DIY_EFI Digest Tuesday, 30 January 1996 Volume 01 : Number 026 In this issue: Re: Diacom, OBDII interface re: Sensor Questions? Re: Engine codes for '84 T/A Poweroutput to injectors re: Sensor Questions? Re: efi555 Re: Sensor Questions? Commercial systems Re: efi555 Re: Commercial systems Re: Commercial systems See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: Jens Knickmeyer Date: Mon, 29 Jan 96 15:34:58 MET Subject: Re: Diacom, OBDII interface wrote: > > Might be of interest, in the latest Motorola Databook, Analog/Interface > IC's Device Data [Q4/95 DL128 REV5] is a datasheet for the MC33199 > > MC33199: IS0 9141 Serial Link Driver. > > The MC33199D is a serial interface circuit used in diagnostic applications. > It is the interface between the microcontroller and the special K and L > Lines of the ISO Diagonositic port. > > The MC33199 has a unique feature which allows transmission baud rate > up to a 200k baud. > > Now do NOT get all excited, there is NO protocols listed! This is > just an interface circuit for the automotive use. Just a general > FYI for those who might be looking for an interface chip. This brings up another question: Does someone know if VW uses an ISO9141 interface in their Digifant ECUs built for the US market? Thanks, Jens ------------------------------ From: John T Stein Date: Mon, 29 Jan 1996 11:54:52 ET Subject: re: Sensor Questions? On Friday Jan 26, "SRavet" wrote the following in response to a request to contrast MAF vs. MAP sensor-based systems: > The difference is that MAF is more complicated, but is more tolerant of > engine modifications. MAP (or SD, speed density) use a pre-calculated > volumetric efficiency value. Basically, rpm determines the volume of air > moving through the engine, and the pressure determines the amount of oxygen > in that volume. The computer then injects the proper amount of fuel. If > you increase the breathing ability of this engine (headers or intake modes, > etc), the computer doesn't know about it and will inject too little fuel. > > MAF systems are really SD based, but the computer is able to modify the > injector on time based on the reading from the MAF sensor. It is much more > tolerant of future engine modifications without requiring the prom to be > updated. > > Steve Ravet > sravet@xxx.com > Baby you're a genius when it comes to cooking up some chili sauce... I have heard this discussion of the "shortcomings" of MAP-based systems before and have always assumed that as the engine management computer observed a long-term lean condition (from the O2 sensor readings), it would adjust the injector "on" time to correct, thereby accommodating any changes to engine volumetric efficiency brought about by engine hardware modifications. In the case of a GM system, I would expect the block learn values to be above nominal (128). Is this assumption correct, or have I credited the engine computer with too much "intelligence"?? John ------------------------------ From: Markus Strobl Date: Mon, 29 Jan 1996 11:15:18 -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? What year is your car? If it's an 80s car, any autostore should have a chilton or haynes. If it's a newer car you'll probably have to order a Helm manual. The phone# should be in your owners manual. If your car is a 94+ the helm manual is a hefty $90. Markus Strobl 96 Z28 6M Black/grph. Borla, !CAGS, PEG2, QLC Dallas, Texas 1LE driveshaft, Honker, T-tops, CD, leather F-member 9/93 14.09 @xxx.5mpg @85mph ------------------------------ From: Tommy.Palm@xxx.se Date: Mon, 29 Jan 1996 14:19:19 -0500 Subject: Poweroutput to injectors Hi! I wonder if anyone here has worked with optimizing the outputstage to injectors. I need to get a outputstage that is as fast as possible and also freqvec= y linear to drive fuelinjectors. At first i thought this was no problem at= all, most people have not even digged deep into this problem. I have a 4cyl t= urbo with DIY_EFI and found that i need as fast open close time as possible. At fi= rst i tried just a freeweel diod to protect the transistor but it slowed down = the injector too much. The best thing yet was using 4 high voltage >300v transistors but they can (the ones i afford) just handle 1 Amp and the p= eak hold system needs about 2,5 amp max (tested with oscilloscope, 5.5 amp according ohms law) I testrunned it for 2 days in bench w/o destroying the transistor but it= should theoretically not last very long. I have with oscilloscope found out that 330-470uF is perfect for the pea= k current (gives 10-13 volt slope for 2ms) and 8-10ohm is optimum for the = hold current on 2,4ohms injectors (they need just 1.3 volts to open). The vol= tage drop is only <0.1v over transistor. The next best system was a capacitance paral= ell with the resistor and injector to decrease voltage over the transistor b= ut see mes too slow the opening. What i have seen on commercial low ohm inj sys= tem is condensator to cut the HV. Have anyone tried a varistor? Is the lifetime= limited? One don't want a short here (flooded cylinder)! I need injectioncycles down to 1,5 ms it was possible with HV-transistor= =2E Here is a circuit pic in windows paint of one of the tested curcuits: Thankfull for any ideas and help! I am not interested in special curcuit= s to solve this. Tommy Palm tommy.palm@xxx.se