Thursday, October 28, 2021

A new diet!


A wire diet, specifically.

The wiring harness just for the top of the engine is insane. I think it weighs about five pounds. And there's some stuff on it I am just not going to use anymore. Certainly the plugs related to the TGV (tumble generator valve) actuators and angle sensors, and possibly other things as well.

But to know what to take off and what to keep, I have to know what everything is, so I spent some quality time on it on the workbench.

First, I just unplugged everything I could, adding labels as I went. Ignition coils, fuel injectors, crank and cam position sensors, etc., etc.

But there were three plugs that had gotten unplugged earlier and not labeled. And with the engine accessories not installed at present, it's pretty hard to figure out what plug goes to what device.

The only way I know of to figure all this out is to go to the wiring diagrams, which is a nightmare in itself. 

I started by pulling back the loom around the wiring a little bit and looking at the colors of the insulation.

Here's an example. Now, these wires have been in a hot, dirty, oily engine bay for fifteen years, so they are not in the best of condition, but one of the wires is pretty clearly red, and the other is green with a stripe. At first, I thought this was a dirty green/white wire (GW in wiring diagram parlance), so I scoured the wiring diagram for any connector with two conductors, R and GW. No luck.

So I looked again and decided maybe it was a yellow stripe - GY. But I still could not find the right connector on the diagram. I then remembered that there's another color - light green, or Lg. So, a third pass, looking for Lg and R.

And this time I found it! It connects to the purge control solenoid. Now I can research that solenoid and figure out if I need to keep that, or if I can take those wires out.

Fortunately, the other two unidentified connectors were slightly easier (knock sensor and PCV diagnostic, respectively), but just searching those three out took a few hours, and completing the labeling took all day.

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