Very odd MPG from one of my drivers

Follow the guy or have someone you trust to follow him. Monitor his CB radio while following him. He's probably selling fuel.

 

Read what I posted Chinatown, you want to actually get real facts and figures out of this, not spy on the guy up close and personal. You can tell a lot by turning on the record keeping stuff in the ecm, like mileage and how the truck was run.

 

Do a ECM dump & insist on all your drivers handing in Fuel receipts (you should have them for IFTA anyway) then compare the figures..

As has been suggested a "random" UA wouldn't hurt either..

 

Can you monitor him on gps? Maybe he is taking a road trip instead of the route. I have some issues with one truck, its engine has some torque derate problems but even with that it never goes under 6.5mpg.
Second option (i dont want blame anybody without having a proof) he might be in the fuel business.

 

First problem I see is your tracking system....or lack thereof.

To effectively track fuel economy, you need to look at the VOLUME of fuel purchased and not $$ amounts...coz what if he's buying at expensive places and possibly getting "CashBack"

Did you account for seasonality?....He may have had the truck over the winter (i.e. more idle, more low speed driving) ...Remember, winter blend diesel burns @ worse mpg than other seasons

Also, why dont you install a GPS tracker?...That way, you get average speed & route taken?...maybe his routing sucks or he's a supertrucker speeder

Finally, get the ECM data dump for that period when he's driving, and compare with other drivers, on different periods....that will tell you how long he holds the truck in the sweet spot.

 

At some point I had a horrible mpg after I hit a deer it went down below 5 mpg, the truck had the bumper replaced and hood redone, but it took a few thousand miles to figure that the air cooler was cracked. I was a little worried that they would suspect me of fuel selling as it was $4/ gal but I was the one who brought the subject up and tested the air charge cooler by letting a stranger push the gas pedal while I sprayed it with soapy water. Even though, I would suspect the driver, I would not openly accuse him of theft, but ask him what he thinks about the situation himself. Maybe I'd let him drive a different truck, if possible and see how that changes the matter.

 

If he's selling fuel the ECM will show it. Reset the ECM and track him. Agree you need to talk mpgs. dollars mean nothing.

 

If he is getting less than 4mpg on any truck he drives, I can't see how that is even possible.

If he doesn't use cruise control, and keeps it in 9th gear and drives at the top of that gear and the RPMs are limited so that he's driving 65mph at 1900 RPMs, and also idles at night, then that MIGHT put him in the 4.5mpg range...MAYBE.

Add up all his fuel purchases from the last 3 months, divide by miles he's driven, and see what his MPG comes out to over the long run.

 

ECM will show idle time

 

GPS tracking isn't that expensive and you'll learn a lot. I'd start with that and see where it takes you.