Flames out the exhaust?

[JHZR2]

Was driving earlier, all of a sudden traffic slowed. A bus in the slow lane was driving slow, spewing black smoke out the back. As we want by, a fairly whispy flame started jetting out the exhaust down to the pavement.

What would cause this?

 

[Scorch]

Gasoline in a diesel motor?

 

[JHZR2]

This was a giant bus

 

[bdcardinal]

Usually no cats to start with. Then an overly rich mixture.

 

[Scorch]

Ridiculously rich, only time I've seen flames out of a diesel exhaust was when a porter filled the tank of an F350 Powerstroke with Gasoline, needless to say we saw smoke, sparks and a raging inferno within a mile, shut the truck off and she was toast. So probably not the case. Was the exhaust routed all the way to the back of the bus?

 

[dparm]

Decel fuel cut. Unspent fuel is going down the exhaust manifold and detonating in the cat converter or even exhaust tubing.

Or was it more like this?

 

[Colt45ws]

injector locked open? Whatever it is, the engine will need a full rebuild. The driver is an idiot to keep driving it.

 

[volk06]

I know you can shoot a candle ( flame out of the exhaust) from a Deere 4440 when some one takes a screw driver to the fuel pump. 130hp to 250hp. For some reason some people love pushing things to the limits to play with.

 

[rjacket]

Ate too many chillis?

 

[Rick in PA]

I have a buddy at work, who in his youth, installed a spark plug in the exhaust pipe and connected it to a Model T coil that he could switch on when he wanted. Coming down a long hill, he'd switch off the engine ignition, and switch on the Model T coil. He said he got a REALLY NICE flame out the exhaust pipe!

I guess you wouldn't want to do that to a catalytic converter.

That reminds me of another buddy that rigged a piece of tubing to a vacuum port on the intake manifold. He could dip it in a jug of oil while driving and lay down one heck of a smoke screen (again, no catalytic converter).

Ah the good old days.

I doubt the bus had either one of those "problems"...

 

[rjacket]

You never know.

What are your friends up to these days?

 

[Shannow]

turbo oil seal on the exhaust...

If it happens on the inlet, runaway and kaboom.

 

[Chris142]

Originally Posted By: Shannow
turbo oil seal on the exhaust...

Thats what I was going to say. It's letting oil get into the exhaust where it can catch on fire. Either that or that bus has an old 220 Cummins and the driver put too big of a button in the pump or too much stinger... I assume any diesel mechanics born after the 70's won't know what I'm talking about.

 

[rslifkin]

If he was having trouble maintaining speed up the hill, my guess would be a failed turbo. Probably locked up, or close to it, causing the engine to be getting far less air than it's expecting, so it ends up running very rich. End result is a serious loss of power, lots of black smoke, and in extreme cases when running hard, flames out the exhaust.

 

[JHZR2]

Originally Posted By: rslifkin
If he was having trouble maintaining speed up the hill, my guess would be a failed turbo. Probably locked up, or close to it, causing the engine to be getting far less air than it's expecting, so it ends up running very rich. End result is a serious loss of power, lots of black smoke, and in extreme cases when running hard, flames out the exhaust.


It was a big, rear engine charter bus. It was running hard up a mountain. Thick black smoke, under load, sounds right.

 

[Rick in PA]

Originally Posted By: rjacket
You never know.

What are your friends up to these days?


The guy with the spark plug in the exhaust trick is a crackerjack with all things mechanical.

The guy with the vacuum tube, I don't know, lost contact, possibly jail?

 

[Jarlaxle]

Old enough to have a nontubo Detroit? If so...normal operation!

 

[JHZR2]

no this was a modern bus. Just thick black smoke radiating from the engine and then an orange flame spewing from the exhaust (which like most big charter busses, is under the bus pointed downward).

 

[eljefino]

Who knows, maybe the charter company leases the bus from yet another third party who's responsible for maintenance. They could have a "return to base if at all possible, if it moves" policy.

I saw a 40+ year old church bus with the "hood" open at Six Flags once. IDK much about them, could have been one of those DT 2 strokes but it had huge and beautiful exhaust expansion chambers & or turbo gear and was absolutely buried in oil, soot, and grime on every conceivable surface. May have actually caught fire?

 

[JTK]

Originally Posted By: Jarlaxle
Old enough to have a nontubo Detroit? If so...normal operation!


Exactly.

Had a neighbor long ago that drove for Greyhound for ~35yrs. He would tell me stories from way back in the day with the old Detroit powered buses. He claimed he would see sparks/flames on occasion out the exhaust when he opened them up on the highway.

Joel