Sweden [jsg -- I deleted the bit map since it was about 1000K bytes. Please contact Tommy if you would like a copy.] ------------------------------ From: SRavet@xxx.com Date: Mon, 29 Jan 96 13:31:32 CST Subject: re: Sensor Questions? John T Stein Wrote: | | On Friday Jan 26, "SRavet" wrote the following in response to a | request to contrast MAF vs. MAP sensor-based systems: | | | | > The difference is that MAF is more complicated, but is more tolerant of | > engine modifications. MAP (or SD, speed density) use a pre-calculated | > volumetric efficiency value. Basically, rpm determines the volume of air | > moving through the engine, and the pressure determines the amount of oxygen | > in that volume. The computer then injects the proper amount of fuel. If | > you increase the breathing ability of this engine (headers or intake modes, | > etc), the computer doesn't know about it and will inject too little fuel. | > | > MAF systems are really SD based, but the computer is able to modify the | > injector on time based on the reading from the MAF sensor. It is much more | > tolerant of future engine modifications without requiring the prom to be | > updated. | > | > Steve Ravet | > sravet@xxx.com | > Baby you're a genius when it comes to cooking up some chili sauce... | | I have heard this discussion of the "shortcomings" of MAP-based | systems before and have always assumed that as the engine management | computer observed a long-term lean condition (from the O2 sensor readings), it | would adjust the injector "on" time to correct, thereby accommodating | any changes to engine volumetric efficiency brought about by engine | hardware modifications. In the case of a GM system, I would expect | the block learn values to be above nominal (128). | | Is this assumption correct, or have I credited the engine computer | with too much "intelligence"?? | | John | John, you are correct, my description above was a little simplistic. As long as the ECM is in closed loop, it will adapt (within the block learn limits). If you aren't closed loop, though, pre-programmed values are used which will result in a lean condition. Steve Ravet sravet@xxx.com Baby you're a genius when it comes to cooking up some chili sauce... ------------------------------ From: pjwales@xxx.net (peter wales) Date: Mon, 29 Jan 1996 15:38:54 -0500 Subject: Re: efi555 At 12:09 AM 1/29/96 -0600, >David J. Doddek wrote: snip > The one problem with an analog >system is that there is a large change in volumetric effeciency at low rpm >causing a rich mixture at idle in gear (automatic) and lean at low speed >cruse (30 mph) However, something like this is not a concern on a race >engine that spends a lot of time at wide open throttle. This is probably >why the race engine that the gentleman at superchips ran well. Again, the point is being missed here. The system runs very satisfactorily on all Turbo Mitsubishi's and the early cars had very rudimentary control over the pulse width at low RPMs. I am not suggesting that a system like this is the equivalent of a mapped ECU design, but it is not too far away. 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: Mon, 29 Jan 1996 20:11:55 -0500 Subject: Re: Sensor Questions? Subj: re: Sensor Questions? Date: 96-01-29 19:16:59 EST From: SRavet@xxx.com [text deleted] >| Is this assumption correct, or have I credited the engine computer >| with too much "intelligence"?? >| John > John, you are correct, my description above was a little simplistic. > As long as the ECM is in closed loop, it will adapt (within the block > learn limits). If you aren't closed loop, though, pre-programmed > values are used which will result in a lean condition. > Steve Ravet In the GM ECM's, whether you are in CL or not, the ECM is running through the same 'preprogrammed' code. Closed loop adds the ability for the BLM to learn. If not in closed loop, the BLM is still used, and if not altered by a complete power off, will still correct the fuel mixture from what it has learned. Part of the equation is: Fuel = Integrator * BLM * (rest of fuel calculation) In open loop, the integrator is set to neutral. The BLMs are whatever has been learned, so the fuel correction still goes on. One caveat is that some ECMs will check (and reset) the BLMs at ignition power on for a tighter limit than is allowed during normal operation. The same things happen when in PE, i.e., the integrator goes neutral, and the BLM is whatever has been learned. The only thing that closed loop adds is the ability to learn, and the integrator (with help) keeps the fuel about 14.7 AFR. Scot Sealander FIScot@xxx.com ------------------------------ From: Bill Date: Mon, 29 Jan 1996 21:22:45 -0800 Subject: Commercial systems Although I am keenly interested in diy_efi, the schedule of my current project requires that I purchase a commercial system. I seems that the big players are Haltech, DFI, and Electromotive. Does anybody have any experience with any of these organizations? I've spoken with them over the phone and although all seem to be knowledgable, have imparted more than a little confusion. I'm told by a competitor of Haltech, for example, that Haltech is a "bank-fired" system.....meaning that after the calculations are complete, all 4 injectors on 1 side of a V-8 are fired simultaneously, then the sequence