My dad started up his 2004 F-450 6.0L Diesel today and said he had to shut it off right away because it sounded really weird, like the engine was running backwards. I guess he didnt wait for the tell tale sign of air coming in from the exhaust pipe and exhaust coming out of the air filter. Started it back up and everything was fine. Anyone else ever have this happen or even heard of it? Kinda funny I thought.

 

Well I guess maybe it could happen. The only thing that would make it do that is if the starter shorted and some how switched polarity to turn it backwards.

No I've never heard of it before but there is alot of things I've never heard of, that by far is not the strangest thing that I've ever heard, but it's up there.

That is the only explanation I can come up with if it was indeed running backwards.

 

Wouldn't it be impossible to run backwards? If air came in through the exhaust there would be no fuel. Although it might blow fuel out of the air filter which could cause a fire.

 

I've seen it happen a few times. it was common on the old Detroit 92.

 

I had my rear wheels once going in the opposite direction as the front wheels at one time

 

Hey Neighbor!

How did you do that?

 

A diesel engine takes in just air, compresses it and then injects fuel into the compressed air. The heat of the compressed air lights the fuel spontaneously.

They do not mix air like a carburator, they have always been fuel injected as far as I know. So yea they would get fuel, since it doesn't spark, then it could run either way.

Honestly I don't know alot about diesel engines, just enough to get mself into trouble and screw everything up.

 

Oh yeah, I was thinking of a gas engine, not diesel.

 

That's what I like about you. You're another Sexual Intellectual.

 

If you catch it just right on a compression stroke and the starter pauses, the engine will kick back and start in reverse.

I have had it happen many times, on many different types of diesels.

 

Yep, seen our Mustang skidloader run backwards. Pushing a pile of dirt and luggin it down and it started to run funny. Ended up it was running backwards. Shut it down and restarted it.

 

I can relate to a diesel tractor... I was starting it and bumped (momentarily turned the key) and it "Kick backwards" and cranked... What a weird sound. I shut it down and restarted, and ran correctly. I really did not know what happened. After reading other post I now understand... BoB

 

Other than the skid loader or other hydro-stat style hydraulic transmissisons. If the Engine is runinng backwards then wont you go back wards?
IE, For a 5 speed transmission, wouldn't you then have 5 speeds in reverse and 1 for forward?
Even with hydraulic trans wouldn't it be backwards too?

 

Diesels will run backwards. It's called, of all things, 'dieseling'.
It usually happens when you stall the engine, then it pukes out oil and exhaust from the air filter(s). I've had it happen a couple of times.

But if you want to really have fun, pull the exhaust headers and set the injectors wrong. Then start it up. You could get a 'run-away', as happened to me. The engine revved to more than the tach would register. Why it never blew up is a mystery to me, but it filled the garage, and I'm talking about 10,000sq', with the absolutely densest exhaust you can imagine. The people living near the shop heard the roar and saw smoke billowing out of the shop. They thought it was a huge fire. The boss ripped off his vest and stuffed it in teh air intake, but that turbo just sucked it in and there were feathers (it was a feather vest) flying all over. I pulled the emergency stop but the mechanic had forgotten to attach the cable, and I ended up with a hand full of ****, and the engine merrily screamed for about 15 seconds until someone grabbed a chunk of plywood and covered the turbo intake. Amazinglly, there was not a bit of damage to anything, except the boss's feather vest.