Questions for anyone who has done a 5.9 swap


TJ99V8

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Motor is now sitting pretty in the engine bay and awaiting new AX15. What throttle cable did you use? Seems my stock TJ 2.5L cable is long enough but not the right connectors to hook up the throttle body? Also, is the fuel line connection at the fuel rail the same from my stock setup to the 5.9L stock? I know it's a bit short and low, but thought I could just get the right high pressure splice fittings to extend it and make mine work. Any suggestions?
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TJ99V8

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Update on my 5.9Magnum and AX15 swap. Driveline is in and runs nice and smooth, but... a few issues I am currently trying to sort, maybe someone has some advice. Starts and runs great when cold and at temp. Was stalling after running for 20 minutes or so and had to cool down before it would start again. New Mopar Crank sensor, I think fixed the stall when at temp issue. Now if I run it for even an hour, shut it off and let it sit for 10-15 minutes it won't start until it cools down more, maybe another 10-15 minutes then fires right up and runs great. I am getting fuel... so I think a spark issue. New Accel coil/wires/cap/rotor, new Mopar crank sensor, just installed new Mopar cam sensor (hoping this may help - will try this weekend). Any other ideas what may cause this?

Next issue, I used the rear wiper fuse slot for my "key on" power to my electric fan control. It will work for a bit, but then blow the fuse (which also kills my cig lighter which is only a phone charger in my case). Where is a better (different) circuit to pull key on from and why would the rear wiper circuit also kill the cig lighter circuit? That fan control only pulls a few amps and I don't have a rear wiper. I used one of those plug in fuse parts with a 20 amp for the circuit it plugs into and a second 10 amp for the accessory I am adding. Any ideas?

Last, my oil pressure gauge will peg to 80 when it's running, then sometimes drop to 50 while driving or idle, but typically pegs back up. Maybe sending unit is bad? Fresh oil and Mopar filter, no sludge has new oil pan, and pickup/etc was clean, so were oil galleys.

Thanks!
 

RangerRick

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Just some thoughts here about it:
Possibly the temp sensor for the engine to know if motor is cold or not causing the no start situation on warm engine.

Possibly the oil pressure sensor is bad. I had one pegging out and changed it and it fixed the pegged gauge problem.

As far as the fuses are concerned, I really don't like electric fans and went with the mechanical fan and stock 4.0L fan shroud for the last two Magnum swaps in TJ's.

I think you should use one of the MAXI fuse holders because the fan can draw 30 to 40 amps peak and will melt any of the smaller fuse holders while running on a hot day for long periods. Not all the MAXI fuse compartments are full in the PDC so find one that isn't used and you can use a junkyard PDC for the wiring and clips to fit in and make it look stock.

Something is fooling the computer so the mixture isn't right or spark table is off when your engine is warm for the no-start situation.

Congratulations on the Magnum swap, it looks great!

I am contemplating doing either a GM 6.2L swap or a HEMI swap in my 2009 JKUR since being spoiled with V8 power in the TJ I recently sold. I am also spoiled with 300 Lb. Ft. of torque in my Diesel CJ so the 3.8L minivan sourced motor is an abysmal excuse for an engine. Looks like my next garage next summer will have another swap going on......

RR
 

TJ99V8

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Thanks for the quick response. I never thought about the temperature sensor... temp reads accurately on my gauge (I have an IR thermometer and have compared as best as I can), but maybe it is tricking my ECM somehow. Odd thing is, now as long as I don't shut it off, it runs smooth, the cutting out while driving was the CPS (don't EVER use aftermarket sensors, they suck new out the box failed me 2x - Mopar only). I'll look into the temp sensor, for sure.

Same for oil pressure sensor/sending unit.... easy try. Can't hurt.

As for the fuse, I have the battery power to the electric fan on a 30 amp fused circuit right off the post on the PDC. The key on (the circuit that is giving me issue) is only used once the thermostat tells the control board to turn on, it is the relay on power, so only draws a few amps. I wanted to use the mechanical fan and 4.0 shroud, BUT, I don't have the space... I used the Advance Adaptors motor mounts per their instructions (using the dowel pin to locate). BUT that only works perfectly when using an auto trans, with the AX15 it had my engine further forward... was a lot of fun modifying that and my gear shifter to come out right.. but once I realized I had everything in and found a slimfit radiator with efan that fit my needs, I made it work.

Thanks again, I'll have a look at that temp sensor if the new cam sensor doesn't correct it. I am sure I can find another key on circuit to try... maybe there is some short in that rear wiper circuit.. it's all factory, no one has every chopped it up so that's why I'm lost. Do you know if it is tied to the cigarette lighter somehow? Cause when it blows the 10amp fuse for the added key on (not the 20 amp circuit fuse) I also lose the cigarette lighter power). Makes no sense, you'd think it would only break the the key on to efan since the 20amp still is good.
 

