Questions for anyone who has done a 5.9 swap

Averytupper

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Check your wiring carefully if the Tach signal isn't present you get no RPM gauge.

If there is a problem with the vehicle speed sensor circuit, you will get no speedo as it is driven from the VSS unit. Grounds and power along with signal are important. Also if you have a gear driven VSS in the output of the transfer case, make sure it is meshed properly rotated to spin the sensor properly. If the mesh is far enough out, you may not have the sensor spinning in the tail housing. This will cause no RPM to indicate and also cause driveability problems because the ECM doesn't know the Jeep is moving.

Unless you have a bad ECM, the 1998 or 1999 will run the 1996-1999 and some very early 2000 TJ clusters assuming the wiring was done right and the speed sensor is spinning in the tail of the TC. Again double check over at Hotwire auto the Mopar swap grid to make sure you're dealing with the correct bus type and haven't accidentally tried to use the wrong type.

RR
I don’t think my transfer case from the Durango has a speed sensor like the jeep had, I have a output speed sensor on the tranny but that’s all i can find
 

RangerRick

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There should be an output speed sensor on the rear of the 231J transfer case. If there isn't, you'll have to swap a transfer case that does have one is the easiest way to do it. The corresponding wires have to be in the harness for the computer to read the speed of the rear drive shaft. You can swap in a TJ NV-231J transfer case in place of the durango case if you have to. All of the cases have the same spline count except 4-cyl manual TJ's. What you have to pay attention to is the stick-out of the transfer case that it will fit and the oil seal will seal against the proper surface of the input on the transfer case. Some are long, some are medium and some short. I'd have to look up what the Durango had but you can compare side-by-side with the old Jeep TC and possibly use the old Jeep TC provided it wasn't a 4 cylinder manual transmission because spline count will be wrong, (it's the only TC that the input would have to be changed on because of spline count) otherwise all other TC's from Mopar are the same spline count except big RAM diesel etc.... If it was an automatic, the spline count is correct FWIW.

RR
 
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TJ99V8

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I believe I narrowed my issued down to the new 1999 PCM. It's at the supplier being retested and hopefully repaired IF they can duplicate my issue, which again is once at temp for awhile, it wants to stumble and hard to start. Leave it cool and it's great. With the 97 PCM in it, it runs great and starts back up even when hot, just no gauges. Hoping they find bad connections in the new one it once hot and this all all for not, but if not.... Question, can I "piggyback" the two PCM's as a fix being it runs awesome with the 97 PCM and gauges work with the "new" 99 PCM? Plug C3 (the one with the Bus +/- and SCI transmit/receive connections) into the 99 PCM and the C1/C2 plugs which run the engine into the 97 PCM ??? Would this work??? At least as a temp fix anyways.
 

RangerRick

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I believe I narrowed my issued down to the new 1999 PCM. It's at the supplier being retested and hopefully repaired IF they can duplicate my issue, which again is once at temp for awhile, it wants to stumble and hard to start. Leave it cool and it's great. With the 97 PCM in it, it runs great and starts back up even when hot, just no gauges. Hoping they find bad connections in the new one it once hot and this all all for not, but if not.... Question, can I "piggyback" the two PCM's as a fix being it runs awesome with the 97 PCM and gauges work with the "new" 99 PCM? Plug C3 (the one with the Bus +/- and SCI transmit/receive connections) into the 99 PCM and the C1/C2 plugs which run the engine into the 97 PCM ??? Would this work??? At least as a temp fix anyways.
Possibly not and probably not worth the time or effort. I kept a 1997 RAM ECM just for emergency operation if the 1998 RAM ECM were to die on me off-road in the middle of nowhere I had a way to get home and drive the Jeep without troubles. These ECM's are over 20 years old and have some issue from time to time so they may need rebuild occasionally.
RR
 

