97-06 Jeep Wrangler TJ ECM / PCM Tuning Options

In the VCM editor under the "Trans" tab, go to "Shift Scheduling" to view the various shift patterns. The important ones are the "Normal" and "Hot" schedules. Each shift has a tab, ( I.E. 3-4), and clicking on it reveals a table with axis of rpm vs throttle position. It's important to note that the row axis is incorrectly labeled as "Engine RPM". Its not. It's output shaft rpm. Adding something like 200-500 rpm to the lower throttle positions will delay the 3-4 shift notably. The same principle applies to the 2-3 shift. The 4-3 downshift can also be tuned to allow a more responsive downshift from overdrive to 3rd gear instead of having to apply heavy throttle to initiate the downshift.

Thanks man!
 
Does anyone have good results on tuning the 2003 4.0 sport 5spd?
 
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I have a1997 4.0 with auto 4X4 and am having trouble with lose of power and engine dying. Any suggestions!! I love my matching numbers blueboy !
 
Does anyone have good results on tuning the 2003 4.0 sport 5spd?

FRP offers a tune for the 4.0L.

I didn’t have any complaints as Ryan did what he could, but not much can be gained by tuning a stock configured 4.0L.

I have a1997 4.0 with auto 4X4 and am having trouble with lose of power and engine dying. Any suggestions!! I love my matching numbers blueboy !

Folks would need more info before they could help you on this.

When do the issues occur, and do you have a check engine light with codes being reported?
 
I want to add to this thread.

I spoke with Dave who owns B&G Performance today for about an hour on the phone. Super nice guy, very friendly, and told me quite a bit of information. Dave worked for Chrysler in the 90s and early 2000s and was one of the original software engineers for the TJ and various other Chrysler powered vehicles.

Because of this, Dave has a wealth of knowledge about these PCMs and how to access them. According to him (and I believe this), he is very well one of the only people in the world who can fully access the PCM on 97-06 TJs (he said he can do it all the way up to 2019 as well though) and have 100% control over them.

Some of the things he mentioned he could do to the PCM are as follows:
  • Activate / deactivate SKIM
  • Disable post-cat O2 sensors (allowing for cat removal without check engine lights)
  • Disable evap system (allowing for evap system removal without check engine lights)
  • Disable purge valve (allowing for removal without check engine lights)
  • Disable any other emissions
  • Change the temperature your cooling fan comes on at
  • Fully tune the air / fuel / timing curves
  • Change the VIN assigned to a PCM (so you can use it on another vehicle)
  • Enable / disable the automatic transmission module on 05-06 PCMs (so you can for instance, use a PCM from a 2005 manual transmission TJ on a 2005 automatic transmission TJ)
The list goes on, but that's just some of what he can do.

He mentioned he can actually tune the PCM even on a stock TJ so that you'll get a bit more performance out of it, and so it will run even better.

You can send him your PCM using this form and he'll tune it (and enable / disable any features you want) for $399, or you can buy the software from him for $599 and do it yourself.

The bottom line is that these PCMs are 100% tunable, we can just blame the misinformation that's been spread on the internet for making us believe that it wasn't possible. I'm very, very glad I looked into this further and decided to spend some of my time pursuing a solution to what many considered to be impossible.

This is actually a breakthrough if you ask me. It will allow TJ owners to keep their vehicles on the road for that much longer, but also tune them the way they want. No need for things like Split Second fuel controllers if you want to run boost, you can just tune the PCM directly and be done with it.

I encourage anyone and everyone to share this information and use B&G Performance for all your needs.

You no longer have to believe the lie that our PCMs are not accessible.

(y)
 
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Fwiw, I recently tuned a @Wranglerfix PCM using the Diablo tuner that comes with an 05/06 Banks turbo kit.

It was previously thought that Mark’s PCM would not take the Banks tune and that’s 100% misinformation. His computers have also been successfully tuned using an HPtuners device. I’ll be updating my tune using HPtuners to increase my 2-3 and 3-4 shift points so lockup follows at a higher RPM (keeps me in boost).

I went the WF PCM route trying to fix a transmission shifting issue that ended up being the transmission.

That said, I’m keeping the WF PCM since it fixed my rough idle issues that caused a CEL for a #3 misfire no matter how much I wrapped the fuel line/rail/injectors.

Btw, FRP is the more modern option I’ve seen guys go with regarding tunes including guys like myself and @Chris who have had FRP’s stock 4.0L tune.