Averytupper

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Hey @RangerRick i need some help, I just swapped my 1999 tj with the 5.9 magnum thanks to the help on this foarm! But I have a no bus error on my dash :( I am using a 2002 Dodge Durango pcm and I also tried a 1997 dodge 1500 pcm both with the same results :/! Can anyone help me out ? Thank you in advance
 
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TJ99V8

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Hey @RangerRick i need some help, I just swapped my 1999 tj with the 5.9 magnum thanks to the help on this foarm! But I have a no bus error on my dash :( I am using a 2002 Dodge Durango pcm and I also tried a 1997 dodge 1500 pcm both with the same results :/! Can anyone help me out ? Thank you in advance
Sorry to jump into this conversation, but I had a No Bus issue, but also no dash gauges. Turns out I had a 1997 motor and 1997 PCM with the 5.9 I swapped in my 1999 Jeep. I had been told it was a 1998, but I was mislead. The gauges were not run via CCD BUS in 1997 and so you will have no gauges and get a "No Bus" in your odometer. I do not remember if 2002 Durango was also different but I ended up having to get a 1999 PCM for a Ram 1500/Dakota with 5.9Magnum. I had to add pins/wires into the the C3 plug at the PCM (engine harness) and run to my OBDII port for Bus + and Bus -. I cannot remember exactly which pins at the plug or which locations at the OBDII port, but will try and find the schematics I used. This was my issue anyways....
 

Averytupper

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Sorry to jump into this conversation, but I had a No Bus issue, but also no dash gauges. Turns out I had a 1997 motor and 1997 PCM with the 5.9 I swapped in my 1999 Jeep. I had been told it was a 1998, but I was mislead. The gauges were not run via CCD BUS in 1997 and so you will have no gauges and get a "No Bus" in your odometer. I do not remember if 2002 Durango was also different but I ended up having to get a 1999 PCM for a Ram 1500/Dakota with 5.9Magnum. I had to add pins/wires into the the C3 plug at the PCM (engine harness) and run to my OBDII port for Bus + and Bus -. I cannot remember exactly which pins at the plug or which locations at the OBDII port, but will try and find the schematics I used. This was my issue anyways....
Thank you for the advice I will try that, in my swap I have no dash gauges either and the no bus code, I will try to jump it like you did ! I’ll get back to you thanks - Avery
 

RangerRick

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It is the PCM year and type you are trying to run vs. the engine and the gauges. Something's not talking to something else. Read below:

Don't need to jumper anything if you follow the correct bus type. Look at the link at the bottom labeled "Hotwire" to follow the ECM bus type. It is a simple problem of you've selected the wrong ECM/PCM to use in your TJ. It's all about the details in this swap and the two year computers you've selected are the WRONG years to use, simple as that.

On Dodge RAM trucks, the 1997 ECM is different and will NOT run the gauges in the dash of a 1997-2000 TJ Wrangler. I went with a 1998 ECM to get it to run the gauges. Also the 2002 will not work properly either as it's the wrong bus type (PCI bus vs. ECC bus) so no communications will happen. You need a 1998 or 1999 RAM ECM to work the gauges in your 1999 TJ.

THIS IS YOUR PROBLEM WITH YOUR ECM's YOU'VE SELECTED.

Also look at this chart from hotwire auto to make sure you're using the correct bus architecture ECM for your TJ.

Hotwire swap grid.
 

Averytupper

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It is the PCM year and type you are trying to run vs. the engine and the gauges. Something's not talking to something else. Read below:

Don't need to jumper anything if you follow the correct bus type. Look at the link at the bottom labeled "Hotwire" to follow the ECM bus type. It is a simple problem of you've selected the wrong ECM/PCM to use in your TJ. It's all about the details in this swap and the two year computers you've selected are the WRONG years to use, simple as that.

On Dodge RAM trucks, the 1997 ECM is different and will NOT run the gauges in the dash of a 1997-2000 TJ Wrangler. I went with a 1998 ECM to get it to run the gauges. Also the 2002 will not work properly either as it's the wrong bus type (PCI bus vs. ECC bus) so no communications will happen. You need a 1998 or 1999 RAM ECM to work the gauges in your 1999 TJ.

THIS IS YOUR PROBLEM WITH YOUR ECM's YOU'VE SELECTED.

Also look at this chart from hotwire auto to make sure you're using the correct bus architecture ECM for your TJ.

Hotwire swap grid.
Okay thank you so much! I will look into getting a 1998 -1999 ecm !!! But other than that best swap in my tj I love the 5.9 in it!!
 

TreverStevens

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Anyone else have issues with the power steering pump and hoses fitting into their TJ on the Magnum swap? The hydraulic hoses dump right into my steering bar (can't think of the right word at the moment). Someone said get a Grand Cherokee power steering setup. SoI bought a mount and waiting to but the pump, but it doesn't really look like it mounts up the same? Will all my problems be solved once I buy the pump and pulley?
 

