Engine/Transmission (1998.5 - 2002) 275 HP VP44 on my 01

[BCronk]

I have read on various posts that you cant interchange VP44 pumps on these trucks, Well I did. I bought a new 275 pump from a friend of mine who is an engineer at bosch. He said the pump was for an FL70 freightliner, I checked with cummins and they confirmed it was for the FL70. I didnt need the pump at the time but I could not pass it up for the price, I got it for less than some of the junk pumps on ebay. So when my pump went out at 100,000 I ask cummins if my 275 pump will work, they said no. I called my friend at bosch he did some research and said it should work. So I pulled my old pump off and put on my new 275 pump and it worked. I now have 112,000 on it, (12,000 on new pump) with no problems. I dont have any fault codes either, and it works fine with my BD tow pro controller. So why are people saying you cant interchange them? or am I in for an unwelcome surprise down the road? Also have you guys heard of any one else doing this?

 

[HBarlow]

BCronk:



Did you notice a performance increase with the 275hp injection pump?



Harvey

 

[McDowra]

I don't know why people say they won't interchange. I have put well over 200K miles on mine with a HO pump, make that 2 HO pumps. There may be one that won't work but I wouldn't know which one it is. Are there advantages to running the other pumps, I don't think so.

Tim

 

[Sticks]

You may have gotten lucky. Time will tell.



It has been my experience thus far that the wrong spec'd pump installed on a vehicle will have issues up to and including; surging, hard start, low power, and white smoke.

 

[Dave Ratcliffe]

I wonder if the 275 pump would work on a HO truck?

 

[Vaughn MacKenzie]

This is quite interesting. BCronk did you notice any change in power, sound, mileage?



McDowra why do you put HO pumps on a regular 24v? They have smaller plungers and not as much power potential but the difference isn't that great. I know if I had an HO I'd be thinking to swap for a non HO pump or if it worked a 275 pump if my VP44 died.



Vaughn

 

[jwilliams3]

The 275hp and 300hp engines were governed around 2500rpms.



So dont expect to have any fuel above those rpms if you install the pump (or at least severe defueling above those levels).

 

[RBallard]

See if your friend at Bosch can provide you the specs for both pumps and do a comparison. I may have missed this but isn't the 275 pump a VP44 as well. I know some of the mechanical internals are different between the SO and HO but I know nothing about the others.

 

[BCronk]

IN reply to some of the questions and coments above. I dont know if the 275VP44 gave performance gains. It seems like It has more bottom end and less top end power. It blows a bigger cloud of smoke when I stomp on it. Fuel milage increasd slightly. My friend at bosch said the pump has a larger plunger and the fueling map in the pump is different. He also said the ecm tells the pump what to do, timing, how much fuel ect, so you should be able to swap pumps between engines. The engine still governs at 3200 rpm but it does defuell after 2500 rpm. the only time I noticed the defueling was while towing my 18,000 lb 5th wheel, I couldnt get over 75 mph. I wouldnt call it severe defuling I can still hit 100 mph as fast as I ever did. I havent had any surging, or missing so far. The only problem I have had so far is sometimes when the engine is hot it will crank longer before starting, if I shut the truck off to run in some where & come right back it might not start on the first crank. When it is cold, has been sitting, or has cooled down for an hour or so it starts with a bump of the key. I noticed this problem after I replaced my lift pump so I dont know if it has to do with the injection pump or not.

 

[jtisdale]

I know of two local guys that have had this "029" pump installed on there SO's. They both defuel sooner than what they did with their 027 pumps. Neither one have had them on any longer than 2 years. One was used in a performance application, the other was not. In the performance application, the defueling was much more noticable.

 

[McDowra]

McDowra why do you put HO pumps on a regular 24v? They have smaller plungers and not as much power potential but the difference isn't that great. I know if I had an HO I'd be thinking to swap for a non HO pump or if it worked a 275 pump if my VP44 died.



Vaughn

When my pump went out on my truck, we were selling the VP44's as fast as we got them. We were out and mine finally got so bad you couldn't drive it, we did have a used HO pump so I put it on because we needed the truck. My truck is not a high horsepower truck by any stretch of the imagination, to be honest just driving it I couldn't tell a difference. And there you have it ,



Tim

 

[SpicyJam]

I know of two local guys that have had this "029" pump installed on there SO's. They both defuel sooner than what they did with their 027 pumps. Neither one have had them on any longer than 2 years. One was used in a performance application, the other was not. In the performance application, the defueling was much more noticable.

The "fat Kid" has had his 029 pump for 2 years now. He is still making good power. So far he is still cranking on it with a TST Comp fueling box and a an Edge EZ. Shall see how much longer it goes... ... ... so far so good.

As far as VP swaping the H. O. ECM can not comunicate with any other VP other than a 028 pump. The SO can..... but not the HO, what happens the HO will fire up and go, but be limited to 1200 rpm or 1500rpm I can't remember. As far as having a hard start when warm is not a good sign. That is the begining of a failure... ..... not good.