DIY_EFI Digest Friday, 26 January 1996 Volume 01 : Number 022 In this issue: Re Lambda Sensors Re: Engine codes for '84 T/A Re: Identify This ECM Re: Identify This ECM Re: Engine codes for '84 T/A Re: Engine Reversal and EFI RE: Cyberdyne A/F meter RE: Simulating an IC engine ... Re: Re Lambda Sensors Re: Engine codes for '84 T/A Re: Engine codes for '84 T/A Re: Re: Engine codes for '84 T/A; DIACOM and OBD-II questions Re: Re: Engine codes for '84 T/A; DIACOM and OBD-II questions aldl data stream Diacom, OBDII interface (was Re: Engine codes for '84 T/A) Re: Engine codes for '84 T/A Re: Engine codes for '84 T/A re: Diacom, OBDII interface (was Re: Engine codes for '84 T/A) Re: Engine codes for '84 T/A Re: Identify This ECM Re: Identify This ECM Re: Identify This ECM See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: sian@xxx.uk (RAGHBIR SIAN) Date: Thu, 25 Jan 1996 11:58:25 GMT Subject: Re Lambda Sensors As the debate about Lambda sensors has been increasing on the list i have decided to release some information that i worked out a while back working for an O.E manufacturer. (no names mentioned.) I measured the values of Voltage by comparing the lanbda display using a Bosch Motorsport lambda conditioning module which is horrendously expensive and is used by most major racing teams not to mention O.E. manufacturers all over the world. The table is for an isolated ground (4 wire) NTK EGO sensor. I repeat this table is only valid for the above sensor. The table is as follows: LAMBDA O/P (mV) 0.64 1188 0.66 1153 0.68 1133 0.7 1130 0.72 993 0.74 973 0.76 953 0.78 933 0.8 913 0.82 904 0.85 891 0.87 883 0.9 871 0.92 854 0.95 829 0.97 798 0.98 782 0.99 616 1 450 1.05 194 1.1 47 1.15 35 1.2 30 1.25 24 1.3 21 1.4 18 1.48 15 Yes it does switch as you can see the gradient changes at three major places substantially. I do not want budding mathematicians to tell me that the gradient changes more than 3 times, i kNOW so save it. I did mathematics too. You should be grateful that somebody has released information like this. Don't tell me you could have done it better cos you haven't done it yet. I hope this will answer alot of the questions asked on the list regarding lambda sensors. The test was carried with both the Bosch sensor (reference) and the NTK sensor placed more or less (+ or - 2mm) the same distance from Exhaust manifold and paced at 180 degrees to each other so as to minimize the temperature and gas composition differential between both the sensors. Regards R.S.Sian >>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<< Raghbir Sian Engine Control and Combustion Analyst "As Always A ***CONTROL*** Freak" A committee is a group of the unwilling, chosen from the unfit, to do the unnecessary.... Anonymous Life is just one damned thing after another... Joseph Heller Time spent on any item of the agenda will be in inverse proportion to the sum involved. E-mail: sian@xxx.uk >>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<< ------------------------------ From: george dailey Date: Thu, 25 Jan 1996 06:17:57 -0600 Subject: Re: Engine codes for '84 T/A At 12:55 PM 1/21/96 -0500, you wrote: >Does anyone have the hexadecimal engine codes for the GM ALDL computers >as used in '82 through '92? > > Any help would be appreciated. > >--- Dan. * * * Dan, I also wish to crack the enigma of the GMC CCC serial data protocol. Here is what I know. Listed below is the "official" pin description from Chilton repair manuals. Notice that GM does not distinguish between M and E. One source has wrote that M is used in conjunction with E for 'high speed communication'. NOT! My '89 350 TPI set up did not have an E connection, just an empty slot. This leads me to believe that it is E or M and not both. My personal tests indicate that serial data will only be transmitted when B is grounded. This test was done by connecting the ALDL to my PC using Procom terminal software. All I got was unreadable data . It appeared in about 3 paragraph chunks that repeated over and over. I'd be willing to bet that it's ASCII. I tried different setting but never got anything readable. GM computers can only transmit data ( up to '92 I think) What's needed to crack the