PCM Reflashing/Programming

[sidewaysstarion]

That is all right, we will hold a prayer meeting for you guys...

No, really...

As I understand it, your PCM is the same as well. All of the pre-COP PCMs are the same at the hardware level.

Coil
On
Plug

Fir those wondering.

Well, there are two different "Hardware levels" Jtec and Jtec+. 96 is a unique year because it's missing a fair bit of code that was added in the later years which makes is a real bastard year. pretty much to the dealers the 96 was un-flashable because it had no flash security routines built in. 97-98 are very similar and are plug and play for a 96. 99 is the first year of jtec+ which included changes like going from a resistance based oil pressure sensor to a 0-5v signal. This is not unique to jeeps, its the same on the rams and vipers.

The way Chrysler setup their ecus with only the drivers there were needed for their given application so like a 4 banger jtec can't run a 6 cylinder and so on, the only exception that I've found is on either the ram or the dakotas the v6 ecu has enough drivers to run a v8.

I can push any flash I want into any ecu and I've even taken my 99 cal and flashed it into a 3.8 KJ ecu and run that on my jeep, I had no gauges because the KJ doesn't have CCD, but it ran the motor just fine.


For extra credit, who knows what JTEC stands for? Also does anyone know why the two jtecs below look completely different from each other? No, they are the same year ECU.

 

[Alexia]

Jeep/Truck Engine Computer

As for looking different? Different company churning out the product. It could be any number of reasons.

So, how are you doing your flashing Sideways? Using J2534 PassThru?

 

[sidewaysstarion]

Jeep/Truck Engine Computer

As for looking different? Different company churning out the product. It could be any number of reasons.

So, how are you doing your flashing Sideways? Using J2534 PassThru?

Chrysler contracted two companies to build the Jtecs, same code, but completely different hardware for different manufacturers, they were worried that if they couldn't get the ECUs that they wouldn't be able to build cars.

As for flashing, I prefer to use a trench coat...

 

[O-Gauge Steamer]

^^OK...

TMI, buddy, TMI

 

[Alexia]

I have read over the various Dodge forums where people have experience using aftermarket flashing devices to flash JTEC PCMs.

A few points:
1.) Stated previously, ability to flash over the diagnostics port.
2.) JTEC PCMs can be made to respond to boost.
3.) People who already know how don't like to talk.

As for the retail places that charge lots of money.
Dave at B&G Performance worked for Chrysler for a long time and can tune any Chrysler PCM.($350 to start)
There is also Chris Jensen/Christuned who also does Chrysler PCM tuning.($250 to start)

My problem getting into this is attempting is working my way around the obscureness of all of it.(At least, to avoid desoldering chips.) Desktop and server programming is so standardized that jumping from one thing to another is easy. If you want to flash firmware on a network device you open its web interface or present it with a TFTP server. With flashing PCMs, first you find out it can be done over the OBDII port. Then finally you learn there is a government mandated standard called J2534 PassThru. "Great, just have to get the flashing software!" Nope, the flashing software is still proprietary to each vehicle manufacturer.

 

[Talyn]

3.) People who already know how don't like to talk.

Why would someone that makes money off of programming want to give away how it is done? There is a lot of time and money in programming these PCMs, its not like GM's or Subaru's (I think these are the two that have open PCMs) where you can buy and inexpensive piece of software and go to it.

As for the retail places that charge lots of money.
Dave at B&G Performance worked for Chrysler for a long time and can tune any Chrysler PCM.($350 to start)
There is also Chris Jensen/Christuned who also does Chrysler PCM tuning.($250 to start)

Last time I spoke with B&G, about 3 years ago, they weren't interested in tuning a PCM for a 4.0L. And if you think that is a lot of money consider the cost of the hardware and software needed to tune a PCM. And then if you want to make an SCT program I believe that is around a $10k buy in.

 

[O-Gauge Steamer]

So then really...

Replacing the PCM with an aftermarket EMS may be the best way to go.

Such as:
http://www.aemelectronics.com/engine-management-systems-9/series-2-plug-play-engine-management-system-30/

And:
http://www.aemelectronics.com/engine-management-systems-9/infinity-stand-alone-programmable-engine-management-system-90/

There are many others out there. Overall, it may be less expensive to toss out the stock PCM and replace it.

Unfortunately, once this is done, the vehicle can no longer be legally driven on the street.

 

[sidewaysstarion]

AEM series 2 ecu's aren't water proof, so that might make things rather interesting...


I don't know if you've looked recently but B&G's site is no more, but he will do 4.0 ecus if you ask nicely.

 

[Alexia]

Why would someone that makes money off of programming want to give away how it is done? There is a lot of time and money in programming these PCMs, its not like GM's or Subaru's (I think these are the two that have open PCMs) where you can buy and inexpensive piece of software and go to it.

For the betterment of the community as a whole.

I work nearly exclusively with open source code at my work place. We contribute whatever can back to the community including coding processes. The company is still a multimillion dollar business and growing rapidly.

With the 1997+ gauge clusters, I was upset that it cost $100 plus shipping at a minimum to send it somewhere for them to reprogram a small EEPROM. So I figured out how to do it and posted a full video tutorial on various forums. I have people buying reprogramming from me now and that was never my intention. The information is out there for them to do it themselves and the tools are cheap.

Some users over at Speed Freaks were working on expanding support for OpenPort/OpenECU project to work with JTEC PCMs. Unfortunately it seems to have died flat late last year.
http://thespeedfreaks.net/showthread.php?7503-Open-Source-JTEC-tunning
http://jtec.info/index.php?title=Main_Page

Last time I spoke with B&G, about 3 years ago, they weren't interested in tuning a PCM for a 4.0L. And if you think that is a lot of money consider the cost of the hardware and software needed to tune a PCM. And then if you want to make an SCT program I believe that is around a $10k buy in.