TJ99V8

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Okay thank you so much! I will look into getting a 1998 -1999 ecm !!! But other than that best swap in my tj I love the 5.9 in it!!
To be clear, like RR said, what I ended up doing was getting the PCM from a 1999 (the 97 is different and will not work - wasted money on my part, but..). Once I installed the 99 PCM What I had to add were the two wires for the CCD Bus + (C30) and CCD Bus - (C28) in my 1997 Ram 5.9 engine harness plug C3 to the OBDII port locations 3 and 11. Sorry, didn't mean to confuse anyone. All works great now! Now if I can only figure out the hard start once hot and slightly surging idle (I will be changing the throttle position sensor and IAC this weekend hoping that's it). Good luck with your swap. See attached.
 

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TJ99V8

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Anyone else have issues with the power steering pump and hoses fitting into their TJ on the Magnum swap? The hydraulic hoses dump right into my steering bar (can't think of the right word at the moment). Someone said get a Grand Cherokee power steering setup. SoI bought a mount and waiting to but the pump, but it doesn't really look like it mounts up the same? Will all my problems be solved once I buy the pump and pulley?
I used a Grand Cherokee PS pump p/n AC Delco 36P1490 and ordered the Grand Cherokee PS bracket (RockAuto has them p/n Mopar 53010256AB ). Your original PS lines should work, but I purchased the GC ones (ACDelco 36366440 hipress); (ACDelco36363680 return). They went on fairly easily with a slight tweak... no issues. Hope that helps and good luck!
 
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Wildman

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Now if I can only figure out the hard start once hot and slightly surging idle (I will be changing the throttle position sensor and IAC this weekend hoping that's it).
What are the chances you are getting heat soak or vapor lock becasue the fuel line is getting too hot? This could cause the hard start once it is hot.
 

TJ99V8

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What are the chances you are getting heat soak or vapor lock becasue the fuel line is getting too hot? This could cause the hard start once it is hot.
I guess it is possible. I do have an idle that wants to jump around some and now wants to sit at 2000 RPM. If I unplug the TPS when it is running, idle goes down where it should. Going to change TPS and IAC tomorrow. It is only hard to start after running to temp then shutting off and leaving sit for 15-20 minutes. If I shut it off and start right back up or even only 5-10 minutes, no issue usually. It's getting fuel. Thanks for the input!
 

TJ99V8

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@RangerRick hey got my dash working today with the 1998 ppm, everything works besides speedo and my odometer :( anyone have anything that can help me on this issue? 5.9 swapped tj
May sound silly, but make sure your speed sensor is plugged in at the transfer case and wiring is good from there up to the PCM. Once I switched to the 99 PCM, all gauges worked great- including speedo and odo.
 

TJ99V8

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I guess it is possible. I do have an idle that wants to jump around some and now wants to sit at 2000 RPM. If I unplug the TPS when it is running, idle goes down where it should. Going to change TPS and IAC tomorrow. It is only hard to start after running to temp then shutting off and leaving sit for 15-20 minutes. If I shut it off and start right back up or even only 5-10 minutes, no issue usually. It's getting fuel. Thanks for the input!
UPDATE! After many hours of checking connections, wiring, pinouts, continuity, I tried swapping my 1997 Ram 5.9L ECM/PCM back into the jeep knowing full well I would lose my gauges again, but wanted to eliminate the "new" 1999 ECM/PCM I purchased as the issue with the hard start when at temp. Problem went away, its the "new" computer. So I need to try and send back to CarComputerExchange and hope they will repair or replace being I've only had for one month and about 20 miles of driving.... Anyways, if anyone has a good OEM ECM/PCM from a 1998-1999 Ram 5.9 Magnum they want to sell (preferably from a manual trans), let me know. If from an auto I'll have B&G flash for me. Hoping CarComputerExhchange will take care of it, but.... they said its a "Swap" so no warranty, no returns.... kind of sh#$%ty as far as I'm concerned!
 

Averytupper

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May sound silly, but make sure your speed sensor is plugged in at the transfer case and wiring is good from there up to the PCM. Once I switched to the 99 PCM, all gauges worked great- including speedo and odo.
Did you use the dodge transfer case ? Or the jeep one ?
 

RangerRick

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@RangerRick hey got my dash working today with the 1998 ppm, everything works besides speedo and my odometer :( anyone have anything that can help me on this issue? 5.9 swapped tj
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
 

TJ99V8

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Did you use the dodge transfer case ? Or the jeep one ?
I used an AX15 from Novak Conversions and had my original Jeep NP231J rebuilt/modified for slip yoke eliminator. There is a plug at the back side of the transfer case for the speed sensor on mine.