Engine/Transmission (1994 - 1998) 2700 RPM Tops

[JoeBioDiesel]

I purchased my first Cummins about 3 weeks ago. I've been following the 3000 rpm governor spring posts with interest. I have a 1996 250 with an Automatic and 4. 10s. It will rev to about 2600 in top gear before hitting the governor and backing off the fuel. It only loses about 50 rpms up hills, and gains about 150 rpms going down. This limits my top speed to a little over 80 MPH. It never goes over 2750, ever. The power is OK at any other engine load or speed. I don't have any smoke and the fuel pressure is fine, so I'm confident it is a governor problem and not a fuel supply issue.

Here are my questions:

Can the 3000 rpm springs be installed with no other mods?

Where can they be purchased?

Can the governor be adjusted without the springs?



Any suggestions or comments welcome.



Thanks,

JoeBiodiesel

1996 250, Automatic, 4. 10s, standard cab, no mods, Biodiesel powered.

 

[Extreme1]

Hi Joe, welcome to the TDR!



The is doing what it is supposed to do. My '94 would poop out at about 2500 RPM. The 3k RPM kit really makes the automatics pull hard because it will accellerate HARD until it upshifts.



The originator and a good vendor is Piers Diesel Research (PDR) and there web page is here!

 

[Jim Fulmer]

Joe if you are willing to spend a little extra money a #10 plate with the 3K's in an auto truck is a really nice addition and not overly aggressive.



Jim

 

[JIM S.]

3000 rpm spring kit

will make a new truck out of it... you will smile and smile... I still do after many thousand miles...

I havent reved past 3200 but pulled hard right up to that!

Jim

 

[JWaters]

springs

I ordered my truck in 1996 and got a 3500 club cab dually. It has 3. 54 in it and is 2 wheel drive. My truck will pull 3000 in 5 gear at 106 mph. I have never done anything to it. With no load out of gear it will turn 3200. Why is this? I have never done anything to this truck and have owned it since it came off the train!!! :--)

 

[champspa]

I took mine to a diesel shop today and asked could they make the thing go to 3k and they said yes. cost about 700 they remove the pump and set the governor and adjust the fuel . I wanted it to pull hard up to 2900 and then let the governor come on after that . does this make sense or does the GSK from piers make more .

 

[JIM S.]

GSK

for sure go with the GSK..... you get more for less Oo.

Jim

 

[JJW_ND]

Big difference in 96 5sp vs 96 auto

The 96+ 5sp had the 215 pump that had more stock rpms ... that is how it achieved the 215 hp vs 180. ALong with several other goodies in the pump.



My 96 would also pull to 3K under a load. I could do 110 stock. Not that it will pull past 4000 it gets allittle fast.



Paying 700 just to get a few more rpms seems kinda steep. GSKs are not to hard to put in. If not there are enough performance shops that can do this. No need to pull pump.



Joe... you should make sure you are getting full throttle travel. Our older trucks were notorius for not getting full throttle. While someone allies full throttle in the cab, check to see if the throttle rod is aganst the stop or see if you can move the throttle rod any more. That last little bit of throttle makes for allot of power.



jjw

ND

 

[JoeBioDiesel]

thanks

Hello everyone,

And thanks for the replies. It looks like I will get the 3000 rpm gov springs.

Jim, I don't think I want to mod it with a plate just yet. I'll wait until I get bored driving it. For now. it's nice just to drive a cummins (I've wanted one for a while). I'll probably install EGTs before I do any mods anyway.

JJW, I'll check to see if it hits the throttle stops tomorrow. I need to turn the idle up anyway.



JoeBioDiesel

 

[Reddog1]

Best thing I did to my truck was the 3GSK's. Cost about $120. First thing I did, first time I worked on the injector pump. Took about one to two hours.



If you buy them from Piers, they come with excellent instructions.



If someone wanted to charge me $700, I would never allow them to work on my truck for fear they might try to sell me the Golden Gate bridge. No need to pull the pump.



Some guys would argue in favor of 4GSK. If I am not mistaken, they require heavier valve springs or valves may float (not good). The heaver valve springs will put increased load on the valve train, impacting longevity. Unless you really want to hammer it, I suggest the 3GSK.



The #10 plate is a great addition also. BUT, you will put your transmission at risk.



Been there and done that, plus a tad more, only after DTT transmission.





Wayne

 

[JoeBioDiesel]

Well, I checked to see if the throttle was opening all the way, and it wasn't. The transmission TV cable was binding and preventing the throttle from being completely depressed. It was also not allowing the TV lever on the trans to return to the closed throttle position, giving slightly harsh 1-2 and 2-3 shifts(and closed throttle downshifts too). I replaced the cable and now it pulls just fine.

thanks for the help

joe