I always like it when the fuel attendant comes out over their little shack 10 feet away from the pump then they start puffing away at their cancer sticks then have the nerve to tell me to turn my truck off!
If they only knew how hard it is to catch diesel fuel on fire.

 

I leave my running. I don't like to turn it off and have to restart it in five minutes. One guy I talked to said the head could warp. I don't know if it's true, but I'm not worried about diesel fumes igniting.

 

The head could warp for a truck idling? I don't think so

 

no he meant for shutting it off, then on...

 

i leave mine running, use a spare key if im in town, not if im just down the street. dont want to wear that starter out too.

 

Most of the time I shut it off but I will let it run if it is cold outside or if the wife and/or daughter are inside and want to stay warm in winter or cool in the summer.

 

When driving professionally I would leave the engine running at around 1100 rpms for long lengths of time until I saw a film showing brass engine bearings pitted from sulfuric acid. The film commentator said an idling diesel engine produces sulfuric acid at lower engine temperatures from a chemical reaction between the water produced in combustion or water from condensation in the oil pan and the sulfur in diesel fuel. After seeing that I always shut off the engine even for short times as those times often unexpectedly became longer then I had anticipated.

Before pulling in to the fuel pump I have already slowed down on the highway and driven slowly to a pump island so that the turbocharger has had time to cool down. With my Dodge I want to keep as many idling hours off the computer as possible. The engine oil film does not run down off the cylinder walls or out of the bearings that soon and restarting a warm injected engine does not use more fuel. I will even turn my engine off if I am stuck in a long line of stopped traffic. A stopped engine saves fuel and wear on the engine.

 

Fay - I basically agree with your reply. But wanted to add that the point of idling up (like at 1,100 rpm or a bit more) was/is to create enough heat in the combustion chamber to completely burn the air/fuel charge injected. Thereby reducing or eliminating the chance of washing unburnt diesel fuel down the cylinder walls, past the rings, and into the oil.

The brass is being pitted from sulfuric acid, due to unburnt diesel washing down the cylinder and mixing with oil ... just as you describe you saw in the film.

Idling up either help or stops the washing down, but shutting it off would definitely eliminate the washdown. I agree that starting a warmed injected engine uses little fuel + the oil pressure comes up quick to minimize start-up wear.

You guys are lucky with the 03+ trucks. You can use the cruise control to idle the engine up and hold it there. Where as us old school Cummins guys have to purchase something aftermarket (which I have not done).

 

When shutting down an internal combustion engine the bulk of the lubricating engine oil in circulation runs back down into the oil pan; nevertheless, due to surface tension and the viscosity of oil a thin film of oil remains on lubricated surfaces of the engine for a time to prevent a dry restart.

My truck also requires an add on part to manually increase and hold the idle speed as it is equipped with a manual transmission. Units with automatic transmissions have computer software to idle up the engine by manually actuating it with some procedure I am not familiar with.

 

Hmmmm. I thought it worked with the manual trannies too? Apply the parking brake, clutch pedal must out (not-depressed - clutch engaged), turn on the cruise control system, put your right foot on the pedal, idle it up to about 1,300 to 1,400 rpm, and push the cruise control "set" button.

Somebody with a manual trans that has tried this, let me know.

- JyRO

 

Jyro , It does not work on all trucks , must be enabled by the dealer with a DRB tool , YOU can do it to your truck also , AFAIK all 24v trucks have this option, as well as automatic high idle , and 3 cylinder idle.

 

Cold winter days, yes I leave it running. I also climb back in the cab and watch the pump out the window.

 

Well, no serious study has been done to show a correlation between engine wear and saving gas vs. idling or turning the engine off. I think both have pros and cons and it is hard to say for sure that there's no unburnt fuel even if you are idling the engine at 1200 rpms. If you're always super careful maybe your engine will last an additional 30k miles. Or maybe you didn't get to changing your motor oil for 8000 miles, which compensates for all the extra care that you put into prolonging the life of your engine by turning it off.

Either way, after 12 years and 300k miles of owning a vehicle, you might want to get a new truck or rebuild the engine with a new "high performance" one anyway.

 

I always shut down when fueling any of my diesel vehicles.

I've read that cigarettes don't burn at high enough temps to ignite gasoline. The big issue is when the smoker uses a match or lighter to light the cigarette. Mythbusters has done various tests with gas pumps, but not sure if they have done the gas and cigarette combo or not.

I also have a VW TDI and one time a gas station employee walked over and shut off the diesel nozzle while I was washing the windshield. He thought I was putting the wrong fuel in my car!

Brian Elfert

 

JKM - That jogs my memory. From what I remember hearing, only the 03+ guys could activate this feature with a DRB tool. The previous to '03 trucks did not have this feature ... so it could not be activated. If someone knows different, I'll have this feature activated asap. Thanks.