A while back someone with considerable knowledge of diesels wrote down how much fuel was being injected when ideling. It was either 800 rpm of 1000, I can't remember. But it was interesting how many injections considering the (3) events. I know it is operator error but I can not find the thread . I will live a full usefull life not knowing how much fuel is inserted at each event and how much fuel per minute or hour the flow is, but it still was interesting.

 

I remember a thread about it but could not find it. I think it was something around 3/4 of a gallon for every hour of idle time at 800RPM. I have slept since then so I could be completely wrong!!

 

One thing is for sure, and that is idleing equals 0 mpg!

 

I for one Idle a minet or two to cool down everything before shuting down,I wonder how much fuel I am watseting? I do see alot of deisel trucks shut down right away with out cooling it down.Is this bad the engine?

 

im not sure about the engine but its bad for the turbo

 

Another post reported 1 gal/hr.https://www.dieseltruckresource.com/...d.php?t=149545

 

I remember reading that the air:fuel ratio was around 500:1 at idle, but maybe that was just a general figure for diesel engines.

In any case, it's way better than the 14:1 gassers use at all throttle positions.

 

After a hurricane a few years ago, I idled my engine for about 8 hours while hooked up to a 2KW inverter that was used to power fans and wet-vacs to help clean out the water from a marina store.

After refilling the truck and dividing by 8 hours I figured it burned under .5 gallons per hour.

 

Was that with the high idle enabled or not?

 

I have often wondered about that, not to hijack. UPS trucks as I understand it also have a Cummins motor. They just pull right up to the house and shut it off. Who knows how many times a day. I have often wondered how the turbos hold together when they do this so many times.

 

Upon stopping they unbuckle their seatbelt, turn the engine off, and are out the door of that truck in one efficient motion and not by accident either. They are all taught to do it that way as time = money. They never idle to save fuel for the company. If the turbos were cooking, failing, and costing UPS money you can be sure UPS drivers would be doing cooldowns. One can only conclude it is not and cooldowns are unnecessary on light duty diesels. The catch here is that these UPS delivery trucks are not hauling, I would guess, any more than 5k max at a time when loaded.

 

Makes you wonder if UPS has installed a oil pump like the VW has to continue the oil circulation thru turbo when it is shut off hot. That or they do actually replace turbos regulary as most of the UPS guys I see sure run those things hard from place to place. I have only heard VW has some sort of electric timmer oil pump for turbo cool down, I am not sure they actually do have it but it sure sounds like a good idea. It has me thinking of finding an electric pump of some sort to try and make a kit for our trucks.

 

I drive for UPS and I can tell you this. Not all UPS trucks are Cummins equipped. Many have the Intl.7.3, Chevy 350s, and the newer modles are using the MB diesel found in the Sprinters. I'd say less than 1/6th of our 100+ trucks at our center have a Cummins.

The reason they do not do cool downs is 2 fold. For one, it waste time.. Time is money and when you figure up the minutes it would take for several thousand drivers x an avg of probably 100+ stops a day the cost would be staggering in wasted time. Keep in mind that UPS does not even allow you to put your keys in your pocket at each stop because it waste seconds to pull them back out-which adds up to minutes over the course of a day.

Secondly, leaving the truck running at a stop unattended is a great way to get fired on the spot. The cost of a turbo is minor compared to a runaway vehicle involved in an accident or a stolen truck full of pkgs. I personally have NEVER seen a turbo failure at work.

That said, I also worked for FedEx for a few years where nearly ALL of their trucks were powered by the 5.9 Cummins. No cool downs and severe service conditions with only the CHEAPEST basic maintenance, I'm talking using oil that you can buy at 7 eleven for .89 a qt.. We had several trucks with 300K+ miles with no major failures. The most common problem was LP failure as you would guess.

Based on what I've seen over the years, you guys that are letting your truck cool for a couple of minutes every time you drive and are dumping big money into expensive oils are just wasting your money and time. Now, if you just pulled real heavy up a grade or something extreme then a cool down is probably a good idea, but just on the avg drive it's a waste.

 

the time that a driver spends at a stop the oil doesn't have time to burn and cause coking.

 

Look at what that UPS driver is saying. It wouldn't burn and cook if it was left there for an hour or more after shutoff. I disagree on the "expenisve oils" comment cause a good bypass filter and oil analysis with extended drain intervals will work out a lot cheaper than dinos every time. Now these guys running bypass' with syns and going crazy with the 3,000 mile oil changes yeah thats a waste.