DIY_EFI Digest Monday, March 27 2000 Volume 05 : Number 125 In this issue: Re: Measuring weight Custom PCM & Injectors Questions Re: O2 sensor response times O2 sensor response times Re: O2 sensor response times Re: Cheap protection... Re: Cheap Protection ... Sorry to do this but...Attn: Scott Uecker Re: MAP sensing for IR systems Re: 8051 EFI Fuel pressure waring light Re: O2 sensor response times Re: 8051 EFI Re: Fuel pressure waring light Re: O2 sensor response times Re: 8051 EFI Re: O2 sensor response times aftermarket ecu etc... Re: aftermarket ecu etc... Re: O2 sensor response times Re: DIY_EFI Digest V5 #122 See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Mon, 27 Mar 2000 08:10:21 -0500 From: "nacelp" Subject: Re: Measuring weight 1% accuracy, would seem plenty close to me. What are you doing that needs such fine resolution of vehicle weight?. Maybe "overkill", here?. Grumpy > In all of the calculating and figuring for the fuel injection system I > came across a little problem. I need an accurate way to measure the > bike. I got a rough idea by putting each wheel on a bathroom scale and > adding the results (366 pounds wet, roughly 25 pounds less than stock :) > However, I'm not happy with that setup since it's only accurate to about > 2-3 pounds (assuming the scale's right) and a pain in the ass to set up. > Anyone know where I could find some kind of gizmo that converts weight > to voltage accurately? I'd like to interface the whole thing to an LCD > that displays the individual weight of each wheel, the total weight, and > the weight distribution. A stamp or Oopic should do that easy. > -- > Steve > 97 Chevy Camaro Z28, Mystic teal, A4, not stock > 90 Kawasaki EX500A4, black, M6, not even CLOSE to stock! > lt1_z28@xxx.net/~lt1_z28 > Aluminum, steel, carbon fiber, titanium, and two cast iron balls. > McMillan Motorsports- http://www.mmsbikes.com > -------------------------------------------------------------------------- - -- > To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) > in the body of a message (not the subject) to majordomo@xxx.org > - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Mon, 27 Mar 2000 08:02:17 From: Bob Tom Subject: Custom PCM & Injectors Questions Hi, all. I have a custom programmed PCM which, among other things, is calibrated to run 30# injectors. I am currently running the custom PCM with the stock 19#. Checking readouts during street and track driving conditions from an OTC scanner seem to indicate that everything is aok in both closed and open loops although on the rich side. Generally, are there any effects on the life expectancy of running the stock injectors with this PCM? I've tried 24# injectors but experience serious bogging under WOT. Also, the computer has been programmed to remove all delays. I do not have any idea what delays are being referred to. What are possible delays that can be removed? Thanks very much for any insights that you may have. Bob (retired) - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Mon, 27 Mar 2000 08:21:38 -0500 From: "nacelp" Subject: Re: O2 sensor response times I don't know the time response, but there have been claims made that they can respond to individual cylinders at 6,000 RPM (v-8) Grumpy > This has probably been asked before - but as I can't access the archives at > the moment, so... > what is the typical response time for these lambda sensors ? > Regards, Paul. - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Mon, 27 Mar 2000 14:26:30 +0100 From: Corner Paul Subject: O2 sensor response times > Hi > > This has probably been asked before - but as I can't access the archives > at the moment, so... > what is the typical response time for these lambda sensors ? > > Regards, Paul. - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Mon, 27 Mar 2000 07:32:21 -0700 From: bearbvd@xxx.net (Greg Hermann) Subject: Re: O2 sensor response times >Hi > >This has probably been asked before - but as I can't access the archives at >the moment, so... >what is the typical response time for these lambda sensors ? > >Regards, Paul. One of the NTK WBO2 pump type sensors is generally capable of picking up a misfire on a V-8 at 3000 rpm---so pretty quick for these! Greg - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Mon, 27 Mar 2000 23:14:04 From: "Mike (Perth, Western Australia)" Subject: Re: Cheap