[StephenTNutter]

Hello. I'm new to the site. I just purchased a '97 Dodge 2500 4x4 with a 5.9L Cummins. I would like to bump up the mpg. The truck has a 4" exhaust. I just ordered an AFE Stage 1 cold air intake system to help it breathe easier. Since it is a 12-valve engine, no chips are available for it. Would you know of any way to increase mpg in this engine/truck. Would taller tires help? It has a 3.55 rear end. Thanks.

Steve

 

[IPOLUTE]

What size of tire do you have on it right now? What is the MPG that you are seeing? Is it an auto or manual? You can put a fuel plate on it that will give it a bit more power and help with the mileage. Run full synthetic in your rear and front axle. Don't go past 2000 rpm's. On the freeway don't do over 65mph and go light on the go pedal

 

[StephenTNutter]

Thanks for your reply. The truck is an automatic. The tires are 265/75/16. I haven't run a tank of fuel through it yet, but the guy I bought it from told me that he gets 19 mpg around town. That seems to correspond with the amount of fuel I put in it after buying it, judging from the mileage on the trip meter divided by the gallons needed to top it off.

What is a fuel plate and how does it work?

I appreciate your tips. Thanks.

Steve

 

[dslhtrdr]

I put a #8 plate in mine when I put 33's on my '94 (when it had the stock auto) and saw a little bit better mileage. DDP injectors might help out too, but like IPOLUTE said, be light on the go pedal!

 

[dslhtrdr]

The fuel plate is in the afc housing on top of the injection pump. Some people also call it a cam plate. If you buy one from bd like I did, detailed instructions come with it. It's a piece of cake to install.

 

[StephenTNutter]

Thanks for the fuel plate tip. When you add taller tires, doesn't your odometer/speedometer reading change (show slower/less miles)? When I put 34" tires on my '77 F-250 years ago, I had to change the gear in my transfer case. Is that the way to keep the gauges accurate on trucks today?

 

[Joe G.]

First of all, 19 MPG is pretty good running around town. These things weight close to 7000 lbs full of fuel and a driver in the seat.

The fuel plate does not affect MPG. It's a throttle stop that controls maximum fueling at WOT. What it does is stop forward (more fuel) travel of the governor control arm at WOT. Another name for the plate is full load throttle stop. At less throttle it is not in play at all.

Best mileage is to drive it as if there was an egg under the pedal.

 

[dslhtrdr]

The guy I bought my truck from said it averaged 19 mpg too. I weighed mine after I got my 18x10's and 33x13.50's, full of fuel, and it came to 6140 lbs, but I wasn't in it.

My speedometer is off by about 2 or 3 mph. I know that because I drive by the radar speed checkers the county puts out on the public roads that say "your speed is..." and I'm going slightly faster than my speedo says. Not a big deal to me.

 

[ykdave]

Like mentioned above, 19mpg intown is not bad at all. these trucks are heavy as all hell and shaped like a cardboard box which doesnt help at all.

My truck used to average 18mpg intown and mid 20s on the highway. You probably arent going to be able to do much for your intown mpg but on the highway you can make a HUGE difference in economy by keeping the rpms around 1800-2000, thats their typical sweet spot that you will see best economy.

These things are by no means speed demons and trying to do much over the speedlimit is going to totally kill your milage.

A few basic things like intake and exhaust and drive it like a granny and you might be able to pick up a bit of milage in town.

Also, how many miles on the truck? Depending on the milage your injectors are likely past due for a cleanup or replacement. Typically, with the smaller aftermarket injectors (+90hp for example) you can pick up an extra mpg or 2 if you can keep your foot out of the pedal (maybe more if your old injectors are totally f'd)

 

[12vBen]

i get 20mpg average

although i have seen better cruisin

 

[race4time]

Heck, I only get 22 and mine's a 2WD.

 

[StephenTNutter]

Thanks for the replies, guys. The truck has 242k miles on it.

Today my aFe stage 1 filter arrives. It looks simple enough to put on. Now, replacing injectors (if that would help), how hard, and how expensive, a job is that?

Steve

 

[ykdave]

a GOOD set of injectors are not all that cheap really, you can expect to pay $600+ for a small set

As for changing them out, its more time consuming than hard because the fuel lines all need to be pulled off. Their are various threads around here on how to make your own injector pullers (using a lugnut and prybar or a lugnut and pvc tube/pipe, ect)

A cheap home made slidehammer/injector puller:

Injector Puller for 12V engines

 

[dslhtrdr]

I paid close to $700 (I think...) for my ddp 3's, which are 90hp injectors. 12v's are easier than most diesels because there's not in the way to get to them. The hardest thing for me was getting the fuel lines back on so they wouldn't cross thread.

I used a prybar to get mine out. DDP suplies you with a nut to thread onto the injector to make it easier.

 

[StephenTNutter]

How do you know when you need new injector(s)?

 

[partyshortbusdriver]

Thanks for the replies, guys. The truck has 242k miles on it.

Today my aFe stage 1 filter arrives. It looks simple enough to put on. Now, replacing injectors (if that would help), how hard, and how expensive, a job is that?

Steve

not that hard to install as long as you take ur time and go over everything so you know what ur doin, i wouldnt put 90hp injectors in with a stock turbo and trans, i have a bigger turbo and can still see very high EGT's. You will have to take ur intake horn, injector lines, and injector fuel return lines off to put ur injectors in. Took me about an hour in a half to change mine.

 

[DJ parris]

get your injectors on ebay just make sure you buy them from a dealer place/company.i have seen them for 300$

 

[dslhtrdr]

How do you know when you need new injector(s)?

I don't think all high mileage trucks need new injectors. Mine didn't look too good when I pulled them out, but I have over 300k on it.

My egt's aren't out of control. They are kinda high since I have a stock turbo, but I have friends with the same injectors, built p pumps and 66mm turbos with nitrous and the sky is the limit with they're egt's. I'm not too worried about it, but everyone's opinion is different.