TJ99V8

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Possibly not and probably not worth the time or effort. I kept a 1997 RAM ECM just for emergency operation if the 1998 RAM ECM were to die on me off-road in the middle of nowhere I had a way to get home and drive the Jeep without troubles. These ECM's are over 20 years old and have some issue from time to time so they may need rebuild occasionally.
RR
Thanks. That's what I thought, but figured it was worth asking. I plan to keep the 97 PCM as my backup spare and get the 99 working correctly. It was a "new" unit I purchased from a place that does just that, refurbs and tests them... they claim they never have these failures out of the box, but I beg to differ... from what I understand this is a common issue with these particular units, maybe somehow it worked enough to get through their tests, but in real world heat it fails until cooling down. Also got the e-fan issue worked out. It was the control board supplied with the Proform Slimfit rad I used. I bypassed it and used a universal efan controller - works great! I am almost there... hope this PCM issue is the last! It was definitely worth the work and all the research!
 
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RangerRick

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Thanks. That's what I thought, but figured it was worth asking. I plan to keep the 97 PCM as my backup spare and get the 99 working correctly. It was a "new" unit I purchased from a place that does just that, refurbs and tests them... they claim they never have these failures out of the box, but I beg to differ... from what I understand this is a common issue with these particular units, maybe somehow it worked enough to get through their tests, but in real world heat it fails until cooling down. Also got the e-fan issue worked out. It was the control board supplied with the Proform Slimfit rad I used. I bypassed it and used a universal efan controller - works great! I am almost there... hope this PCM issue is the last! It was definitely worth the work and all the research!
Agreed! ECM problems are way more prevalent than the re-manufacturer is leading on to be. I know many swappers and stock vehicle owners who have had the ECMs go bad or have issue and have had to swap a couple of times to "get it right" on a reman ECM. So many things that could fail or become thermally intermittent if you've ever had the cover off one, you'll know just what's involved especially with that silicone potting gel they used in those years.

RR
 

TJ99V8

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Agreed! ECM problems are way more prevalent than the re-manufacturer is leading on to be. I know many swappers and stock vehicle owners who have had the ECMs go bad or have issue and have had to swap a couple of times to "get it right" on a reman ECM. So many things that could fail or become thermally intermittent if you've ever had the cover off one, you'll know just what's involved especially with that silicone potting gel they used in those years.

RR
you got any ideas how to add some form of cooling to help mitigate this? Heat sinks, small fan? I mounted the PCM in the factory TJ location passenger side firewall.....
 

RangerRick

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you got any ideas how to add some form of cooling to help mitigate this? Heat sinks, small fan? I mounted the PCM in the factory TJ location passenger side firewall.....
The later PCM's had a cast aluminum chassis with heatsink built in. Unfortunately the generation we're talking about is just in a stamped metal housing with a smaller aluminum cast frame. It's a heat thing, maybe installing it behind the glove box or up under the dash where it maybe doesn't get such extreme heat & cold would be better long term but the manufacturer seemed to think it was okay under the hood at the firewall by the battery. I think the cab of the vehicle is better and some manufacturers do mount them inside the cab but many put theirs under the hood somewhere still.

RR
 

Wildman

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Something I don't see a lot of people talking about when doing the Magnum V-8 swap is setting the fuel sync. The Magnum engines use the distributor not for timing but instead to tell the injectors when to pulse and squirt fuel into the cylinder. Now if you don't know about this and turn the distributor trying to set the timing or if you added performance parts or a new cam you need to set the fuel sync with a scan tool.
Of course the EXPENSIVE way is to take it to a dealership and have them set the fuel sync for you. Now I don't know if they will set it to whatever setting you want or to factory settings. The next option is to buy your own scanner. I know there are many scanners that CAN do this BUT I choose to use a Snap On MT2500 like this one on Ebay.

https://rover.ebay.com/rover/1/711-53200-19255-0/1?icep_ff3=2&toolid=10001&campid=5337789113&icep_item=333489856702

This PDF file explains it more.
 

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