repeats for the other side, and so on. Has anyone ever heard of such a system? I'm also wondering about how the effect of manifold vacuum or pressure affects the rate of fuel delivery, all other factors being equal. For example, if a given pulse width results in 10 #/hr of fuel with a given fuel rail pressure, does that mean "on the bench"? What happens when the same injector is spraying into a 10" or 20" Hg vacuum? Does that tend to suck extra fuel. Or what happens when the boost is run up to 20 psig? Clearly, its the pressure differential that is at issue here. And nobody seems to be talking about modulating fuel rail pressure in response to manifold conditions in an attempt to keep the pressure differential constant. Is this really an issue, or am I making this more complex than it has to be? Lastly, does anyone know of a commercial system that is soon to be retired in favor of a later model? Or does anyone have a funtional DIY_EFI for sale at this time? My parameters are as follows: Small block Chevrolet motor (377 cu in) in flat-bottom V-drive boat (2) AiResearch TO-4 turbos Powerglide Crank-driven ignition Gasoline fuel with methanol enrichment at higher power levels (>5 psig boost) 6000 RPM maximum Thanks for any and all information. William Sarkozy Kalamazoo, MI ------------------------------ From: pantera@xxx.com (David Doddek) Date: Mon, 29 Jan 1996 21:46:10 -0600 (CST) Subject: Re: efi555 >Again, the point is being missed here. The system runs very satisfactorily >on all Turbo Mitsubishi's and the early cars had very rudimentary control >over the pulse width at low RPMs. I am not suggesting that a system like >this is the equivalent of a mapped ECU design, but it is not too far away. > >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 did not mean to say that the engine would not run or that the performance would not be acceptable. What I was saying was just that the low rpm range is the area that the most noticable effect of a non mapped system will occur. The computer in my car is currently running with the map zeroed out, meaning that it operates the same as an alalog system. My only complaint is a slight rich mixture when stopped idling at low idle speeds. Using the same computer on our Formula SAE race car last year had a zero map as well and ran just fine. So don't take me to mean it won't work, because it will. I have actually hooked one up and proven it. By the way, does superchips make a chip for the T-bird SC? David J. Doddek |pantera@xxx.com Owner SGD Electronics & Development Engr for Caterpillar |h 309 685-7965 Formula SAE Team Sidewinder 94-95 |w 309 578-2931 89 T-bird SC, 69 Fairlane w/SGD EFI |fx 217 428-4686 74 Pantera w/Electromitive Tec-II Twin turbos and Nitros | Hey, If you are going to go fast, go REEEAAL FAST. | ------------------------------ From: Hadzic Muhammed <3mh31@xxx.ca> Date: Tue, 30 Jan 1996 00:40:12 -0500 (EST) Subject: Re: Commercial systems On Mon, 29 Jan 1996, Bill wrote: > Although I am keenly interested in diy_efi, the schedule of my current > project requires that I purchase a commercial system. I seems that the big > players are Haltech, DFI, and Electromotive. Does anybody have any > experience with any of these organizations? I've spoken with them over the > phone and although all seem to be knowledgable, have imparted more than a > little confusion. I'm told by a competitor of Haltech, for example, that > Haltech is a "bank-fired" system.....meaning that after the calculations are > complete, all 4 injectors on 1 side of a V-8 are fired simultaneously, then > the sequence repeats for the other side, and so on. Has anyone ever heard > of such a system? > > I'm also wondering about how the effect of manifold vacuum or pressure > affects the rate of fuel delivery, all other factors being equal. For > example, if a given pulse width results in 10 #/hr of fuel with a given fuel > rail pressure, does that mean "on the bench"? What happens when the same > injector is spraying into a 10" or 20" Hg vacuum? Does that tend to suck > extra fuel. Or what happens when the boost is run up to 20 psig? Clearly, > its the pressure differential that is at issue here. And nobody seems to be > talking about modulating fuel rail pressure in response to manifold > conditions in an attempt to keep the pressure differential constant. Is > this really an issue, or am I making this more complex than it has to be? > > Lastly, does anyone know of a commercial system that is soon to be retired > in favor of a later model? Or does anyone have a funtional DIY_EFI for sale > at this time? My parameters are as follows: > > Small block Chevrolet motor (377 cu in) in flat-bottom V-drive boat > (2) AiResearch TO-4 turbos > Powerglide > Crank-driven ignition > Gasoline fuel with methanol enrichment at higher power levels (>5 > psig boost) > 6000 RPM maximum I being fairly new to the DIY_EFI group also used it to learn more about EFI. Being in my fourth year in Mechanical Engineering at Queens University I decided to add EFI to my motorcycle. as my thesis. However, I knew I would not have time to design the electronics myself. This lead me to research various EFI companies. These included Motec, Accel, Electromotive, Haltec, Hahn Racing, RB racing, and EFI technologies. From this group I found Electromotive to be the