Wiring Help

[Baikal Bimmer]

So the engine is installed and it’s time for wiring. Our engine, harness, and ecu all come from a 1992 735 automatic car. We have however changed to an l jet intake, injectors/fuel rail, and throttle body. Thanks to several days of research, we have been able to eliminate a few of the obvious wires that we don’t need, however, I am willing to bet a lot more can go.
Here are our questions:

1)since the car was an automatic, the throttle position sensor is a round plug, and we only need three of the wires that run directly to the ecu. Now the l jet throttle body has a 3 pronged tps sensor, so we have sourced the corresponding plugger end to attach to the three wires we will be using. The question is, I’d assume certain wires need to connect in a certain order with the two tps pluggers, so what order do they go?

—I can clarify if needed

2. What else can I get rid of on this harness?



3. If we were to go to megasquirt, could we use this harness? What would we need to change/add? Is it better to go straight to megasquirt?

4. What wires connect to the coils from the chassis harness?

5. There are many threads about the wiring, but sometimes they give conflicting information, I would like to know, specifically with my type of harness, definitively what wires connect to the e9’s chassis harness

6. What’s this for? It’s not the clock so I don’t know where it goes.


If anything needs clarification I would be happy to do so.

 

[HB Chris]

6 could be hazard switch?

 

[Baikal Bimmer]

Another question related to the ones above, how does the ecu get power? Does it come from wherever the harness attaches to the chassis harness, or does it receive power separately?

 

[HB Chris]

Motronic 1.3 has two relays, one power to ecu the other for fuel pump. Power is green switched power from chassis to both relays.

 

[HB Chris]

My coupe is not here, hope I get this right, b35 harness to chassis harness:

1. Tach double black wire, use center shielded wire only to thin black tach wire (or was this coil - )
2. Black/yellow to black for starter
3. Green ignition power to green
4. Blue to blue for Alt D+
5. Brown/violet to brown/white for water temp
6. Brown/green to brown/green for oil pressure

I removed wires before putting in coupe, I removed diagnostic plug and removed those wires back to the 51 pin ecu plug. Don will correct me!

 

[Baikal Bimmer]

My coupe is not here, hope I get this right, b35 harness to chassis harness:

1. Tach double black wire, use center shielded wire only to thin black tach wire (or was this coil - )
2. Black/yellow to black for starter
3. Green ignition power to green
4. Blue to blue for Alt D+
5. Brown/violet to brown/white for water temp
6. Brown/green to brown/green for oil pressure

I removed wires before putting in coupe, I removed diagnostic plug and removed those wires back to the 51 pin ecu plug. Don will correct me!

That aligns with what I’ve read so far regarding the chassis connection. As far as the ecu harness goes, and as you mentioned sfdon can correct us, I’d assume much more than the diagnostic plug can be eliminated. I’ve already removed the auto trans connection, but it still looks like a rats nest.
— thanks for taking the time to respond

 

[Baikal Bimmer]

I spoke to Carl Nelson down in La Jolla, he was able to give me the right three pronged connecter for the tps, but he wasn’t able to tell me which wire goes to which port on this connector, if that makes sense