JTEC and SBEC2 tuning

[JeepsAndGuns]

Interesting. I thought the general consensus all over the internet was that the SBEC2 was not tuneable.
I might send him a email. Curious of how much it would cost and what type of gains should be expected.

[jsawduste]

For the most part it isn't tunable.

There are a handful of late model SBEC2 ECM`s that have a oddball PROM that is not read only. You have to actually get the PROM number to see if the software will work.

If all you need is to run the engine you could literally cut the harness at the ECM and splice a JTEC in. Not the proper way to do but if you study the wiring diagrams you'll soon find out the circuit logic is very similar.

[JeepsAndGuns]

I had thought about splicing in a JTEC. One thing stopping me is the requirement to run two o2 sensors. One before and one after the cat. I, umm, "cough"...may not have a working cat on my jeep.
Could the 2nd o2 sensor be tuned out? Also doesn't the obd2 stuff use can bus or something like that to talk to the instrument cluster and whatnot?

[jsawduste]

I had thought about splicing in a JTEC. One thing stopping me is the requirement to run two o2 sensors. One before and one after the cat. I, umm, "cough"...may not have a working cat on my jeep.
Could the 2nd o2 sensor be tuned out? Also doesn't the obd2 stuff use can bus or something like that to talk to the instrument cluster and whatnot?

Depending on where you live and what emissions laws are in place dictates what a tuner like Chris or Ryan might do. If you have emissions laws in place and they knowingly provide a tune that is different than factory they are opening themselves up to liability. Be forewarned

Having said that,
All of the emissions related inputs and outputs can be caled out. The engine will run just fine on a single pre-cat O2 sensor.

JTEC does use Can-Bus to communicate with the gage cluster. However, if your converting from SBEC your gages non Can-Bus already. The SBEC cal/gage doesn't care.

You can cut the Can-Bus outputs out of the harness and use the SCI outputs to read codes.

In the simplest of terms.

YJ SBEC now YJ JTEC

JTEC ECM only runs the engine. No emissions stuff at all/no CEL for emissions but do have CEL for anything related to running the engine. Yes a good tuner can select what does and does not turn the CEL on.

SCI outputs from the ECM to read codes. Can-Bus wiring deleted

Autometer gages so like the OEM SBEC everything is hardwired.

VERY happy and more so the engine is very happy being fed properly.

[2001 Red XJ]

I'm very interested in this upgrade for my 01 Jeep Cherokee with a 68-232-4 cam, ported throttle body,banks header,and a cat back system.

[JeepsAndGuns]

Depending on where you live and what emissions laws are in place dictates what a tuner like Chris or Ryan might do. If you have emissions laws in place and they knowingly provide a tune that is different than factory they are opening themselves up to liability. Be forewarned

Having said that,
All of the emissions related inputs and outputs can be caled out. The engine will run just fine on a single pre-cat O2 sensor.

JTEC does use Can-Bus to communicate with the gage cluster. However, if your converting from SBEC your gages non Can-Bus already. The SBEC cal/gage doesn't care.

You can cut the Can-Bus outputs out of the harness and use the SCI outputs to read codes.

In the simplest of terms.

YJ SBEC now YJ JTEC

JTEC ECM only runs the engine. No emissions stuff at all/no CEL for emissions but do have CEL for anything related to running the engine. Yes a good tuner can select what does and does not turn the CEL on.

SCI outputs from the ECM to read codes. Can-Bus wiring deleted

Autometer gages so like the OEM SBEC everything is hardwired.

VERY happy and more so the engine is very happy being fed properly.

Where I live in alabama, we have no emission testing or inspections.

Yes all of my gauges are factory so they are "hard wired" and do not effect the factory ecm except for the VSS input. And on that note, does the factory YJ VSS have the correct output for the JTEC?
I was not sure of not having the can bus would cause the ecm to throw trouble codes or go haywire because it is not seeing the other modules.

[jsawduste]

Where I live in alabama, we have no emission testing or inspections.

Yes all of my gauges are factory so they are "hard wired" and do not effect the factory ecm except for the VSS input. And on that note, does the factory YJ VSS have the correct output for the JTEC? Same VSS signal. The circuit splices, one leg to the speedo and the other to the ECM.
I was not sure of not having the can bus would cause the ecm to throw trouble codes or go haywire because it is not seeing the other modules.[/quote] It will throw codes unless the inputs are caled out. Assuming your talking of emissions related components that are removed.
Don`t get can-bus and ECM inputs confused. They are two different things.

[darkcorp]

Is there any possibility DRBIII can write modyfied programm to JTEC?

[SilverXJ]

DRBIII would only flash factory calibrations.

[Alexia]

JTEC does use Can-Bus to communicate with the gage cluster. However, if your converting from SBEC your gages non Can-Bus already. The SBEC cal/gage doesn't care.

You can cut the Can-Bus outputs out of the harness and use the SCI outputs to read codes..

JTEC uses Chrysler Collision Detection(CCD) bus and SCI. 1997-2001 XJ gauge clusters all run on CCD bus.

[brycecoxXJ]

Bringing this thread back up!

Hey Chris, I'm very interested in what you have been doing and I would really like to talk to you about my possible options. Just let me know man! Thanks!

[darkcorp]

Does anyone have a definition file (xdf) for TunerPro for JTEC PCM?

[11diamondguy]

Hi I'm trying to run the newer ngc style 4.7l v8 in a truck that originally came with the 4.7l v8 older 3 pin jtec and separate tcm. I'm thinking it's got to be possible to flash and reprogram the jtec to run the newer style engine they are the same 4.7l v8's out of identical trucks. The only difference is the amount of teeth on the tone wheel.can anyone point me to the flash I need or possibly make one from scratch?

[DaveyG]

Hi I was googling and stumbled upon this post about your tuning capabilities. I am building a turbo setup for my truck (5.9 magnum v8, 1999) and I have been trying to figure out how to hack the ECU, so I could tweak the factory tune to use larger injectors and compensate for boost, and I was thinking of using RomRaider, and I already purchased an OBD-2 to USB data cable, but I had hoped to pick your brain a bit on the subject before I get too carried away. Have you done any tuning on dodge pcm with a turbo added? Should I stick to my plan of DIY or would I be better off hiring your services?

[Cummins90]

Do you have the factory ecu still installed? JTEC 3 plugs black, white, grey?