@xxx.edu Fri Jan 6 12:24:09 1995 Date: Fri, 6 Jan 95 09:15:32 GMT @xxx.edu @xxx.za Subject: Majordomo file: list 'diy_efi' file 'archive_num_15' -- >From Diy_Efi-Owner Thu Jun 2 03:26:09 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA29041; Thu, 2 Jun 94 03:26:09 GMT Received: from knuth.mtsu.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA29035; Wed, 1 Jun 94 23:26:03 -0400 Received: by knuth.mtsu.edu (Smail3.1.28.1 #17) id m0q93PE-000AVxC; Wed, 1 Jun 94 22:25 CDT @xxx.edu> @xxx. Lusky) Subject: Re: 82c54 based computer "tachometer" To: DIY_EFI Date: Wed, 1 Jun 1994 22:25:20 -0500 (CDT) @xxx.com" at Jun 1, 94 09:07:14 am X-Mailer: ELM [version 2.4 PL23] Content-Type: text Content-Length: 1872 Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI @xxx.com writes: >A few weeks ago,the local public access channel had a "learn-at-home" mechanics > course that was being broadcast from a couple of tech schools down south. > Anyway,they were working on the crank sensor on a 3.8buick when they went into > a discussion on this very subject. Seems a lot of servicemen were forgetting > to put the shielding back on the crank/cam sense wires, and it was causing > random intermittent problems. The instructor then fired the car up without the > shielding, and showed the crank waveform on the scope. Full of spikes! The > engine was also running like crap. Shield back on, everything was fine. A lot > of the problems had to do with proximity to the coil packs. I got hit by the same thing in a Formula-SAE car last year. We were using a crank sensor from a quad-4. Engine ran great on the dyno, dropped it in the car and it would only run intermittantly... itermitant spark. Checked all of our wiring, ran new wires to the MSD just in case, still intermittant. Checked the output of the crank pickup with a scope, and it wasn't really pretty, but we had no idea what it should look like. Decided to check another crank sensor, and in the process of removing it we had to pull the coil which was mounted to the side of the car directly above the sensor. Left the coil out while we cranked, and bingo: beuatiful wave on the scope--so we figured it must have been a bad sensor :). Finally realized the problem when the car went back to its old tricks after putting the engine back together (and after sending our ECU back to the manufacturer to have them test it and spending 4 hours bench abusing (testing) our MSD). -- @xxx.edu "Turbos are nice but I'd rather be blown!" 89 Jeep Wrangler - 258 / For Sale: $8000 obo 80 Toyota Celica - 20R / 5spd >From Diy_Efi-Owner Thu Jun 2 03:35:25 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA29063; Thu, 2 Jun 94 03:35:25 GMT Received: from knuth.mtsu.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA29057; Wed, 1 Jun 94 23:35:19 -0400 Received: by knuth.mtsu.edu (Smail3.1.28.1 #17) id m0q93YD-000AW9C; Wed, 1 Jun 94 22:34 CDT @xxx.edu> @xxx. Lusky) Subject: Re: Boost detection To: DIY_EFI Date: Wed, 1 Jun 1994 22:34:37 -0500 (CDT) @xxx.com" at Jun 1, 94 02:46:15 pm X-Mailer: ELM [version 2.4 PL23] Content-Type: text Content-Length: 1426 Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI @xxx.com writes: > I need a method to detect a certain level of boost on a '91 GMC Syclone. > (P4 ECM, Turbo 4.3L) > I'm trying to design a booster (fuel)pump system that will provide added > volume when the boost is greater than 14 psi. > What I'm thinking so far is to use the MAP sensor to trigger a FET/relay > to turn on the second pump, but I'm not really sure I know what levels to > expect out of the MAP. Seems like a lot of trouble when all you need is a hobbs switchs. > Anyone have any pump recommendations? I need pump capable of at least 80 psi, > and I would prefer a high volume unit as well. 80 psi at what volume? > Also, anybody got any good ideas on how to monitor O2 output at the track? > OTC's are pretty expensive, but the only other method I can think of is a > DMM in max mode.(would get a rich indication anyway) Stoich on GM sensors is > around .4-.45 volts, correct? O2 sensors are pretty much useless except at idle and cruise. 450mV is stoich... actually about 400-500mV I guess is "damn close" to stoich. Anything roughly between 300mV and 600mV is "real close" to stoich. Anything outside of that range is inconsistant and is best interpretted as "somewhere rich" and "somehwere lean". -- @xxx.edu "Turbos are nice but I'd rather be blown!" 