I had to run to Savannah GA and back today - just a little over 800 miles. I fueled up at a Shell station and today I got the best fuel mileage I have ever gotten. 17.75 mpg running between 70 - 75 mph without a trailer. Also the truck seemed to have better acceleration and throttle response.

Just wondering if anybody else has noticed if a certain brand of fuel makes their truck run better

 

All the ultra low sulfur fuel comes from one refinery in the US, it only matters how well the stations take care of thit's fuel, basically how often they cange the filters on the pump. You will always get better mileage on a long run, normally a couple better then normal.

 

I know with gas each company have their own blend of additives. Wasn't sure if it was true with diesel.

Since so many of my trips are long runs like MT->TX, MT->CT, FL->MT, TX->FL, TX->CT I am aware that normally a constant rmp delivers better mpg but this was the best I ever got. When I fuel up I am the guy you hate to have at the pump you are waiting for. I always take the time to completely fill the tank so even the fill neck is full. Its the only way I know to get an accurate mpg.

I have been having rough starts and running until it warms up and my mpg have been running in the high 15mpg. So with the 17+mpg I was thinking it might have been the fuel or maybe some "dirt" got flushed out of an injector.

 

There's a huge discussion I followed on a TDI forum I'm on, about where to fill up and where to avoid. Those guys with those cars, actually aim for the stations that tend to fall on the high end of the price spectrum, typically they have higher cetane than others, according to them. When you're talking a small % increase, it's something we may not notice. Say for instance, a 5% increase in fuel economy. On a truck getting 15mpg, 5% is not much., it's .75mpg better. Are you going to pay $4.30 instead of $4.10 for that fuel? Probably not. Do that same calculation for a TDI, likely pulling 50mpg... 5% increase is 2.5mpg better in that car. When you have a small tank and high mpg, every little extra counts. In the truck I don't really worry about it too much though.

So this kind of goes against what Bob said... I'm not saying either side is right, but I'm definitely interested. Bob, do you think even though they're all from the same refinery, it's possible the cetane rating is different at different stations? I mean they each must add their own additives etc right? I'm not too well versed in pump fuel myself.

 

How or why do you think dirt was in your injector. A single spec of dirt would more than likely completely shut your injector down. Don't forget that it's pushing fuel out at almost 30,000psi, so if there was something in the nozzle, it would be blown right out. Now if it was somewhere else in the injector... injector would probably lock right up. Look how bad they get with a little "stiction." Rough starts and low MPG... FICM?

 

Unfortunately I didn't have my laptop with me so I couldn't hook up my AE and record numbers - ICP and ICP desired.

I have tested the FICM on a number occasions and also monitored with the AE software. It has always tested fine. The "dirt" theory was just really said kinda tongue in cheek. When I checked the cylinders with AE they were so close it looked like a single line. I am still learning the software and have to figure how to check individual cylinders.

I was just happy the truck was running as well as it was. With 177,xxx+ on it I am surprised that it has gone this far without losing an injector - my buddy had one and he went through injectors like they were going out of style. He sold the truck because of it and the fact that Ford would only replace one at a time. On one business trip with a trailer he got towed into Fargo ND and had an injector replaced. Didn't make it all the way to Chicago before he was towed again and another injector was replaced. Thankfully this was all under warranty but put him behind schedule.

 

That sounds more like a case of misdiagnosis than actually bad injectors... could be from a number of things. Bad oil, wrong oil filter, high pressure oil leak, an injector loosening up, etc...

I've been through probably 6 out of 8 injectors on mine... some probably didn't even need replacement, some did.

I had a buddy with 300k on his original 6.0, didn't even touch an injector until that point, he had a couple that had some really bad stiction that came about around 275k miles. He had the cab off for studs and just replaced a couple then... we both used the same oil as well, so who knows.

 

I have observed that the "best" stations to use are the ones with the MOST diesel activity. People will say it's the fact that the fuel is fresh with the high turn over rate of fuel being used.

That being said I recently found an Exxon that had a decent price and noticed the "45 cetane" sticker on the pump. I didn't think anything of it and filled up. With the boards never really bringing up cetane ratings I wasn't expecting any difference. After driving that first tank I had to keep stopping at the same station to see if my results would repeat. Needless to say I'm running 45 cetane and it seems to made quite a difference in performance and MINOR mpg changes. As the temps outside start dropping I'll see what the truth holds.

 

Still learning my AE - so that may be true


Last time I checked this was the ICP numbers

ICP-..................... ICP (PSI)
Desired (PSI)
580.1................. 578.98
580.1................. 578.98
653.2................. 646.4
580.1................. 577.28
580.1................. 577.85


I run only Motorcraft or IH filters and I am running Rotella T-6

Had the HPOP replaced at 99,100 so it shouldn't be (hopefully isn't)that.

Still working on it.

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I never even thought of looking but next fill up there I will check and then start comparing to other places I fuel up. When I travel I use Flying J a lot or the second choice is Love's.

 

could be something as simple as " you weren't fighting a head wind"