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Tins
18th January 2026, 11:26 AM
We know that oil migrates from the injector harness to the red plug and parts beyond. My question is, does it travel down the outside of the wires , or inside the insulation down the metal itself, or both ?

Captain_Rightfoot
18th January 2026, 12:00 PM
We know that oil migrates from the injector harness to the red plug and parts beyond. My question is, does it travel down the outside of the wires , or inside the insulation down the metal itself, or both ?
My understanding was it was in the wire. What's remarkable is that in a defender it actually has to go up hill a bit to get to the plug.

I seem to replace a loom every few years. I don't have that particular issue at the moment though. [bigsmile]

Tins
18th January 2026, 04:54 PM
Capillary action will do that.

Thanks.

Tins
18th January 2026, 07:10 PM
I’m thinking about 3D printing a box to put the ECU in. My car has a different battery tray to standard. Trying to come up with a plan to stop the oil. Haha.

Blknight.aus
18th January 2026, 11:43 PM
The oil migrates between the insulation and the individual wires that make up the wire in total.

My solution as part of fitting new injector harnesses inside the head is to cut the wires (one at a time) and solder in about 15mm of 1/1.25/1.5mm (depending on what I can get) enameled copper wire (use motor grade stuff the enamel has a higher temp rating) The solder joints get heat shrink applied which covers each solder joint but leaves at least 5mm of the enameled wire exposed.

From memory from the first day you see oil at the head side plug you have under 5K Km till it hits the ECU.

Once the mod is completed if you're leacing the vehicle for several days unplug the ECU side plug and the oil will slowly drain out...

In a previous post I showed a method of getting metho in a bottle onto the ECU side of the harness to flood the oil out of the injector harness.

Good luck

Tins
19th January 2026, 09:38 AM
The oil migrates between the insulation and the individual wires that make up the wire in total.

My solution as part of fitting new injector harnesses inside the head is to cut the wires (one at a time) and solder in about 15mm of 1/1.25/1.5mm (depending on what I can get) enameled copper wire (use motor grade stuff the enamel has a higher temp rating) The solder joints get heat shrink applied which covers each solder joint but leaves at least 5mm of the enameled wire exposed.

From memory from the first day you see oil at the head side plug you have under 5K Km till it hits the ECU.

Once the mod is completed if you're leacing the vehicle for several days unplug the ECU side plug and the oil will slowly drain out...

In a previous post I showed a method of getting metho in a bottle onto the ECU side of the harness to flood the oil out of the injector harness.

Good luck

That's the sort of idea I'm looking for. Got a couple of spare injector harnesses to practise on. Have you put a vid up on your YT channel?

Blknight.aus
21st January 2026, 02:38 AM
That's the sort of idea I'm looking for. Got a couple of spare injector harnesses to practise on. Have you put a vid up on your YT channel?

not yet,

and the mod gets done on the engine side of the plug, not the harness that sits inside the rocker area. Althoug the wire is the same and practicing on dead injector harnesses is a good idea to develop your "dealing with oily wires when soldering" skills