code is a program that reads a serial data line and prints it as raw binary data. Then, any electronic hacker worth his weight in semiconductors can figure out what's going on. I'm still assuming it's ASCII though, I sure as hell don't know for sure. If one of our suave programmers can write the program, I would be willing to connect it to my hardware and share the information that the ECM regurgitates. If anybody's interested, the program needs to do the following in general: Read pin #3 of a RS232 port Determine the frequency of the incoming transmission (show us just how clever you can be) Collect a few paragraphs (ugh pages?) of data Print the data to an ASCII data file, line by line in the following format 101000110111001110000111110100101110001010101010001110001001 inform the user of the calculated transmission frequency The user then pulls up the ASCII data file in a word processor and tries to assemble it . 3 endings are possible. *The code is cracked and we will be immortal in the eyes of all GM car owners. * The code is cracked and GM marks us for termination. *We can't make heads or tails of the data and admit defeat. PS a company called DIACOM makes software that can read the serial data and print the engine diagnostic information to a IBM PC/AT via RS232 for $300.00 800-888-4146 >Pin Function >A Ground >B ALDL Diagnostics >C >D >E serial data >F >G >H not used >J not used >K not used >L not used >M serial data > > The connector pinout is arranged in this fashion: [This is true] > F E D C B A > G H J K L M > gmd@xxx.com > > > ------------------------------ From: FIScot@xxx.com Date: Thu, 25 Jan 1996 07:44:50 -0500 Subject: Re: Identify This ECM Subj: Identify This ECM Date: 96-01-24 23:52:31 EST From: ravalent@xxx.com (Bob Valentine) > Can anyone identify it from these numbers: > Service Number: 1227165 > Sticker on ROM: Delco ABYA 5400 > Sticker inside box: 5088365 > Barcoded sticker on harness connector: 310038212158301 > Are there any simple tests I can do on the unit to see if it's alive, > aside from powering it up and hooking up a check light? I don't have > access to a TPI car to try it in. Bob, That service number ECM is used in 86-89 Camaro TPI's and maybe Corvettes from the same era. I don't know from the ABYA whether it is 305/350, standard or automatic, but if you could send me the code, I could look at it and tell you what it was intended for, and also whether the PASSKey is enabled. (If so, you would have to substitute the PASSKey signal, or modify the EPROM.) The 89 models did not use the cold start injector, and would not have the 9th injector connection in the harness. The 86-88 models did use a cold start injector. All model years 86-89 also used a MAF, not a MAP sensor. If you are looking for a cleaner looking installation, I would consider using a MAP based system. If you have DIACOM, power the unit up and see if it communicates! Otherwise, it is hard to tell just from the CEL the exact status of the ECM. Scot Sealander FIScot@xxx.com ------------------------------ From: pjwales@xxx.net (Peter Wales) Date: Thu, 25 Jan 1996 08:44:29 -0500 Subject: Re: Identify This ECM The ABYA 5400 Eprom goes into a 1987 Camaro L98 Motor 5.7l MFI MD8 Transmission, 4spd Auto Axle GH3 2.77:1 What else do you needto know? Peter Wales President Superchips Inc Florida Chairman Superchips Ltd Buckingham "Timing is everything" Superchips home page with all the answers http://www.superchips.com ------------------------------ From: FIScot@xxx.com Date: Thu, 25 Jan 1996 09:30:00 -0500 Subject: Re: Engine codes for '84 T/A Subj: Re: Engine codes for '84 T/A Date: 96-01-25 08:09:17 EST From: gmd@xxx.com (george dailey) > Dan, I also wish to crack the enigma of the GMC CCC serial data > protocol. Here is what I know. Listed below is the "official" pin > description from Chilton repair manuals. Notice that GM does not > distinguish between M and E. One source has wrote that M is used in > conjunction with E for 'high speed communication'. NOT! My '89 350 > TPI set up did not have an E connection, just an empty slot. This > leads me to believe that it is E or M and not both. My personal tests > indicate that serial data will only