oops, I over reved

Tractor Nubi · Dec 22, 2008

Have a Dong Feng 354 and was plowing the drive way. Neighbour was stuck so I took off the load and went to help. I had the rpm up to ~2800 for no more than 5 seconds before I noticed it. I heard a pop (kind of like a poof) and then it started to smoke white smoke and loose power. It will start easily and run but I cannot get any measurable power and cannot get rid of the smoke.

Tractor is a diesel and has ~153 hours on it. When it was newer ~75hours I had a similar smoking incident (no overreving and no pop/poof sound) and people on the forum told me to put it under load (1800-2000 rpm) for a number of hours. It worked and it has been great. I tried that and it didn't work.

I added fuel (that had been in a jerry can for a month) that day and had changed the fuel filter at 110 hours.

any suggestions? Is there a governor that needs to be reset?

greg_g · Dec 22, 2008

Tractor Nubi said:
I had the rpm up to ~2800 for no more than 5 seconds before I noticed it.

What does your engine manual show for max RPMs? On my KM454, I wouldn't really consider 2800 serious. Throttle stop is currently ~2650, but I'm sure I could get more out of it without incurring damage.

But the noise and the white smoke is curious. Have you looked for water in the sediment bowl?

//greg//

Marc L. · Dec 22, 2008

Good day,

Did the "Poof" came from the exhaust or from the engine (fuel pump). As well, did you check your coolant? Is the coolant turning darker or disapearing (would be a blown head gasket). Have a look at the oil, is the oil milky (head gasket again).

Water in the fuel could cause the engine to smoke with loss of power.

Good luck with this.

Marc

Ranch_Hand_Supp · Dec 22, 2008

Can you tell if the engine has droped a cylinder ?, not running / idleing smooth ?, sounds different ??

Ronald
Ranch Hand Supply

Tractor Nubi · Dec 23, 2008

I love this site! Lots of help. I think the poof was from the exhaust but I was looking at the tach when it happened. We have 2 feet of snow here and normally it does not dip below 0 (Vancouver Island BC Canada) in the winter here and we get lots of rain. I have ordered a fuel filter and a diesel conditioner as I am worried about gelling of the fuel.

Word to the wise in rainy climates, a tin can over the upright exaust will stop pin holes developing in the exhaust manifold outlet (learning the hard way).

It will start and run with blue smoke at idle and will pour out white smoke under load.

I am unsure where the sediment bowl is on this unit.

Any other suggestions are appreciated.

dfkrug · Dec 23, 2008

Tractor Nubi said:
It will start and run with blue smoke at idle and will pour out white smoke under load.

Blue smoke means you are burning engine oil. That will be caused by a
broken piston ring, most likely, as your engine is young and valve guides take
a long time to wear out. Or a scored cylinder wall, which does not happen
suddenly, so I am ruling that out.

If you blew a head gasket, you would get low compression and low power
from 2 adjacent cylinders, most likely, and that would probably make it
impossible to start. I am assuming that is a 3-cylinder engine. A blown
gasket that affects only one hole IS possible as Marc suggests, and that
COULD allow oil from the head passages to get into that cylinder.

I would test for a dead hole, as Ronald suggests, and the easiest way is
to use a non-contact thermometer. $40 at Harbor Fright. DO this at
startup, before the engine heat-soaks the whole exhaust manifold.

psj12 · Dec 23, 2008

White smoke can be from coolant (steam and will taste sweet like AF when breathed) or fuel which is oily and will stick to your hand or cardboard when held infront of the exhaust.
If it is fuel it could be you lost the tip of an injector. If it is coolant it could be a head gasket or broken cylinder liner leaking coolant into the cylinder. I also like the idea of the non-contact IR thermometer aimed at the exhaust ports for each cylinder to determine which cyl it is. Best when performed when cold and just started.

Bob Rooks · Dec 23, 2008

Blue smoke on startup of a newer engine that goes away after operating temperature is reached is indicative of an engine that has not been broken in yet, or improperly broken in. Piston rings have not seated yet or the liners are glazed. Also, it takes some time for engines to reach thermal equilibrium, where all heat related expansion stops.
White smoke also means unburned fuel; usually due to a dribbling injector, poorly seated poppet valve, or low compression.

greg_g · Dec 23, 2008

Bob Rooks said:
Blue smoke on startup of a newer engine that goes away after operating temperature is reached is indicative of an engine that has not been broken in yet, or improperly broken in.

The model year and engine in the OP DF354 wasn't specified, so this is a shot in the dark. But you just reminded me that there have been a few posts about problems with the EGR system in some EPA-certified engines too.

//greg//