Engine/Transmission (1998.5 - 2002) Is Inj. pump on 275hp RV's interchangeable with DTC?

[ihegdal]

Does anybody know if the VP44 pump that Cummins used on their RV and bus engines in past years is interchangeable with the VP44 pumps on the Dodge trucks?



If so, what hp options were produced? Does somebody have the CPL's, Cummins PN's for the pump, or engine serial # for an RV or bus with a VP44 pump?



Thanks



Ian

 

[jstarnes]

I think the only difference is the ecm flash???



and injectors(edit)

 

[jwilliams3]

They will interchange, but they will not operate at the same parameters.

You will often find when using an industrial VP44 that the RPM's will not reach the 3k+ mark as the Chrysler version does.

The Industrial VP's should run at about 2. 5-2. 6k Rpm.



IMO



--Justin

 

[CFAR]

How about Auto vs Manual vp's, such a thing or not?



98. 5 to 2002 use the same basic vp? What is the diff between a ETC and a ETH vp?



Just curious I picked up a vp for a 99 Auto cheap spare and I'm curious. It will be a spare until I take it apart that is.

 

[jwilliams3]

Auto and Manual VP's are the same.

The ETH VP is different though, it will function on an ETC engine but will not yield as high output as fuel when modified.

I do not suggest installing an ETH pump on an ETC engine.



Someone else can enlighten us on exact cc's of fuel delivery each pump provides.

Also the popoff pressure from what I recall is higher on the ETH pump.



--Justin

 

[ihegdal]

I see that part way down the page @ http://dodgeram.org/tech/dsl/Facts/01ISBspecs.html#parts that, under the same test conditions the ETC injectors deliver more fuel than the ETH injectors.



If this is correct it would then seem to me that the ETH pump must have been built to deliver significantly more fuel than the ETC pump to be able to provide 10 additional hp thru smaller injectors.



I have been told by folks at a Bosch shop that installing an ETH pump on an ETC engine will result in about 20 hp by itself and that any other fueling power enhancements are then slightly more effective than they would have been on a pure ETC engine.



This is what got me to wondering what other VP44's in the 250-275 hp range might be compatible with the Dodge ECM.



Ian

 

[rkressg]

Software issues are the difference in RPM. The Cummins ECM's usually limit the rev's to 2,600 RPM. Internally, there is no difference, because they are the same thing. What is different is the Pump Timing Key. There are 21 different keys for these pumps. These keys have a direct effect on the timing and more importantly, the HP developed. The key that is in the pump on the ECT and ETH motor are different, thus allowing for the difference in HP. The key in a motor home with a 300 HP motor is also different.

So in conclusion, the internals on the pump are the same. The only thing different is the key and some software.

 

[ihegdal]

RGilbert,



If I understand what you saying correctly, then all 235 hp pumps have the same key #, all 245 hp pumps have the same key # , but one that is different than the 235 hp key and so on for each different hp rated pump.



This is different than what I understood each pump/key combination was used for. I thought that each pump was given a specific key during the manufactoring calibration process so as to compensate for internal pump part variations. The key was used to fine tune the pump timing to meet design spec's.



Am I wrong on this?

 

[jwilliams3]

RGilbert,

I am no expert on VP44's by any means.



Here are some questions for you:



1. Why was there 21 keys when there is less than say 6 or 7 pumps for industrial and DCX usage?



2. If only software differences effect RPM's on industrial ISB's, why when installing an industrial pump on a Chrysler ISB will it suffer from severely low RPMs?



3. Are you sure there are no internal differences in the ETC vs. ETH fuel pumps?



4. Why can ETH engines rev higher than ETC engines, is it software or the VP44 or a combination?



Enquiring minds would like to know!



--Justin

 

[rkressg]

Originally posted by jwilliams3

RGilbert,

I am no expert on VP44's by any means.



Here are some questions for you:



1. Why was there 21 keys when there is less than say 6 or 7 pumps for industrial and DCX usage?



2. If only software differences effect RPM's on industrial ISB's, why when installing an industrial pump on a Chrysler ISB will it suffer from severely low RPMs?



3. Are you sure there are no internal differences in the ETC vs. ETH fuel pumps?



4. Why can ETH engines rev higher than ETC engines, is it software or the VP44 or a combination?



Enquiring minds would like to know!



--Justin

I will try to answer some of these questions. It is hard to be sure because no shops rebuild these pumps. I can only go by my experience and what I have read and been told by various sources, such as Cummins, D/C, and other mechanics. Well, here goes.



1. I do not know why there are 21 different keys; these engines come in many different HP rating from around 80 bHP to 300 bHP. This pump has also been in use since 1998, there have been many minor variations made to it since its introduction into service, possibly explaning the many different keys.



2. It will not suffer form severely low RPM's. To a diesel mechanic, any heavy oil burning engine that revs past 2000 is over revved. Our diesels rev much faster a normal heavy duty or medium duty inline 6 cylinder. The highest possible rpm of our engine as by Cummins is 4150 rpm, though I would not suggest you try to obtain it. Again, it does not suffer, it just revs to higher numbers than the commercial use engines.



3. To the best of my knowledge, there are no differences in the internals of the pump according to Cummins. According to the D/C service manual, there are differences, yet the pumps from Cummins have the same part number with different key numbers.



4. Again, to the best of my knowledge, the differences are in the software and timing of the ECM and the processor on the injector pump. The only major difference between the ETH and the ETC are the pistons. The ETC has a compression ratio of 16. 3:1, the ETH has a compression ratio of 17:1. The only other difference is in software. Some sensors might be different also.



I hope this can shed some light.

P. S. A Cummins ISB part manual will not always work when looking up parts for our trucks. An example of this is the MAP (Turbo Boost) sensor. The ISB has a different part number than the Dodge B series engine.



-Rich

 

[jwilliams3]

RGilbert,



A Chrysler engine with an industrial pump will suffer from about 1000 rpms too low (hi idle rpm).



On pumps with same part #.

When Cummins manufactured these engines the Pumps for the ETC and ETH had different part numbers, not just key numbers.

Although maybe you are referring to the recon pumps marketed by Cummins shops.



The sensors are the same on both engines (eth and etc).



Unlocking the mysteries of the VP44!



--Justin