be transmitted when B is grounded. > This test was done by connecting the ALDL to my PC using Procom > terminal software. All I got was unreadable data . It appeared in > about 3 paragraph chunks that repeated over and over. I'd be willing > to bet that it's ASCII. I tried different setting but never got > anything readable. GM computers can only transmit data ( up to '92 I > think) I understand why you (and others) are having a hard time! ;-) This is not a flame, but there is *ALOT* of misinformation in the previous paragraph. The 89 Camaro can do BOTH slow and fast ALDL speeds. When you ground the ALDL pin B, the ECM goes into slow ALDL mode. In that mode it is only transmitting data at the slow rate. (Unless of course if you ground the pin while already in the fast mode, then it ignores the ALDL pin.) C3 ECMs can only transmit, and only in the slow mode. The fast ALDL is limited to the P4 and newer ECMs. P4 and above require much more knowledge to get the ALDL data. Basically, the E pin is slow data, and the M pin is fast data. But this too is not hard and fast. Sometimes both are connected together. In the above case, the fast and slow data are both on pin M. To enter fast ALDL mode, you have to listen to the ECM, wait for the correct data to be sent, and send it the correct message that it is expecting. Won't spit out all that data without it! But even this is not universal. I have seen a P4 that only transmits in fast mode, and does not receive. The data is not in ASCII, but regular 8-bit (mostly) unsigned integers. There are some 16-bit values that come out. The factory service manual explains alot of what the data is that comes out, and all you who want to figure this out need to RTM. > What's needed to crack the code is a program that reads a serial data > line and prints it as raw binary data. Then, any electronic hacker > worth his weight in semiconductors can figure out what's going on. I'm > still assuming it's ASCII though, I sure as hell don't know for sure. I think it is much easier to read the EPROM, figure out the code, and then know what is going on. > If one of our suave programmers can write the program, I would be > willing to connect it to my hardware and share the information that the > ECM regurgitates. If anybody's interested, the program needs to do the > following in general: [text deleted] > The user then pulls up the ASCII data file in a word processor and > tries to assemble it . 3 endings are possible. > * The code is cracked and we will be immortal in the eyes of all GM car > owners. > * The code is cracked and GM marks us for termination. > * We can't make heads or tails of the data and admit defeat. I'll bet #3. > PS a company called DIACOM makes software that can read the serial data > and print the engine diagnostic information to a IBM PC/AT via RS232 > for $300.00 800-888-4146 For 300 USD you will spend a lot less overall to just buy it! How many hours will it take to figure it out? A mere 500/600 hours of labor? This is 50 cents an hour. You better be doing it for the love of it. Also, remember the code changes model to model, year to year... There are too many variables..... Buy DIACOM and save some grief, unless you like to hack..... now that is another story! Scot Sealander FIScot@xxx.com ------------------------------ From: jgn@xxx. Napoli) Date: Thu, 25 Jan 1996 09:38:03 -0500 Subject: Re: Engine Reversal and EFI Reverse-spin motors also need provision for distributor thrust. I believe that this is handled by reversing the cut of the gear on the cam and a 'reversed' dist drive gear. > >On Wed, 24 Jan 1996, Clinton L. Corbin wrote: > >> >down. Often twin engine installations in boats run the engines in >> >opposite directions, so you might look into SBC marine setups to see if >> >a reverse direction engine is produced, and what they've done to >> >support it. >> > >> >/Bill > >> My understanding of the twin (and triple) engine installations in off-shore >> power boats is that both (or all three) engines turn in the same direction. >> The only difference is that the outdrive (be it sterndrive, v-drive, or >> other) is geared for reverse rotation. Just my two bits... > > I've seen it