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Thread: Hacking/tuning the jeep ecm

  1. #1
    Fuel Injected! JeepsAndGuns's Avatar
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    Hacking/tuning the jeep ecm

    So I have done some google work and constantly come up empty handed. My daily driver is a 93 jeep wrangler 4.0 straight 6. It has the factory sequencial multiport injection. With all the fun I have been having tuning the gm system I put in my cherokee, I would love to be able to tune the system in my wrangler. I know there would be much improvement with a mostly stock engine. But in the future I plan on building it into a stroker. For those who dont know about it. Its where you take the crank and rods from the older 258 straight 6 and put it in the 4.0 block and use the 4.0 pistions and you get around 4.6-4.7L out of it. Very popular thing to do with these engines. I plan on doing it once this one wears out. The normal thing people do is just swap for bigger injectors to compensate for the extra displacement. But I figure there is so much more that could be done because the engine is now pretty far from stock.

    The jeep ecm is a underhood weathertight one. I have a extra one and I pulled the cover off and can see through the plastic/gel stuff and see the board and what appears to be the EPROM. The gel seems easy to dig out. If I dig it out and desoder it, what are the chances I would be able to read it with my autoprom and the tunerpro prom I/O and save it to a file? Then, finding someone to write a tunerpro defination file for it?
    I'm thinking the ecm being weatherproof is the reason no one has tried to do this before. And I am not asking for someone to write a defination for free. I would be fully willing to pay for this. I would also need a datastream defination too. If these could be made, then I could simply soder in the moates adapter that allows remote mounting of the eeprom, and run a cable to under the dash and mount the eeprom there. Probably make a small box to put it in. I would then reseal the underhood ecm.
    The jeep system actually uses lots of real simmilar sensors and even a couple are GM (such as the map sensor, its the exact same one on the chevy tbi systems) It has a 3 wire tps, 4 wire iac, has a cts, iat, cam and crank sensors. I think if I could find someone smart enough and willing, it could be done. Looking at all the many many definations on tunerpros website, I dont see why it couldnt.

    What say yall.
    79 Jeep Cherokee, AMC 401, T-18 manual trans, hydroboost, 16197427 MPFI system---the toy

    93 Jeep YJ Wrangler, 4.0L, 5 speed, 8.8 rear, homebrew hub conversion and big brakes, hydroboost, 2.5in OME lift, 31x10.50's---the daily driver

    99 Jeep WJ Grand Cherokee limited, 4.0L, auto, 2wd, leather and power everything, 99% stock---the long distance highway ride.

  2. #2
    RIP EagleMark's Avatar
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    I think it would be easier to repin what you have to a GM weatherproof under hood ECM. Then tune it...

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
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    Fuel Injected! JeepsAndGuns's Avatar
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    About the only gm ecm/pcm I think I would swap to, would be the 1220411. Its sequencial, has great aftermarket support, and can run a 6cyl. But its just so freaking expensive to tune. It would also require harness mods, and probably a couple diffrent sensors, and a crank trigger wheel/pickup fabed for it, cause the jeep one would not work. It would be really hard to hack up the factory untouched harness in my jeep (that I have had for a long time, and has always been my baby) If I modded the stock ecm, then thats the only thing modded. If it didnt work, or work out, I could just swap back to the original ecm and be done.

    So lets "pretend", for now, swapping to a diffrent ecm/pcm is not a option. I would like to keep the discussion on "is it possiable" I pulled the top cover back off the spare ecm I have, and looked through the gel with a flashlight, and its a 27c256 eprom in it, with the little picture of texas on it, also has a sticker covering the window and a bunch of numbers on it. There is a setting in the moates prom I/O for that chip. So I'm thinking it could be read? The jeep ecm's also have a 7 diget number on them, with the last 3 being twice the size of the first 4. The spare one I have is from a 93 cherokee automatic (my wrangler is a 93 5 speed) I had read the cherokee is supposed to have a "better" timing table. All I noticed was slightly less torque, so I swapped back to my original one.
    The first 4 digets are the same on both, so I would assume this would translate into a ecm service number (if we want to think of it like that) and the last 3 digets are whats diffrent. So I would assume thats gonna translate into a BCC or the tune on the chip.

    I just want to make sure, that beyond any reasonable doubt, that the jeep ecm is absoultely postatively not hackable/tuneable before I even start to think of swapping to a diffrent/gm pcm. I dont mind chip bruning, and I just LOVE emulation/real time tuning. And emulation is just so expensive to do with the 411.
    79 Jeep Cherokee, AMC 401, T-18 manual trans, hydroboost, 16197427 MPFI system---the toy

    93 Jeep YJ Wrangler, 4.0L, 5 speed, 8.8 rear, homebrew hub conversion and big brakes, hydroboost, 2.5in OME lift, 31x10.50's---the daily driver

    99 Jeep WJ Grand Cherokee limited, 4.0L, auto, 2wd, leather and power everything, 99% stock---the long distance highway ride.

