Will the engine run backwards?


I have a Kubota direct injected diesel tractor, I stalled the engine but the loader was over loaded forcing the bucket down in the up position forcing the hydraulic pump to start the engine in reverse direction, exhaust though the air cleaner. Key switch was off pulled the manual stop witch is a butterfly in the intake that didn't work so I Stalled it in gear.

I have seen an International semi-truck do this also. Guess it could be possible, hope not !!!

Maybe we can make diesel and air from exhaust smoke and heat. http://dieselplace.com/forum/smileys/HiHi.gif

But seriously, I'd think new engine technology electronic would prevent engines from running backward.

Yes a diesel can run backwards, had it happen several times driving Mack boom trucks all have been while using the truck off road on job sites.

Running backwards... That's an interesting concept.

I was originally going to reply that this was impossible on a four stroke engine because the intake and exhaust strokes would be reversed.

This would be impossible on a GAS FOUR STROKE engine because there would be no spark on the combustion stroke to ignite the gas. BUT, this would be possible on a diesel since there's no igniition needed.

I have had this happen quite regularly on 2 stroke model airplane engines. They usually get your finger when they do that too. Doesn't feel too good. That's why you learn to use an electric starter so that your fingers don't get whacked. http://www.dieselplace.com/forum/smileys/Big Smile.gif

CADman_ks

The original question though was can a dmax do it. Maybe I missed it, but I don't ever recall hearing a story of it occuring.

I would not think a Dmax could do this because the key would most likely be shut off, not letting the electronics work the injection pump. No power, no fuel. At least in this case I believe.

JohnEdited by: 502_Jimmy

Normally, A DMax couldn't run backwards as they have electronic injectors [no fuel]. Usually, only engines with mechanical injectors can spin the wrong way. However, I have seen diesel engines run backwards and suck oil from the crankcase to use as fuel. The only way to shut that engine down is to plug off the intake so it doesn't get any air. Normally requires an air filter replacement when the smoke clears...

Ever seen an old Harley Davidson 2 stroke golf cart? They had two sets of points I believe and reverse happened when the other set of points were energized and the starter/generator spun the engine backwards. It ran backwards fine and the intake and exhaust weren't reversed.


I don't think a Dmax could run backwards partially because I beleve it uses a Crank sensor for timing ( I think) and the electronics may not be able to make sense out of reversed timing signals (I think). How does the fuel injection system stil provide pressurized fuel when turned backwards? I would think it would pump fuel backwards if turned backwards.


I do know that a Diesel will run off of crankcase oil though. I flipped a farm tractor over on myself many years ago and it continued to run for quite some time even after I got the fuel turned off.

I know that some older Detroit diesel's could be converted to run backwards. They were used in dual engine boats to balance each other out.

I doubt it, injection timing would probably prevent it. You MIGHT get one possibly two ignition events, but unlikely to "run".
I have an old 2 stroke trials bike that reverses its direction at the worst possible moments if the timing isn't right. Get it down to a very slow idle in first gear and get the stall condition just as I open it up for a little bit of power and it starts right up in reverse. This is pretty much what the o/p described, except with the Kubota its CI and not (wrong moment) spark.

Had it happen in my cummins pulling truck a couple months ago. Some scary $hit.