protection... At 11:04 PM 26/3/2000 -0800, you wrote: >GM uses the 4049 in their older ECMs to buffer "switch" type inputs. >They also use a 100K series resistor, a signal diode to VCC, and a small >filter capacitor (perhaps 1000pF). The switch inputs also have a 1200 >ohm resistor to either ground or the 12V battery voltage. The 1200 ohm >is before the 100K series resistor. Look at: > http://www.cruzers.com/~ludis/1227170sheet3.gif OK, its good to know there are CMOS devices which diverge a little and sidestep that particular latchup problem, lets hope all the variants from different manufacturer's share that feature, Thanks but, I still don't feel comfortable using Vcc as a sink, a 'dirty' dedicated sink which bleeds back to Vcc via the reg should be OK though. Used that on an inverter where we drove the core with a heap of noise to get maximum efficiency - sometime before EMC issues became a problem... Tah for that feedback, Rgds :) Mike - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Mon, 27 Mar 2000 10:05:28 -0500 From: David Rhoads Subject: Re: Cheap Protection ... - -------------------------------------------------------------------- Date: Sun, 26 Mar 100 19:35:34 +0800 (WST) From: Bernd Felsche Subject: Re: Cheap protection... snip ... Well, I'm not measuring analogue voltages. But I will see a total of about 60A fused potential from the battery if I'm not careful. Clipping the input voltage is the trick I've been looking for. A 5-cent signal diode is an attractive option. - -------------------------------------------------------------------- After the series resistor and diode clamps, try feeding the switched signal into a MAX6818 for debouncing. This will prevent the need to do it in software. - -- . David Rhoads II . Applied Dynamics International . 3800 Stone School Road, Ann Arbor, Mi 48108 . (734) 973-1300 . rhoads@xxx.com - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Mon, 27 Mar 2000 12:31:26 -0600 From: "BOWEN, SCOTT M. (JSC-CC)" Subject: Sorry to do this but...Attn: Scott Uecker I tried to send you my Nissan EPROM Editor, but it is too big and your E-mail Account keeps rejecting it... Do you have another account I can try? Scott Bowen Bastard Motorsports Engineering Houston, TX 281-244-9669 - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Mon, 27 Mar 2000 14:10:46 -0500 From: "nacelp" Subject: Re: MAP sensing for IR systems Speaking in the realm of GM ecms: MAF, in some applications, maybe. The only real problem with MAF is the lag of the wire changing temps, and the correction for that. MAP, shouldn't be a problem, unless you run into problems filtering it, then Alpha-N. To me Aplha-N's are just for when you run out of camshaft manners at idle, and the transistion off idle. Once ya get over 1,500 in just about any engine, you should be able to read a MAP well enough to get a handle on things. It's the low speed sesitivity that gives you problems, not the lack of it. There are two items here, the electronics of the matter, and the mechanicals. You need to filter, both to some degree. The Apha-N, is the poorest of lot, since it doesn't even do that. Then if your running a vac referenced regulator, you got another bucket of worms to resolve. Having a foot or so of 1/16", or 1/8", for a tieing things together, isn't going to make or break the system, IMHO. Bruce > >MAP and MAF just aren't fast enough. - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Mon, 27 Mar 2000 19:30:44 +0100 From: Paul Corner Subject: Re: 8051 EFI Hi Mike The flavour of 8051 is the Siemens 80C515 - 8 channels of 8 bit AD Serial interface & baud rate clock, 3 16 bit counter/timers one with 4 capture/compare inputs. Plus the usual IO ports. It may not be everyones cup of tea - It seemed to be the best choice at the time. At least being an 8051 core, the programming tools are cheap or even free. I never had plans to 'go into production' too many others chasing after a niche market. I just wanted a couple of boards for myself and someone else who had said they wanted one. The local PCB house made some up, plus a couple to cover possible rejects. When I collected them, a zero defect gave me six boards, and as this 'someone' didn't collect, I still have them all. With two coil drivers and six injector or relay drivers on board, plus a small scratch pad area - I would like to think it will do