let her idle or shut her down

[Bumble]

Well, being that I spend alot of time working on PowerStroke diesels(maybe not a tractor, over the road or off road), I can tell you from personal experiecne that with todays EGR system equiped diesels, the coking problems are much more evident than ever before.. No, it didnt start with them, just becomes magnified because of the cooling effect of the exhaust gas.. If you were to pull codes on 90%(again personal experience, with idling customers, leading to an educated guess) of the 7.3L's on the road today, you would get a code for the EBP sensor... This sensor reads the exhaust backpressure to tell the PCM if the exhaust backpressure valve is working, to provide a quicker warm up on a cold engine.. The reason for the code is that the tubes will clogg with carbon/soot and not alow the sensor to read the pressure... This is because of the cold combustion temps and incomplete combustion of an idling engine.. Some have reasons to idle excessively, most do not... My recomendation from personal experience, is not to idle excessively(>5min) if you dont need to.. If you decide to, I dont have a problem with that either... JMO...

Working on a lot of Ford gas engines in passenger cars, I also see the EBP or DPFE code A LOT. might not be a diesel thing but a Ford thing.(J/K) Most newer cars seem to have a bit of distance or very akward passages between the EGR and intake area, and every turn is a place for deposit. After a while, the deposits plug the passages and EGR codes are set.
Just my .02
Jim

 

[HGM]

Working on a lot of Ford gas engines in passenger cars, I also see the EBP or DPFE code A LOT. might not be a diesel thing but a Ford thing.(J/K) Most newer cars seem to have a bit of distance or very akward passages between the EGR and intake area, and every turn is a place for deposit. After a while, the deposits plug the passages and EGR codes are set.
Just my .02
Jim

While you are right, the carbon in a gas burners EGR system is more from the PCV system and takes much longer to build up than the diesel fuel does.. Plus, these engines have very little Ford influence.. I have heard of similar experiences with all diesels, nature of the beast..

 

[daTeacha]

I'm with Wilkesland. I leave it run when hooking up or unhooking so I can move the 3 point as needed. Otherwise, I usually shut it down. With the newer tractors, the starting is almost instanteous, so it hardly wears out the starter much. Besides the fuel use, there is the extra little bit of air pollution. If you're working around the tractor at the time you can get a pretty unhealthy does of diesel exhaust which has been proven to be pretty dangerous with respect to lung cancer and such due to the particulate emissions.

 

[RobJ]

What is "wet stacking"?
Bob

General term that if you let the diesel idle for long periods the unburnt fuel will begin appear in the exhaust. When I rebuilt engines we also used this term for lightly loaded diesels that never really broke in correctly (seated the rings). In some extreme cases we would put the engine on our water brake dyno and run them for a few hours. To give you an idea some of the engines could be in the field for weeks and the paint on the muffler is still there. After about 60 seconds on the dyno at full load (and 900 degree exhaust temps) the paint would burn off in no time. On the generator sets we build we loaded them by hooking the gens to a water tank grounder thing (not sure what they really called it). But basically a 6x6 water tank that had a metal eletrode (connected to the gen) that was slowly winched into the water to create a load. We liked that one better because it was outside!!! Earphones, earplugs, etc....

 

[joerocker]

So, what you're all saying is that with a diesel...hotter is better...to a point of course. Let it idle ONLY when necessary...and when you do, keep the revs up a bit to keep the temperature up...

 

[flusher]

General term that if you let the diesel idle for long periods the unburnt fuel will begin appear in the exhaust. When I rebuilt engines we also used this term for lightly loaded diesels that never really broke in correctly (seated the rings). In some extreme cases we would put the engine on our water brake dyno and run them for a few hours. To give you an idea some of the engines could be in the field for weeks and the paint on the muffler is still there. After about 60 seconds on the dyno at full load (and 900 degree exhaust temps) the paint would burn off in no time. On the generator sets we build we loaded them by hooking the gens to a water tank grounder thing (not sure what they really called it). But basically a 6x6 water tank that had a metal eletrode (connected to the gen) that was slowly winched into the water to create a load. We liked that one better because it was outside!!! Earphones, earplugs, etc....

Correct. But the unburned diesel fuel also washes the lubrication off the cylinder walls, rings, pistons causing potential increased wear.

 

[CurlyDave]

Think Safety. Shut it down.

Everything around here is on a slope. Sooner or later a piece of idling equipment might start creeping away while I'm looking the other way. Or worse, toward you while your back is turned.

This is excellent advice.

Another reason that safety dictates shutting down is that it is very easy to brush a control when mounting or dismounting. I just do not need any unexpected motion while I am half in and half out of the seat. Plus consider the issue if you slip and instinctively grab the joystick.

I only need to avoid geting run over once to pay for a lot of new starters and fresh batteries.

 

[cp1969]

Working on a lot of Ford gas engines in passenger cars, I also see the EBP or DPFE code A LOT. might not be a diesel thing but a Ford thing.

Exactly. I've had one of those DPFE sensors/valves/whatever-it-is shoot craps on a 3.0L V6 Ford gas engine that has as little idle time on it as one could reasonably expect to have.

I suspect all that is more of an EGR thing than a diesel thing. If diesels can no longer idle whereas they once could, then the problem is an EGR related issue, not a characteristic of diesel engines themselves. And the engines in question here have none of that EGR junk on them.

 

[ArchyD]

At $3.00 a gallon for diesel, shut it down!

 

[HGM]

Exactly. I've had one of those DPFE sensors/valves/whatever-it-is shoot craps on a 3.0L V6 Ford gas engine that has as little idle time on it as one could reasonably expect to have.

Did you change it yourself? If so, you would know that it failed because of moisture build up due to condensation....Not carbon/soot...

I suspect all that is more of an EGR thing than a diesel thing. If diesels can no longer idle whereas they once could, then the problem is an EGR related issue, not a characteristic of diesel engines themselves. And the engines in question here have none of that EGR junk on them.

I suppose you can continue to believe that if it makes sense to you.. For those that are still interested in the personal experience opinion, EGR does in fact magnify the coking issue, no denial there.. But carbon build up, wet stacking, or whatever you like to call it most certainly is a characteristic of the cold combustion of an idling diesel.. You would just have no indicator of it unless you disassembled it, so unless you do your own work on your diesels, you wouldnt know..You may want to look at the exhaust system on as many diesels as you can, trucks, tractors, cars, whatever.... You will notice they vary from remarkably clean(for a diesel), dry powder like, to heavy buildup, wet and sticky..Then you could ask the owners how they treat idle time..

The EGR systems produce problems because the EGR will stick open, this will cause a reduction in boost, so the PCM will fuel up to correct for the lower boost, producing black smoke..In your case, described earier, it makes good sense to leave it running due to extremely low temperatures as it would be running at significantly higher temps than ambiant, though a raised idle is still a better idea..