Holy Crap, It's on FIRE!!!!

Friday night I was cruising the circuit and racing some imports out at the local Sam's Club parking lot. I was driving for a good 3 hours that night. It never got up to 210*. After that I went to my buddys house to hang out and like 20 minuites after I got there I had to go outside and get something from my truck when I noticed it was glowing from under the front of the truck. I ran inside and told everyone to grab a fire extinguisher and we came out, I popped the hood and we put it out. Then like 15 seconds later the thing sparked a few times then caught fire again. We grabbed the hose and sprayed it down again. Then it lit up a third time and I realized it was something electrical so I unhooked the battery and it was fine after I put it out for the last time. The next morning my buddy towed it the 2 miles home with a towstrap and we finally got to look at it. The only things that burnt were both battery cables, the starter selinoid, the oil pressure sending unit and some of the spark plug wires. Were there any recalls on anything that could start a fire in a 88 MJ 4.0L? Its had a rear main leak for about 7 months and it had a valve cover gasket leak for like 2 months. The motor was sort of covered in oil on that side. Is oil flamable enough to lit on fire? What could have made the spark?

Oil is plenty flammable enough to catch fire (nothing like old motor oil to give a little boost to the brush pile), though it usually doesn't flash just when it spills on the exhaust, and isn't likely to have done so if the oil wasn't pretty fresh. But once it's gotten hot enough to flash it will reignite pretty easily. I've had a couple of cars catch fire from oil spilled on the manifold when adding sloppily, and one from a ruptured power steering hose. I'm guessing something either with the battery cables or the starter solenoid itself sparked it, but after you replace the burnt wires you may never know for sure.

I finally took it all apart today after school. It looks like it was the oil pressure sending unit(the thing that is inbetween the block and the oil filter) That looks like it is the most melted and it looks like that dripped onto the UCA. One of the motor mounts melted pretty bad so now I need a motor mount for a 88 4.0L. If anyone has the passenger side one that they would be willing to donate. I, of course, would pay S&H.

Back in 92 I bought a base-line model 4banger 2-door XJ brand new and had it for about a week until I had something like what you described, had it towed back to the dealer and since it was under warranty I got fulle reimbursed, never did find out what the cause of it was...

I always heard that the o rings on the fuel injectors were prone to leaking in the Renix 4.0ls and that could cause fires.

Yes, Oil is flamable. It is a petroleum product. Don't ask how I know...

Will.

Atl XJ said:

I always heard that the o rings on the fuel injectors were prone to leaking in the Renix 4.0ls and that could cause fires.

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It was on the other side of the motor and it was more of a slow burning plastic fire/electric fire.

I had the alternator go nuts on me, and instead of the fuse popping it just got hot, melted the whole PDC into one big glob of plastic. I had to cut the wires off and rewire them into an aftermarket fuse block. I have a HO motor but still something for you to check.

Dingo

PM me with your address, got a brand new mount you can have. Its for my 90 XJ but they should be the same.

dizzymac said:

PM me with your address, got a brand new mount you can have. Its for my 90 XJ but they should be the same.

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