I Have A 1999 Dodge Ram 2500 Cummins Turbo 24 Valve 5 Speed 5.9L Truck That I Have Switched With A 1994 12valve Diesel Engine. I Need To Know Either Two Things. Does Anyone Know How To Hook Up The 1994 Wiring Harness(12 V) To The 1999 Ecm Unit? Will the PCM talk correctly to the BCM to get the tachometer to work?
Any help would be appreciated.
I am new here so I don't know whether to post this on the 12 valve forum or 24 valve.

 

Two totally different animals. The 24 valve computer is worthless for the 12 valve engine.

 

Do You Have Any Suggestions Other Than Putting Back The 1999 Engine?

 

Convert the 99 engine to p-pump and put it back in. It would be really really difficult I think to get that 12v to work.

 

You should be able to get everything to work with a 1998 12valve harness as this was the year the trucks switched to 24 valve halfway through.

 

you will need the pcm and all 1998 engine and trans harness, transmission and valve body should be the same, pcm on the new truck uses rpm and apps signals, the 12v uses cam and tp sensors as inputs. but i agree convert the 24v to a p-pump, i always wanted to do this. 1 more injection pump goes and 1 will!

 

The posts above seem to suggest that there is an option to convert a 24-valve to a 12-valve by switching to EITHER a p-pump OR by changing out the wiring harnesses+pcm. Wouldn't you have to change out all of it?

 

Just put a p pump on the 24V engine. There is kits available to do this. Its easier than you think.

 

If I understand you correctly, you already have the 94 engine in place. In that case I would get a PCM and harness for a 98 12V, for an automatic if you have one, or a 5 spd if you have that and plug everything together and it should work. You may also need to get a 98 12V gauge cluster too, but I would try without it to start and if needed, get that part later.

 

You can get a plate made-up for the camshaft so you can use the existing tach pick-up sensor. Its relatively easy for stick truck, you just need the gearbox of a 12v, 12v camshaft (lift pump lube), 12v lift pump, fuel shut-off valve. You'll need a spacer for the air horn. Notch the head slightly for the pump. New injector lines for the new pump. Haisley builds a kit to do the swap. You could even get the throttle cable off the earlier truck. You might have to rig up a way for your cruise to work again. Later VP auto trucks need the APPS sensor for throttle position to shift correctly. I was just gonna build a spacer to lift enough to clear the P pump. Get the P pump brace off the 12v as well. I would run the 98 block, as there is a second drain for twins. Do a search on P pump conversion, there tons of info...

 

http://haisleymachine.com/product_in...oducts_id=2480

 

This is the route I would look at going. You've already got the engine in, its easy enough to have running if you don't already. The wiring is the big pain. What you need to make the dash happy would be a crank position sensor (but there is no provision in the 12v block for it), cam sensor is a nice, but not neccesary on the 98-00 engines. The rest would be for grid heaters and oil pressure, etc. You could look at robbing the tone ring off the 24v crank and attaching it to the 12v damper, and running the crank sensor off the front of the engine, just like the engine speed sensor on the 12v now.