = lamps)
RADIO = 12v+ only when radio is on (meaning when key is in ON position and/or when key is in ACC postion)

Thus, you can just move that wire from wherever it is to the slot marked IGN - then it will only get power when key is ON, and not get power when key is turned backwards for ACC.

Those slots accept any standrad 1/4 inch male spade connector.

And now you know what the others are for - lots of cool things like extra interior/exterior lighting, etc. you can add using those extra slots.

camaronewbie

You can see the fuse block in this diagram, and see where those extra single slots are at:

http://www.austinthirdgen.org/mkport..._continued.gif

They are the little squares with the line through it.

THETANK

I hooked it back up so the green wire was not wired to the radio slot in the fuse box. I put it back to the stock location and now have the green wire hooked back into the relay. The fuel pump primes but does not keep pumping. I verified this through my FP gauge hooked to the fuel line ( no pressure). For some reason the pump des not get power unless directly wired. My oil sender is sill in tact. My car was switched over to CARB and no longer uses the ECM. Could this have anything to do with it?

andy74

im following this because i have the same issue-op let me know what you come up with

camaronewbie

Yes, this has everything to do with it. The ECM runs the pump. Priming it is a function of the ECM getting powered on - so it will still prime. But running the pump after startup is a function of the ECM reading an ignition signal from the distributor (which it is no longer getting) - so the pump will not run off the fuel pump relay.

Now - alot of folks will still get a running fuel pump, from the OPSU circuit - but it can take 30 seconds or more of cranking before the OPSU gets pressured up to 'turn on' the fuel pump. THis all assumes that you still have your OPSU wired same as stock, and that the OPSU is working, and that the fuse beside the battery is not blown.

So - you either need to verify that the OPSU wiring is still all in tact, and that the OPSU is working, and that the fuse is good, and then have patience and allow the car to crank for a longer time so the pump starts running ...

Or, you need to get a 12v+ wire to that green/white relay wire so that when the key is on the relay activates and runs the pump ...

Or, you need to wire up the fuel pump with another method so that it gets 12v+ when the key is on.

Suzuki

so it won't burn out the pump, having it running stedy?