89 Jeep Wrangler - 258 / For Sale: $8000 obo 80 Toyota Celica - 20R / 5spd >From Diy_Efi-Owner Thu Jun 2 07:36:52 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA29317; Thu, 2 Jun 94 07:36:52 GMT Received: from relay2.geis.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA29311; Thu, 2 Jun 94 03:36:49 -0400 Received: by relay2.geis.com (1.37.109.9/15.6) id AA1519135850; Thu, 2 Jun 1994 07:36:42 GMT @xxx.com @xxx.com> Date: Thu, 2 Jun 94 00:35:00 UTC To: diy_efi Subject: Some ideas... X-Genie-Id: 2319919 X-Genie-From: P.BEAUBIEN1 Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI Hi all, I don't want to sound ignorant or anything, but what exactly is the WWW server and home page? I'm access this list through Genie, so all I really have access to is the messages (for now anyway). I've been pretty idle for the last little while on this net, partialy becuase I haven't had much to add, but mostly because I haven't had the time. Now that the list has died down a little, I thought that I'd leave a message to see if I could get some more discussions going. Should we design the system such that it is a speed density or MAF system? I think that a MAF system would be much better and easier than a speed density type, but I have seen some messages where people have stated that they wish to use a speed density system. Why? Now about sensors. Can someone suggest a car from which I could cannibalize a MAF sensor/throttle body? An arrangement that could allow a maximum of 200 hp would be plenty (for now atleast... ). Something reasonably cheap and common would be nice. I'd most likely be getting the setup from an auto recycler. Are there specs available for MAF sensor that give a current vs. mass of air curve? If I understand what I've read correctly, the computer determines the current necessary to maintain a constant temperature accross the wire in the sensor. Is this a part of the controller, or is it done automatically inside the sensor? What sort of support circuitry would be required to use a MAF sensor if it doesn't have the built in "smarts"? Now for O2 sensors. I've heard (incorrectly?) that Honda uses an O2 sensor that gives you a better idea of the mixture, rather than just rich or lean. I'm sure that it would cost quite a bit (if this puppy even exists) but I have a feeling that it would be worth the extra effort and cost to implement. Lastly, how many timing marks should the wheel (or whatever) have to provide accurate info for the computer. The article on a distributorless ignition system from PEM uses only 8 marks. At say 8000 rpm, how accurately can the computer determine the angle of the engine, and how accurate does it need to be? One degree? Two? Would it be better to have many marks, say each representing 2 crank degrees, so that the computer doesn't have to constantly calculate the speed of the engine? Instead, all that you would have to do is tell it to count so many marks from a known positition, activate injector number 1 for x number of counts (depending on MAF and RPM etc), count Z many more marks, fire coil, repeat for next cylinder, etc... Which would require less processing power? I have a feeling that up to a certain point (RPM wise), one would be better than the other. Does any of this make any sense, or am I way out in left field playing my own little ball game? Thanks, Matt. >From Diy_Efi-Owner Thu Jun 2 14:12:54 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA00203; Thu, 2 Jun 94 14:12:54 GMT Received: from hwking.cca.rockwell.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA00197; Thu, 2 Jun 94 10:12:52 -0400 Received: by hwking.cca.rockwell.com (5.65/DEC-Ultrix/4.3) id AA03953; Thu, 2 Jun 1994 09:12:49 -0500 Received: by ohura.cca.rockwell.com (5.65/DEC-Ultrix/4.3) id AA05196; Thu, 2 Jun 1994 09:12:02 -0500 @xxx.com> To: DIY_EFI Subject: Re: Boost detection In-Reply-To: Your message of "Wed, 01 Jun 94 22:34:37 CDT." @xxx.edu> Date: Thu, 02 Jun 94 09:12:01 -0500 @xxx.com X-Mts: smtp Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI @xxx. writes: >Seems like a lot of trouble when all you need is a hobbs switchs. I wanted to try to use something that was already there. The aftermarket kits use a hobbs switch, but it requires cutting a tube and installing a fitting, and I really didn't