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Hey guys,

The wire harness that runs near the top of fire wall is getting all melted. My mechanic thinks that the turbo is melting it. But, that seems weird because the car is bone stock (far as I know) and there is a good 6 inch gap between the turbo and cable.

Have you seen it be this bad in a stock setup?
Something wrong with the turbo?
Electrical short melting the wires?
Missing a piece of duct work that cools the turbo through the scoop?
I'm driving like a maniac and pushing it too hard?

I will try to take a photo sometime tomorrow.

A photo would definately help.

did I read that correctly? You're missing your chimney? (heat shield that covers the turbo and directs it's radiated heat either up through the hood scoop or down from the hood scoop, depending on velocity)

I'd say the chimney is pretty important for keeping turbo heat out of the engine compartment....

I ran without my chimney and at 16 psi on the stock turbo for about a year without melting my wires. My DP is ceramic coated though but the turbo wasn't. My new turbo is ceramic coated too, however.

Nice.

Yeah, I know people run without their chimneys on this board and this is the first time I've heard of wires melting as a result of it.

Without a photo, it's tough to tell. But the turbo's exhaust/turbine side definately gets hot enough (especially if he drives like a maniac, as some of us tend to do in these vehicles) to melt things should they get too close.

Your turbo/exhaust may be getting unusually hot, as if it's running lean for some reason.

The grounding kit i had on the TW ran from the battery over to the passenger-side strut tower, and was frequently drooping over within inches of the turbo housing. It browned, but never burned.

That sounds possible, given what we know so far. If that's the case, you should look at your fuel system, something may be clogged or starved...

The wires are not loose, and are nowhere near the turbo. So from the sounds of it, something must be wrong.

Lemme go get a photo

To me it doesn't seem unreasonable that the missing heat shield could cause this type of problem.

Is the little diverter under the hood scoop still in place?

What about getting one of those thermo tec insulators.

Maybe these will settle it. Am I normal?









Hi res below. Warning, my web server is SO slow

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Sorry, my web server is so slow

More clues:

1) My ECU was reset due to dead battery. After I charged it up again, if I did hard pulls when the ECU was still learning, would my mixture be off because it hadn't learned properly?


2) Once in a while, but not always, I get all 3 ECU codes on ignition:
24 - Air Control Value Inoperative
35 - Canister Purge Solenoid Valve Inoperative
44 - Duty solenoid valve (waste control) inoperative

I reset ECU pretty much immediately so that I didn't have to drive around limping. After reset, it starts and drives great no codes. But two times, it threw all 3 of those when I tried to start her up.

Even with the high res photos, it's hard to tell what the damage looks like in great detail. Is it possible that a rodent or squirrel did this damage. I had a squirrel do some chewing in my car before. One even found a way inside and was nesting in my glove box.

With that new info, maybe it's possible you have a low res or direct short between two wires. Try ringing them out to see if they're shorted together. If you have a megger you could check for insulation breakdown.

creel wrote:Even with the high res photos, it's hard to tell what the damage looks like in great detail. Is it possible that a rodent or squirrel did this damage. I had a squirrel do some chewing in my car before. One even found a way inside and was nesting in my glove box.

Good thought. But it doesn't look like it was chewed. It definitely looks like it melted.

creel wrote:With that new info, maybe it's possible you have a low res or direct short between two wires. Try ringing them out to see if they're shorted together. If you have a megger you could check for insulation breakdown.

What about this?

The turbo heat is not going to cause that kind of localized damage.

Yeah I agree it looks like a heat issue at that localized spot, but right next to it, the wiring loom looks fine.

First off, you would have to generate HUGE amounts of heat to melt the harness from that distance. Second, if you generated that much heat, there's no way it would cause such localized damage.

What about this?

Yeah, I can definitely check that out. I didn't respond right away because I might not be able to check that for a couple days.

Legacy777 wrote:The turbo heat is not going to cause that kind of localized damage.

Yeah I agree it looks like a heat issue at that localized spot, but right next to it, the wiring loom looks fine.

First off, you would have to generate HUGE amounts of heat to melt the harness from that distance. Second, if you generated that much heat, there's no way it would cause such localized damage.

L777 - so are you also saying that you think some electrical problem with those wires generated the heat?

I agree that it seems like pinpoint devastation. I was wondering if maybe a crack in the turbo ducting / hood scoop or a crack in the exhaust might "blow" a stream of hot air at that one spot. Probably far fetched I guess.

My mechanic was convinced that I was missing a peice of ducting

The wiring behind the wiring loom looks ok. It's the loom itself that is melted. Plus one wire shorting out, shouldn't cause that much heat.

I would say that whatever caused the loom to melt, did it from the outside. You can take a look at the wires in there, just to double check.

I can't see things too closely in the pics, but the wire looks to be ok, and the ribbed portion fo the loom looks to have become stringy, basically the plastic started melting away. A direct contact heat source would melt through the outer ribs first, and then start melting in.

I'm really quite baffled what caused it. How long has it been there? Did it happen all of a sudden?

Very astute, Josh. Yes, the wiring inside does not appear to be melted it's just the loom. And you're right that all the ribbing on the loom is still there - it's just the the wall of the loom is long gone. It's so weird.

I don't know anything about the history because I just bought the car a couple weeks ago. All I know is the strange clues I've encountered in the past two weeks:

1) dead battery once and I don't know why (maybe I left a light on)
2) the melted harness
3) intermittent ECU codes - 3 that are completely unrelated (maybe due to wiring getting scorched?)

Sorry I don't have more info, I will have to keep poking at it when I get a spare moment of daylight that I can sneak out of the office

Man, I wish I had my company's thermal imaging camera, but it's off site right now.

Why does it look wet on the firewall right around the wiring harness?

Freon isn't bad for plastic, is it?

It does look like something corrosive got spilled on it, explaining why the ribbing would still be there as it is probably just a little bit thicker.

Yep, It looks like I might be on to something.

I did a little research and found that Freon is, in fact, a solvent that isn't good for plastics. The recent warm weather probably prompted you to turn on your Air conditioning, which through a pinhole leak in your non-stock AC line (that is an N/A AC line), sprayed freon onto the wiring loom and melted it.

The evidence is in the wet look on the firewall around where the melting occured. Right next to the A/C line where a hole is VERY likely to be.

I bet if you check your A/C system pressure, it'd be slightly low.

I bet things will no longer corrode if you replace the AC line.

[phil] "The game is a foot!" "it's quite elementary my dear Watson"[/phil]

That's it Phil, I'm getting you a sherlock pipe and one of those funny double billed hats!