Hacking/tuning the jeep ecm

[EagleMark]

OBDII now that is easy cause they all must meet same standard...

http://en.wikipedia.org/wiki/OBD-II_PIDs

[JeepsAndGuns]

Well if the datastream for OBD2 is standarized, what about code, and tuning? Could you swap to a OBD2 jeep ecm and harness and have easyer tuning than the obd1?

That 99 grand cherokee I bought is OBD2, it has DIS, witch I think is cool.

[rts91tsi]

I am curious which microprocessor your ECU has. I have been searching around via Google and found that some of the SBECs used the exact same Motorola processor that the DSMs use, for which there is documentation available.

[JeepsAndGuns]

I am curious which microprocessor your ECU has. I have been searching around via Google and found that some of the SBECs used the exact same Motorola processor that the DSMs use, for which there is documentation available.

Not sure how I could find out. If your not having any luck finding out, I doubt I would have any luck. Would the numbers off my ecm help? Its the factory original ecm, and its a 93 wrangler 4.0 inline six, and a 5 speed manual trans.
Also, pardon my ignorance, but what is DSM?

[rts91tsi]

Not sure how I could find out. If your not having any luck finding out, I doubt I would have any luck. Would the numbers off my ecm help? Its the factory original ecm, and its a 93 wrangler 4.0 inline six, and a 5 speed manual trans.
Also, pardon my ignorance, but what is DSM?

The link I posted will show you where to look for the microprocessor, then get the numbers/letters off the top of the chip.http://starparts.chrysler.com/starli...n/Electric.pdf

I also found a Snap-On PDF, that has specific ranges for data items that may be useful to building an ADX. http://www1.snapon.com/display/DocMg...px?fileid=4669

Once you find those numbers, if documentation is available for the processor, it should contain a listing of the opcodes necessary for operation and execution of the eprom's bin. Then the real fun begins!
De-solder the EPROM, figure out the offset for the chip being used, read and upload the chips contents to a file on the computer. Depending on how much information you want to find out, there is a program called Binutils, that should be able to help if you want to disassemble the code. http://www.gnu.org/software/binutils/

DSM is an acronym for Diamond Star Motors, the collaboration between Chrysler and Mitsubishi, which is mostly associated with Eagle Talons, Plymouth Lasers, and Mitsubishi Eclipses. These cars were produced at a factory in Normal, IL and technically an American made car.

[EagleMark]

Then if you can figure it out? I read on TGO that a guy is commenting a disassembled code and he is up to 20,000 lines and about half done! He new were most things were. TunerPro software is 40,000 lines of code I read somewhere Mark has into it...

I have over 100 hours into making an adx for LT1 and half the code was written by TunerPro, I just entered parameter information, it's only 2000 lines... and I had the address of where things were.

Cracking GM code was done as a project at Ohio State University way back when by genius type computer geeks who knew microprocessor languages and took a team and years to get it done... luckily all the rest of GM code was similar so we have hacks for most...

I commend you for even thinking about doing this and the conversation is great! I am enjoying it... but even if you had the info you are talking about years of work... but you are getting closer and may find a way!

[hexdmy]

My specialty is calibrating the SBEC2 and JTEC engine controllers, like the one used on your Jeep. A couple of pointers ,

- Chrysler ecus use a special serial communication routine that runs at 7812.5 and 62500 baud .

- TunerPro will work for the 3D tables (yes SBEC2 ecus use 3D tables) and constants, but will not work for the functions, as Chrysler uses a 16 bit slope value between breakpoints.

- You can connect a Moates Ostrich to the ecu and emulate as long as your ecu is not using a latched chip.

[JeepsAndGuns]

The link I posted will show you where to look for the microprocessor, then get the numbers/letters off the top of the chip.http://starparts.chrysler.com/starli...n/Electric.pdf

Ok, back home. I pulled the top off the spare ecm I have, and it looks a little diffrent on the inside than the one in that link, but I think I got the correct numbers.
The numbers goes as follows:

SC80571VFN
672T02
C96N
ZQESI9312

Also the eprom is a 27C256-20

[rts91tsi]

Ok, back home. I pulled the top off the spare ecm I have, and it looks a little diffrent on the inside than the one in that link, but I think I got the correct numbers.
The numbers goes as follows:

SC80571VFN
672T02
C96N
ZQESI9312

Also the eprom is a 27C256-20

The SC80571VFN is a Motorola processor. I'm not familiar with it, but there is info out there about them.
http://www.seekchip.com/icstock-S/SC80571VFN.html

The C96N is also a Motorola Processor which also has documentation.
http://www.alldatasheet.com/view.jsp...68HC11A0P-C96N

There are also a few tools out there if you are serious about making your own hack. This IDE should work for the C96N, and has colored syntax for opcodes.
http://autos.groups.yahoo.com/group/...u/message/8159

[sev]

I am curious which microprocessor your ECU has. I have been searching around via Google and found that some of the SBECs used the exact same Motorola processor that the DSMs use, for which there is documentation available.

SBEC-IIs used in the jeep are 68HC11s

( I know.. 7 years later...)

[JeepsAndGuns]

Very interesting. If someone makes a complete XDF (or whatever it is called in their program) for the jeep 4.0 cal, I would be very interested. I have yet to convert mine over the the GM ecm (life has been getting in the way)

[34blazer]

Very interesting. If someone makes a complete XDF (or whatever it is called in their program) for the jeep 4.0 cal, I would be very interested. I have yet to convert mine over the the GM ecm (life has been getting in the way)

JG, working on piggybacking the JTEC in my Ram with a 7727. About 2/3 complete. Maybe ill share once its running, hopefully.

[vwnut8392]

I have done some work on the renix jeep ECU for the 4.0. i liked it because of the fact that its a true speed density ECU. my goal was to see if it was possible for it to be used in a turbo 4.0 application with larger MAP sensor and scale in larger injectors for more fuel. finding the basic timing and fueling tables was fairly easy using winOLS. i have since made basic timing and fueling adjustments to the ECU and it made a world of a difference in how it ran. in a non turbo application all you really need to work with is timing and fueling mapping to have a basic tune that will work. well just giving some info even though you was working with the later ECU thats not the bastard like the one i have as everyone calls it.

[EagleMark]

OBDII is in everthing 1996 and newer, but tuning software is very expensive and more complex, thats if the Jeep engine is covered under any of them...

These are for PIDS, the error codes, the ALDL side and they are all not identical but have standardized most paremeters for emissions, each manfacturer still has other PIDS and they can change from car to car, car to truck, auto to manual etc... and I know very little about this subject. My Scan Tool tells me anything I need to know about any OBDII car... and OBDI for that matter.