I believe the assumption is to be a single stroke is one complete cycle or two revolutions,
and 1 RPM is half of that since it takes two revs for a complete combustion cycle.
At least that's my assumption.

I haven't done my high idle mod since I don't have a need to let the truck idle much, but I think it's time.

FWIW. i remember reading a few years ago in the 7.3l forum that engine used 1/3 gal per hour at idle (not high idle)

but yeah like all the guys have said it's too long. cut it in 1/2 and drive easy. i'm the same way i don't like to drive on a cold engine (and i live in So Cal) so i take it real easy and warm it up for a few minutes every time. also i think that is your pushing more power that this is more important.

How cold is cold? I'm talking +20 deg F down to -15deg F. I've got a long semi steep half mile + hill to go up right after I pull out of the driveway. If I ease into it going up the hill i'll be holding up traffic. My idle time (10-15min) is one of the reasons I did the EGR delete soon after I bought the truck. When I leave from work at the end of the day I only let it high idle until the engine gets up to 80 deg (4 min) then ease into it from there.

IMO, the key is to have the high idle mod (like you do)!

BTW - a LONG time ago, someone put up a post that stated it is cheaper to warm up w/ a block heater than burn diesel with idling (the assumptionis that the block heater use would REDUCE the idle time). I don't live in climate that requires a block heater or extended idling very often, but the last few days we have been in the low 20's. The high idle for 3-4 minutes is a BIG help, but I think I will try the block heater (first time) tomorrow morning.

I agree with that. I figured it up not too long ago. I think it was half the cost to plug it in vs idle it. I do still plug it in every morning for around 3hrs. When it's really cold (below +5 degrees F) I will plug it in at work too. The block heater will get the truck up to about 85 degrees, it will read higher before starting (115), but as soon as it starts it will go down to around 80.

edit: For plugging it in i was assuming 2.5 hours and idling for 15 min.

Fill it to the top, let it idle for an hour and then fill it again then you will know the exact amount without having to run it dry.

are you saying to fill it till you see it ready to come out of fill tube, cause any other way you could be off, but that is a sound thought, I'm wondering if the AE software gives a exact number of gallons as a reading maybe that is an option.

i still say at low idle .5 gph is too high of a number IMO...

its hard to measure that small of flow rates without precise equipment and i doubt every superduty is equipped with the right senors for AE(or any plug in software) to be very accurate. its more or less a ball park figure.

IF you can get the factory mass-fuel-desired and fuel-volume-desired numbers from the PCM, it's not terribly difficult to FIGURE a decent assumption.

The problem is that those two values are excessively difficult to pull out correctly. Especially if the engine is running a tune of any kind.

-blaine

It all depends on how cold is it. Block heater only gets you 120 degrees water and the rest is cold, oil for example. So, in our temps at -20 C oe -30, yeah more idle time is required. Thats -30 F as well. So, idle of 15 minutes dont warm much. I am seeing easily 1 gal an hour on idle, faster and more with higher idle due to temps in the cold, hi idle mod overide at 1250 is likely more than that...

I suspect that with all the EPA considerations, the 6.0L is designed to use more fuel at idle than previous year models in an effort to get heat in the engine more quickly. This will increase the speed at which the emissions get under control. Just a guess though.

I can attest to that. Best solution plug it in, get a pan heater and plug it in as well. Even with the high idle though mod, the temp doesn't get anywhere close to operating temp. Plus without any kind of load, your engine builds carbon. Key is to get it "warm", then drive gentle and get a little load on her to help in the warm up. I can be up to 180 on the gauge, and at -40 it will drop down to 150 in a matter of seconds once i stop and let her idle.

I think regular extended idling is a very bad for modern light high speed diesels. Sometimes there is a good reason as when I had a diesel (Landcruiser) up north and let it idle all night at 50 below, but I had a hand throttle and brought the rpm to around 1400.
I never idled my 97 power stroke for long even with a cold minus 20 start, this truck had an auxiliary ecm and set that for idle at around 1200. Idled just long enough to take the cold out then drove easy - under 2000 rpm. With my 2004 i live in a mild area with occasional frosty mornings, I start let run about 15 to 20 secs so the oil is going around and then drive - under 2000 rpm till thoroughly warm. People behind me hate me for being slow - too bad for them. Well over 300,000 Km on my old power stroke and engine still ran like new. My 04 has just over a 100,000 Km and runs great. (miss the old manual glow plugs and hand throttle)

I recently bought a Scangauge II and it reports Gallons Per Hour on my 2005 PSD. The gauge reports injector pulse with and needs to be calibrated for accuracy. I filled my tank to the brim. When I refill and adjust gallons used reported by the SC II vs. actual gallons, I should be able to report GPH at normal and SEIC up idle.

I calibrated my Scangauge II today. Its predicted fuel usage was only 3.5% high. After correction, it reports my 2005 PSD:

.41 GPH at idle

.60 GPH at SEIC high idle

Winterized fuel + Power Service anti gel at +32F


I bet that's very close to reality.