legacycentral bbs

That was some damn good deduction. I'm impressed.

Oh man, this is why this board is so much better than nasioc. One of the things that came up on state inspection was that I needed a re-charge!

Best deduction ever.

Are there fusable links in that segment of wire?

No; it's just wire. As far as I know, there aren't fusible links anywhere in the harness of the entire car.

Check and see if the loom around the hole is wet or slimey. If it is, the chances of the freon idea is less likely a chance.

Aww shucks guys *blush*

Matt - I've always wanted one of those hats and a pipe

All the more impressive that you beat the rest of Scotland Yard (LC) to such a wierd conclusion.

I was always good at riddles and always famous in school for finding loopholes.

Check for the sliminess like I mentioned. I personally have my doubts that freon did that.

Right or wrong it's still a brilliant deduction, perfectly logical. Phil, I seriously think you should be a mechanical engineering student or at least try out to be on Monster Garage.


My idea wasn't too bad either....

Josh - If someone had done an R-134a retrofit, I think it could happen. I believe both PAG and polyol ester oils can eat plastic. Yeah, the refrigerant itself shouldn't really do much damage there, since it would be a cold gas, but maybe the oil could do it.

I've had esther oil on my hands.....plus it comes in a plastic bottle.

Not saying it didn't happen, but in my mind the chances are low.

Ok, massive burst of clues....

Headlines:
A) I don't think it was the freon, but I can't say for sure
B) It melted from the outside. The only thing hot near it was the exhaust. My hunch says exhaust is most likely culprit
C) There's a lot of funky electrical stuff going on... maybe unrelated but pisses me off and complicates things.


Clues:
1) The place where it melted has a lot of possible culprits:
a) directly above the hot-as-crap exhaust (downpipe?)
b) directly behind the turbo
c) there is an electrical junction in the harness right where it melted (see photos)
d) the clean trail on the firewall below the trouble spot.

2) The clean trail is clean, not wet. It goes straight down towards that downpipe. I wonder if it was cleaned by oil from the turbo, freon from the AC line, rainwater from the hood, or heat from the downpipe?

3) I blasted the AC for a 10 minutes and the joint wasn't leaking as far as my hand could tell. And the AC defintely got goin' because it was cooling the passenger compartment very well. Plus, the freon idea seems far fetched the more I think about it.

4) No slimyness around the plastic, Legacy777.

5) There seems to be a lot of oil around on the outside of the engine near the turbo. There was also traces of black fluid inside the vacuum line that goes to the pressure sensor (from the intake manifold). Normal or bad sign?

6) The harness was clearly melted from the outside not from the inside. I cut the shell off the harness and took pics (see below). You can see that the plastic in-wiggles were preserved while the out-wiggles melted away. This is the only thing that makes me think that it is not the wiring overheating - because every other clue points to electrical probs.

7) The CEL codes became really persistent - they kept coming back right away - even after I cleared the ECU many times. I couldn't drive the car or generate boost due to limp mode.
24, 35, 44 (idle air control valve, canistor purge solenoid, wastegate solenoid). Decided to concentrate on electrical problems instead of melting harness since I couldn't drive.

I checked out the wastegate solenoid. 19 ohms. The harness appears to have connectivity and no short between the two wires. None of the readings on that harness connector seemed to change when I poked at the trouble spot on the firewall. What else should I check?

9) After poking at the connectors, plugging and unplugging, I haven't gotten the codes for the last few starts and was able to drive again. Stupid connectors!!!

10) what's going on with the wiring in the photo? One black wire comes from the right. The other three black wires come in from the left, then curl around and bundle with the first one. Then they head off to the left as a bunch. Those three black wires couldn't be the three things that are throwing codes, could they?

11) I just hooked up a boost gauge (and did a really shoddy job of it!). Off boost: -20 in.Hg. On boost: 9-10 psi (full throttle in third). Nothing unstable about the boost. Vacuum wandered around a bit based on my light throttle application (normal I assume?) Good boost makes me think that wastegate solenoid is working and the codes are bogus.