for engine management. Just got to get the software running right. Interested ? Regards, Paul. On Mon, 27 Mar 2000, you wrote: > Paul Corner mentioned a home built EFI project: (complete quotation below) > > >I've been playing around with . . . > . . . ending up with a 12MHz 8051 based design. > WWhat state of play are others at ? > > > Hi, Paul, > I have an application in mind for a custom ECU, myself. I'm curious just > _which_ '8051' you have chosen. I have a so-far unused Dallas > "Speed It uP" (Dallas' own pun) DS80C320, which is, as it sounds, a fancy > 8032, but with a high clock speed and reduced clock-cycles per instruction. > After a bit of (attempted!) rational thought, I have considered strongly > using a Motorola processor (designed for the application), if not the > (totally irrational?) Infineon AUDO TC1775 TriCore, which is also aimed at > engine management (just plain 'heavy sand' - fun). > > A "batch of boards", you wrote; is this an idea for production? > > What's your application? > > Mike - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Mon, 27 Mar 2000 14:03:53 -0600 From: "Clint S." Subject: Fuel pressure waring light I would like to install a fuel pressure idiot light, I have a turbo and would like to know if pressure drops off at high boost . - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Mon, 27 Mar 2000 12:47:03 -0800 From: garwillis@xxx.com (Garfield Willis) Subject: Re: O2 sensor response times On Mon, 27 Mar 2000 07:32:21 -0700, bearbvd@xxx.net (Greg Hermann) wrote: >On Mon, 27 Mar 2000 14:26:30 +0100, Corner Paul >wrote: > >>> This has probably been asked before - but as I can't access the archives >>> at the moment, so... >>> what is the typical response time for these lambda sensors ? >One of the NTK WBO2 pump type sensors is generally capable of picking up a >misfire on a V-8 at 3000 rpm---so pretty quick for these! This is an interesting question. As Dr. Pelican and Greg have mentioned (in the original NTK article, they give these same numbers for misfire detection on an I-4), there are some "varying claims". If you add in the high-end meter mfg's specs for response time (I remember seeing one claim 0.05secs!; ECM Inc says their NTK-based boxe$ response time is "<150ms", while curiously NTK doesn't spec the response time of their own blue box system/interface), so you've got all kinds of all-over-the-place specs. Even in the NTK article, there seem to be potentially conflicting numbers; in one place, they show the response time for AFR deltas/excursions of around +-4AFR, and show these response times in the several hundreds of milliseconds! Then, in discussing the ability to detect misfires (seeing the lean excursion that occurs from one cyl's mix not burning), they show blips in the sensor's outputs that are as narrow as say <100ms, and conclude from that "...by using the lean signal [the lean excursion blips I mentioned prior] with the ign timing signal, the misfired cylinder also can be distinquished". How this all corresponds to picking out misfires at 3-4kRpm I'm still unclear on. The numbers just don't seem to match up. Add to this, the diagram they (NTK) give for their misfire test setup shows all four exhausts collected and then the AFR being measured *downstream* just prior to the cat. Thus, there is definitely some gas mixing. Remember that mass transport (exh gas movement) occurs at a much slower speed than pressure wave propagation, so just because the exhaust puffs indeed have a distinct and sharp delineation in pressure, gotta consider that in a manner akin to waves propagating in the ocean, the pressure phenom may be very distinct along with considerable mixing/diffusion of the mass of the media taking place as it transports downstream. As an extreme example of this phenom, consider the flow at the end of the tailpipe, where even tho the pressure pulses from each cylinder are still clearly distinct, the individual mixture packets from each cylinder are by then pretty thoroughly mixed/averaged. Having given all those caveats, what seems to be universally accepted is that these sensors are indeed noticeably faster than say the older HEGOs like the LSM-11s (Frank Parker showed me an example where his NTK box caught a funny rich blip/excursion on his Typhoon when you quickly released the throt, but IIRC, his LSM-based equipment misses that