jonjonwells

Ok here's the story. My car had until friday the what I assume to be stock wire loom around some of the components under the engine bay. This is to include some heater hoses, vacume lines, etc. Well I did a 1 hour road race to work at roughly 90+ MPH. As I was pulling in to work, the car died and smoke started pouring out of the engine bay. Upon close inspection, It seems that this loom actually caught fire where it was resting near the engine block. It was covering the vacume line coming from the oil filler tube to the firewall. This caused a little bit of damage to other items under the hood, but nothing disasterous. I just happended to have a fire extenquisher handy.

So here's the deal, has anyone ever had this happen to them, or ever heard of it happening? Do we all need to make sure to have better clearance?

trochoid

iTrader: (6)

Sounds like the heat melted the wire covering and you had what started out as an electrical fire. Did it catch the oil on the pcv system on fire too? I have wondered about allowing wires and vacuum hose to lay directly on top of the engine, I'll be more careful with that now. Sorry to hear about your mishap, I carry a fire extiguisher too.

jonjonwells

Thats the weird thing, NO electrical was damaged. All the wires are fused together in a ball, but none are exposed or grounding to each other. It was just the shroud. And the oil didn't get a chance to light either, i'm sure that would have been fun. I do however need a new choke cable. It fused the sheith to the core wire.

trochoid

iTrader: (6)

I'll bet it's still an electrical short/surge somewhere. I have heard of the choke and/or accelerator cable doing that due to a missing ground. The cable itself ends up being a direct ground from the engine to the chassis. Do you have a ground wire coming from the firewall to the top of the engine. I don't rmember if there was one there or not?

jonjonwells

not sure, will take a pic tommorow. at least now i have a good reason to clean up the wire harness.

totensiebush

it isn't easy to light motor oil on fire. I have had my motorcycle dripping oil onto the exhaust manifold on long trips, and although it produces quite a bit of smoke it has never actually caught fire.

Kentetsu

If your engine is running hot enough to melt wiring, then you have important issues to deal with (unless electrical issues started the problem). If it was melted due to engine heat, check your timing and coolant system.

jonjonwells

Timing and Coolant checked by Trochoid just two weeks ago.

trochoid

iTrader: (6)

John, the more I think about this, the more I think it needs another ground to the engine. Since we took off all of the rat nest and replaced the carb and intake with the Mikuni, you lost some of the normal grounding paths. Couple that with the MSD's hotter spark, it went through the choke cable and what was left of the rats nest wiring. Not something I would have expected, but we all learn from the little mistakes.

jonjonwells

Here's a couple of pics of the burn't area.

Not great pics, but you can see the damage done to the choke cable really well in pic 3.

trochoid

iTrader: (6)

Looking at the pics, I would say a wire shorted/grounded in that bundle. The choke cable damage appears to be from the fire only. The heat from that hard run may have melted the sheathing, or one of the wires simply grounded out. Did you blow any fuses?

I'll have to look around, but I should have and entire choke unit and cable in the shop.