  4. #4
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    I looked into this a couple years ago when I thought a mopar 5.2 or 5.9 swap might be good into my cherokee. I did not come up with anything except that you needed special hardware to program the PCM's and startup costs were in the $3000 range. So basically unless you were doing it on a shop level where the hardware and software would pay for itself its not DIY friendly. I did not find anyone disassembling the chips either...

  5. #5
    RIP EagleMark's Avatar
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    That's going to be a major project. Since it's such a popular vehicle if it were possable I think it would have been done. What are guys doing when they build an engine for that vehicle?

    There's an easier way to make changes to ECM for what's needed to tune the engine after you build it. PiggyBack tuners. They get wired into existing harness and make changes needed in signals to tune the new engine. I have used the Perfect Power products for vehicles such as yours with great results.
    http://www.perfectpower.com/index.ph...&id=5&Itemid=7

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
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  6. #6
    Fuel Injected! JeepsAndGuns's Avatar
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    I bet anything it has been done, but like said by cmaje72, its probably been on a shop level where they make/have lots of money and hire someone fulltime to do nothing but hack/tune the ecm.
    My guess why it hasnt been done on a wider scale is because it (appears to be) a eprom based ecm, not flash based. The eprom is sodered to the motherboard and then its all encased into the waterproof gel. Its not like the gm computers where you simply take two screws out and can uber easaly remove the chip, read, hack, tune, and reinstall it. I think thats why it has been done so much and easaly on the gm ecm's. And the ford the same way, so many out there, I'm sure the mustang builders pretty much demanded a way to tune the ford computers. So a way was found. The jeep ecm on the other hand is gonna take a little more work to get to the chip. I would have no problem doing this, I however am nowhere near smart enough to read the code and do all that magic to where it can be displayed in a tunerpro format where I can understand it.

    Anyone have a lead on any other forums I could join, or people to email to get in touch with someone smart enough to do said work?
    79 Jeep Cherokee, AMC 401, T-18 manual trans, hydroboost, 16197427 MPFI system---the toy

    93 Jeep YJ Wrangler, 4.0L, 5 speed, 8.8 rear, homebrew hub conversion and big brakes, hydroboost, 2.5in OME lift, 31x10.50's---the daily driver

    99 Jeep WJ Grand Cherokee limited, 4.0L, auto, 2wd, leather and power everything, 99% stock---the long distance highway ride.

  7. #7
    RIP EagleMark's Avatar
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    I'm telling you the piggy back tuners are what guys use in cases like this. I have personally used several from Perfect Power. They will do everything we do here with GM stuff. They also work with all the GM ECMs instead of doing the chips. They also have capabilities for tuning nitrous, turbo and superchargers. Once you find out how much they cost and the ease of installation and use compared to re-inventing the wheel you will believe me.

    But if anyone would know if your Jeep ECM could be done would be Westers Garage.
    http://westersgarage.eidnet.org/index2.html

    As far as someone to hire to disassemble a chip, write an XDF and ADX look for Traxion or Cal Editor on:
    http://www.monodax.com/forums/forums.php

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
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    Imagine you want to get more power from an engine but you have no idea how it works. You don't have books, you don't have the 'net, and you don't have someone else to ask. You don't know what a cam is, you've never heard of compression ratio, and the word piston has never been spoken near you. You have some tools but they may or may not fit the engine and they may or may not work together to disassemble the engine. You know someone somewhere has modified their engine so you have faith it can be done, but you have no idea what it took them to do it. All you know is if someone did their engine, then they or you should be able to modify yours. Doesn't seem like an easy job, does it?

    Making a definition file and coming up with a disassembly is a huge undertaking. Around 2001 Lyndon Wester actually hired a guy to work full time on disassembling GM code for him because it takes so much effort and time to get it done. And that's with a known processor and known examples of code from similar computers. Working with an unknown ecm can take even longer. If it were simply a matter fo finding someone and handing over cash, everything would have been hacked a long time ago. What stops these efforts is the sheer time it takes to work out the details.

    You can probably read the eprom in your ecm. But what you'll get won't look like anything you recognize. Will it be code? Or calibration data? Or both? You'll need to pass it throught a disassembler to know that. And in order to know what disassembler to use you'll want to know the type of processor used in the ecm. And then the disassembler may choke multiple times forcing you to make manual modifications and restart the process.

