Engine/Transmission (1998.5 - 2002) Can someone tell me why my truck gets 12mpg?

[Silver Bullet Ram]

It has been like this since the new vp-44 was installed last fall. Dealer said that some other people have complained about the same problem, with no resolution. Sometimes it runs good and sometimes it just lacks the power it used to. A few weeks ago I was getting 17 mpg. The fuel mileage flucuates, but normally hangs around 12mpg. This truck used to get about 20 mpg when it was new. Lift pump appears to be working, looks like about 15 psi.



Gary

 

[Graphic man]

Gary

pull your IAT sensor and clean or replace it there around $20 and replace your Map sensor

they are to 2 big ones for MPH

try and keep it around the 60-65 mph for the best MPG

 

[Silver Bullet Ram]

Since they went electronic on these trucks seem to have a lot of problems. My personal opinion diesels shouldn't be computer controlled.



Gary

 

[Lsfarm]

Mpg

Here is a list of things that can improve fuel mileage:



Air up your tires to max level, this reduces rolling friction

Change both differentials to synthetic gear lube

Change the engine oil to Synthetic oil

check and clean the MAP and IAT sensors

Make sure the air filter is clean



The hardest one: Slow down, 65mph instead of 75mph

is good for 2mpg. Tough to do but it works



Another driving technique, try your best to not build boost, this

means drive with a very light foot. Boost means you are adding enough

fuel that the engine is building backpressure enough to spin the turbo.

You can drive this way, I have done it. But is it nerve racking to say the least.

Take one of your wife's Valliums helps too. [just kidding]



I have found that if you have the stock turbo [small ex housing]

and have a stuck or sticky wastegate you will have increased drive

pressure and this reduces mpg. Check your WG to see that it moves freely



On both my '01, and my '9812v when I went to an HX40/16 the mpg took

an immediate jump up by about 2 mpg. This is the result of the engine

breathing much easier through a 16 cm housing instead of a 9cm or 12cm housing .



It has happened often enough on other trucks [turbo swaps] that I don't believe it is a fluke.



You can try some Diesel fuel conditioner, but other than Amalgamated [sp?]

I've not heard consistant positive results. My results with conditoners are mixed at best. Some seem to make the engine smoother, but I've not seen any consistant fuel mileage improvement with a conditioner. I've heard that Amalgamated has given repeatalbe consistant fuel mileage increases. I've not tried it myself.



As a last resort try a mild fueling box, with a light foot these often net better

mpg



Hope some of this works for you, Greg L

 

[Silver Bullet Ram]

I have changed about everything except sensors and differential fluid. Even changed my driving habits. I am going to take it back to the dealer and make them fix it.



Gary

 

[cosborne]

Well let us know what they say. I am in the same boat it appears. I replaced the vp44 and lift pump just 2 months ago and my mielage has not been the same since. I was getting a consistant 17-18 and now its like 11 and 12. Err.....



Corey

 

[rivercat]

LSfarm what do you mean about the fuel conditioner?



"You can try some Diesel fuel conditioner, but other than Amalgamated [sp?]"



what is amalgamated? is that good or bad?



I personally like fuel treatments and can feel the difference when I don't use them and hear the roughness of the motor



I like one called Fuel power (or polar power for cold weather)super small white bottle has a soapy smell and is super consentrated one 10 or 8 (cant rember) oz. bottle treats 220 gallons I split one bottle up into 8-10 tankfulls for $5 can't beat that and if nothing else it helps does something to water to help disalve or suspend it or something.

The display sold me it had three bottles of difrent stuff the stp was the worst you could see the big droplets sitting on the bottom after you shook it

 

[HEMI®Dart]

rivercat,



I use Amalgamated's Diesel Fuel Conditioner and it's good stuff. You can only buy it in a five gallon can. Use search on how to buy.

 

[Silver Bullet Ram]

Cosborne, I will let you know. I am glad I am not the only one. I did take it back right after the injector pump replacement and complained about the fuel economy. The said they are aware of the problems, mine wasn't the only one and they don't know how to fix it. This time I going to make some stink with them and tell them to fix it or keep it. I sometimes regret getting rid of my 98 gasser for this thing.

I do use fuel additive. Power Service.



Gary

 

[Lsfarm]

check my edit

Sorry, that sentence didn't make sense. Check my edit. Amalgamated is a fuel additive that some folks have had consistent repeatable fuel mileage increases when using,





Greg L

 

[rivercat]

graphic man,

Gary

pull your IAT sensor and clean or replace it there around $20 and replace your Map sensor

they are to 2 big ones for MPH

try and keep it around the 60-65 mph for the best MPG

hey The map is next to the fuel filter can right? any special tools to take it out is it fragile?



where is the IAT?



I haven't noticed worse milage just increased smoke wanted to clean em don't think they are bad cause no codes but I do want to clean them







Im only running a power puck and a newly cleaned K&N drop in Hope I don't have a boost leak or turbo problem.

 

[Graphic man]

The IAT is on the driver side at the rear of the motor it has a plug on it and the map is on the same side about 8" in front of it

the IAT is easy to clean and are about $20 new the map on the other hand is hard to clean and is a lot more $$ around $80 i think



Hope that helps a little



Scott

 

[rivercat]

thanks scott can you get to them better from bottom ?

 

[B.G. Smith]

thanks scott can you get to them better from bottom ?

You can reach them from the top, it would be much easier if you had two elbows in your arm. The IAT is a smaller size but the MAP is 1-1/4" and you will need a deep socket for both. bg