fuel filter/mpg question

[magothy1]

Hm, doesn't look like my signature line stuff comes up ; 2016 Tradesman dually, 6.7, 112,000 miles, 3.4 rear end. Mudflaps are the only mods. Bought the truck used in September of 2019 to pull a 5th wheel. I haven't done enough of that yet.

A few weeks ago I had a quick trip to Maryland pop up, changed just the rear filter at about 8,000 miles and the mpg numbers picked right up, this was running just truck, no trailer. On a trip a year plus ago from SE South Carolina out to Colorado and up to far north central Washington I got 19.3 mpg, running 72-73 on the cruise control. With the new spin on rear filter, I got 19.0 + again. When I got back I changed the front filter. I had that done by a shop the last time, but I did it myself this time. I had a shrimp boat for 40 years, I've changed a few filters, this was easy enough. But, mpg dropped right off to barely 17 on the highway. What do you suppose I did wrong ? The old filter was a Carquest, the one I put on is Mopar from Geno's.

I tried to follow Marion's youtube, I think he's tootall something on here. It sure seemed like a straightforward piece of work.

Thanks for any help.

Steve in SC

 

[NIsaacs]

Are you doing the math or using the display?

 

[Topzide]

@magothy1 ,You're far better off staying with Mopar on the engine and Fleet - Racor or Mopar on the rear. The fuel system is a bit sensitive on what it likes. On the EVIC, I just had 19.6 headed west through western MD to western PA. Return trip showed 17.8. Those numbers don't really mean much unless you keep the same driving conditions till you fill up. when I hand calculate, numbers are 2.5 -4 MPG less. I have a transfer tank with water filter that I use to fill truck, so that means 3 filters before it gets to the engine! Winter fuel has lowered the numbers. With summer blend, Numbers are way higher! JM2C.

 

[AH64ID]

Unless you are getting bad fuel, or running the filters WAY too long, you shouldn't notice anything different from a fuel filter change. Even if one drops the inlet pressure a few psi it's not something you will notice with fuel economy.

There are a dozen other things that could effect the fuel mileage.

Both filters should be changed at the same time, every 15K miles, and you want to stick with MOPAR/Fleetguard for them.

 

[Cummins12V98]

Unless you are getting bad fuel, or running the filters WAY too long, you shouldn't notice anything different from a fuel filter change. Even if one drops the inlet pressure a few psi it's not something you will notice with fuel economy.

There are a dozen other things that could effect the fuel mileage.

Both filters should be changed at the same time, every 15K miles, and you want to stick with MOPAR/Fleetguard for them.

Don't forget RACOR for the rear.

 

[AH64ID]

Don't forget RACOR for the rear.

Yes you can use that one. It's the OE supplier for 13-18 and would be same filter as a MOPAR one.

No Racor or Fleetguard alternative for the MOPAR canister rear on 19+.

 

[magothy1]

Thanks very much for the replies. I was a little suspicious about the Carquest filter. I always ran Baldwin everything on the boats if I could get them, Racor for the fuel filters. I'll check by hand calculations, too. I can tell it was a good bit lower mpg by where I had to refill on this last trip north.

 

[Tuesdak]

Look for posts by @slowmover on MPG.

X2 You may have gotten #1 winter Diesel that gets lower MPG due to lower BTU content.

Any fuel leaks esp. by the filters? Otherwise the filter change has nothing to do with it.

 

[magothy1]

No leaks, that was one thing I had thought about. I'm spoiled lately, I park in a small plane hanger, painted concrete floor. High living, indeed.

 

[Newsa]

Question:. CP3 on my 2013. Occasionally use a fuel conditioner (a few times per month). Daily driver with 82,500 miles and several interstate trips. I realize that if the high pressure pump goes it likely takes some injectors with it.

What is average life of the high pressure fuel system if I am lucky enough to get quality fuel and change fuel filters every 12k- 15k?

Does cold weather affect the life expectancy?

 

[AH64ID]

Failed CP3's rarely take the injectors out with them, the CP4 on the other hand is known for that thou.

They often last hundreds of thousands of miles. It's not something to be overly concerned with.