CaddyDaddy Posted June 18, 2004 Report Share Posted June 18, 2004 Just curious if any of you have programmed your own PROM chip for your ECM/PCM. I can't seem to find anyone that has. At least to a Cadillac. If you have no idea what I am talking about check out this page Making your own PROMs And some software: A free ECM editor TunerPro He has a program called TunerPro RT that allows you to tune you car in real time with the correct hardware (ROMulator) and lets you modify your current factory settings on the PROM chip in your ECM and burn it to a blank EEPROM(Pocket Programer). Kinda like making your own performance chip. Very complex but very possible. Some other good links for this topic: Also a program to do the same as TunerPro but needs registered: GMPCM The hardware to burn a EEPROM chip: Pocket Programmer Use this to emulate a PROM chip before acutually burning one Acutally see your modifications in real time. Need the Pocket Prgrammer before this cones in handy: ROMulator I am ready to make my chip I don't know about you, They also make an adapter that you can put into your ECM that allows you to put in a bigger PROM chip (128Kilobyte) and a switch. So you can burn your factory settings onto this chip along with a performance program. So when your ready to race that N* engine, flip the switch to performance mode and go. Then when you need your gas milage flip it back. Any way I think we need some people and there Caddy's to get into this. Seems mostly like Camaro and Firebird guys are getting off on this right now. Check them links out! Link to comment Share on other sites More sharing options...
bigfoo Posted June 18, 2004 Report Share Posted June 18, 2004 And of course, as usual, nothing for OBDII :/ Link to comment Share on other sites More sharing options...
CaddyDaddy Posted June 18, 2004 Author Report Share Posted June 18, 2004 Nothing as in what?? Link to comment Share on other sites More sharing options...
bigfoo Posted June 18, 2004 Report Share Posted June 18, 2004 Absoutely nothing. Nobody and I mean nobody has anything that works with OBDII computers.. No chips, no reprograms, etc. Which means, no superchargers, turbos, MAF replacements, etc. So it's kind of very difficult to modify.. If you happen to have a pre OBDII car ( i think 1995 and below) then you are in a lot more luck Link to comment Share on other sites More sharing options...
CaddyShack24 Posted June 20, 2004 Report Share Posted June 20, 2004 Hey thanks for that info CaddyDaddy! I'd like to get into this stuff, besides the performance tweaking.. i'd like to change those messages on the DIC, you know "Press brake to shift" and "Traction Control Disabled" Glanced threw it all, wil be more thourgh tonight, thanks again man bookmarked! Link to comment Share on other sites More sharing options...
CaddyShack24 Posted June 20, 2004 Report Share Posted June 20, 2004 bigfoo, i saw on some forum where these guys were using harneses to convert the OBDII to OBDI.. still had both, just flipped a switch to toggle no link, sorry.. i think it was the toyota guys Link to comment Share on other sites More sharing options...
bigfoo Posted June 20, 2004 Report Share Posted June 20, 2004 I'm thinking about putting a MSD DIS in there somewhere and just in line with the factory one.. Talking to msd about it. If anyone is interested i"ll post what I learn Link to comment Share on other sites More sharing options...
CaddyDaddy Posted June 25, 2004 Author Report Share Posted June 25, 2004 I'd like to get into this stuff, besides the performance tweaking.. i'd like to change those messages on the DIC, you know "Press brake to shift" and "Traction Control Disabled" Yea that would be nice but I think that information would be in the BCM. Let me know if you get anywhere on this. Link to comment Share on other sites More sharing options...
CaddyDaddy Posted June 26, 2004 Author Report Share Posted June 26, 2004 Turns out on these old ECM's like mine that they have three memory chips. The PROM, ROM, and RAM. Only one is removable without soldering. So one these older ones you gotta pull the ROM out and read the program code on it in order to really understand where any of the tables are (spark advance vs. RPM) But all you guys with those newer PCM's have it all Programmed on a EEPROM or FlashROM. The only thing that bothers me is that no one tends to upgrade there cadillac enough for anyone to have a engine tuning program thats compatible with a cadillac. So you have to understand all the computer code yourself in order to modify anything. Hopefully someone else out there will be interested in cracking the cadillacs ECM code so we can start fine tuning our cars for performance. I really like the idea that you can put a bigger EPROM in your ECM with a switch to change from different programs (factory default/performace) so you don't have to lose you fuel economy for good when you put your new chip in. Link to comment Share on other sites More sharing options...
bigfoo Posted June 26, 2004 Report Share Posted June 26, 2004 I like that too, but nobody makes one for the newer cadillacs (except I think the escelade but not sure). So I'm basically out of luck :> I would have to replace the entire PCM or get someone to reflash it with a new program(code). Basically it's like a computer. It has a processor, ram, nvram, flash, possibly other stuff I haven't really looked into it that much. It keeps track of TONS AND TONS of things in the car which I am totally amazed about :> Anyway it has an operating system that you can 'flash' onto it. All the settings and everything are in the operating system so you can't change anything unless you replace the whole code with new code. Problem is, the code is of course compiled so you can't just edit it very easily. I haven't done a lot of research into the pcm itself yet so i'm not 100% positive, but that's the jist of it. I believe the older ones store settings in a prom and you can replace the prom to change the settings.. again not 100% sure YET.. I will know everything about the PCM when I have time to research it and take mine apart too :> Link to comment Share on other sites More sharing options...
CaddyDaddy Posted June 26, 2004 Author Report Share Posted June 26, 2004 I think your pcm will be much easier than mine. Since you have the FlashROM you don't even have to take the chip out to reprogram it. Plus all your code is on that flashROM unlike mine. I have to desolder the ROM to find the rest of the code, constants, tables and what not. Right now I don't have the funds to get deeply into this but I definetly have the time. diy-efi.org is a pretty good site for information on reprogramming your PCM. Link to comment Share on other sites More sharing options...
32v_dohc Posted July 1, 2004 Report Share Posted July 1, 2004 Yes I have reprogrammed mine (93 ETC) using the general ideas described. Caddydaddy, Your 89 seville should be a P4 ECM. You should be able to remove the MEM-CAL and read it. My suggestion is to find someone in your area to read it. Once you have a bin file I can show you how to unravel the info to be able to program your own chips. Bigfoo, as far as OBD2 stuff goes I know a little. One of the things that has kept me from getting a newer Cad is the lack of good info and programming ability. If you want to break the OBD2 computers I am willing to help. John Link to comment Share on other sites More sharing options...
bigfoo Posted July 1, 2004 Report Share Posted July 1, 2004 OBD2 is just a specification of interface.. It's really not the computer itself. A ton of new cars have obd2, fords, saturns, chevy, cadillac, etc. The problem is that the 'new' PCM is a EEPROM (flash programmable). It doesn't have a MEM-CAL or anything like that. It's a single flash chip with the OS. There is no separate place to store settings or anything.. To upgrade it you have to re-flash the EEPROM with new code. Instead of a settings file to deal with now you have a whole code to pick through (assembled) to figure out what's going on. It still wouldn't be that hard with the proper tools. It's the reflashing part that is tricky.. It would be all too easy to do irreversible (at least to US) damage to the PCM. It would be like formatting the hard drive on your computer and not having a boot disk. There's nothing you can do (that I know of) if you screw up the reflash (besides taking the eeprom out and reflashing it in another unit, but it's probably soldered in). Anyway, i'm working on it I'll be beta testing some reflashes on my car and i'll probably buy a couple extra PCMs just in case. If anyone knows where to get some used PCMs let me know. Link to comment Share on other sites More sharing options...
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