kkime

I have a 2006 2500 Mega Cab 5.9 Diesel 4x4, everything is stock, and have just purchased this used 4 months ago and have been getting terrible mileage in the city like 10.4 mpg last tank hand calculated 334 miles on 32 gals and 16.5 hwy. So I decided to take it to the dealer for diag. and that said it was running too rich, was getting 100% fuel & the diesels are not suppose to get that much fuel and that why its running rich, also they blame it on my lift pump, which seemed weird to me, cause the truck runs fine no issues but the poor mpgs. Then I got involved in the bad fuel trap, they checked my tank and found debris in it and at first said I needed everything replace in the fuel system for $11k, then after fighting them they said if I paid them to clean my tank, injectors, replace fuel filter that they would warranty my pump for the exchange which would add up to $661.00. I dont know if I really need a new pump or could it be something else, they said my Inj pump, fuel regulator, and other stuff checked out fine. They have had my truck for 8 days now and I cant get it back till tomorrow and am paying them 95.00 for diag, and made them just put it all back together for me. Any help on this would be appreciated. mileage is 51k on the truck now and it had 48k when I bought it.

CamperAndy

Run, as fast as you can from that dealer. You can not go from needing to replace everything to just the lift pump.

Run a couple of tanks of fuel with Power Service and see if it clears up some of the mileage issues. Also get a fuel pressure gauge, then you can monitor the fuel filter and lift pump performance.

Sandhopper

Ouch that seems steep. I am sure there are folks on here that can help. My 06 gets on average 18-20 mpg mixed driving.

NickBeek

Welcome to the forum.

RUN don't walk away from that dealer! A bad lift pump will not cause "extra fuel" to go to the engine. The injection pump and injectors control that. It is impossible for your engine to get 100% fuel, air needs to be present for combustion to occur. A diesel engine's speed is controlled by controlling the fuel going in, so if you add more fuel it will turn faster and suck in more air to do it.

Take a fuel sample from the fuel filter yourself, drain some fuel into a clear container and look for water, of dirt in the bottom of the container. Check / change your air filter / fuel filter, buy fresh fuel from a reputable dealer that has good quality fuel, make sure you tires are properly inflated.

If you live in an extremely cold area and take short trips, your mileage will be terrible. These trucks need to be warm and well worked often to achieve great mileage. If you drive short trips most of the time in cold weather the engine never gets fully warm and combustion is not complete, this leads to carbon buildup on the injectors which makes matters worse. Assuming that your injectors are physically OK and I would suggest you have them fully checked out at a reputable dealer, some hard work for your truck is in order. Hook up to a heavy trailer and get on the highway with some good hills on it and drive it hard for a good long distance. This will get it warm enough to clean off the injector tips and you should notice a nice gain in mileage.

One more thing, a stock '06 truck lift pump will only put out about 9 -10 psi at idle and 6-7 under heavy load. Well that is what mine puts out and it made 414 hp with those numbers for fuel pressure.

Good luck and keep us posted.

kkime

I live in North Texas and do make more short trips than long ones, but I always warm up the engine for atleast 10-20 min before making them. Will cleaning my injectors help out, the truck runs great besides the poor mpgs. I usually pull my boat a few times a week and a 16ft enclosed trailer weekly and I was noticing terrible mileage while pulling these also. I have driven diesels for the last 10 years had Ford 7.3 2001, n 2006 GMC 6.6 Duramax and traded for the cummings due to all the history of how well the run efficiently. I didnt think it would be the lift pump either, if that fails my truck would not stay runnning instead of getting too much fuel? still stumped/

NickBeek

The 10 - 20 minute warm up is a bad thing also, these trucks HATE to idle for long. The manual says not to idle for more then 10 minutes. I let it warm up for about 5 minutes max then drive off easy.

I also have owned other diesels a 7.3 and then a 6.0. Towed the same camper with all three trucks. My 5.9 gets about 1.5 - 2 mpg better then either of the others got pulling the same load, and about 1 - 3 better empty. For comparison, I am getting 18 - 20 mixed driving, 9 - 13 pulling my camper (9000lbs).

kkime

A liitle heads up the Dealer is Allen Samuels Dodge off I-35 in Fort Worth, TX, beware of the danger and stay away and tell all Dodge owners to stay away. lol

kkime

Anymore suggestions, Im all ears right about now!

kkime

What type of fuel pressure gauge do I need and where to buy it from?

tlloyd

What rear end gears you running?

STate

you can buy guages here at the DTR store. http://www.dodge-diesel.org/. Larry will give you a member discount over the phone. Do a search for "gauges" or "fuel pressure gauge" and you will see some threads showing what types of gauges others have used and where they have mounted theirs in the truck. Also you may find some of the installation write-ups that include pics if your are a do-it-yourselfer.

Scott

dieselfreak21

Lack of fuel delivery on these trucks will cause poor fuel mileage. Never been able to figure that out but have experienced it. If the truck had a pressure box on it by the previous owner you could have an issue with the pressure relief valve and opening to soon with doesn't allow the correct rail pressure and atomization. If you have dirty fuel filter it sort of does the same thing. Dodge dealers are hurting right now and so is Fiat on these warranty claims. My milage really went into the tank when my injectors started failing. I used to get 18-22 depending on my foot and trype of driving and speed. Couldn't get over 17 in the last 10k miles i put on the truck. Had the injectors rebuilt and fuel mileage has almost returned but doubt I will see 22 again with this ULSD and since not a a daily driver i don't drive is 60 mph any more. Good luck these are great trucks over all just the fuel system is a little pretensious since ULSD came out.

p035970

Any time you idle your truck is getting 0 mpg. Cut out the extended idle times and watch the mileage go up. This is the same problem the 7 mpg feed truck has.

ssandlin

^^^^^x2 on this, stop the 10 - 20 minute warm up idle time and your mileage will increase! Give it a try and then recalculate your mpg.

AaronT

Your 10 to 20 minute idle for warmup is where your mileage has gone south. The manual recommends 2 minute warmup and go easy.