Engine/Transmission (1998.5 - 2002) Poor milage (14.25mpg) - considering edge ez - any suggestions?

[MCarstens]

Hey guys. I just joined, and am trying to read as many posts as I can so I don't repeat questions. I have a 1999 2500 (99,500 miles) that I have a contractors topper on. It sits about 6" above the cab, and adds about 750# (loaded). I am a bit disappointed with the milage. This is my third diesel, and my first Dodge. The other two were 1/2 ton Chevy's ('82 & '92). Both of these got 22-25 mpg. I was expecting better than this from the cummins. Do you think I need something done to it? I have the k&n air filter, am running #2 diesel, mostly highway driving at about 62 mph. Pen and paper calculating runs at about 14. 25mpg. I am considering a box - Edge maybe? I pull a 16' enclosed trailer about 10% of the time (mostly empty) - need economy more then horsepower. Any suggestions would be greatly appreciated!

Thanks in advance!

Mike

 

[Beast2B]

Welcome to the TDR, Mike. First, go to the user control panel under the Discussion Forums tab and fill in your profile and signature, that will help others and you won't have to describe your truck when you want some info!

If you've browsed the forums, you probably know to check your lift pump fuel pressure ASAP, there's a Schrader valve at the inlet to the injection pump for testing. Make sure you're getting 12-15psi idle, that usually will correspond to enough pressure running down the road.

Is this truck new to you? Any idea how it was treated before you got it?

That does seem low for mpg, I was getting ~20-21 before I modified almost everything! I still get 17+/- now. If you can keep your foot out of the throttle, the EZ will increase mpg, but make sure there are no trouble codes in the ECM before you start changing things.

 

[MCarstens]

Thanks Galen!

I'll get on the lift pump pressure check ASAP.

The truck is new to me (about 4 months now). A little old lady from Iowa owned it before me (ha ha). It seems to have been taken pretty good care of. I haven't done anything to it yet but drive it. I'm still trying to get used to it and figure it out.

I'll get the profile done right away too. Thanks again.

Mike

 

[Beast2B]

no problem, there's a TON of info on these 2nd gen forums.

also, it would be prudent to do all of the fluids and filters that you aren't SURE have been done recently. fuel filter can cause some mpg and fuel pressure issues. if it's an auto trans, it could probably use fluid/filter and band adjustment. as soon as you get the mpg better, get ready to be infected with the BOMB bug (Better Off Modified, Baby!). Once you get the EZ on and feel how much a little power helps, it's a slippery slope to 500+ horsepower and 1000+ lbs of torque! It's addicting.

 

[MCarstens]

I have yet to get used to the auto transmission in this thing. It is quite different from any other truck I've had. I would love to have some more performance, and I've heard from others that my foot would enjoy it also... .

Do you think the EZ is the way to go?

 

[Beast2B]

for quick simple and effective, it's great. seat of the pants is VERY noticeable. response is dramatically improved. before any mods i borrowed an ez for my truck, and without any wastegate mod (to allow higher boost), i gained 30hp and 140lbs of torque! your wastegate (auto truck turbo is different than manual truck) has a 'hard line' feed from the pressure side of the turbo to the wastegate - you can use a turnbuckle or spring to adjust the wastegate opening. without adding gauges to monitor boost, EGT, fuel pressure and maybe trans temp I'd suggest you stop with the EZ.

pretty common on this website is to stay away from k&n filters. they flow well because they don't trap as fine of particles, and they've been known to allow filter oil to get in the turbo.

 

[Holzarbeiter]

Welcome,

99's don't have the schrader valve at the injection pump. Your best bet is to buy and install a gauge permanent inside the cab, you wont be sorry about the money spent. Another option is to use a basic fuel pressure gauge from any auto parts store and use the adapter that works with rubber fuel lines. The metal fuel line going from the filter to the injection pump connects to a rubber line, tap in there for fuel pressure reading.

You didn't mention if you are 4 wheel drive and what gear ratio, 4. 11's and 4 wheel drive you wont see much better than 15 mpg.

 

[Beast2B]

thanks Holzarbeiter, i can't remember when they changed some of those things... i can barely remember my own truck's config!

 

[Holzarbeiter]

No sweat, I learned a lot doing the swap to the 56

 

[MCarstens]

I am 4x4. I don't know what ratio I am. I'm ignorant about the ratio's. I'm geared for speed more than power - what that means in ratio unfortunately I don't know.



I do have another quick question - what do I do to keep up on these posts? is there an automatic update if I stay here? Do I go to a certain spot to keep track of them? I've been just checking back every now and then to the "new posts" section.

Thanks,

Mike

 

[Beast2B]

stock ratios were 3. 54 or 4. 10. should be a sticker inside the glove box or a tag on the rear axle by the diff cover.

i have the email notification turned on in my profile, so i get a message when something new comes into a thread i've posted on. i don't see any auto updates, refresh the page and it'll bring in the new stuff.

 

[Holzarbeiter]

With auto and 4x4, not to mention the six tires I'm draging down the street, I used to get about 16 mpg before the mods, that includes some city and freeway. To improve milage you have to take it easy on the go pettle.

With my currend mods and a motor with only a couple of thousand miles on it, I'm getting about 14 to 15 and that includes some towing. Your best bet prior to any other mods is to install a set of gauges. Driving with Boost below 10 psi and keeping your EGT's at or below 600 will help some with mpg.

 

[Holzarbeiter]

Beast2b is right 4. 10 was the other option. There should be a sticker under the hood if i remember right that should also list your gear ratio.

 

[MCarstens]

I've made some updates in my user info. Hopefully this will help a timely response.

I don't have any extra guages right now. How strongly do you suggest the money spent for guages when I'm just an average user?

 

[Holzarbeiter]

The injection pump (VP 44) needs to have a certain amount of fuel pressure to live a good and healty life. Replacement of this pump is expensive, a fuel pressure gauge mounted inside the cab will let you know if you have a filter or lift pump going bad. This is a vital gauge for our trucks.

If you don't plan on any bombs you can get away with out the EGT or Boost, you have already mentioned an EZ and bombing is a slippery slope so again I would highly recommend gauges before anything else.

 

[MCarstens]

What is the difference between a lift pump and the injection pump? Is there a lift pump before the injection pump? Are they one in the same?

(I'll get the guages)

 

[Beast2B]

lift pump brings fuel from the tank to the injection pump. inj pump supplies high pressure fuel to the injectors. POOR design from the factory uses an electric pump to pull fuel from the tank and they have a tendency to get weak and fail. since the Inj pump uses fuel for lube and cooling besides feeding the cylinders, a failed or weak lift pump (~$150) can lead to a failed inj pump (~$2000). cheap insurance to monitor the lift pump!

 

[Holzarbeiter]

Lift pump, also known as transfer pump or pusher pump ( that's what it was designed for) transfers the fuel from the tank to the injection pump. The injection pump directs the fuel to the injectors.

 

[Holzarbeiter]

Well Beast2b you beat me to it, LOL

 

[MCarstens]

I see!!! Guages will definitely go on soon!