ECU plug, pin B4 question

[mblum]

So I'm trying to hunt down my random Code 42 issue, and I think I've found it. Plug B4 on the Ecu connector is loose in its socket, plus a previous owner appears to have spliced a wire onto this lead.

In the pic you can see the ugly white wire with the red wire spliced to it, this is pin B4.

To me the red wire spliced onto B4 doesn't appear to be OEM. I've tried to follow it and see where it lands but it doesn't follow the rest of the wires on the ECU harness and breaks out and goes up under the dash (circled in yellow)2. I can trace it up under the dash near the right side of my dash cluster but from there I can't see where it goes without ripping the dash apart.

Anyone have any idea what reason someone would want to splice into pin B4? The purpose of this?

I have a new ECU plug splice from Caspers that I plan to install this afternoon to address the OEM plug thats in poor condition, but I'm questioning this red wire.

Any help is appreciated

 

[Nigel]

That is the spark control wire, correct? Could have been for an early MAF translator that had timing adjustment.

 

[mblum]

Yes, it is. From what I could tell its a possibility to tap into this wire for a 2 step, rpm tach ect. An older style MAF translator is a possibility too.

I'm going to remove it from the equation, I don't have any reason to believe its being used and I dont need more sneaky issues to deal with.

Got 4 more wires to solder up and both ECM plugs and the ignition module plugs will be new.