SupraRunner

Anyone have any suggestions. In the process of my jz swap into my 91 4runner. Fuel lines are done, just working on wiring for the pump. The old 3.0 used two different relays, one main and one with inputs from airflow meter box and tps. The jz ecu has two outputs that fed a separate "fuel ecu" that controlled the pump with it's variable voltage from 9v to 12v at full. I do not have this separate ecu and it is not an availabe option. For the moment i have wired it at full flow using one relay to operate it at 12v off the ignition2 hot in on and start line, and let the presure regulater manage it and return the rest through the return line. Any potetial problems??? Other than the fact that if i was to wreck bad enough to rupture a line but still had battery power, and could not turn my key off, i would pump fuel out continuosly. Anyone have a sugetion?? Oh and i am using the pump off of a 94 tt supra so flowrate is not a problem. Thanks.

milehigheric

There is nothing wrong with running a pump at full voltage all the time. The only downsides is increased fuel temp (if your chasing dyno numbers it will be an issue but not for street) and pump noise as sometimes high flow pumps can get loud.

You should really wire it up to a 'deadmans' circuit simply for the reason you mentioned however.

vital22re

iTrader: (2)

why not run it off the cor like the factory runner should? my 3.4 swap uses an input from the mass air flow to trigger the cor relay. how does the main ecu know when to start the signal to the ecu for fuel control? I would think it would need an imput from the mass air to let the ecu know to turn on fuel.. Just some thoughts. I'm no expert on the jz motors by any means. good luck on your solution

milehigheric

JZ would my MAP sensed wouldn't they...not MAF.

annoyingrob

Correct, the 1JZ is MAP based. The ECU monitors the engine RPM, and if it stops, it cuts fuel. The separate fuel ECU you're talking about is simply a resistor and relay, also used on several other engines (Like a 7M-GTE).

What I would do is operate the relay off of the FP wire from the ECU ather tha the ignition. I wouldn't worry about trying to get the dual voltage setup working. Mine crapped out on my 1JZ, and I ran it full voltage just fine. In fact, my 1.5JZ runs full voltage to both my fuel pumps all the time with no problems.

vital22re

iTrader: (2)

hey like I said... no expert on those supra's just throwing out ideas.

SupraRunner

thanks for the help guys, i will keep the single relay i have and try to run it off that output from the ecu, now i just need to see witch one of the two outputs i need to use, I think it will be the FPC instead of D1.

annoyingrob

Wire it up to one, if it starts, runs for a few seconds, and stops, you picked the wrong one