done both ways, but most commonly one motor is >reversed. Every reverse-rotation Crusader marine engine I've seen is >PLASTERED with caution stickers about its rotation and not to set the >timing too far back. > > A marine mechanic I spoke to said the only difference between a CW >and a CCW motor was the cam and the starter - makes sense. He also >mentioned that the reverse motors usually had a hotter cam since they >didn't make as much power as their normal rotation cousins. > > --> Bob Valentine <-- > --> ravalent@xxx.com <-- > "Clinging Tenaciously to the Trailing Edge of Technology" > > Napoli ------------------------------ From: Mike Wesley - SLIP Date: Thu, 25 Jan 1996 10:31:28 -0500 (EST) Subject: RE: Cyberdyne A/F meter On Wed, 24 Jan 1996, Timothy Coste wrote: > Hey Mike, > > Be careful at 9:1. I was flipping through our Horiba manual and > it says that the sensor life can be measured in tens of hours when > run that rich. I can't quote the numbers right now (it was actually > late last week I was reading up on it) but the way rich running > just kills the poor suckers. And our university budget can't take > replacing $900 sensors once a week. Hopefully your budget is better > than ours though. :) Just though I'd mention it in case you weren't > aware. Yeah, the UEGO's don't live too long under extreme conditions. When I was at Ford, we could only use them for 3 hours with continuos operation at WOT and then they would go south. I wrote some software for Ford that would control the dyno sweeping fuel and spark at WOT to find MBT, BDL and LBT so we would be at WOT for extended periods. For my racing company, I normally use my Bosch LA2 with the LSM11 sensor. It can take more abuse and is quite accurate except for extreme lean conditions. Plus I can tap into the LSM11 output and feed that into the EEC-IV so it can use the LSM11 for closed loop and I can monitor lambda. Saves me from having to put an extra bung in the exhaust. I should have a low cost A/F ratio tool available real soon. Just finshing up the temperature compensation. Good from 9:1 to 24:1, datalogs A/F, RPM and spark advance for analysis, and it's cheap >$700! Mike... ------------------------------ From: pmc1eng@xxx.uk Date: Thu, 25 Jan 1996 16:16:50 +0000 Subject: RE: Simulating an IC engine ... I'm using a 4 stroke engine simulator software for my graduation project. It's called "Dynomation" and there's a demo version available at: www.public.iastate.edu/~punk/dynomation/dma.html Pedro Costa (MadMax) ------------------------------ From: Land Shark Date: Thu, 25 Jan 1996 09:50:28 -0700 (MST) Subject: Re: Re Lambda Sensors At 11:58 AM 1/25/96 GMT, you wrote: >I measured the values of Voltage by comparing the lanbda display using a >Bosch Motorsport lambda conditioning module which is horrendously expensive >and is used by most major racing teams not to mention O.E. manufacturers all >over the world. > >The table is for an isolated ground (4 wire) NTK EGO sensor. I repeat this >table is only valid for the above sensor. Thanks for the table .. TWO QUESTIONS though :) 1) Isn't the "voltage vs. Lambda" somewhat dependent on the temp of the sensor and if so, how is that controlled to eliminate that variable.. 2) WHICH NTK (ala NGK) sensor is it?? do you have a PART # for me (please please) Oh (OK it was really 3 questions ;) how expensive IS a Bosch system?? I'm looking for a really DECENT lambda measuring device ... Jim ------------------------------ From: Markus Strobl Date: Thu, 25 Jan 1996 11:12:07 -0600 Subject: Re: Engine codes for '84 T/A > PS a company called DIACOM makes software that can read the serial data and > print the engine diagnostic information to a IBM PC/AT via RS232 for $300.00 > 800-888-4146 Yes, but doesn't the diacom package contain some kind of interface box? I know GM PCMs use a weird speed, 8192. BTW, if anyone has ANY info on the new OBDII boxes (ie how to communicate with them), PLEASE drop me a line. I would love to hook up my PC to it. Markus Strobl 96 Z28 6M ------------------------------ From: scicior@xxx.com (Steve Ciciora) Date: Thu, 25 Jan 1996 12:50:19 -0700 Subject: Re: Engine codes for '84 T/A > From owner-diy_efi-outgoing@xxx.edu