Disco 2 TD5 Injector loom - clean or replace red plug end of harness?

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WLJayne

WLJayne

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Hey guys,

Me injector loom is fecked. I'm buying a new one, but I was wondering what I should do about t'other end of the loom with the ECU plug on it seeing as presumably that will still be full of ****e even after I've replaced the injector loom.

Is there any way to clean it?

Ta :).
 
Use circuit cleaner, in the red plug. You can remove the white cover to really clean it out.

Plus some people open the ECU to check in side and clean if required. ( Do this at your own risk. )

Once injector harness changed , clean the red plug once in a while as the residual oil comes out.

cheers
 
Cheers mate. Cleaning out the plug has made it just about driveable around town so I can see the sense in that. I'm guessing the oil creeps down the outside of the wires, so maybe I'll douse it with cleaner both ends when I change the loom and hope it thins the oil and drips out of the split in the harness tube. I imagine a few treatments should sort it after the loom is replaced. I'm just praying is it the loom and not the fecking fool pump or summat expensive...
 
I'll just have to clean it out a few more times after I've replaced the loom then. Should get it all out eventually.
 
I concur with everything said so far.
The loom from the head to the ECU becomes contaminated by the oil running along the actual copper wires inside the insulation so it's almost impossible to detect visually. There's not a vast quantity in there but it can take a while to get it out.
Some people use brake cleaner, some use IPA or circuit cleaner which doesn't leave a residue, unlike some "switch cleaners".
If it's really bad, then it might be a reasonable idea to check inside the ECU but as has been said that's at your own risk.
The plug can be partially dismantled which will allow deeper cleaning, and if possible, leave the plug disconnected and disassembled preferably hanging below the cylinder head overnight to try to get some of the excess oil to drain out under gravity.
 
So what actually causes the issues? Is it oil in the wires/pins or oil in the ECU? When I take the ECU out I'll leave it to drain over night, if not much oil comes out then I won't open it.
 
From what I can understand of the problem is that over time the seals start failing on the connection system at the cylinder head end which then allows the oil which is present inside the cam cover (if there's no oil there then we've got bigger problems to worry about :eek: ) to find its way into the insulation covering the wires in the loom to the ECU. When you replace the injector loom, the actual faulty part you're replacing is the seal system.
Once the oil is inside the insulation on the wires it travels by capillary action until it finds itself at the red plug, where it just builds up and then starts seeping into the ECU.
Oil itself is a well known insulator when it's clean, however engine oil also contains particles of carbon and sometimes even metal, and it's those contaminants which can cause the worst of the symptoms. There are also thoughts that the oil can alter some of the deeper electronic characteristics such as capacitance between the wires which might upset slightly the timing of the injectors, but I think it's probably the effects of the contaminants which is more noticeable.
The only way to ensure that the new loom lasts as long as possible is to pay extra care when cleaning out the old seals and fitting the seals of the new loom.
 
Lots of switch cleaner inside the plugs and down the wires I cleaned a mates loom up and its been fine now a good 6 months also split the ecu and gave that a good clean to as oil had seeped in, please use proper electrical switch cleaner maplins sell it don't use anything else. The best cure is a new loom as its fairly cheap and simple to replace
 
biketeacherdave said:
Lots of switch cleaner inside the plugs and down the wires I cleaned a mates loom up and its been fine now a good 6 months also split the ecu and gave that a good clean to as oil had seeped in, please use proper electrical switch cleaner maplins sell it don't use anything else. The best cure is a new loom as its fairly cheap and simple to replace
Click to expand...

There are a number of things which must be considered when choosing a cleaning medium for decontaminating oil soaked components:
  1. The compound used should not leave a residue. Many switch cleaner type solvents do contain a fine lube to treat the cleaned switch faces. The use of such cleaners for this job should be avoided (as I stated in post #6).
  2. The solvent used should not attack any of the original materials, such as plastics. Some such solvents if incorrectly chosen can be of a type which might attack some types of plastics, obviously the use of such solvents should be avoided.
  3. User safety must be of prime importance when using any solvent based cleaner. Two suitable solvents which meet the above points are Iso-Propyl Alcohol or IPA and1,1,1-trichloroethane (not to be confused with trichloroethylene, often called "Trike" which is now probably a banned substance). Both can be referred to as switch or circuit cleaners and can be purchased either in a can or bottle package or as an aerosol spray can which is probably more convenient. If users are unfamiliar with the recommended safety guidelines when using such solvents, the supplers are bound by law to provide a materials safety data sheet upon request, but such information is often available online.
https://en.wikipedia.org/wiki/1,1,1-Trichloroethane
https://en.wikipedia.org/wiki/Isopropyl_alcohol
The usual safety precautions should always be observed when using chemicals and solvent, no smoking or naked flames, use in a well ventilated place, nitrile or rubber gloves, eyeshield, etc. There no need for breathing apparatus, hard hats, ear defenders or the ilk.
 
Last edited:
need to do mine now, best place for a loom and gasket? used jgs before and seem ok, what contact cleaner should I use, WD 40 do a quick dry one
 
Halfords sell electrical contact cleaner which I used when I did my loom
About £8 iirc but a little goes a long way

+1 on jgs, think I got my loom off them actually, it's been fine. Used them for a few things
 

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> The solvent used should not attack any of the original materials, such as plastics.

Good shout - encountered this today using Servisol for exact same job. Rubber seal in red plug doesn't like it and swells up. IPA probable better bet
 
Regardless of the supplier buy only badged Genuine LR loom, dont mess with aftermatrket or so called "OEM" cos they are bad from the beginning
 
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