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Discussion Starter · #1 ·
Hello, i have a 94 dodge diesel, 12 valve cummins, straight piped, new air filter, 35 inch tires, 5 speed standard, at 100 km/h the rpms are 1750. I just purchased it and i haven't been able to get over 15mpg and it is extremely gutless, won't go past 120km and won't pull past 2200rpm. what do you think is wrong?
 

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You need a 3 or 4kgsk to get fueling past the 2200 rpm-ish range. As for mileage lighten your foot and as petie said check for leaks in the fuel line and fuel filter also.
 

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ok thanks, yea i put a new fuel filter on it and it didn't change any, but i did notice the rod that goes from where the throttle cable is connected, to the back of my pump on a lever (assuming its something to do with the swash plate?) was taped on from the previous owner and fell off, so i called the dodge dealer and theres a re-call on that, hoping that will play a key part in my mileage. Now i was looking on the net, and are dynomite injectors and fuel plates decent products? what would you guys recommend for a good gain in power but nothing too ridiculous?
 

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ok thanks, yea i put a new fuel filter on it and it didn't change any, but i did notice the rod that goes from where the throttle cable is connected, to the back of my pump on a lever (assuming its something to do with the swash plate?) was taped on from the previous owner and fell off, so i called the dodge dealer and theres a re-call on that, hoping that will play a key part in my mileage. Now i was looking on the net, and are dynomite injectors and fuel plates decent products? what would you guys recommend for a good gain in power but nothing too ridiculous?
Before you consider injectors read up on the tech articles for these trucks. You can free up about a hundred horsepower with nearly free mods.
94-98 Tech Articles - Dodge Cummins Diesel Forum

The mods I would start with are, a fuel plate (you can grind yours down, pull it out completely, or buy one off ebay for 35 bucks), 3k or 4k governor spring kit (from TST Products), an AFC spring kit (also from TST products), an adjustable boost elbow (these are cheap), and tuning your afc. Also have you tabbed the killer dowel pin yet? If not get on that. You can make your own or buy a kit from TST with a new timing cover gasket. Now, start with those mods and see how you like how it drives. Keep in mind that you will need a new clutch with these mods because your stocker won't hold up. Valair or South Bend are two great clutch companies. As for injectors get a hold of SDX or a guy by the name of partyshortbusdriver here on the forum. Either of these guys will be able to get you way better injectors than DDP (no offense to ddp) at a much lower cost.

Start with reading up on those tech articles though and then come back with questions for us. :thumbsup:
 
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sounds like your truck is fine, operates like it was designed to. if ya read the beginners section, ya would know stock gov spring start defueling at 2200 rpm.
"straight piped" why does everyone think this is such a notable upgrade?
And like JT422 said, is easy and almost free to get around 100hp extra out of your rig, and you'll be well on your way to frying your stock clutch.
 
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sounds like your truck is fine, operates like it was designed to. if ya read the beginners section, ya would know stock gov spring start defueling at 2200 rpm.
"straight piped" why does everyone think this is such a notable upgrade?
Lol yup. I lost about 1.8 mpg with my 5 inch system. :S:
 
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Discussion Starter · #9 ·
thanks guys for the help and information, with putting that new nation wide change up kit (throttle cable, fuel filter, return springs, and ball valve ends for the govenor shaft), the truck is running way better, the guy before me just had the shaft taped on and it wasn't connected properly. Yes i agree with you FreeWheelin, a 4" exhaust system doesn't change the trucks performance much unless you are cranking out big power, just makes them sound good thats all. I will check up on that tech articles to see how to tune this engine up properly and maybe gain a little more power.
 

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sounds like your truck is fine, operates like it was designed to. if ya read the beginners section, ya would know stock gov spring start defueling at 2200 rpm.
"straight piped" why does everyone think this is such a notable upgrade?
And like JT422 said, is easy and almost free to get around 100hp extra out of your rig, and you'll be well on your way to frying your stock clutch.
Going from my stock 3.5" (that was rotted out) to a 5" w/ flow through muffler (3.5->4->5" downpipe), I picked up a couple mpg. Has a nice growl to it too.

Also, I love your sig. lol
 

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Lol yup. I lost about 1.8 mpg with my 5 inch system. :S:
Not understanding why you would have lost fuel mileage with a larger system. Unlike gas engines that require the proper sized exhaust for proper cylinder scavenging, diesels don't rely as much on scavenging due to the forced air intake with no fuel charge. The larger the pipe the sooner the cylinders will clear of exhaust gases.

liteweight
 

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How fast is 120km? That's like 27mph, right?

I'm glad we had this talk...:thumbsup:
 

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How fast is 120km? That's like 27mph, right?

I'm glad we had this talk...:thumbsup:
Haha I probably hate the metric system more than you do. But hey at least our dollar is stronger than yours now.
 

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Haha I probably hate the metric system more than you do. But hey at least our dollar is stronger than yours now.
With a prez like ours, I would hope so...:thumbsup:
 

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With a prez like ours, I would hope so...:thumbsup:
Wanna trade head honchos??? I don't think our PM is any better At least your diesel is only $4.00 a gallon. Ours is $1.25 a litre. There is approximately
4 1/2 litres to a gallon. Don't need to be a math xpert to fiqure to fiqure that one.:banghead::banghead::banghead:

liteweight
 

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fuel

Wish could buy 1.25 fuel 1.35 here a litre my crane takes 800 litres i'm in vancouver. But got 18 mpg with camper on towing a 4x4 to mexico this year. Love my 12v pickup
 

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Never really cared about the price of diesel. But I badly want to move to Chilliwack, BC.
 

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Ah I've been paying around 1.089 in Alberta. Mind you fortmacs around 1.27. and it's 3.78l to a us gal.
 
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