Something weird happened today.

Situation: Wx cold (22deg) but clear no wind. Both times following a truck that was mid 80's and engine's were buring oil (exhaust smoke was black).

I wa driving along at about 45-50 mph. Got a strong electrical burning smell for 2 seconds or so. let off the accelerator and immedicately started to check all gauges (idoit one--I hv not gotten my gauges yet), checked all lights but did not see anything wrong. Truck behaved normally. About a half hour later while following another mid 80's truck with an engine that looked like it was also buring oil (yes there are a lot of trucks in Kodiak that burn oil) I was doing close to the same speed. It sounded like 2 loud bangs (my first thought was I hit something, a tire blew out or the engine backfired). both coming from the rear of the truck. Again, I let off the speed and started checking all mirrors for oil in the road, signs I hit something or pieces of the tires. but nothing. I heard 2 additional bangs (one right after another) but these were quieter almost faintly. I also checked my exhaust brake. When I got to where I was going I checked underneath the truck for any signs but there was nothing. Tonite on the way home no problems

My question is what should I be checking? Can a diesel backfire? What could be wrong electrically and where do I start?

Help please

Dawna

 

A diesel cannot backfire unless it drops an exhaust valve, so rule out engine problems if it is running good. The 98 with the 12 valve also rarely has any mechanical or fuel system problems. If your truck still has the cat converter, it may be that it is plugged and starting to get hot spots. Most guys remove the cat and deposit it at the nearest recycle center.

I would suspect that your exhaust brake has been used to warm the engine on cold mornings, and that the cat was not getting enough heat to warm up the entire matrix, and that you stepped on it and dumped a bunch of unburned fuel into a cold cat, and then only the few hot spots from plugging ignited the fuel.

 

Could have been rocks popping out at high speeds also....I know when I get on the freeway I have them come out over 50mph and hit frame fenders and anything else in the way...Just a thought.