I'm installing my fuel only computer on my 88 N/A and I'll be leaving the factory computer in place to take care of the ignition duties. What I need to know pretains to the wiring harnes that runs thru the passenger side of the firewall. I think I've got it separated down to only needing two of the plugs and the ground to the engine itself and those two plugs aren't needed for the ignition. I just want to keep the factory guages working.

I'm leaving the oil temp sender plug(goes to sensor just below the oil pressure sending unit on the back plate), the ground wire that bolts to the #2 rotor housing and the plug that goes to the back of the altenator. The rest of the plugs go to the solenoids, injectors and other sensors that aren't needed with my fuel computer(has its own harness and sensors).

The second harness that goes thru the drivers side of the fire wall will remain untouched for now. It seems to be where all the ignition related items are.

Have I missed something obvious or am I on the right track? And also, will the igniton go into a default limp mode if the none of the injectors or sensors aren't plugged in?

 

1) Three of the ECU's grounds go to that rear rotor housing point, not 1...Don't know if that's going to affect you, though...
2) Gonna need to retain the CAS inputs (4 wires)
3) As long as the igniters are getting juice, and the CAS is doin' it's thing, I don't think you could have an ignition "limp mode".

 

1. The ground I'm talking about has two wires terminated at one connector. Not sure about the third one you mentioned but I'll look for it. There is another ground from the firewall to the rear plate but I don't think thats what your talking about.

2. That input is on the other part of the factory harness that routes thru the firewall at the drivers side. I haven't touched any of it.

3. I hope its that simple. Would be nice.

Thanks for the reply Wayne.

 

That 3rd ECU ground I'm talking about splices into the harness at some point before it gets to the housing ground...I don't know exactly where, as well I don't know if you'll even need it...2 of the 3 come from the same ECU plug as the all the injector wiring, so I've always assumed that is the ground for the injector circuit that the ECU switches, so, you might not need those either (but I would keep them just in case)...

 

I know which one your refering to. I saw it when I was unwrapping the harness. The injector grounds are gathered together. When I first saw it I thought that someone must have repaired the harness before I bought the car(10 years ago) but then I figured it out. Seems like I'm set then.

Thanks again.