Thu Jan 25 12:42 MST 1996 > From: Markus Strobl > Date: Thu, 25 Jan 1996 11:12:07 -0600 > To: diy_efi@xxx.edu > Subject: Re: Engine codes for '84 T/A > > > PS a company called DIACOM makes software that can read the serial data and > > print the engine diagnostic information to a IBM PC/AT via RS232 for $300.00 > > 800-888-4146 > > Yes, but doesn't the diacom package contain some kind of interface box? I > know GM PCMs use a weird speed, 8192. > Well, it acutally hooks up to the parallel port. And the instructions imply that the software has to initialize the hardware molded into the specialized cable. Have not gotten around to look at what goes in and out of this cable yet, since I no longer need to home-brew an ALDL interface. The only reason I can think of for there to be hardware in the cable is so that my 4.77 MHZ laptop can still read in 8192 baud data. I imagine a faster computer can just pole the parallel port and read in the data that way. > BTW, if anyone has ANY info on the new OBDII boxes (ie how to communicate > with them), PLEASE drop me a line. I would love to hook up my PC to it. > > Markus Strobl 96 Z28 6M > - -Steven Ciciora ------------------------------ From: m_mcdonald@xxx.com Date: Thu, 25 Jan 96 15:32:48 EST Subject: Re: Re: Engine codes for '84 T/A; DIACOM and OBD-II questions >> PS a company called DIACOM makes software that can read the serial data and >> print the engine diagnostic information to a IBM PC/AT via RS232 for $300.00 >> 800-888-4146 This is an excellent software package. A demonstration diskette is available for $5.00 from DIACOM's manufacturer, Rinda Technologies in Chicago. It's also available as a download from Compu$erve. Once logged in there -- either GO AUTO or GO AUTOS, select For Techs Only, and look for library files with the keyword DIACOM. BTW, the DIACOM cable connects to a PC's parallel port instead of to a serial port. > Yes, but doesn't the diacom package contain some kind of interface box? I > know GM PCMs use a weird speed, 8192. The DIACOM hardware/software package is complete. It takes care of weird speeds such as 8192 baud. > BTW, if anyone has ANY info on the new OBDII boxes (ie how to communicate > with them), PLEASE drop me a line. I would love to hook up my PC to it. I'm pretty sure that DIACOM software will handle the new OBD-II hardware and software combination. If you want to make your own package, begin by purchasing the Society of Automotive Engineers (SAE) document with OBD-II standards. It's a maroon-covered manual with a number of HS-3000 or HS-3500. The SAE is in Warrendale, Pennsylvania with an area code of 412. The manual costs either $45.00 (ouch!) or $65.00 (ouch! ouch!), but it contains the information you need. For example, I recall reading that the OBD-II data stream is 10400 baud and 8/N/1. > Markus Strobl 96 Z28 6M Marll McDonald KB1AGM 1993 Ford Escort 1.9L, 1940 Ford coupe with flathead V-8 engine m_mcdonald@xxx.com ------------------------------ From: Markus Strobl Date: Thu, 25 Jan 1996 15:00:58 -0600 Subject: Re: Re: Engine codes for '84 T/A; DIACOM and OBD-II questions Thank's for your reply. > I'm pretty sure that DIACOM software will handle the new OBD-II hardware > and software combination. I've been told that it doesn't work for OBDII. Does Rinda tech have a e-mail address? Or phone #? > If you want to make your own package, begin by > purchasing the Society of Automotive Engineers (SAE) document with > OBD-II standards. It's a maroon-covered manual with a number of HS-3000 > or HS-3500. The SAE is in Warrendale, Pennsylvania with an area code of > 412. The manual costs either $45.00 (ouch!) or $65.00 (ouch! ouch!), but ouch, ouch, ouch! > it contains the information you need. For example, I recall reading that > the OBD-II data stream is 10400 baud and 8/N/1. ^^^^^ Where do they get those baudrates from? I'm I right in assuming a standard PC serial port can't read that speed? If so, what kind of HW would be needed to interface? Once the HW connection is made, it shouldn't be that hard to communicate, since OBDII PCMs have to follow the offocial standard. Atleast that's what I hope.. > > Markus Strobl 96 Z28 6M > Marll McDonald KB1AGM