bcmopar1

well posted this a couple times, here we go again have 96 ctd 5spd 3.55 rear, milage sucks about 13-14 empty @70mph turning 2100 rpm did the filters, checked for leaks, and a week ago had timing advanced to 16 degrees, stock plate forward, star wheel turned in, but got the terrible milage before these mods, any HELP ??? this is really starting to suck both of my prev. 92 c.t.d. got 20-21 loaded or empty constantly, starting to think the 2nd gen. sucks (in more ways than one :P)

infidel

Go though the list of possible problems in the section half way down this page entitled Low power and/or poor fuel economy
http://dodgeram.org/tech/dsl/trouble...2v_trouble.htm

DRM

FYI - I just ran the first tank full through my "new to me" 98 12v 4x4 QC truck w/ 274,000 miles, and it looks like just over 14 mpg. Was hoping for more, but not complaining either.

wiz-1

i don't know whats wrong with yours but mine gets 21 to 22 all the time and it has 126 on it

CoastalDav

You got a problem with the milage for sure. My sons 96 has 220k on it and still is getting 20-22.5mpg. His is an automatic. I think you need to visit a cummins dealer and let them look at it. It will be worth the hour of labor for the
answer.

Dave

Mostwanted

My milage just bit the dust here recently. I am not sure if it's my new tranny, or I installed my fuel filter wrong(?), or the winter fuel sucks. I need to get timed

Mtman6698

I'm a newbie that's been lurkin' but this got my attention. My '96 is only getting 13-14 mpg, mostly around town and I keep hearing stories about 20+ mpg. It is a new truck to me and I have no history on it but has 110,000 on the speedo. I've gone thru the oil change, filters, new belt, and thermostat (didn't work). Trans is full and looks clean and seems to shift o.k. (It's an RE). I see the list of things to look for and one of the top on the list is a plugged cat. Sooo.. How does one tell if they are plugged? How will the truck be effected if I take it off? Why they on there to begin with?

infidel

About the only way to tell if it's plugged would have been to monitor the exhaust back pressure since the cat was new and watch it rise. Most cats are clogged around 60k. Easier way to see if it's clogged is to remove it and try looking though it, once you've gone that far might as well leave it off.
With it removed you will have a different exhaust sound at idle, neither better or worse, just different.
'94 and early '95 didn't have cats, they were added to comply with emissions requirements. I haven't heard of anybody getting busted in a smog check for having a removed cat.

Your mileage will never be all that great with city driving, it takes a lot of juice just to get the heavy truck rolling. The guys getting 20+ mpg are mostly highway driving.

Mtman6698

Thanks infidel. At some point in time, after guages and other things I need to do to it, it will get a new, bigger exhaust system and the cat will get a proper retirement (tossed).

bcmopar1

well, got timeing set up to 16 degrees, didnt help a bit, this really sucks any more help

kd460

Lose the cat, get a new overflow valve (or at least check the spring length and stretch as needed-but will still need to replace) Do a search on overflow valve.

I agree the cat could be the problem, also do a search on rubber fuel lines. They can cause mileage and performance issues. Did you check (clean or replace) the prefilter? And finally check your fuel pressure and look for any boost leaks at the rubber boots and plenum gasket with soapy water.

14 mpg's is about normal for the city, and don't forget that winter fuel blends will make your mileage drop.

If you go to the link that infidel provided (and that website) you will get lots of troubleshooting info. Hope this helps, Kevin

bcmopar1

cat already ran away with the muffler,have 31 psi of boost

bcmopar1

cleaned screen, havent checked fuel pres. yet stretched out overflow once didnt seem to matter, didn't want to just throw parts at it though

DRM

I commented earlier I was getting a tad over 14 mpg, I adjusted for tire size and got a corrected mileage average closer to 15 and a quarter. Better, but not as good as I would like (of course )

I am still running the cat, and stock-type exhaust, hope to replace it all with a turbo-back 4" kit shortly and see what is up there.

Steve Roseman

Could be an easy cure, try slowing down for one tank. 10 mph makes a big difference on my mileage, 18-19 mpg @70-75, 20-22 mpg @ 60-65.