Rumor control: Can Jeep dealers modify the computer? -

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post #1 of 9 Old 05-28-2013, 06:28 PM Thread Starter
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Rumor control: Can Jeep dealers modify the computer?

Hi, I normally hang out over on the CJ side, but I have updated my 1983 CJ-7 with a number of YJ systems and parts so I occasionally come over here seeking information.

I replaced the head and carb setup on my CJ with the 4.0 head and MPFI setup from a 1991-1995 era YJ, and the computer came from a 1994 Grand Cherokee.

It works fine, but I have recently heard that Jeep dealers can do a "limited amount" of programming on these computers. So, naturally I'd like to find out:

1) True?

2) If so, is there any worthwhile benefit?

Thanks for any info y'all can provide.

"We are all of us in the gutter...
Some of us are looking at the stars."
~ Oscar Wilde via Chrissie Hynde
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post #2 of 9 Old 05-28-2013, 08:46 PM
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The feeling I get everytime I go to the dealership for something is that they don't want anything to do with the Yj models anymore.

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post #3 of 9 Old 05-28-2013, 09:03 PM
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the yj computer can not be reprogrammed or reflashed if it be a dealer or a tuner. the chip that is in the computer is an eprom and located under the gel in the computer the chip requires the gel to be removes the chip to be un soldered and a new flasable chip soldered in. after that nobody has wrote the code to be-able to read the chip meaning that even if you put a new chip in you would not know what to put on it.

i have done a lot of research on the subject of tuning a yj or any obd 1 jeep
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post #4 of 9 Old 05-28-2013, 09:11 PM
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All we can do is upload new software onto the vehicle that we download from DealerConnect. The only things we can change is simple stuff like horn beep when doors lock. We can't just go in and change different tuning parameters.

Edit: And good luck finding a dealer that still has a working DRB2 with a Jeep adapter. You're best off going to a independent tuner.

1990 YJ-The wheeler
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post #5 of 9 Old 05-28-2013, 09:23 PM
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1993 YJ Wrangler 
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i think you are talking about a tj the yjs the only thing the computer controls is the motor and cant be flashed

tuners cant tune a yj as the chip cant be read
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post #6 of 9 Old 05-29-2013, 06:57 AM
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1989 YJ Wrangler 
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100% No. I did a lot of testing with the OBDI in development. It is not flashable, that being said there are other options you can use to trick it into thinking differently. Wideband O2 sensors, adjustable map sensors, and even relocating the crank sensor to change advance and allow for bigger cams. The question is at that point why would you. There are other options available and unless you are stroking a 4.0L it is a waste of money and effort. You would be fiurther ahead getting a 350 with the effort you would need to use to do any of the serious tuning.
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post #7 of 9 Old 05-29-2013, 03:13 PM
Typical /f12 Hooligan
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The dealership said they could rework my YJ into a JK for about $400 a month.

91 YJ "Alice" 4.0L, AX-15, NP 231 w/HnT Flange, Adams Driveshafts F/R, 2.5" OME 36Rs, 5/8" /f12 Booms, 32" Yoko ATs, 4.10 D30/35 Aussie Lockers F/R Busted Knuckles YJOTM never
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post #8 of 9 Old 05-29-2013, 04:22 PM
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There are people/companies that have hacked the SBECII ecm and made it tuneable, however its mainly on other mopar cars. There was a guy at one time working on a jeep specific definition for the bin on the chip (that has to be dug out of the gel, de-soldered from the board, then read. However I think they lost interest in it.
If interested, you might try contacting these guys and see if they have any suggestions.

'93 YJ 4.0L, AX-15, NP-231HD/SYE, 8.8in rear, OME 2.5 lift, home made front hub conversion, hydroboost. Warn M10000 winch. Currently building a stroker.

'79 Cherokee Chief, 401 MPFI fuel injection, T-18/D-20 and hydroboost. Otherwise stock.
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post #9 of 9 Old 05-29-2013, 05:54 PM
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sbec 2 had a sci line and was designed to be flashed. sbec 1 was not. if you have heard of anything to modify it I would like to know how.
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