Fuel Filter Change?

[neakypete]

I know this is probably a stupid question but this is my first diesel and I am currently getting horrible gas mileage out of it and I want to change the fuel filter but can't find any sort of information as to HOW to do it. I've read many things about the system losing prime and other issues if it's not done properly. Any tricks would be appreicated.

[More Power]

A search in this forum will result in lots of information. In addition, we have an illustrated set of instructions available in the Member's Area content section showing how to replace the Duramax Fuel Filter (http://www.thedieselpage.com/members/duramax/dmaxfuelfilt.htm) .

Jim

[markrinker]

What is 'horrible' fuel mileage? Towing or empty? More info and we may be able to help pinpoint the reason why.

[JimEd]

I have had my 2006 2500HD for two weeks now, I got 19.7 average MPG on a 650 mile trip. I only had 250 miles on truck when I started trip. I was not towing on this trip.

I just got back from a 240 mile trip towing my 13,000# fifth wheel, averaged 10.6 MPG on this trip, I have 1200 miles on truck now. I was hoping for better MPG while towing,maybe it will improve with more miles on engine.

It towed my trailer great, I was very impressed..

[JD Diesel]

jimed what do you have truck wise. sure wish i was getting 19 mpg. JD :confused:

[JimEd]

I have a 2006 2500 HD Duramax,,,
When it is in sixth gear (overdrive) the tach is at 1600rpm at 65mph. I take off slow keeping it less than 2500 rpm. Ireally expect to get over 20 MPG after I change the oil and get a few more miles on it.

[neakypete]

My bad for not looking closer for the filter changing instructions. As far as bad mileage, I get 12.4 MPG no matter what. The truck has almost 11,000 miles on it. It's a 2500 HD 4x4, crew cab, short box with all the toys. I have switched oil over to Amsoil which is supposed to get you a bit better mileage and also put on a K&N cold air intake which should have gotten me a single MPG or so. I picked it up from the dealership getting 12.6 and it's done nothing but dropped to 12.4 since. No matter how I drive, fast, slow, city, highway, it's all the same. I have not done any major towing over a long distance so I'm unsure if it would drop on a long trip. I did have an injector go bad around 8500 miles and they fixed that but I'm convinced that something is still wrong.

[More Power]

Every once in a while I receive an email (or see something in the BB) from a Duramax owner stating that his truck only gets fuel economy in the 12-13 range when not towing.

My 2001 delivers 12-mpg on average while towing our 27' travel-trailer at 70-mph. I can't imagine how another truck could only deliver 12-mpg when running unloaded - if the engine starts and runs normally, and makes normal power.

I'd like to spend some time with one of those trucks in an attempt to learn more about the low fuel economy problem. Bring it to Montana.... I'll buy you a tank of fuel. smile.gif

Jim

[Jim Brzozowski]

Running empty, there is no way I can get my truck to get 12 mpg. I've held it at the speed limiter for probably an hour somewhere out in west Texas and it dropped to around 16. Normally gets 19 and better if I drive easier. Something is definately wrong with your setup. 12 is just unbelivable unless you are towing. If you are logging the miles and the gallons used, I'd like to see them if you could put them on the site. I've not heard of anyone getting in the 12 mpg range while running empty, just the truck by itself. Thats terrible at todays diesel prices.

[sluggerjoe]

Originally posted by JimEd:
I have had my 2006 2500HD for two weeks now, I got 19.7 average MPG on a 650 mile trip. I only had 250 miles on truck when I started trip. I was not towing on this trip.

I just got back from a 240 mile trip towing my 13,000# fifth wheel, averaged 10.6 MPG on this trip, I have 1200 miles on truck now. I was hoping for better MPG while towing,maybe it will improve with more miles on engine.

It towed my trailer great, I was very impressed.. Man, that is really good for a brand new pickup. You'll be over 20mpg a ways when it gets broken in. I have an 05 and it has never come close to 19.7 mpg.

I was suprised at how much better the mileage was after about 4000 miles.

[neakypete]

When I drove my truck off the lot it was getting 12.6 and from there has only gotten worse. I changed over to Amsoil and also added a cold air intake and the truck now has 11,000 miles on it and I've been getting 12.4 for about the past 4,000 miles. I wish I knew what was wrong with this pile of crap.

[Spartus]

Mine dropped off like a rock earlier this year. I tracked it down to the gas station I was filling up at. They must have recieved a bad batch of fuel. I switched to Meijers and my mileage has ALMOST recovered. I was getting 12mpg around town compared to my normal 17.5. And 16 highway compared to my normal 21 mpg.

Try switching to a different station that sells a lot of diesel. Some stations don't go through the stock quick enough, so who knows what's growing in the tank down there.

ALSO, if using an oiled air filter(K&N), the oil can get on the MAF sensors and mess up the metered air readings. That won't help things either.

[pepper]

Neaky Pete - There is something wrong with that truck, I get better than that pulling a 20 ft boat. Usually 13-14 pulling the boat,12-13 pulling landscape equipment and supplies (ie dirt, rock, mulch and compost). The other day I went for a 500 mi one way trip and was getting above 20 most of the time, best was 22+, yes they need to FIX THAT TRUCK!!!

Even if you ride the brakes, have it in 4 wheel with the emergency brake on and load of dirt in the back you should do better than 12!

Wish I were more knowledgeable so I could help, just know enough to know that it isn't functioning as designed.

[neakypete]

I have a small bit of good news to report on my crappy mileage. I just took a trip up north with a very light load (camping) in the bed and got around 400 miles to my 26 gallon tank which calculates out to about 15.4 MPG but here is my actual question: How quickly is the DIC supposed to respond? I didn't even realize I was getting better than my normal 12.4 until I checked my trip and realized that I was at 390 miles for that tank. Even right now it's still reading 12.4 which makes no sense to me. I do have 285's on this truck. Do you think this could be messing with my DIC or does it just adjust very slowly?

[Spartus]

285's are like 3" in diameter larger ( 7% ). Your truck is calibrated for 245's.

Take your trip miles traveled such as 390, and multiply by 1.07. Example: 390 x 1.07 = 417.3 miles.
You will have to multiply by 7% each time you fill up to get actual miles traveled. The onboard computer is now useless and can only be used as reference. I get 16.49 MPG from your last tank.

[neakypete]

Spartus, you might just have to be my hero for the day. LOL I kept wondering if those tires were throwing everything off. Not that 16.5 is all that great unloaded but it's better than the DIC indicated as I suspected. Does your chip allow you to factor in the wheel size? Also, why are we multiplying by 1.07? I got 16.05 for the MPG's. How did you get 16.49? I used a 26 gallon tank. Am I off somewhere?