So my dad and I tried to resurrect his '84 xjs today that has been sitting for about 5 months. It wouldn't start and we ran the battery dead cranking it. Recharge the battery for a second go and it fires up finally. We sit in the car letting it idle for about 5 min and shut it off. After we got out of the car burning oil smoke was billowing out under the hood. I assume it is just some leaky cam gaskets that has been seeping oil that just needed to burn off.

What was more alarming though was when I popped the trunk and got a face full of smoke. This smell was no oil. It had me hacking and coughing for 10 minutes. It was sweetish and dry and smelled like something was on fire. The smoke was whitish with some gray. I disconnected the battery, choking on the smoke which seemed to be coming from the right side, behind the ecu. It died out after another 5 min. What The Heck!?

 

Sounds scary. Electrical fire in the trunk maybe?

Cheers
DD

 

Ok so I FINALLY got back to this project. Traced smoking to a rogue ground wire with all of its insulation gone for a good 8 inches.

Heres the scary/depressing/difficult part. It comes from a loom with a ton of ground wires together. It terminates with about 6 other ground wires. 4 (it included) go into a single connector and two more with another connector, bolted under one bolt 2 inches in front of where the battery ground cable is grounded to the body as well.

I have NO IDEA how I am going to trace this wire which seems to disappear behind the fuel tank (great electrical fire + gas).

The photo attached may explain things better. basically I need to know where this wire goes, why it is all of the sudden shorting, and above all else how to fix it.

Thanks

PS (this is my dad's '84 not my 87' in my signature)

Just noticed the bottom caption got cut off. Its supposed to say exposed wire, insulation thats left is black)

 

UPDATE: car starts with wire disconnected. Car does start with wire connected but it glows red hot and smoke starts to billow. Why is no fuse blowing?

 

The pic isn't very clear.

Are other wires damaged? Can you get far enough into the loom to find undamaged wires?

Cheers
DD

 

You'll want to clean those ground lugs before all is said and done :-)

I *suspect* you'll find more burn damage, and possibly the source of the problem, if you open up the loom as far as you can.

Cheers
DD

 

Cut all wrapping off of harness and found that it merged with the ECU plug harness. Swapped the ECU and no more smoke! As you said too Doug, about 2 ft of the wire is damaged so I'll have to splice in a new section of wire and get an ECU. (the guinea pig was out of my car). So there is the answer! ECU problem = Smoking trunk.

Also: took the old ecu apart and nothing inside looked burned up or charred as you might expect with such a problem. hmmm.