    If the ecm is a chrysler design similar to some of the cars and trucks there are a few places to go. Like the GM stuff, you'd better be prepared to do some research first.
    http://www.omniglht.com/cal.html
    http://www.omniglht.com/sbec.html
    http://www.turbo-mopar.com/forums/fo...?36-EFI-Tuning
    http://www.turbo-mopar.com/forums/kn...BEC-Tuning-FAQ

    I wish you guys would stop thinking everything needs to be SFI. The 86-87 GN is sfi and it uses an older "C3" ecm. But the Syclone is batch fire and can do everything the GN does.

  9. #9
    Fuel Injected! JeepsAndGuns's Avatar
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    Looks like I have plenty of reading to do from all those links. Might take me a little while to get through them. But it looks more promising than all the rest of the info I have been able to find.
    79 Jeep Cherokee, AMC 401, T-18 manual trans, hydroboost, 16197427 MPFI system---the toy

    93 Jeep YJ Wrangler, 4.0L, 5 speed, 8.8 rear, homebrew hub conversion and big brakes, hydroboost, 2.5in OME lift, 31x10.50's---the daily driver

    99 Jeep WJ Grand Cherokee limited, 4.0L, auto, 2wd, leather and power everything, 99% stock---the long distance highway ride.

  10. #10
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    There appears to be more info out there but still no less spendy solutions since I last searched. Do some searched using JTEC.
    More reading:
    http://thespeedfreaks.net/showthread...l-Or-PCM-Flash
    http://www.jeepsunlimited.com/forums...d.php?t=474337
    http://dodgeram.org/tech/repair/Pcm_diags/Page1.htm

  11. #11
    Fuel Injected! JeepsAndGuns's Avatar
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    Well it looks like the ecm in my jeep is whats being called a "SBEC" ecm. Its used in lots of the same year range dodge and chrysler vehicles. Seems like the dodge ones have been hacked some and people can and do read the chips, make changes, and burn new chips. But the software appears to be nothing like tunerpro. I havent even found any good info about what tuning software they are using. But I'm still searching and reading.



    But just to keep the conversation going, incase tuning the jep ecm doesnt work out, and since the 12200411 gm pcm is so expensive to tune. And since I know nothing about chevy engines and all the diffrent chevy engines. Are there any chevy obd1, tunerpro supported, sequencial multiport, V6 ecm/pcm's that might could be a possiable swap. I'm still gonna exhaust most options I can find to tune the jeep ecm, but like I said, jut to keep the conversation going and explore other options, what is there out there? Not sure if I want to learn another tuning sofware, it took me so long to learn what little I know about tunerpro, and I really like it. So if I it doesnt look like I will be able to fine anyone to make a tunerpro defination, then I may start exploring those other options.
    79 Jeep Cherokee, AMC 401, T-18 manual trans, hydroboost, 16197427 MPFI system---the toy

    93 Jeep YJ Wrangler, 4.0L, 5 speed, 8.8 rear, homebrew hub conversion and big brakes, hydroboost, 2.5in OME lift, 31x10.50's---the daily driver

    99 Jeep WJ Grand Cherokee limited, 4.0L, auto, 2wd, leather and power everything, 99% stock---the long distance highway ride.

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    There are no Chevy engines which meet your criteria.

  13. #13
    Super Moderator dave w's Avatar
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    I'm often asked to tune Jeeps, but I always have to decline. For what it's worth, would the Moates.net Road Runner be an option for the DIY Jeep computer?

    dave w

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    RIP EagleMark's Avatar
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    There's also a guy who installs a MegaSquirt board in LS1 PCM case... now that I think of it why not gut your case and install a MegaSquirt to the ECM plug! All you need then is a longer cable to reach inside the cab to hook up to the laptop.

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

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    I'd use a 7730 myself. Lots to gain by switching to an ecm you can adjust.

    But the Mopar stuff looks kind of neat. I found an article a while back describing the ChryCo approach to fuel and spark and I was trying to find it again. While GM took to making tables, Chrysler used functions. So they've got "ramps" for spark and for fuel based on coolant temp, rpm, iat, tps, & etc. After working with cells and specific rpm/map intersections the Dodge approach seems lacking but when you think about the VE smoothers and the way many people fill in spark and VE tables, we do the same thing.

    Was a guy a long time ago who swapped a GM ecm onto a Jeep I6. Was one of the first ones I know of. I think it was Jeremy Gonyou, same guy that got a job at Ford by reverse engineering GM code. :) Can't find any references right now but it wasn't a bad project for something done back in the dark ages.

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