Need help making bare bones ECU harness for '92 Sundance Duster 3.0L

[Bayley]

Need help making bare bones ECU harness for '92 Sundance Duster 3.0L

Having some rather nasty electrical gremlins in a 92 Duster that has been prepared for Lemons racing duty. It basically hates road racing and wishes it was NASCAR racing instead. Turning left is no problem... but on right turns, the car stumbles and all things electrical shut down.

There is obviously a short circuit somewhere that has rubbed though the insulation, but good luck finding that. Instead, I want to run just bare minimum number of wires from the ECU to the engine. We are a fully gutted race car with no interior, electronics or headlights / tail lights.

All I need is a working ECU to control the engine fuel / spark. Keeping the factory gauge cluster would be nice, but I'll worry about that later (if anyone has a cluster pinout, I sure would appreciate it).

This is what I've come up with: (more post below picture)



Green = I understand it
Yellow = I do not fully understand it
Orange = optional (will likely hard wire to switches on the dash)
Gray = not used

So let's go over the pins I don't fully understand:

3. Fuel pump auto shutdown - Huh? On other SBECs this is simply a +12V battery feed. What (if anything) is different about the 3.0L ECU?

4. Signal Reference (Logic) - what sensors is this a return for? Distributor pickup?

7. 8V Supply - what sensors use this 8V supply?

29. Brake sense switch - any idea what this is used for? Do I need it?

44. Distributor Sync pickup - third wire for distributor?

51. Auto shutdown relay control - Is this an input or output? Does the ECU control the ASR, or is it a slave to the relay?

57. Injector / sense / alt feed - Any idea what this is used for?

Any help is appreciated. Our next race is June 8th and 9th, so we've got our work cut out.

-Andy

[shackwrrr]

Are you using the stock headlight wiring? If not, start at the right headlight and remove those wires from the pack all the way to the left side. That's a good solid 3/4 to half in of wire bulk gone.


I will go over your list later when I'm not on my phone.

[ShelGame]

Yellow wires - you need all of these as far as I can tell.

#2 Fuel Pump - Not sure what this is for exactly
#3 Signal GND - this is the dedicated ground line for all of the engine sensors. You don't want to use just a chassis GND, too noisy.
#7 8v feed - powers the HEP (distributor pickup) and the SDS (speed sensor)
#29 Brake Sw - OK, maybe this one can go. It's only used by cruise control.
#44 Distributor Sync - this is the 2nd distributor signal. It's used to tell which cylinder is at TDC
#51 ASD Control - this is the power for the ASD, which in turn powers the Fuel pump, coil, and injectors (12v).
#57 Inj Sense - this tells the ECU if the injectors are actually closing (diagnostics) without it it will set codes. Maybe it can be deleted, though.