want to hack anything up. Maybe I can find a test guage plug somewhere. >> Anyone have any pump recommendations? I need pump capable of at least 80 psi, >> and I would prefer a high volume unit as well. >80 psi at what volume? All I can get. :) Actually, I'm still trying to find out the specs from the Syclone guys. There is an aftermarket kit out that basically parallels two stock units, with the second pump being activated at 14 psi by the hobbs. I want more volume capability and I think I can find a stock pump from some other vehicle much cheaper. The only question I have is finding a pump that can keep up with 19 psi boost. >O2 sensors are pretty much useless except at idle and cruise. They can give you at least a binary rich/lean indication, which is better than nothing. As far as telling you "how rich", I can't say I really care. Sure, it would be nice to have a perfectly linear device that would allow you to have some sort of an accurate tuning equation, but I can live without it. I heard the 4-wire heated sensors were closer to being linear. Comments? Dig @xxx.com >From Diy_Efi-Owner Sat Jun 4 04:00:20 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA09204; Sat, 4 Jun 94 04:00:20 GMT Received: from eigen.ee.ualberta.ca by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA09198; Sat, 4 Jun 94 00:00:18 -0400 @xxx.edu> Received: by eigen.ee.ualberta.ca (1.37.109.4/15.6) id AA15360; Fri, 3 Jun 94 22:00:10 -0600 @xxx.ca> Subject: Re: Boost detection To: DIY_EFI Date: Fri, 3 Jun 94 22:00:09 MDT @xxx.com" at Jun 02, 94 9:12 am Mailer: Elm [revision: 70.85] Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI > They can give you at least a binary rich/lean indication, which is better > than nothing. As far as telling you "how rich", I can't say I really care. > Sure, it would be nice to have a perfectly linear device that would allow > you to have some sort of an accurate tuning equation, but I can live without > it. > > I heard the 4-wire heated sensors were closer to being linear. Comments? > Standard O2 sensors actually are almost useless unless you use it to run an oscillating control system. They don't give very accurate readings unless you oscillate them, for some reason. The output of the O2 sensor depends highly on temperature, which can change a lot. THe SAE readings on sensors for the past 20 years is a great place to get an idea of how they work. Some '4-wire' sensors are just heated ones... you have to get the correct 'pump' type O2 sensors. These often have 5 or 6 wires on them... check a Honda Civic SI. These use the sensor, and it costs about $400. It also needs some wierd driver circuit, which I haven't tried yet... -Dale >From Diy_Efi-Owner Sat Jun 4 04:31:08 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA09254; Sat, 4 Jun 94 04:31:08 GMT Received: from eigen.ee.ualberta.ca by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA09248; Sat, 4 Jun 94 00:31:06 -0400 @xxx.edu> Received: by eigen.ee.ualberta.ca (1.37.109.4/15.6) id AA15476; Fri, 3 Jun 94 22:31:04 -0600 @xxx.ca> Subject: Re: Some ideas... To: DIY_EFI Date: Fri, 3 Jun 94 22:31:02 MDT @xxx.com" at Jun 2, 94 12:35 (midnight) Mailer: Elm [revision: 70.85] Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI > type, but I have seen some messages where people have stated that they wish > to use a speed density system. Why? S-D is more reliable. You also need to calibrate both of them, no matter what, since MAF has to calculate reversion. > mass of air curve? If I understand what I've read correctly, the computer > determines the current necessary to maintain a constant temperature accross > the wire in the sensor. Is this a part of the controller, or is it done > automatically inside the sensor? What sort of support circuitry would be > required to use a MAF sensor if it doesn't have the built in "smarts"? A GM MAF sensor gives a frequency output, which can be measured using an input capture function on the 68HC11. > > Now for O2 sensors. I've heard (incorrectly?) that Honda uses an O2 sensor > that gives you a better idea of the mixture, rather than just rich or lean. > I'm sure that it would cost quite a bit (if this puppy even exists) but I > have a feeling that it would be worth the extra effort and cost to implement. It costs about $400 Canadian, and uses a wierd driver circuit. I don't know exactly how it