Markus Strobl 96 Z28 6M ------------------------------ From: DAN FURGASON Date: Thu, 25 Jan 1996 15:50:16 MST Subject: aldl data stream The ALDL for my 89 Suburban is a continuous 160 bit/sec bit stream. It begins with a sync character of 9 consecutive "1" s. Each subsequent byte begins with a "0" and then the 8 data bits. The stream continues until all data is read. Another sync character is sent and the stream repeats with updated values. If you program in C++ there is a printer status call to read the parallel port, so the code to get the data is really easy(timing is a pain). Among other things, o2, throttle pos, and map are in the data stream. Dan Furgason ------------------------------ From: Markus Strobl Date: Thu, 25 Jan 1996 17:07:55 -0600 Subject: Diacom, OBDII interface (was Re: Engine codes for '84 T/A) > > > PS a company called DIACOM makes software that can read the serial data and > > > print the engine diagnostic information to a IBM PC/AT via RS232 for $300.00 > > > 800-888-4146 > > > > Yes, but doesn't the diacom package contain some kind of interface box? I > > know GM PCMs use a weird speed, 8192. > > > Well, it acutally hooks up to the parallel port. And the instructions > imply that the software has to initialize the hardware molded into the > specialized cable. Have not gotten around to look at what goes in and > out of this cable yet, since I no longer need to home-brew an ALDL interface. > The only reason I can think of for there to be hardware in the cable is > so that my 4.77 MHZ laptop can still read in 8192 baud data. I imagine > a faster computer can just pole the parallel port and read in the data > that way. Could you please explain more about this. I'm no wizard when it comes to parallel ports. What is meant by poling the port? And how do they adapt the parallel port to a serial interface? I bet the cable could be duplicated for a few bucks, and if someone can explain what it does, I'd be happy to experiment on this. Markus ------------------------------ From: george dailey Date: Thu, 25 Jan 1996 17:26:16 -0600 Subject: Re: Engine codes for '84 T/A At 11:12 AM 1/25/96 -0600, you wrote: >Yes, but doesn't the diacom package contain some kind of interface box? I >know GM PCMs use a weird speed, 8192. > >Markus Strobl 96 Z28 6M > >Mark, from what I have seen in advertisements, the interface connector is so small, that if any electronics are used, they are very few, very small, and probably consist of protection devices if they exist at all. The interface was dirt simple. An ALDL on one end and a RS232 DB9 connector on the other. No external power supply leads. George M. Dailey GMD@tecinfo ------------------------------ From: george dailey Date: Thu, 25 Jan 1996 18:22:46 -0600 Subject: Re: Engine codes for '84 T/A At 09:30 AM 1/25/96 -0500, you wrote: RTM > >What GM service manual do I need to purchase? The last time I went to my GM dealer I asked about a service manual and was told they could not get service manuals. What's the part number? BTW, When I was trying to defeat the vats system, several GM service and parts people said they never herd of a VATS module. gmd@tecinfo way down south in Greenville, Mississippi > > > > ------------------------------ From: SRavet@xxx.com Date: Thu, 25 Jan 96 18:41:40 CST Subject: re: Diacom, OBDII interface (was Re: Engine codes for '84 T/A) Markus Strobl Wrote: | | > > > PS a company called DIACOM makes software that can read the serial data | and | > > > print the engine diagnostic information to a IBM PC/AT via RS232 for | $300.00 | > > > 800-888-4146 | > > | > > Yes, but doesn't the diacom package contain some kind of interface box? I | > > know GM PCMs use a weird speed, 8192. | > > | > Well, it acutally hooks up to the parallel port. And the instructions | > imply that the software has to initialize the hardware molded into the | > specialized cable. Have not gotten around to look at what goes in and | > out of this cable yet, since I no longer need to home-brew an ALDL interface. | > The only reason I can think of for there to be hardware in the cable is | > so that my 4.77 MHZ laptop can still read in 8192 baud data. I imagine | > a faster computer can