what is the pin number on the connector on the relay board for the fuel pump?

I am going to use it for the AAR.

It's been so long since I've messed around with the relay board, I've forgotten.

Thanks

Thanks Andy, It looks like the AAR is connected to #12 on the smaller connector on the back (towards the rear of the car) of the relay board?

From what i recall when last digging into it, AAR and FP are both powered by the FP relay to begin with, that relay is controled by a transistor grounding in the ECU.


What is the reason you want to change the wiring to the AAR anyways? Is this a stock setup you are running?

I'm running a Megasquirt FI. It has the capability to run a on and off AAR selonoid but for some reason it is not working.

I am going to use the stock AAR until I get my MS fixed.

I am running the FP through the R B on for the MS so the stock connector is avail.. I figured I'd tap into that for now.

Just tie it in to a spare port on your megasquirt. That way you have some control when it closes.

Messing around with megasquirt is the reason i know the stuff i do about the fuel pump circuit. Basically, the stock AAR wiring will not work with a standard MS install as the AAR is powered by the fuel pump relay which is no longer being activated by the stock ECU. Attempting to wire the AAR directly to the stock fuel pump source is not going to solve your problem because they are both fed by the same relay. I will have to go find my notes to give you exact details but, there is a wire that runs from the stock ECU to the fuel pump relay, this pin needs to be grounded to activate the stock fuel pump relay. Normally this is done by the stock ECU but with MS the stock ECU is gone so neither the fuel pump nor the AAR will be powered . Megasquirt can be pretty easily adapted to trigger the stock fuel pump relay which I think is the best way of doing it however you could also just wire the AAR into the MS fuel pump circuit or just put a manual switch on the stock relay.

Ideally if you are using the stock AAR you want it powered at the same time as the fuel pump, i.e. only when the engine is running. Simply powering the AAR with key on 12v could heat it prematurely and defeat the purpose of having it all together.

You're correct, I forgot about the Stock ECU triggering the FP.

For now, I am going to wire it to the FP on the RB for MS. I was trying to get around that because the wire run is longer and more cumbersome than tapping into the stock RB.

since this is temporary I can live with it for now.

If you come across how to activate the FP WITHOUT the stock ECU, I'm all ears.

Think carbs ...

http://www.914world.com/bbs2/index.php?showtopic=25954

Thanks Andy......you're the man

Why not use the stock relay. the MS output to trigger the relay is a ground, just like the stock unit. Mine has been working like that for 2+ years now, with the ms triggering the stock fuel pump relay. Hell, it even get power for the MS on the stock relay board.

before I rebuilt the motor, I had mine setup like yours. When I pulled the engine for the rebuild, I changed it all over to the MS relay board.

I forgot about the little ground jumper wire to power everything up.

Hey Jeff, would you mind looking at my MS board to see why it is not triggering the on/off AAR solenoid?

I will be taking the car down in Feb. doing the 5 lug conversion. this would be a great time.

Sure, I can put it on the scope and see if it's a transistor failure or what. I do know the aux transistors can't handle a lot of current, it would need to switch an external relay. Do you have the sim board? That would help to diagnose things.

Thanks, I have an old stim board, I dont think it would show the solenoid switching on and off.

I had the setting in megatune set at 88*, thinking that would be the problem, I changed it to -40 and it still does not work.

Once you know how to do it its actually pretty easy to activate the stock FP relay via Megasquirt. Like i said, its activated via grounding the wire that normally connects to pin 19 on the ECU. The Megasquirt FP relay is controled the same way by switching ground on pin 37 of the DB37, so all you need to do it connect pin 37 from Megasquirt to pin 19 of the stock harness. If you are using the MS relay board it would proabably be easiest to just pull the MS FP relay and jump the output of pin 37 from there. If you are using your own harness then just find were pin 19 would normally connect back at the stock relay board.

As soon as i can find some time i might get around to doing a full write up on how to do an MS install using a completly unmodified stock FI harness.

Looking at the diagram Andy posted, pin 13, which looks like the FP pin is tied into pin 12 which looks like the pin for the AAR.

If I ran a ground wire to activate the FP circut again, this should activate pin 12 for the AAR correct?

That's what it looks like to me.