best choise for the cost. Thier options including timing control put then at a lower cost than most competitors. Big warning about Haltec, I hear they may be going through some major restructuring there or they might be going out of business. These are only rumours I've heard. Besides they have the worst reputation of all the EFI companies I heard of. They also gave me a 8 week run around on triing to get a firm quote from them. They eventually did get me one but the run around makes me wonder about thier product support and future in the market. I have also read a lot of trash talk about then on the Formula SAE net. Many of the teams in the SAE competition like and use the Electromotive system. I did end up purchasing the Electromotive system and just recieved it in the new year. I haven't installed it yet but I hope to by the end of Feb. I have more on the systen comparisons and contacts if you need it. As for the fuel rail pressure, you can keep it constant by using a pressure regulator at the return side for the rail that is pressure regulated from the intake manifold. Bosch makes a nice one for only about 60 CND. Have par number if you need it, but you need to get an adaptor to make it pressure regulated. Let me know what type of project this is (ie educational, thesis, personnal) because most places will give educational discounts. If you need any leads on finding things I will help if I can. Muhammed Hadzic Queens University Kingston, Ontario Canada ------------------------------ From: Johnny Date: Mon, 29 Jan 1996 21:50:14 -0800 Subject: Re: Commercial systems Bill wrote: > > Although I am keenly interested in diy_efi, the schedule of my current > project requires that I purchase a commercial system. I seems that the big > players are Haltech, DFI, and Electromotive. Does anybody have any > experience with any of these organizations? I've spoken with them over the > phone and although all seem to be knowledgable, have imparted more than a > little confusion. I'm told by a competitor of Haltech, for example, that > Haltech is a "bank-fired" system.....meaning that after the calculations are > complete, all 4 injectors on 1 side of a V-8 are fired simultaneously, then > the sequence repeats for the other side, and so on. Has anyone ever heard > of such a system? > > I'm also wondering about how the effect of manifold vacuum or pressure > affects the rate of fuel delivery, all other factors being equal. For > example, if a given pulse width results in 10 #/hr of fuel with a given fuel > rail pressure, does that mean "on the bench"? What happens when the same > injector is spraying into a 10" or 20" Hg vacuum? Does that tend to suck > extra fuel. Or what happens when the boost is run up to 20 psig? Clearly, > its the pressure differential that is at issue here. And nobody seems to be > talking about modulating fuel rail pressure in response to manifold > conditions in an attempt to keep the pressure differential constant. Is > this really an issue, or am I making this more complex than it has to be? > > Lastly, does anyone know of a commercial system that is soon to be retired > in favor of a later model? Or does anyone have a funtional DIY_EFI for sale > at this time? My parameters are as follows: > > Small block Chevrolet motor (377 cu in) in flat-bottom V-drive boat > (2) AiResearch TO-4 turbos > Powerglide > Crank-driven ignition > Gasoline fuel with methanol enrichment at higher power levels (>5 > psig boost) > 6000 RPM maximum > > Thanks for any and all information. > > > William Sarkozy > > Kalamazoo, MI Want to race when you are done? I have a Steve Jones boat with FE Ford, 2 Holley Projections on a Dove tunnel ram feeding a set of Dove medium riser aluminum heads. Just got it all done. I went with the Projection units so I wouldn't have to build an intake and everything else for this one. Convenient to just throw those suckers on a conventional tunnel ram. For your app though, with the SBC and all, I would go with the Haltech unit and probably an Accel intake and air door. The reason for the Haltech recomendation is that it seems to be the best suited for a boost/methanol or nitrous injection setup. The other thing you might consider is trying Accel's newest ECU, the Sequential Spark/Fuel Management (SSFM) unit. This baby will do spark and fuel on a per cylinder basis and allows 3 separate nitrous stages with independent fuel and spark control of each, which you can use for your methanol enrichment at various boost levels. They will sell you a complete package including all the hardware, harness, ECU, and programming software. Get your Visa out and prepare to max it though. You can call there EMS division direct by calling 216-398-8300 and ask for extension 488 Mark Hammel. BTW, the unit is compatible with GM's GM-ZR-1 DI if you can find one in a junk yard somewhere, or if you wanted to really get trick, you could call Firepower and get a dumb box and 4 of there awesome coils. When you have it all together, drop me some E-mail and we will go run 'em. There aren't two many of us Flat V-drive guys left alive, or the boats either for that matter. - -j- ------------------------------ End of DIY_EFI Digest V1 #26 **************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. 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