excursion...correct me if I err here FP). And what's probably most important, they DO seem to be fast enough to catch any possible mixture excursions that present EFI controllers can produce. Hardly a "spec", but reassuring nevertheless. We just haven't had time to set up an apparatus to do our own response time testing, but I can tell you that EGOR does absolutely NO smoothing or averaging of the sensor output, so whatever the bandwidth of the sensor itself is, you're getting/seeing all of it at the output of our electrics. I have no way of knowing if this is true for other mfgs. If I had to guess from the mongrel mix of specs, the response time is probably somewhere between 100-200ms. Just a swag, tho. Gar - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Mon, 27 Mar 2000 12:47:08 PST From: "mike mager" Subject: Re: 8051 EFI [see my reply about halfway down] >From: Paul Corner >Reply-To: diy_efi@xxx.org >To: diy_efi@xxx.org >Subject: Re: 8051 EFI >Date: Mon, 27 Mar 2000 19:30:44 +0100 >Hi Mike >The flavour of 8051 is the Siemens 80C515 - 8 channels of 8 bit AD Serial >interface & baud rate clock, 3 16 bit counter/timers one with 4 >capture/compare inputs. Plus the usual IO ports. It may not be everyones >cup of tea - It seemed to be the best choice at the time. At least being an >8051 core, the programming tools are cheap or even free. >I never had plans to 'go into production' too many others chasing after a >niche market. I just wanted a couple of boards for myself and someone else >who had said they wanted one. The local PCB house made some up, plus a >couple to cover possible rejects. When I collected them, a zero defect gave >me six boards, and as this 'someone' didn't collect, I still have them all. >With two coil drivers and six injector or relay drivers on board, plus a >small scratch pad area - I would like to think it will do for engine >management. Just got to get the software running right. >Interested ? - -------------> begin my reply <------------ Very intersting! Yes, I am always interested in what somebody can think of, and get to function; and, no (probably) not interested in getting one (yet), but I'm not even sure . . . [Those aren't puns - I _hate_ puns!] When I subscribed to the '332 list, I was just a bit too late into the '332 project, and by the time I had thought it over, the group buy was closed. Is yours oriented to a four-cylinder engine? I really need to do some planning on the whole EFI matter! I drive a carb'd vehicle - with an integral intake manifold! - so hacking an ECM on my 'daily driver' is out. My 'big project' engine is not even in hardware yet (design only). Maybe I do want to scratch-build my own; wouldn't be 'better' than any other, but it would be optimised for my application (yeah, right, buddy), and I would know the 'why' of every little detail. Some of us have a drive to do that! (you know) On the software, no major snag, I hope? Thanks, Mike - -------------> end my reply <------------------- >Regards, Paul. > > >On Mon, 27 Mar 2000, you wrote: > > Paul Corner mentioned a home built EFI project: (complete quotation >below) > > > > >I've been playing around with . . . > > . . . ending up with a 12MHz 8051 based design. > > WWhat state of play are others at ? > > > > > > Hi, Paul, > > I have an application in mind for a custom ECU, myself. I'm curious >just > > _which_ '8051' you have chosen. I have a so-far unused Dallas > > "Speed It uP" (Dallas' own pun) DS80C320, which is, as it sounds, a >fancy 8032, but with a high clock speed and reduced clock-cycles per >instruction. After a bit of (attempted!) rational thought, I have >considered strongly using a Motorola processor (designed for the >application), if not the (totally irrational?) Infineon AUDO TC1775 >TriCore, which is also aimed at engine management (just plain 'heavy sand' >- fun). > > A "batch of boards", you wrote; is this an idea for production? > > What's your application? > > Mike ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Mon, 27 Mar 2000 13:05:20 PST From: "mike mager" Subject: Re: Fuel pressure waring light Clint S. said: >I would like to install a fuel pressure idiot light, I have a turbo and >would like to know if pressure drops off at high boost . Sure, but do you need a computer to do it?! What precision, accuracy, resolution, are you considering? Mike ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Mon, 27 Mar 2000 16:29:44 -0600 From: Gary Peyton Subject: Re: O2 sensor response times First, let me say that I'm a complete novice in here bumping around trying to learn enough about EFI to play around with/modify/replace the unit on my Datsun 280ZX, so this may be a stupid question.... I had read somewhere that the response time of the platinized zirconia sensors was 2-3 seconds, and that was one reason why they werent very good for close engine management during acceleration (along with the way the L-jetronic system used that information). If a sensor like the LAF O2-pump type sensor employs 2 of these, how can its reponse time be any better? Maybe I'm suffering under a misconception here, since the www.tech2tech.net discussion says that "A good O2 sensor will usually module several cycles per second.". Are they referring to a simple one-wire zirconia sensor? Please correct my thinking, because I'm here to learn, and starting to think about buying parts to play with. Thanks, Gary Peyton At 12:47 PM 03/27/2000 -0800, you wrote: >On Mon, 27 Mar 2000 07:32:21 -0700, bearbvd@xxx.net (Greg Hermann) >wrote: > >>On Mon, 27 Mar 2000 14:26:30 +0100, Corner Paul >>wrote: >> >>>> This has probably been asked before - but as I can't access the archives >>>> at the moment, so... >>>> what is the typical response time for these lambda sensors ? > >>One of the NTK WBO2 pump type sensors is generally capable of picking up a >>misfire on a V-8 at 3000 rpm---so pretty quick for these! > >This is an interesting question. > >As Dr. Pelican and Greg have mentioned (in the original NTK article, >they give these same numbers for misfire detection on an I-4), there are >some "varying claims". If you add in the high-end meter mfg's specs for >response time (I remember seeing one claim 0.05secs!; ECM Inc says their >NTK-based boxe$ response time is "<150ms", while curiously NTK doesn't >spec the response time of their own blue box system/interface), so >you've got all kinds of all-over-the-place specs. Even in the NTK >article, there seem to be potentially conflicting numbers; in one place, >they show the response time for AFR deltas/excursions of around +-4AFR, >and show these response times in the several hundreds of milliseconds! >Then, in discussing the ability to detect misfires (seeing the lean >excursion that occurs from one cyl's mix not burning), they show blips >in the sensor's outputs that are as narrow as say <100ms, and conclude >from that "...by using the lean signal [the lean excursion blips I >mentioned prior] with the ign timing signal, the misfired cylinder also >can be distinquished". How this all corresponds to picking out misfires >at 3-4kRpm I'm still unclear on. The numbers just don't seem to match >up. Add to this, the diagram they (NTK) give for their misfire test >setup shows all four exhausts collected and then the AFR being measured >*downstream* just prior to the cat. Thus, there is definitely some gas >mixing. Remember that mass transport (exh gas movement) occurs at a much >slower speed than pressure wave propagation, so just because the exhaust >puffs indeed have a distinct and sharp delineation in pressure, gotta >consider that in a manner akin to waves propagating in the ocean, the >pressure phenom may be very distinct along with considerable >mixing/diffusion of the mass of the media taking place as it transports >downstream. As an extreme example of this phenom, consider the flow at >the end of the tailpipe, where even tho the pressure pulses from each >cylinder are still clearly distinct, the individual mixture packets from >each cylinder are by then pretty thoroughly mixed/averaged. > >Having given all those caveats, what seems to be universally accepted is >that these sensors are indeed noticeably faster than say the older HEGOs >like the LSM-11s (Frank Parker showed me an example where his NTK box >caught a funny rich blip/excursion on his Typhoon when you quickly >released the throt, but IIRC, his LSM-based equipment misses that >excursion...correct me if I err here FP). And what's probably most >important, they DO seem to be fast enough to catch any possible mixture >excursions that present EFI controllers can produce. Hardly a "spec", >but reassuring nevertheless. We just haven't had time to set up an >apparatus to do our own response time