They seem to explicitly offer it on their site now.
http://www.bgperformance.com/tuning-jeep-and-conversion.aspx

 

[sidewaysstarion]

Well Alexia you're more then welcome to buy in as an SCT dealer and start giving away free tunes and flashes, but what you are looking for just isn't possible due to the cost of the software and hardware needed to do JTEC tuning, we are talking $20k+ here to do it without SCT.

You're more the welcome to shell out $4k and get a DRBIII and try and hack the update process to load your own flashes, but then you still run into the issue of you don't have a hex map to know what to edit. Also if you brick you PCM the DRB can't recover it and you'll have to send it to either christuned or B&G.

Also word the the wise Chrysler legal WILL pay you a visit if you start posting up about hacking their tools.

 

[streetxj]

Well, there are two different "Hardware levels" Jtec and Jtec+. 96 is a unique year because it's missing a fair bit of code that was added in the later years which makes is a real bastard year. pretty much to the dealers the 96 was un-flashable because it had no flash security routines built in. 97-98 are very similar and are plug and play for a 96. 99 is the first year of jtec+ which included changes like going from a resistance based oil pressure sensor to a 0-5v signal. This is not unique to jeeps, its the same on the rams and vipers.

The way Chrysler setup their ecus with only the drivers there were needed for their given application so like a 4 banger jtec can't run a 6 cylinder and so on, the only exception that I've found is on either the ram or the dakotas the v6 ecu has enough drivers to run a v8.

I can push any flash I want into any ecu and I've even taken my 99 cal and flashed it into a 3.8 KJ ecu and run that on my jeep, I had no gauges because the KJ doesn't have CCD, but it ran the motor just fine.


For extra credit, who knows what JTEC stands for? Also does anyone know why the two jtecs below look completely different from each other? No, they are the same year ECU.

Great info. So, will it be easier or harder for Chris to tune my 96' computer since it is missing some code?

 

[Alexia]

Well Alexia you're more then welcome to buy in as an SCT dealer and start giving away free tunes and flashes, but what you are looking for just isn't possible due to the cost of the software and hardware needed to do JTEC tuning, we are talking $20k+ here to do it without SCT.

You're more the welcome to shell out $4k and get a DRBIII and try and hack the update process to load your own flashes, but then you still run into the issue of you don't have a hex map to know what to edit. Also if you brick you PCM the DRB can't recover it and you'll have to send it to either christuned or B&G.

Also word the the wise Chrysler legal WILL pay you a visit if you start posting up about hacking their tools.

I can write software and build hardware. I have no plans to drop tons of cash on this project. Ideally I do not want to spend more than $100 on this, but likely I will spend $200 to $300 grabbing PCMs from the junk yard for testing.

Any reverse engineering I do will be legal even if there is encryption involved.(There is no encryption until 2012-ish PCMs.)
http://en.wikipedia.org/wiki/Reverse_engineering#Legality

 

[O-Gauge Steamer]

It is perfectly legal to reverse engineer. Has been done since the dawn of time. I, for one, applaud your efforts and am looking forward to entries, here, on the subject.

Then, I sort of have a vested interest, yes?

 

[sidewaysstarion]

Great info. So, will it be easier or harder for Chris to tune my 96' computer since it is missing some code?

It just has to be flashed a special way or a 97-98 ecu swapped into its place.

Also there are only 2 people in the US that can do realtime tuning on a Jtec, Chris and B&G. Don't believe me, here's the proof.

 

[HappyDog]

Hi Sideways, I'm trying to figure out something. You say

Also word the the wise Chrysler legal WILL pay you a visit if you start posting up about hacking their tools.

as if you believe it, but you also posted this

I can push any flash I want into any ecu and I've even taken my 99 cal and flashed it into a 3.8 KJ ecu and run that on my jeep....

Aren't you advertising that you can hack Chrysler's tools?

 

[Alexia]

Mekkis is making great progress over on Gearhead EFI on this. He has a sample 1997 JTEC XDF file for TunerPro. He has had some trouble with socketing the ROMs due to static discharge.
http://www.gearhead-efi.com/Fuel-Injection/showthread.php?1369-Tuning-options-for-Dodge-Mopar/page7

 

[gradon]

Hmm, I see driving down to B&G and getting dyno-tuned in my Jeep's future.

 

[sidewaysstarion]

Hi Sideways, I'm trying to figure out something. You say

as if you believe it, but you also posted this



Aren't you advertising that you can hack Chrysler's tools?

No, not at all, I never said i could hack a DRB or even tried for that matter.

 

[Root Moose]

I'm out of the loop on this stuff but...

Why don't people say to he11 with the ChryCo PCM and do Megasquirt? For all the talk and gnashing of teeth over this stuff couldn't there be a well developed/understood MS setup for the 4.0 and modded variants by now?

Just a random thought. I don't have the interest to pursue it myself.

 

[Talyn]

Also there are only 2 people in the US that can do realtime tuning on a Jtec, Chris and B&G. Don't believe me, here's the proof.

I'm confused... that says DC Performance...

Why don't people say to he11 with the ChryCo PCM and do Megasquirt? For all the talk and gnashing of teeth over this stuff couldn't there be a well developed/understood MS setup for the 4.0 and modded variants by now?

Many reasons. Cost, learning curve, lack of OBD II for emissions testing, wiring, sensors, field service(half way across the country the MS dies... can't go to the local salvage yard and get a new one), unable to interface with the TCM or gauge cluster.