works.... > Lastly, how many timing marks should the wheel (or whatever) have to provide > accurate info for the computer. The article on a distributorless ignition > system from PEM uses only 8 marks. At say 8000 rpm, how accurately can the > computer determine the angle of the engine, and how accurate does it need to > be? One degree? Two? Would it be better to have many marks, say each > representing 2 crank degrees, so that the computer doesn't have to > constantly calculate the speed of the engine? Instead, all that you would > have to do is tell it to count so many marks from a known positition, > activate injector number 1 for x number of counts (depending on MAF and RPM > etc), count Z many more marks, fire coil, repeat for next cylinder, etc... > Which would require less processing power? I have a feeling that up to a > certain point (RPM wise), one would be better than the other. If you know the speed of the engine, degrees can be translated into timer ticks, which is how most engine computers do it. For example, a timer tick is 250 usec on my ECM, so if it takes 12000 timer ticks per cylinder on a 4-cylinder.... well, you can easily figure out speed with a division, and the spark angle is translated to, perhaps, 10000 ticks after the first reference. If you want to use a 68332 processor, you *could* use a degree wheel, becuase in a 68HC11, the processing overhead of too many ticks can get heavy. I found that more than 8 ticks per revolution tends to slow things down too much. > > Does any of this make any sense, or am I way out in left field playing my > own little ball game? You sound like you're kinda on the right track. The biggest thing is different processors have different timers, so the HC11, which is useful for almost all ECM needs, lacks in here... the 68332 series looks NICE. I was going to try one... -Dale >From Diy_Efi-Owner Tue Jun 7 06:08:39 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA18616; Tue, 7 Jun 94 06:08:39 GMT Received: from relay2.geis.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA18610; Tue, 7 Jun 94 02:08:36 -0400 Received: by relay2.geis.com (1.37.109.10G/15.6) id AA039519310; Tue, 7 Jun 1994 06:08:30 GMT @xxx.com @xxx.com> Date: Tue, 7 Jun 94 05:50:00 UTC To: diy_efi Subject: Re: Some ideas... X-Genie-Id: 2394086 X-Genie-From: P.BEAUBIEN1 Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI Dale, > S-D is more reliable. You also need to calibrate both of them, no matter > what, since MAF has to calculate reversion. Isn't S-D a lot more complicated to calibrate (ie. map)? Reversion is when you basically get a standing wave in the intake or exhuast pipes, correct? You'd have to account for that in a SD system as well, correct? Does reversion show up as a dip on a VE graph of an engine? > A GM MAF sensor gives a frequency output, which can be measured using an > input capture function on the 68HC11. > What other smarts are built into this GM MAF sensor. I take it not all GM's use this type of MAF sensor. Do you know which ones do? Is the frequency directly proportional to the amount of air passing through? > If you know the speed of the engine, degrees can be translated into > timer ticks, which is how most engine computers do it. For example, a > timer tick is 250 usec on my ECM, so if it takes 12000 timer ticks per > cylinder on a 4-cylinder.... well, you can easily figure out speed with > a division, and the spark angle is translated to, perhaps, 10000 ticks > after the first reference. How accurate is this when the engine is accelerating? I guess good enough. It sounds like you've built a little something; can you share what you've done? > If you want to use a 68332 processor, you *could* use a degree wheel, > becuase in a 68HC11, the processing overhead of too many ticks can get > heavy. I found that more than 8 ticks per revolution tends to slow > things down too much. Which are you using? So you think that it's better to have a few (say 4) ticks/rev and interpolate the position of the engine rather than have a bunch of ticks/rev knowing basically where the engine is. > You sound like you're kinda on the right track. The biggest thing is > different processors have different timers, so the HC11, which is > useful for almost all ECM needs, lacks in here... the 68332 series > looks NICE. I was going to try one... What I'd like to do is hook up the sensors on the engine and then be able to monitor them. Then I'd get into have a microprocessor actually control bits and pieces until it can handle most everything. Once I get some sensors connected etc., I'll think more about which processor I'll use. Thanks for your help. Matt. >From Diy_Efi-Owner Tue Jun 7 16:09:29 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA21150; Tue, 7 Jun 94 16:09:29 GMT Received: from localhost.eng.ohio-state.