testing, but I can tell you that >EGOR does absolutely NO smoothing or averaging of the sensor output, so >whatever the bandwidth of the sensor itself is, you're getting/seeing >all of it at the output of our electrics. I have no way of knowing if >this is true for other mfgs. > >If I had to guess from the mongrel mix of specs, the response time is >probably somewhere between 100-200ms. Just a swag, tho. > >Gar > > >---------------------------------------------------------------------------- >To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) >in the body of a message (not the subject) to majordomo@xxx.org > ====================================================================== Gary R. Peyton Senior Professional Scientist Watershed Science Section Illinois State Water Survey Illinois Department of Natural Resources (217) 333-5905 FAX (217) 333-6540 =================================================================== - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Mon, 27 Mar 2000 22:23:49 +0100 From: Paul Corner Subject: Re: 8051 EFI Hi Mike My toy is based around a Renault Alpine 1400cc cross flow - originally fitted with some horrible down draught carb. Ran it for a couple of years with a pair of Webber DCOE's. Then some 'erb told me that fuel injecting that lump was immpossible period. So I rigged up some throttle flaps, one for each cylinder, and breadboarded a simple control based on the SSI 67F687. It ran, eventually. But since the chip never made it to the market, it was time to have a rethink. Picked up a 4 wire Lambda sensor today - so once I've added a boss to the exhaust pipe, I can play around with a closed loop control. More questions - differential input buffer, input impedance, low pass filter, cut off frequency... I suppose suck it and see. Wonder how far down stream I need to mount the sensor on a 4-into-1 exahuast.... As far as the software goes, most of the problems I have can be put down to the fuel map - at the moment, a best guess data. With a lambda sensor, I hope to have a self teach mode. Communication with a laptop is one area that needs to be sorted. Then I can have a go at the ignition system - some bright spark will tell me it can't be done. So there you have it, four sequential injectors and two coils on a 100x160mm board. Still interested ? Regards, Paul. > Very intersting! Yes, I am always interested in what somebody can think of, > and get to function; and, no (probably) not interested in getting one (yet), > but I'm not even sure . . . > > [Those aren't puns - I _hate_ puns!] > > When I subscribed to the '332 list, I was just a bit too late into the '332 > project, and by the time I had thought it over, the group buy was closed. > Is yours oriented to a four-cylinder engine? I really need to do some > planning on the whole EFI matter! I drive a carb'd vehicle - with an > integral intake manifold! - so hacking an ECM on my 'daily driver' is out. > My 'big project' engine is not even in hardware yet (design only). Maybe I > do want to scratch-build my own; wouldn't be 'better' than any other, but > it would be optimised for my application (yeah, right, buddy), and I would > know the 'why' of every little detail. Some of us have a drive to do that! > (you know) > > On the software, no major snag, I hope? - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Mon, 27 Mar 2000 15:36:20 -0800 From: garwillis@xxx.com (Garfield Willis) Subject: Re: O2 sensor response times On Mon, 27 Mar 2000 16:29:44 -0600, Gary Peyton wrote: >I had read somewhere that the response time of the platinized zirconia >sensors was 2-3 seconds, and that was one reason why they werent very good >for close engine management during acceleration (along with the way the >L-jetronic system used that information). Ahh, this allows me to clear up a possible mistake I made a few posts ago when Mike "tah" M. asked about a "platinum O2 sensor". AFAIK, the platinum is just used to provide the metallic connection between the ZrO2 material and wiring to the sensor. It's probly vacuum-deposited onto the outsides of the layers of ZrO2 that make up a sensor, giving a metallic area that can be wired to. Don't quote me, I'm not a physical chemist; there might indeed be other electro-chemical reasons as well why platinum is the material of choice, but it appears from diagrams on how most all ZrO2 sensors are built, that the platinum IS the metallic/electrical connection to the ZrO2 substrate. In the real world, you're likely to see anything from 2Hz to 0.5Hz stoich-crossing frequency. 