Fellows, I picked up a 94 Cummins 12 valve 5 speed today. It's a 4x4 dually with 4.10 gears.

Is it supposed to be this slow? I mean, it totally quits pulling at 2200 rpm or so. Going down the road at 60 mph, I'm at 2000 rpm and pretty much done.

Maybe I'm used to my other 2 trucks, but ****, I can't keep up with traffic in this 12 valver. I know the 4.10 gears aren't for high speed, but I can't drive on the interstate here.

I'd appreciate your comments...

 

Yep, them 4.10 are not helping. the 93 350 4x4 I once had was a real turd also. My 95 at 65 or so is doin 2000 rpm around. your running out of steam. The 95 I just got is a dog comparing it to my 93 250 with the performance pump. I think its time for a fuel plate. It should have a cat also which Im told probably is plugged by 100k. Hows the idle? if its rough, stalling, smoking, A new overflow valve might help. Its on the pump, in front top, with a banjo bolt and fuel line to it. Do a search on it youll find more info. Also fuel lines under the manifold area, return and feed, are prone to failure or leaking air in. Replace the fuel filter also (fun).
its a start, see what it gets you.

 

Mine was about the same when I got it. The stock govener limits the engine to about 2200 RPM before defueling. I put a #10 plate in mine and adjusted the starwheel and it made a big difference a 3000 RPM governer spring kit is next. Try a search and you will find a ton of posts on fuel plates, governer springs, AFC and starwheel mods.

 

Simply, no it shouldnt be that slow. It sounds like your cutting out on fuel. Either that or your timing is way the hell off. Is there unusual noise or smoke?
Ryan

 

My wife followed me home for about 100 miles. She never saw it smoke at all. Taking off, shifting, lugging it, never any smoke.

The engine seems to run very smoothly. Has the sweet 12 valve burble to it. Nothing like my obnoxious 02 24 valve HO. This truck idles real pleasant.

This truck has 180k extremely hard miles on it. I have no idea as to maintenance or repair history.

It is very weak. I'd not want to pull any kind of serious trailer with it.

I'll start with a fuel filter of course, then I'll look into timing and such to see if I can get a decent baseline on this thing before I consider any modifications.

 

By the way, the cat is extinct on this truck with a straight pipe front to back.

 

Check your fuel shutoff solenoid and make sure it is opening all the way. Saw one falling apart once and that truck felt like a real dog to drive. It was close to redline before it got close to making all its boost. also check your wastegate actuator for boost leaks.

 

i got my 95 last september totally stock and it pulls till 2600rpm ...wheni got it the cable that runs to ur actual gas pedal was stretched and i had limited travel of the pedal...so i got down there took the slack out of the cable and increased pedal travel that made life very enjoyable driving all the other mods will definitely help but check for loose throttle cables, pedal cable...and timing may have retarded over the years....

 

it is all easy to fix, you can get about as much power as you can stand. glade to see some one local to me, i live just north of lake weatherford.

 

Sounds to me like the boost is bleeding off.tighten all the clamps on the boots going to and coming out of the aftercooler.and make sure the airfilter is clean

 

If it is not any of the other of these problems you can click the stock governer springs in 1 or 2 clicks and gain some rpm, but I recommend the new spring kit as it is only $150 and is the best mod ever on my truck. My truck was exactly like yours before I installed mine.


good luck

justmy.002

 

Well guys, I got it straightened out.

I found the accelerator was only stroking the pump about 1/2 travel. I made a spacer to take up the slack/ stretch in the cable and made sure it gets 100% throw now. That seemed to be the problem.

I also clicked the starwheel about 20 or so clicks after that.

It runs real fine now. Not like my 02 HO, but pretty good. I ran it all the way up in 4th gear, and it will turn about 2700 rpm under full throttle.

I sure appreciate everyones input on this situation. I'm new to 12 valves, so this is all greek to me.

Now, I need to fix a bunch of cracks underneath the cab around the cab mounts and back wall of the cab.

 

If you have a problem with the throttle cable you might want to see if it is covered under a recall. I had mine replaced for FREE last year.

 

yeah go to the dodge website and there is a place to enter your vin and it will show what recalls havent been done on your truck,any dealer will fix it free.the throttle cabel is for sure on the 94.Tighten those aftercooler clamps just to be sure.it take 5 minutes or so

 

now u gotta be ready for ur contacts to go soon as well as the lil blue wire that connects to ur driver side battery terminal (the busy one) that lil blue wire will eventually give u starting trouble as will burned contacts inside the starter ...all that junk can be cleaned good ol sanding paper and brake cleaner will take care of that or just get bigger contacts...if ur like me and have the original speakers and sound system in there thats prolly got all kinds of corrosion so its gonna crackle when the radio is one every now and then

get ready for a 5th gear loose nut in ur tranny eventually too

after u get rid of that stuff the truck is indestructable!!!!!!!!!