just pole the parallel port and read in the data | > that way. | | Could you please explain more about this. I'm no wizard when it comes to | parallel ports. What is meant by poling the port? And how do they adapt | the parallel port to a serial interface? I bet the cable could be duplicated | for a few bucks, and if someone can explain what it does, I'd be happy to | experiment on this. | | Markus | First off, the ALDL connector uses TTL positive logic voltage levels (5v=1, 0v=0). The serial port on the PC uses RS-232 voltage levels, (-13V=1, +13V=0). So the serial line from the ALDL cannot just be connected directly to the serial port of the PC. You could get a level inverter/shifter (MAX 232?) and produce the proper voltage levels for your serial port, but now you have the problem that 8192 is a non-standard baud rate. You can program you PC to 8192 is 8228, which is probably close enough. So that would work, except that earlier GM ECMs are 160 baud and some non-standard format that isn't RS-232. So Diacom connects the ALDL serial port to a PC parallel port. How does that work? the logic voltage levels on some of the printer port pins can be read directly by software thru an I/O port. Diacom implements a software UART. The software polls the printer port until it sees the start bit, then it collects the other bits using the computers timer to tell when they are on the line. This works without any hardware for any type of data stream, which is why they use it. You plug in the VIN, and Diacom knows what type of baud rate to expect from that. I hate posting stuff from old memory, but I can't find my J1850 (OBD-II) article. So here's what I remember about it: it supports two data rates, I think 1MB/s and 2MB/s. It is not even close to RS-232 regardless of the data rate, so it'll never hook to a serial port. Harris (and maybe others) make a two chip set for it, one is the basic data framer, the other is an 8152 clone with OBD-II intelligence built in. Steve Ravet sravet@xxx.com Baby you're a genius when it comes to cooking up some chili sauce... ------------------------------ From: Bob Valentine Date: Thu, 25 Jan 1996 22:22:21 -0500 (EST) Subject: Re: Engine codes for '84 T/A > Dan, I also wish to crack the enigma of the GMC CCC serial data protocol. > and not both. My personal tests indicate that serial data will only be > transmitted when B is grounded. This test was done by connecting the ALDL > to my PC using Procom terminal software. All I got was unreadable data . > It appeared in about 3 paragraph chunks that repeated over and over. I'd be > willing to bet that it's ASCII. I tried different setting but never got > anything readable. GM computers can only transmit data ( up to '92 I think) I can't find it, but I had a old, old, OLD mail note that said the baud rate is 8192, and that can be obtained by changing the crystal on a old serial port board (XT type). > If one of our suave programmers can write the program, I would be willing > to connect it to my hardware and share the information that the ECM Mabye one of the RS232 hackers can figure out what crystal to choose. 8^) > gmd@xxx.com --> Bob Valentine <-- --> ravalent@xxx.com <-- "Hard Acceleration Saves Costly Aggravation" ------------------------------ From: Bob Valentine Date: Thu, 25 Jan 1996 22:52:39 -0500 (EST) Subject: Re: Identify This ECM Can anyone identify it from these numbers: Service Number: 1227165 Sticker on ROM: Delco ABYA 5400 Sticker inside box: 5088365 Barcoded sticker on harness connector: 310038212158301 Scot Sealander wrote: > Bob, That service number ECM is used in 86-89 Camaro TPI's and maybe > Corvettes from the same era. I don't know from the ABYA whether it is > 305/350, standard or automatic, but if you could send me the code, I > could look at it and tell you what it was intended for, and also > whether the PASSKey is enabled. (If so, you would have to substitute > the PASSKey signal, or modify the EPROM.) Ummmm... what code are you looking for? > cold start injector. All model years 86-89 also used a MAF, not a MAP > sensor. If you are looking for a cleaner looking installation, I would > consider using a MAP based system. > Scot Sealander