turboefini88

iTrader: (1)

Who has installed an independent Relay and Fuel pump cutoff switch in their FC? Im talking about totally bypassing the stock relay/resistor to feed power to the pump?

Do I expect to have problems with other circuits or anything else that I cannot see in the Diagrams from the FSM?

arghx

iTrader: (3)

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/pics-my-overkill-fuel-pump-rewire-732904/

that's my setup, which bypasses the stock resistor relay but keeps the circuit opening relay for safety. you don't have to worry about the debate over the safety of the wire in fuel, that's just a side debate, the wiring is correct. You can just tap a switch into one of the wires going into the relay I hooked up.

TitaniumTT

or if you have an aftermarket alarm you can use a circuit that latches to ground when the alarm is disarmed. That way if the alarm is ripped out the car still won't start.

turboefini88

iTrader: (1)

What Im looking to do is to come from the battery, through a circuit breaker then the relay. From relay to the pump. Power from Igition 1 (hot in start and run) to the switch, then to the coil side of the relay. This will eliminate the relay/resistor and the circuit opening relay.

rotaryracer1

iTrader: (1)

i did this fuel pump rewire on my 88t2 a few years ago and have had no probs but i used diagram #1 on the link. one thing though i did notice is when i get in the car and turn the key to prime the pump before starting it, the fuel pump does not pressurize and will continously run before i start the car, has that happened to anyone else? my bro has an 88 as well and his pump pressurizes just fine before he starts the car. wierd

arghx

iTrader: (3)

This is pointless, it's just more wires to run and it's less safe because you don't have the AFM cutoff. Why bypass the circuit opening relay? There is no advantage to this. Are you building a 7 second drag car that needs to save every possible ounce of wiring for weight reduction? The circuit opening relay is there for safety (if AFM snaps shut in an accident, it should cut off the fuel pump), and it allows you to use the fuel pump check connector. The fuel pump check connector is your friend when you are working on your fuel system--it lets you check for leaks with the UIM off.

The stock stuff is fine, you are only using it to trigger current straight from the battery so that you can get higher voltage to the pump, which is the entire point of this mod. Cut out your resistor relay under the hood, jumper the 4 (bluish?) wires that originally went to the resistor relay (two are left unused), just like in the diagram. Then in the rear hatch area take the blue wire that feeds the pump voltage (black/white on the pump side of the fuel pump connector I think, at least on my 88 T2) and use it as a trigger wire for a 4 pin relay (mount the relay in the hatch area). Put the rear harness side of the OEM pump wire on the 86 terminal, then put the fuel pump side of the wire you cut to the 30 terminal. 85 Terminal gets chassis ground and 87 terminal gets constant +12V straight from the battery. You can wire a switch inline on the wire coming from the battery to the 87 terminal on the relay.

That setup retains all the useful functionality of the circuit opening relay while cutting out the resistor relay and installing a fuel pump kill switch. If you really want to be fancy, take an Auto Adjust Suspension switch and use it as your fuel pump kill switch, that's how I used to have it in my car (thanks to Smoken' for that one).

turboefini88

iTrader: (1)

ARGHX, I have modified my origional idea to only power up when the car is in run and start. Not directly from the battery. Im not building a drag car, but a time attack/drift car. As far as a safety cutoff in case of an accident, I am looking into using a FORD inertia switch which shuts the pump off in an accident in stock form on most fords. (We have alot in NOS @ work heh heh)

I am also looking into eliminating JUST the stock relay/resistor setup and installing a shut off switch on the middle black/white stripe wire on the circuit opening relay.

arghx

iTrader: (3)

That's what I was trying to explain how to do actually, along with bypassing the resistor relay. Look at the diagram in the thread I posted. Install the toggle switch on the wire from the battery to the 87 terminal of the relay. That in essence cuts power to the black/white wire on the pump.

As far as the inertia switch goes, you would have to explain how it works--does it interrupt a ground or something in the event of an accident? You can probably make it work with the stock wiring pretty easily.