Fuel pump rewire diagram

[isnms]

How would this do for a fuel pump rewire.

I'm going to go with the MKIV pump which draws a lot more amps. If I'm right, I will be able to keep the low voltage feature. Also, I can keep the relays in the engine bay and just run one 10awg power line to the pump.
[thumb]http://i80.photobucket.com/albums/j187/isnms/Supra/rewire_relays_fp.jpg[/thumb]

 

[3p141592654]

That will work. A potentially more elegant solution is to get the MKIV fuel pump control computer ($230 new from Toyota). It accomplishes the same thing but in a single box.

This is something I've been pondering for a while. I'll be interested to hear how your install goes.

 

[jetjock]

"Crude...but effective".

Yeah, that'll work as long as the two blue connections at "FP" are connected together, though if that's where the pump is going to be you'd better not quit your day job .

 

[isnms]

Yeah, that's the pump low speed path. The pump is at the end of the red wire.

The blue B+ and FP are equivalent to check connector B+ and FP since the stock wiring harness is not in use any more. If you need to run the fuel pump for testing you connect those together.

 

[isnms]

I changed the diagram.
Now all you have to do, to run the fuel pump, for testing / pressure setting..., is move B+ to FP, pin 87a, relay 1.

 

[3p141592654]

That will work. What are you going to use for the dropping resistor?

 

[isnms]

I planned on using the stock resistor.

 

[3p141592654]

The question would be whether the 0.7ohm resistor from the MK3 pump circuit will work with the heavier current draw from the MK4 pump. You are looking for 9V at the pump in low-speed mode. It is possible the MK3 resistor will drop too much voltage and the pump will bog. I suppose the best plan is to try it and measure the terminal voltage.