12) After doing a 4-5 hard pulls in 3rd gear on boost, I poked around out the engine compartment. Turbo shield was lukewarm to touch. Downpipe was hot - didn't touch! Wires were warm but touchable (nowhere near melting).

Slow Res:
http://www.freewebs.com/rallysam/P5040004.JPG
http://www.freewebs.com/rallysam/P5040009.JPG
http://www.freewebs.com/rallysam/P5040013.JPG

Fast Res:

could a chemical have been sprayed in there by the previous owner and melted the plastic?

or maybe you had an uppipe leak at one time.

Could hot ass coolant have sprayed under pressure out of a ruptured coolant line (like the turbo supply line) ? Can coolant get that hot?

This seems equally improbable as the A/C system causing the damage, but just to throw it out there: maybe a pinpoint exhaust leak (cracked exhaust housing/downpipe/gasket) could cause a directed stream of hot gas and it just happens to be hitting the wiring loom? Like I said, seems kind of farfetched but stranger things have happened.

Not sure about where the black wires are routing. You could try peeling back the tape and taking off the loom to see if you can determine what's going on.

coolant typically doesn't get above 200 F So I would say that's probably not the cause.

Personally, I'd be suspicious of the previous owner screwing with things.

Legacy777 wrote:
Personally, I'd be suspicious of the previous owner screwing with things.

Yea, one thing I'm not sure Sam mentioned: is this damage new, or it is something that occured prior to your ownership of the car? Could it be that someone simply set a drop light on thing and melted it a long time ago or something (Tom M's suggestion, not mine)?

Hey Armitage, thanks for stopping by!

I have no idea if the damage is new or old. I've only had the car for a few weeks.

It could be one of these "ancient history problems" a lot of you have suggested (one time he put down something hot, one time there was a coolant leak, one time somebody sprayed chemcals, etc...) but I have no way to know. So, I kinda want to verify that I don't have something ongoing before I assume that you are right.

One thing that makes the think it might be ongoing is that these electrical problems have gotten a lot worse since a few weeks ago when I first bought it.

So, what are the last critical things to check out before I can safely ignore this problem? Remember that I have no idea the history of the car.

- fix ECU codes somehow
- verify boost is under control (DONE)
- verify I am not lean and superheating exhaust (buy EGT?)
- verify that the clue about oil all over the place is not a problem sign (thoughts?)

rallysam wrote: So, I kinda want to verify that I don't have something ongoing before I assume that you are right.

Could try wrapping the affected area in heatshrink tubing and drive the car around and see if the problem is ongoing. It should manifest itself quickly because the tubing would contract in areas exposed to high heat.

I have no experience with your car, but to me, when you start experiencing all sorts of new computer-related problems all at once, I'd go to the source and check your ECU. On my car, the capacitors in the ECU start leaking over time, causing damage to the circuit board and all sorts of fun electrical gremlins. Got a known-good spare you can swap in there and try?

armitage wrote:Could try wrapping the affected area in heatshrink tubing and drive the car around and see if the problem is ongoing. It should manifest itself quickly because the tubing would contract in areas exposed to high heat.

Oh, that's a cool idea! I'll swipe some heat shrink from the office this weekend and see what happens.

armitage wrote:I have no experience with your car, but to me, when you start experiencing all sorts of new computer-related problems all at once, I'd go to the source and check your ECU. On my car, the capacitors in the ECU start leaking over time, causing damage to the circuit board and all sorts of fun electrical gremlins. Got a known-good spare you can swap in there and try?

Ugh, the ECU scares me. Sure, I'm an EE by day. But that just means that I KNOW how bad of a mess I am getting myself into. If I had a spare, I'd drop it in. But I don't want to borrow one that someone is using if my car might hose it.

Before I go there, I'll probably spend more time tracing wires and poking with a mulimeter to see if there is a cabling problem.