For everyone who was kind enough to contribute to my previous post, "Fire in engine compartment, now need info on alternator wiring", ...

http://www.brickboard.com/RWD/volvo/1517333/220/240/260/280/fire_engine_compartment_now_need_info_alternator_wiring.html

I found what I think is the cause of the fire! And it wasn't what I had originally thought!

I reconstructed a new wiring harness (had to buy a crimper for $75 for a 6-AWG wire's insulated butt connectors and terminals), and hooked it up without much fuss. The car started right up, and all but one of the idiot lights behaved properly, along with my gauges (voltmeter, etc.).

But the idiot light that was flickering on was the oil pressure light. I was confident that I really had good oil pressure, so I took a closer look at the pressure sender (to make sure I had put the connector on the stud properly) and saw oil dripping out (about one drop per 2 seconds) of the short tube (around the connector) as well as out the edges of the sensor.

Then I realized that the exact site of the fire was directly beneath this sender, on the cross beam below. So now I'm figuring that the oil had somehow ignited and was the fuel for the fire that consumed the wiring. But I had never heard of this before on this forum. Is this the first case?

QUESTION: I'd like to ask if anyone can please tell me the size of the socket (I know I need a long version) to unscrew the oil pressure sender. Almost all my sockets are too short (that tube protecting the stud is in the way), so I can't try them out for size.

Anyway, I can see (in retrospect) how I missed that. It was a small leak, and my attention was fixed on the fire -- it seemed easy to blame the wiring or the alternator, since they were right there in the midst of the flame.

Comments welcome.