Engine loom has melted on my 300 tdi

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ryan_1993

ryan_1993

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Just been in Scotland and last night my engine loom melted.

Managed to get to Gretna and decided it wasn’t worth the risk so got it recovered home.

The engine loom has completely melted and I am not sure why.

We have done heat gasket last weekend so wondering if some wires got disturbed?

Can I buy a non immobiliser engine loom from autosparks and just bypass the alarm on it? As its a 90 CSW
 

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It's melted because it's been rubbing on the manifold by the looks of it.
Replace the damaged wires with new cable of the relevant amps?
 
Anaconda said:
It's melted because it's been rubbing on the manifold by the looks of it.
Replace the damaged wires with new cable of the relevant amps?
Click to expand...

The whole loom has gone right around the engine all the plastic covering has popped open and all wires are exposed.

That portion touching manifold was from an old kenlow system i think thats long since been removed.

I just moved it for the purpose of photo
 
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Trapped wire, short circuit and burnt the loom out rather than blowing a fuse?
Some bodged up previous owner modification?
Hard to say with the photo as it doesn't really show that much damage.
 
Anaconda said:
Trapped wire, short circuit and burnt the loom out rather than blowing a fuse?
Some bodged up previous owner modification?
Hard to say with the photo as it doesn't really show that much damage.
Click to expand...
Apparently the loom isn’t fused? For the engine? But i don’t know enough about the wiring setup on defender
 

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ryan_1993 said:
Apparently the loom isn’t fused? For the engine?
Click to expand...
Really, nothing on the engine loom is covered by any fuse?
That's a bit worrying isn't it?
I'm not an electrical expert but it might be wise to remove the outer loom insulation and try and find exactly what has melted and why if possible.
 
Anaconda said:
Really, nothing on the engine loom is covered by any fuse?
That's a bit worrying isn't it?
I'm not an electrical expert but it might be wise to remove the outer loom insulation and try and find exactly what has melted and why if possible.
Click to expand...

I don’t think any defender engine loom is fused not specific to my vehicle.
 
The melting of wiring like that is likely a case of something earthing that should not be doing so rather than a "bad"earth.
Or it has been exposed to something like an exhaust leak. Looks to run close to manifold joint.
 
tottot said:
The melting of wiring like that is likely a case of something earthing that should not be doing so rather than a "bad"earth.
Or it has been exposed to something like an exhaust leak. Looks to run close to manifold joint.
Click to expand...

Now I have it at home the wire which has melted appears to be for the ignition I think.

The other two although a bit scorched definitely aren't the source of the issue that is ignition then

Well its the lowest connection point to the alternator anyway
 
So still struggling to work out what that connector actually is.

The further connector down on the alternator which melted seems that it could be several things and I am a bit confused.

one post said it could be the battery warning charge light. Now that the wire has been pulled the battery light is still going out as normal.

The other to stop the radio going fuzzy???

Another that its if you want to fit a rev counter but my defender doesn’t have that

Then one being the ignition live, but again that still all works with the wire pulled. So I am a bit stumped
 
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ryan_1993 said:
So still struggling to work out what that connector actually is.

The further connector down on the alternator which melted seems that it could be several things and I am a bit confused.

one post said it could be the battery warning charge light. Now that the wire has been pulled the battery light is still going out as normal.

The other to stop the radio going fuzzy???

Another that its if you want to fit a rev counter but my defender doesn’t have that

Then one being the ignition live, but again that still all works with the wire pulled. So I am a bit stumped
Click to expand...
Google A127 alternator wiring diagram, proper simple how they should be, only needs two wires to work.
Only thing that carries real power is the fat (brown I think) wire that runs to the starter positive.

Of course some muppet could have got the power for some accessory direct from the alternator positive?

Tbh that does not look really burnt, have you checked manifold gaskets etc as @tottot suggested above?
 
lynall said:
Google A127 alternator wiring diagram, proper simple how they should be, only needs two wires to work.
Only thing that carries real power is the fat (brown I think) wire that runs to the starter positive.

Of course some muppet could have got the power for some accessory direct from the alternator positive?

Tbh that does not look really burnt, have you checked manifold gaskets etc as @tottot suggested above?
Click to expand...

I don’t know what proper burned is, but hopefully this photo helps its closer

The smaller wire on the lower terminal has shed its out pvc skin completely through the loom as I have pulled it through. Managed to get it up to the Thermostat elbow atm will continue pulling it through if i can.

It isn’t touching the exhaust manifold the part what goes off to the right I moved to get a better photo of the dameg, that part of the loom is from an old Kenlow pre heater system it had fitted some time ago. The wires on that end are cut blanked off is and left in like a cylindrical rubber housing normally it just sits in the wheel arch.
 

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That does look proper melted, no covering left on wires.
It looks to me it could be an add on line taped on the outside of original wire cover.
Peel right back and try and see where it goes and maybe find a bit with cover colour still on it.
 
tottot said:
That does look proper melted, no covering left on wires.
It looks to me it could be an add on line taped on the outside of original wire cover.
Peel right back and try and see where it goes and maybe find a bit with cover colour still on it.
Click to expand...
Its the same through the entire loom so far
 

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dag019 said:
that will be the wire that has earthed without a fuse. What was it connected to at the end? by following it back hopefully you will find where it has contacted to earth out.
Click to expand...
Its the redundant EGR system all the electrical gubbings are still present though so something either failed or overheated in that. The EGR was blanked off but all the control systems are still present.

I am going to strip it out
 
ryan_1993 said:
I don’t know what proper burned is, but hopefully this photo helps its closer

The smaller wire on the lower terminal has shed its out pvc skin completely through the loom as I have pulled it through. Managed to get it up to the Thermostat elbow atm will continue pulling it through if i can.

It isn’t touching the exhaust manifold the part what goes off to the right I moved to get a better photo of the dameg, that part of the loom is from an old Kenlow pre heater system it had fitted some time ago. The wires on that end are cut blanked off is and left in like a cylindrical rubber housing normally it just sits in the wheel arch.
Click to expand...

Seen that before with a pinched wire at the back of the head ...
 
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