Hey all, So here's whats up, I have a 300a in-line with my ground in between the battery neg and where it connects to my car's frame for ground, my question is, which pins on my PM5 ECU are for ground because I want to run an individual ground line for it, so it does not reset every time turn off the kill switch.

Any and all help would be appreciated, I know 2 of the pins say straight ground, and 2 others say Ground/Main Relay.

I just don't know which ones I need to connect to my neg terminal through a fuse, also...15a fuse sound right for those grounds right?

 

Bump

 

Really now? Nobody has any Ideas?

 

If I'm understanding you, you put a disconnect in between the battery ground and chassis. When you disconnect the ground you want to be able to keep the ecu from resetting.

When you interupt the battery ground to chassis it would be equivelant to removing the battery completely from the car thus no power to the ecu for memory.

The batteries + and - have to be connected to the car for there to be power.

Maybe you could use a seperate small back up battery like used for security systems tied to the back up circuit.

 

I was just thinking run the 4 wires on my ECU labeled ground, into one wire, and then to the hot side of the kill switch, thus, the ecu would have ground, but nothing else, I just need to know if its safe to ground both the pins that read (Ground/Main Relay) on the pinout as well as the 2 that just say (Ground), so in total four wires. (Main Relay/Ground pins are A2 and A4,) (Ground only pins are A16 and A18)

 

What are you looking at for a pin out? What you listed, A2 (#4 injector driver), A4 (vtec solenoid), A16 (altenater control) and A18 (auto trans) should be empty.

What's the purpose of your disconnect? Security?

I would think to hold ecu memory you would need to connect A23 and/or A24. This would need to be to the battery side of your disconnect. I would test continuity to ground for these with the battery disconnected and the ecu unlugged.

I wouldn't do it personally. This would effectively be bypassing your disconnect with a smaller gauge wire with a direct link to the ecu. If anything were energized (try to start the car) with the diconnect open it would likely melt the wire and possibly start a fire.

 

http://www.clubcivic.com/board/showthread.php?t=90486

Thats the pin-out I'm using, you're thinking wrong ecu, and was thinking the same thing with wire burn out, I was going to use a small in line fuse,just to let enough juice through to stop the ECU resetting every time, so I'm thinking a 5a or 10a fuse, it'll draw power through its normal wires unless the kill switch is in the off position. and if someone were to try starting it while it was off, that fuse would blow, and id just keep a spare or two in the car.

 

You're right, you said PM5 and I was thinking P05.

A2, A4, A16 and A18 all go to the thermostat housing. Tying into any one of them would effectively be tying into all of them.

If you were to fuse it I'd put nothing bigger than a 5 amp on it. It's just constant power for memory so it should need less than 1 amp.

 

So basically just run a fused ground between the battery and thermostat housing?

 

You don't need to go all the way to the thermostat housing. You can drop a ground straight to chassis right by the battery. You just need the battery tied to chassis before your interrupt.

 

ok thanks man. much appreciated, I'll get that done as I swap out my engine.