FIScot@xxx.com And Peter Wales wrote: > The ABYA 5400 Eprom goes into a 1987 Camaro > L98 Motor 5.7l MFI > MD8 Transmission, 4spd Auto > Axle GH3 2.77:1 > What else do you need to know? Easy way to see if it's alive, without a scan tool, Diacom, or car to throw it in. I'm gonna fire it up tonight and see what the idiot light does. If it does live, does anyone have a stock MAP Eprom they want to get rid of? Would make the installation much easier. Does changing throttle body sizes have any effect on the calibration of the unit? Where it's going I would NOT be using the factory style TPI throttle body. Since this box would be going on a Olds motor, and the original TPI motor had a electronic distributor, would I be able to just hook the newer distributor module to the Olds pickup (It's got a standard HEI in it now) to get the right signals for the ECM? Does the TPI distibutor have a Hall Effect unit in it? > Peter Wales Thanks guys... I got the replies before my message even showed up! --> Bob Valentine <-- --> ravalent@xxx.com <-- ------------------------------ From: arthurok@xxx.com (ARTHUR OKUN ) Date: Thu, 25 Jan 1996 23:47:54 -0800 Subject: Re: Identify This ECM You wrote: > > > Can anyone identify it from these numbers: > > Service Number: 1227165 > Sticker on ROM: Delco ABYA 5400 > Sticker inside box: 5088365 > Barcoded sticker on harness connector: 310038212158301 > >Scot Sealander wrote: > >> Bob, That service number ECM is used in 86-89 Camaro TPI's and maybe >> Corvettes from the same era. I don't know from the ABYA whether it is >> 305/350, standard or automatic, but if you could send me the code, I >> could look at it and tell you what it was intended for, and also >> whether the PASSKey is enabled. (If so, you would have to substitute >> the PASSKey signal, or modify the EPROM.) > > Ummmm... what code are you looking for? > >> cold start injector. All model years 86-89 also used a MAF, not a MAP >> sensor. If you are looking for a cleaner looking installation, I would >> consider using a MAP based system. > >> Scot Sealander FIScot@xxx.com > >And Peter Wales wrote: > >> The ABYA 5400 Eprom goes into a 1987 Camaro >> L98 Motor 5.7l MFI >> MD8 Transmission, 4spd Auto >> Axle GH3 2.77:1 > >> What else do you need to know? > > Easy way to see if it's alive, without a scan tool, Diacom, or car to >throw it in. I'm gonna fire it up tonight and see what the idiot light does. > > If it does live, does anyone have a stock MAP Eprom they want to get >rid of? Would make the installation much easier. > > Does changing throttle body sizes have any effect on the calibration >of the unit? Where it's going I would NOT be using the factory style TPI >throttle body. > > Since this box would be going on a Olds motor, and the original TPI >motor had a electronic distributor, would I be able to just hook the >newer distributor module to the Olds pickup (It's got a standard HEI in >it now) to get the right signals for the ECM? Does the TPI distibutor >have a Hall Effect unit in it? > >> Peter Wales > > Thanks guys... I got the replies before my message even showed up! > > --> Bob Valentine <-- > --> ravalent@xxx.com <-- > > > you can get an map updated chip from your local gm dealer for under $50 ------------------------------ From: "Dari Anis" Date: Fri, 26 Jan 1996 16:25:18 +007 Subject: Re: Identify This ECM Date sent: Thu, 25 Jan 1996 08:44:29 -0500 To: diy_efi@xxx.com, DIY_EFI@xxx.edu From: pjwales@xxx.net (Peter Wales) Subject: Re: Identify This ECM Send reply to: diy_efi@xxx.edu The ABYA 5400 Eprom goes into a 1987 Camaro L98 Motor 5.7l MFI MD8 Transmission, 4spd Auto Axle GH3 2.77:1 What else do you needto know? Peter Wales President Superchips Inc Florida Chairman Superchips Ltd Buckingham "Timing is everything" Superchips home page with all the answers http://www.superchips.com I want to know about MFI. What kind of processor do you use? - - anis - ------------------------------ End of DIY_EFI Digest V1 #22 **************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. A non-digest (direct mail) version of this list is also available; to subscribe to that instead, replace "diy_efi-digest" in the command above with "diy_efi".