Ok I'm stumped. (Ignition relay-what tells it to operate?)

[biggreen96]

I have been tracing the hell out of the wiring diagrams, looking for where the current that operates the ignition relay comes from. My end goal is to be rid of the ignition switch in the steering column(rally car) and have a panel under the HVAC controls with a switch to operate the ignition relay, a switch to operate the fuel pump relay, and a push button starter.

But I'm having trouble understanding how exactly the stock system energizes the ignition relay when you turn the key to the "ignition" position.

OK SHIT i think I just got it. Maybe. After finding this diagram of the fusebox.

SO, help me if im not on the right track, the relay is energized by:
1. turn key to "on"
2. current flows from the column switch through the RED wire to the headlight relays and a number of fuses, no.16 in particular.
3. leaving fuse no. 16 on a YELLOW wire the current energizes the fuel pump relay and heads into the ecu via b58.12 "ignition switch" and right back out of the ecu via f47.5 "self shutoff control" on a LIGHT GREEN wire that finally energizes the ignition relay.

[Legacy777]

Take a look at this diagram, specifically the B63 connector at the top right.

http://www.surrealmirage.com/subaru/fil ... uting2.jpg

There are four wires going to the ignition switch, the lead from the battery, the feed to the accessories, the feed to the ignition and accessories, and then the starter.

Being that it's a rally car, I would not worry about just the accessory lead. If you want to have a switch to turn on the accessories (like the radio) you can just add another switch.

So what you need to do is run the battery lead (connector B63, pin 1) to a high current switch, and then run the output to the ignition feed (connector B63, pin 5). Then for the starter button, again tie into the battery lead (connector B63, pin 1), and then run the output from the starter button to the starter feed (connector B63, pin 4).

I would NOT recommend putting the fuel pump on its own separate switch. Leave the ECU control the fuel pump. The reason being is that if the car is rolled or crashes and the engine stalls/shuts off, the ECU will kill the fuel pump. The last thing you want is the fuel pump to keep running and pumping fuel if there's a broken fuel line.

Make sense?

[biggreen96]

Yeah, it does. I was interested in finding the relay trigger mostly because I couldn't find a suitable high amperage switch at the autoparts places. It never occurred to me to check radio shack until today, voilà.

I still want to have a switch for the fuel pump, because I'm going to rig up dual pumps and want to be able to switch in case one dies. I can still have them ultimately controlled by the ecu though.

[biggreen96]

I think the only real rollover protection is from the loss of pressure when the pump starts sucking air once the car is upside down. And once the car stalls, then the ecu shuts off the pump. I've heard of a check valve that wont let fuel flow when it's upside down but I have no idea where it might be...

[Legacy777]

There is a roll over valve. It's located near the tank.

[cj91legss]

would that be the little valve under the driver's side of the car by the rear door with the fuel lines going to it?

[Legacy777]

Yes that should be it.