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA21144; Tue, 7 Jun 94 12:09:27 -0400 @xxx.edu> To: DIY_EFI Subject: EMI and logic families Date: Tue, 07 Jun 94 12:09:26 -0400 From: John S Gwynne Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI -------- Before I start construction of my CPU board for my engine controller, I'm interested in the experience that others have had with EMI. past experience: I have used the HCT logic family IC's with no problems even within a foot of an MSD 6 without the optional "noise" filter. I have been using wire-wrap with no ground plane and no additional shielding. Unfortunately, these devices are sloooooow.... I have also used National Semiconductor's GALs, but I have had EMI problems with these. I found that wires of more than 3 or 4 inches in length would pick-up enough noise (what appears to be energy above 100MHz) to "screw things up". I would think that a ground plane and a shielded enclosure would cure this, but since I'm working on a first generation proto-type I've elected to slow the devices by simply adding series resistance right at the input pins (I did not need the speed; just the convenience of a GAL). This seems to work an does not obscure access to the boards. new concerns: I now want to add a semi-fast 16-bit CPU using ALS, GAL, and maybe even AS. This is going to be tough to build via wire-wrap in the first place let alone in the presents of a MSD ignition module. My question to the group: Have other encounter similar problems? Has anyone used ALS or AS with a MSD ignition module nearby? What have you built and what logic families have you used? How much shielding? John S Gwynne @xxx.edu _______________________________________________________________________________ T h e O h i o - S t a t e U n i v e r s i t y ElectroScience Laboratory, 1320 Kinnear Road, Columbus, Ohio 43212, USA Telephone: (614) 292-7981 * Fax: (614) 292-7292 ------------------------------------------------------------------------------- >From Diy_Efi-Owner Tue Jun 7 17:33:41 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA21561; Tue, 7 Jun 94 17:33:41 GMT Received: from stdvax.gsfc.nasa.gov by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA21555; Tue, 7 Jun 94 13:33:39 -0400 Date: Tue, 7 Jun 1994 13:32:02 -0400 (EDT) @xxx.GOV (DIRK BROER) @xxx.GOV> Subject: Re: EMI To: DIY_EFI X-Vmsmail-To: @EFI Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI >My question to the group: > >Have other encounter similar problems? Has anyone used ALS or AS with a MSD >ignition module nearby? What have you built and what logic families have you >used? How much shielding? Well I have used AS or ASL chips with a cicuit built on a perf board by a professional technition. The chips in quest where 54XX series. We need a quick way to convert 1773 (fiber optic) to 1553 (tri-state broadcast bus). Not only did the AS chips prove to be noisy - they actually changed output state so fast - due to nose spike etc. - that the fiber optic transmitters would latch due to a high pulse and never unlatch do to the negative going half of the pulse. These chips also seemed to be very sensative and as a comparator any little ripple was likely to cause a large response. Basically they added noise to the circuit. Since we were only worried about signals at about 1M Hz a switch to HC chips was all that was needed. FYI 54xx series logic is the mil spec version of 74XX logic. I suspect that rather than a high speed cpu, you might want to consider off -loading some of the calculations. For example - frequency counting. So you get a high accuracy clock.. divide down the output frequencies so that you have a 1Hz clock to gather slow data and maybe a 1K Hz clock to gather fast data. At the pulse you latch whatever data is there (and maybe reset the counters). The cpu can then read the latched data at is leasure and make adjustments accordingly. Dirk ÿ