Engine/Transmission (1998.5 - 2002) 98.5 24v to 12v conversion electrical questions

[beee]

I have a 98.5 24v cummins 5speed, It has a cracked block and a bad lift pump, probably bad IP, so I would like to do a 12v swap. To have a fully functioning truck, cruise, check engine light, stock gauges, etc what are my options?

1. I have read that I need a 98 pcm, but wouldn't there be more then one part number for 98 pcms? I could see there being different ones for: (auto/manual), (cruise/no cruise), (California, non cali emissions) (air conditioning/ or no a/c). Is there a part number list? Am I wrong is it much simpler?
2. What about a 97 pcm, would it not communicate with the other computers and instrument cluster?

3. Which harnesses do I need? I read I need firewall forward which is 2 separate harnesses? One is an engine harness, and the other is what the fuse box? Can I use 97 harnesses or does it have to be 98?

4. I shouldn't have to change the instrument cluster or any in cab harnesses correct?

Any help would be great because getting a complete donor vehicle is very unlikely and I will have to piece it together probably sight unseen via ebay. I would hate to by parts that aren't compatible.

 

[RonaldLarson]

Why?

I have a 98.5 24v cummins 5speed, It has a cracked block and a bad lift pump, probably bad IP, so I would like to do a 12v swap. To have a fully functioning truck, cruise, check engine light, stock gauges, etc what are my options?

1. I have read that I need a 98 pcm, but wouldn't there be more then one part number for 98 pcms? I could see there being different ones for: (auto/manual), (cruise/no cruise), (California, non cali emissions) (air conditioning/ or no a/c). Is there a part number list? Am I wrong is it much simpler?
2. What about a 97 pcm, would it not communicate with the other computers and instrument cluster?

3. Which harnesses do I need? I read I need firewall forward which is 2 separate harnesses? One is an engine harness, and the other is what the fuse box? Can I use 97 harnesses or does it have to be 98?

4. I shouldn't have to change the instrument cluster or any in cab harnesses correct?

Any help would be great because getting a complete donor vehicle is very unlikely and I will have to piece it together probably sight unseen via ebay. I would hate to by parts that aren't compatible.

Seems much simpler to buy a 24V reman and eliminate all the hassle.

 

[beee]

I don't want to turn this into a 12v vs 24v thread, but the obvious reason for me is that if it had a 12v from the factory it wouldn't need a new engine and injection pump at only 137,000 miles. If I could get the answers to my questions changing a wiring harness and pcm would not be a hassle, pretty damn easy compared to pulling the motor.

With that being said do you have a recommendation on a reasonable reman company? Remember I have a cracked block, I might have trouble getting my core money.

 

[RonaldLarson]

I don't want to turn this into a 12v vs 24v thread, but the obvious reason for me is that if it had a 12v from the factory it wouldn't need a new engine and injection pump at only 137,000 miles. If I could get the answers to my questions changing a wiring harness and pcm would not be a hassle, pretty damn easy compared to pulling the motor.

With that being said do you have a recommendation on a reasonable reman company? Remember I have a cracked block, I might have trouble getting my core money.

First, there is nothing inherently wrong with the 24V engine. If you got a 53 block, you might have issues, but you have not told us why your engine failed. There is virtually zero difference between the 12 and 24 valve blocks. If you had monitored your fuel pressure, changed fuel filters and/or added fuel treatment, you could have prevented the IP failure. At 137 K miles, the cylinder hone marks are hardly touched. How many oil filters (Stratapore only) have you used in that mileage? What brand filters did you use?
Obviously, I am suspicious of the cause of your "Failure". These Cummins don't roll over and die without a lot of help.
For a reman engine, Cummins is the best source. You get a truly re-manufactured engine.

 

[beee]

First, there is nothing inherently wrong with the 24V engine. If you got a 53 block, you might have issues, but you have not told us why your engine failed. There is virtually zero difference between the 12 and 24 valve blocks. If you had monitored your fuel pressure, changed fuel filters and/or added fuel treatment, you could have prevented the IP failure. At 137 K miles, the cylinder hone marks are hardly touched. How many oil filters (Stratapore only) have you used in that mileage? What brand filters did you use?
Obviously, I am suspicious of the cause of your "Failure". These Cummins don't roll over and die without a lot of help.
For a reman engine, Cummins is the best source. You get a truly re-manufactured engine.

A cummins reman is out of my price range...... I am glad you are happy with your 24v. I wish the 12v had the reduced nvh of a 24v or the automatic high idle when cold but I will deal with that if it means simpler more reliable setup that gets roughly equivalent mpg and performance.

 

[jkidd]

the conversion will cost more than a good complete engine. The vp44 is the most advanced pump bosch created. If you change from a vp44 you lose dynamic timing, high idle, most likely cruise. The dynamic timing will get you better mpg.

pump = $500-1000 if you can find one
conversion kit to work on a 24v is about $1500-2000

pull cummins engines are closer to $2000-2500 with vp44 all day long.

best reason to go p-pump is if you are trying to get over 650HP as the VP44 has limitations.

 

[beee]

the conversion will cost more than a good complete engine. The vp44 is the most advanced pump bosch created. If you change from a vp44 you lose dynamic timing, high idle, most likely cruise. The dynamic timing will get you better mpg.

First I am doing a complete engine swap not a p-pump conversion so the price would be the same for the motor, and then about $900 dollars more for the 2 harnesses and pcm. Can you point me towards a study demonstrating that the dynamic timing on the 24v gives better mpg? While it is capable of better mpg I do not think that is the case because of NOx emissions. To meet government standards timing tends to be retarded reducing mpg. I am not to familiar with the programmers available. Perhaps it would be different with the proper programmer, but you can only do so much with piggyback style.

 

[Dieseldemon]

You need a 98 12v non cal man tran PCM everything else should work fine. The wiring for the CKP and cam pos sensor leave alone as the PCM controls all of that.