3 seconds is getting on the slow side. >Maybe I'm suffering under a misconception here, since the www.tech2tech.net >discussion says that "A good O2 sensor will usually module several cycles >per second.". Are they referring to a simple one-wire zirconia sensor? Yeah, sorta. What's in view there is the overall cycle-time of the control loop in closed-loop mode. From the time the controller sees the measured mixture is lean of stoich, till it increases the injector pulse-widths, till the time the mixture passes from lean thru stoich to rich of stoich, and the sensor now says "we're rich", and the cycle starts over again. Ordinary switch-type O2 sensors/controllers all work this way, be they one, two, or heated 4-wire (there are some wideband 4-wire sensors, but I'm of course leaving them out of the switch-type category). Obviously one of the parameters in the phase-lag of this feedback loop is how far from the combustion chamber in *time*, the O2 sensor actually sits. Transport delay of the gases to the sensor, has to be added to the sensor and controller delays. Also, one of the key aging/contamination phenom of all these sensors is that they become sluggish in their response to changes in exh gas. This will slow down cycle-time of the controller also, of course, because it will take longer for the sensor to SEE the mixture change that the injectors are providing, the slower the sensor is to respond. He's just giving a ruleOthumb for these stoich-crossing type controllers. BUT even in controllers based on wideband sensors, which ARE capable of holding the mixture right at stoich (or any other commanded AFR) without any significant excursions lean or rich, AFR swings MAY be programmed into the controller *anyway*, to provide the cat with needed lean & rich periods, depending on what type of cat is used in the design of the exh system. This is explained on pg. 656-657 of Heywood's "Internal Combustion Engine Fundamentals". [BTW, especially if you're a science type as your signature suggests, you should have this book or something like it that's as good. There is a wealth of both real-world practical insights AND good in-depth understanding on many DIY topics in Heywood's book.] >If a sensor like the LAF O2-pump >type sensor employs 2 of these, how can its reponse time be any better? Well, the description of the pump-type sensors as "being made of 2 ordinary switch-type sensors" is no doubt an "operational analogy" for the sake of explanation, not necessarily a statement of actual fact of physical construction and performance/behavior, per se. My refuge as a person who hasn't a clue about stuff such as "solid electrolytic nernst reactions" or "gas ion diffusion constants in porous ceramics", is to say, "well, they just are faster". Heh. There's your daily dose of/on exhaust gas. Gar - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Mon, 27 Mar 2000 17:18:57 -0800 From: "Toby Atwater" Subject: aftermarket ecu etc... Sorry I know this isn't "Do It Yourself", more like "Pay it Yourself and break the bank" Does anybody know of a aftermarket ECU that has some kind of PC output? All the ones I have seen either have a separate unit with a small b/w lcd screen, or else they have some kind of data logging capabilities that will off load to a PC "after the race". What I am looking for is something with a PC output that will display what is being inputting into the ECU through it's sensors in real time, or close to real time. I basically want to monitor what is happening inorder to 1) learn more about how it's doing its thing, 2) troubleshoot sensors and other things if things aren't working 3) the coolness factor. Ideally the PC output function, would come with some software and it's source code, in order for me to make my own display and own apps. A PC INPUT on the ECU would also be pretty clutch. Imagine tuning things in the ECU on the fly. Maybe even have a few profiles, economy mode, power mode, pass smog test mode etc... but maybe that's my imagination going off again. This is for my onboard PC project. I originally thought of turning a PC into a ECU but then I just realized that depending on either a Microsoft OS or