Engine/Transmission (1998.5 - 2002) Still getting 11 mpg out of options now. Any suggestions.

[Silver Bullet Ram]

Injection pump was replaced last fall, fuel mileage went down. I've changed the map sensor and the iat sensor. I put a SuperChips in it to see if that would help, got more power, fuel mileage stayed the same. I switched to synthetic, that didn't help either. Changed all my filters, didn't make a difference. Changed my driving style that didn't help either. Waste gate isn't stuck, turbo is working. I reset the apps. Fuel pressure is 15 psi idle and 10 psi wot. Dealer says nothing is wrong, no codes show up. The reason I bought this truck was so I could get a decent fuel mileage with a big truck. In the earlier days it was getting 19mpg. I am furious and I have let the dealer know this too. Told them I am not buying anymore new trucks there. Seems like this truck has become a costly mistake. The only thing else I know to do is to find it a new home.

Out of options.



Gary

 

[SnoKing]

How much boost will it make? Are you carrying around the camper all the time? SNOKING

 

[darkhorse]

Something has got to be wrong. My '01 with several BOMBs gets 19+ mpg at 70 mph. The worst milage I've gotten was about 15 busting deep snow drifts in 4WD with tire chains.



I wish I had an explanation for you. I gather the milage drop came with that new injection pump, but why? I'll watch this thread to see if an answer showes up.

 

[CrimeFighter]

Man ... . I know this sounds dumb but are draggin a brake or something ??

 

[MRose]

Bad injectors?

 

[Silver Bullet Ram]

I have had some brake issues with the abs, but I would think they would have to be almost locked up to create that much of a problem. I have wondered about the injectors. Sometimes it does have a rought idle once in awhile. I have noticed the more fuel treatment I dump to it the better it runs. Could this be low sulphur diesel fuel problem? I might put a set of rv injectors in it and see what that does.



Gary

 

[Silver Bullet Ram]

Also I was wondering, if when the pump failed if it sent some shrapnel into the injectors making them stick?



Gary

 

[jeepit]

May want to do a search. I remember reading a thread along the way of a VP44 install that had the wrong one installed and it was identified by the last digit stamped on the pump. It was suffering from poor mileage? Hope this may help you.

 

[Clmsnow]

Ever since my injecttors were put in I went from about 17-19mpg to 14mpg. Doesn't matter if it is freeway or in town. What gives?

 

[Silver Bullet Ram]

I think they put too many electronics on these things not to mention an underdesign fuel system. If I had 8 grand to burn, it would get a p pump. Somedays it runs good and some days it doesn't. I have noticed if I dump a lot of fuel additive to it, more than the amount required, it runs better.



Gary

 

[DirtyDodge]

Mine stock is only getting 15 - 15. 5 hand calculated. Factory VP44, New lift pump though. I drive 70 mph mostly freeway (95%) to and from work 38 miles each way. Just cleaned IAT and check the map sensors. Truck consistanly goes 360 miles before the fuel light comes on. I have never been impressed with the milage of mine. It now has 67000 miles on it. I believe the 20 mpg thing is not achievable with a 4wd. I have 285/75 - 16, they are slightly bigger. This may be dropping my milage a little, but I wouldnt think that much.

 

[darkhorse]

I believe the 20 mpg thing is not achievable with a 4wd. I have 285/75 - 16, they are slightly bigger. This may be dropping my milage a little, but I wouldnt think that much. [/QUOTE]



My 4X4 gets just under 20 mpg at 70-75 mph on the Interstate. Now I do have 265's & the 3. 54 rear end.

 

[SnoKing]

My 2001. 5 Auto with 4:10 has always been able to get high 19's on the freeway if you keep the speed to around 65, run faster with the traffic and it gets high 18's. Around town it gets 15. Towing 11. 25K Fiver is up to around 11. 5 to 12 now that it is broken in and has been mod'ed. It is usually towing either the the 5th wheel or the snowmobile trailer (66% of the time) and has averaged 14. 72 from 7800 miles to 36000 miles. SNOKING

 

[Walt-L]

Look into the Sprint RV 275 nozzels from http://www.kermatdi.com/ ,They are supposed to be one of the best fuel atomizing nozzels out there. Thats why I picked up a set. I just haven't had the time to get them in the truck yet. I'll post the MPG increase (if Any) later this summer. Right now I was getting 17+ to work.

 

[rivercat]

I hear that sometimes a new iat will give just as bad a signal at a bad/dirty one do a search on it there is a way to test the cold/ hot signal but Im not good with electronics, shame to being my father is a retired electronic engineer for NASA. Guess some times the apple does fall far from the tree :--)