Engine Harness vs Engine Control Harness

[YNGFrankenstein]

Hello All, 
I'm in the process of navigating the wiring modifications done by a previous owner on my 88 Jeep Comanche 4.0L Automatic. I purchased the 88 electrical manual and found diagrams for both the Engine Harness (picture attached) and Engine Control Harness. I already have a replacement Engine Control Harness from a 1990, but would like to replace the "Engine Harness" as well.  

My questions are, is there another term used for the Engine Harness?
I've looked online for an Engine Harness replacement but I only find Engine Control Harnesses. 

Also, the previous owner deleted the ECU to Engine C103, C104, and C109 connectors and has some under hood lights spliced into the Engine Harness. Is deleting the ECU to Engine connectors a typical move? 

Best, 

 

[Ωhm]

21 hours ago, YNGFrankenstein said:

My questions are, is there another term used for the Engine Harness?

 

Don't know here, just what the 88ElectManual calls it.

 

 

21 hours ago, YNGFrankenstein said:

Is deleting the ECU to Engine connectors a typical move?

 

This is different, but we don't know the reason for it. Correct?

 

 

 

Does your 1990 Engine Control Harness have connectors C103, C104 & C109? Is that the reason for the Engine Harness request?

[gogmorgo]

Deleting connectors isn’t standard practise, but can be done without consequences (other than complicating disassembly) as long as you do it nicely. Usually it’s only done if there’s an issue with the connector pins, corrosion, melting, that sort of thing. But I won’t even attempt to get into a previous owner’s headspace… sometimes it’s better not to ask questions you don’t want an answer to.

Unless the thing is completely butchered I wouldn’t be too concerned about just splicing the new engine control harness directly into the existing wiring. Solder and double-wall heat shrink tubing are your friends. You might even be able to track down new connectors if you really want to. 

[YNGFrankenstein]

1 hour ago, Ωhm said:

 

Don't know here, just what the 88ElectManual calls it.

This is different, but we don't know the reason for it. Correct?
[YF] Correct, I'm not sure of the reason behind it. 
 

Does your 1990 Engine Control Harness have connectors C103, C104 & C109? Is that the reason for the Engine Harness request?
[YF] That is correct, C103, C014, and &C109 connectors are on the 1990 harness but are no longer on my truck. The thought was to replace the Engine Harness to help get the wiring cleaned up. 

Not sure if this is typical with modified renix era Jeeps, but I had the truck towed to two different shops and neither shop would work on the truck with the wiring in its current state, which is why i'm navigating down this path.
 

 

[YNGFrankenstein]

57 minutes ago, gogmorgo said:

Deleting connectors isn’t standard practise, but can be done without consequences (other than complicating disassembly) as long as you do it nicely. Usually it’s only done if there’s an issue with the connector pins, corrosion, melting, that sort of thing. But I won’t even attempt to get into a previous owner’s headspace… sometimes it’s better not to ask questions you don’t want an answer to.

Unless the thing is completely butchered I wouldn’t be too concerned about just splicing the new engine control harness directly into the existing wiring. Solder and double-wall heat shrink tubing are your friends. You might even be able to track down new connectors if you really want to. 

Good points.  "Unless the thing is completely butchered" is likely where we're at. As noted in my reply to Ωhm,  I had the truck towed to two different shops and neither shop would work on the truck with the wiring in its current state, which is why i'm navigating down this path. The recommendation from one shop was to find a donor stockish XJ to wipe the slate clean, but before I sink too much more money into the project, I figured I would spend some time on the electrical myself. 

[Ωhm]

1 hour ago, YNGFrankenstein said:

I had the truck towed to two different shops

 

Sound like this jeep ain't running at all.

 

 

1 hour ago, YNGFrankenstein said:

I figured I would spend some time on the electrical myself. 

 

What are your symptoms?

NO CRANK

CRANK NO START

START WON'T STAY RUNNING etc, etc.

[YNGFrankenstein]

41 minutes ago, Ωhm said:

 

Sound like this jeep ain't running at all.

 

 

 

What are your symptoms?

NO CRANK

CRANK NO START

START WON'T STAY RUNNING etc, etc.

Symptom is idle starts around 800rpm and fluctuates to +1500 about 8-10 seconds after starting. If I don't shut it off, it continues to fluctuate and climb. From my research, this is possibly a vacuum or sensor issue, so maybe shouldn't be worried about the wiring and focus on the vacuum, but diving into the wiring has helped me figure out the difference between my jeep and a stock one. The truck has a lot of aftermarket modifications, so i'm assessing what it will take to give me and others a baseline to troubleshoot issues moving forward.