either another OS to run your car was a bad thing. Blue screen of death would probably cause you to roll to a stop and start cursing. Also I just wasnt sure of any of the OSes are real time, could they be fast enough inorder to keep up at 9000 rpm. Thanks Toby 1969 Austin Healey Sprite 1971 Toyota Land Cruiser. - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Mon, 27 Mar 2000 20:29:21 -0500 From: "nacelp" Subject: Re: aftermarket ecu etc... Try looking at Haltech, and too bad the gm ecms aren't aftermarket, cause with them you can use diacom, and get about what you want, as far as read outs, no source code available for it thou Grumpy > Sorry I know this isn't "Do It Yourself", more like "Pay it Yourself and > break the bank" > > Does anybody know of a aftermarket ECU that has some kind of PC output? All > the ones I have seen either have a separate unit with a small b/w lcd > screen, or else they have some kind of data logging capabilities that will > off load to a PC "after the race". What I am looking for is something with a > PC output that will display what is being inputting into the ECU through > it's sensors in real time, or close to real time. I basically want to > monitor what is happening inorder to 1) learn more about how it's doing its > thing, 2) troubleshoot sensors and other things if things aren't working 3) > the coolness factor. > > Ideally the PC output function, would come with some software and it's > source code, in order for me to make my own display and own apps. > > A PC INPUT on the ECU would also be pretty clutch. Imagine tuning things in > the ECU on the fly. Maybe even have a few profiles, economy mode, power > mode, pass smog test mode etc... but maybe that's my imagination going off > again. > > This is for my onboard PC project. I originally thought of turning a PC into > a ECU but then I just realized that depending on either a Microsoft OS or > either another OS to run your car was a bad thing. Blue screen of death > would probably cause you to roll to a stop and start cursing. Also I just > wasnt sure of any of the OSes are real time, could they be fast enough > inorder to keep up at 9000 rpm. > > Thanks > > Toby > 1969 Austin Healey Sprite > 1971 Toyota Land Cruiser. > > -------------------------------------------------------------------------- - -- > To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) > in the body of a message (not the subject) to majordomo@xxx.org > - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Mon, 27 Mar 2000 17:35:30 -0800 (PST) From: Orin Subject: Re: O2 sensor response times > Ahh, this allows me to clear up a possible mistake I made a few posts > ago when Mike "tah" M. asked about a "platinum O2 sensor". AFAIK, the > platinum is just used to provide the metallic connection between the > ZrO2 material and wiring to the sensor. It's probly vacuum-deposited > onto the outsides of the layers of ZrO2 that make up a sensor, giving a > metallic area that can be wired to. Don't quote me, I'm not a physical > chemist; there might indeed be other electro-chemical reasons as well Heywood pg 301: "Equilibrium is established in the exhaust gases by the catalytic activity of the platinum metal electrodes." So yes, there are other reasons. Orin. - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Mon, 27 Mar 2000 19:40:31 -0600 From: "Gerald Pelnar" Subject: Re: DIY_EFI Digest V5 #122 Bernd Felche wrote: > To "cut my teeth" on uC practical applications, I'm designing a > uC-based system (fancy interior light delay with acoustic warning) > with 5 inputs from switches and "12V" from various automotive > circuits. The uC is running at 5V. > So far, a simple voltage divider with forward signal diode, and > filter capacitor feeding into a (hex) Schmitt trigger (74C14) is how > far I've got. But the voltage can vary from about 8V to perhaps in > excess of 16V, but I want those levels to be "true" always. The > Schmitt will sense 3.5 to 5V as true when running at 5V. Bernd-- To condition 12v inputs to your uP use a 74c901 or 74902 instead of the 74c14. the 901 and 902 are buffers for 15V in to 5V out and operate from the 5V supply. Gerald Pelnar wd0fyf@xxx.net McPherson, KS - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ End of DIY_EFI Digest V5 #125 ***************************** 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".