DIY_EFI Digest Monday, May 17 1999 Volume 04 : Number 289 In this issue: Re: O2 voltz Re: O2 voltz Re: O2 voltz Re: LT1 Spark info wanted Re: I'm BACK...but NOW as a VENDOR 2.5L 730bins ?? Re: switching eprom Re: KS Attenuation, or Dampening Re: horse power/acceleration Board group buy Re: KS Attenuation, or Dampening Re: O2 voltz Re: Board group buy new auto scam Re: 2.5L 730bins ?? BOUNCE diy_efi@xxx.edu: Admin request of type /\buns\w*b/i at line 4 (fwd) Re: 2.5L 730bins ?? Re: 2.5L 730bins ?? Re: switching eprom Re: O2 voltz O2 Volts Re: O2 voltz Re: LT1 Spark info wanted Re: O2 voltz/epa article Re: O2 voltz Re: O2 Volts Re: O2 voltz Re: O2 voltz Re: O2 Volts Re: O2 voltz Re: Variable Restrictiveness Exhaust - Meet Mr Helmholz Re: 2.5L 730bins ?? RE: BMFC, Tiiming, and Coatings See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Mon, 17 May 1999 07:04:42 -0400 From: "Bruce Plecan" Subject: Re: O2 voltz From: G. Scott Ponton Subject: Re: O2 voltz > Ok guys I have sat back and waited for awhile for you all to get this > straight. The sensor "compares the amount of oxygen in the exhaust stream > with the amount in the outside air. The reason it doesn't seem to work this > way is two or three fold. Then why do I get any voltage reading when using the heater, and in free air?. Bruce ------------------------------ Date: Mon, 17 May 1999 08:03:48 -0400 From: Wen Yen Chan Subject: Re: O2 voltz On Sat, 15 May 1999, Bruce Plecan wrote: > For the lack of anything else to do, I hooked the heated O2 up, and was > looking at the voltage drop across a sensor resistor, I been thinking of > using. > As the heater warmed up, the voltage drop across the resistor changed, > just meaning the heater was drawing less current. > I had hooked the scope probe across the O2, and cold there was no output, > to be expected, but as it warmed up the output swung toward, .2v. Just in > atmospheric conditions. Ok, so then it should go way high in pure O2 right, > nope went a little over .3, and stopped there. I think you have got it backwards. The sensor should be reading a very low voltage as there is no difference in the concentration of O2 on both sides of the sensor. Wen > Did I need to load the sensor?. > The heater doesn't go to a high enough temperature for the O2 to fully > swing high?. > Does the engine side need to see a slight amount of pressure to reference > to?. > Grumpy > > ------------------------------ Date: Mon, 17 May 1999 07:02:48 -0500 From: Steve Gorkowski Subject: Re: O2 voltz So what you are saying is that what Bruce is doing wasting his time ? He can't read AFR off the 14.7 value? If you could give me the range AFR numbers when sensor is corrected for temp or are you saying this will not help expand the range? Can you define very narrow range (numbers please)? Have a great day Steve G. Scott Ponton wrote: > Ok guys I have sat back and waited for awhile for you all to get this > straight. The sensor "compares the amount of oxygen in the exhaust stream > with the amount in the outside air. The reason it doesn't seem to work this > way is two or three fold. > > 1. The sensor needs to be at a "reasonably" stable temp before its output is > "reasonably" stable. > > 2.The sensor only works in a very narrow A/F ratio. As the amount of oxygen > climbs above a certain point it can't drop the voltage any lower and the > oppisite is just as true. The output voltage is also limited by the design > of the sensor. After a point removing more oxygen can't effect a voltage > change. > > Much has been said and made of the "wide band" sensors too. After reading > much on the "wide band" sensor it works exactly the same way as a "normal" > sensor. The difference is through outside influences, either a standard > sensor or electronics atached to the output, are used to create a "current > pump" when the sensor cross stoich the "outside" control device switches the > current in the sensor so that it breaks oxygen atoms away from the oxidized > gases in the exhaust. By know at what rate this happens chemically we can > use the output of the sensor to "roughly" ( better than what we started > with) determine the amount of oxidized fuel (and other such nasties as NOx) > in the exhaust stream. > > Notice the word normal used to desribe combustion as we currently use it on > a daily basis. This doesn't include off the wall or experimental engines > which use some sort of modifided combustion cycle. Why not you ask? This is > going to get very long if I have to get into everything that can effect > this. Simply put: > > Within the range of "normal" combustion, a little either side of stoich, the > leaner the mixture the greater the amount of free oxygen in the exhaust > stream as there isn't enough fuel to combine with all the oxygen in the > cylinder. As the mixture is enrichened the amount of free oxygen drops for > exactly the opposite reason. > > If you go to the point of misfire all bets are off. Although a lean cylinder > will tend to dump more free oxygen into the exhaust than a rich one as until > the mixture is extremely rich some part of the air charge ingested will be > used as the fuel attemps to oxidize ( burn) whereas in a extremely lean > cylinder next to nothing oxidizes as our current ignition system cannot > produce the energy needed to properly promote combustion of these mixtures. > > Testing a sensor with argon and other similar gases doesn't work very > well unless they are in an enclosure with only the tip of the sensor exposed > to the "inert" gas. I won't try to get into ther chemistry involved at this > moment as I will have to research the chemistry of inert gases before I can > explain it in those terms. At this point my chemistry is rusty to say the > least. At least that part of it which doesn't deal with the above as I use > this nearly every day. > > OK let the flames begin!! LOL :-) > > Scott ------------------------------ Date: Mon, 17 May 1999 09:00:52 -0400 From: Ken Kelly Subject: Re: LT1 Spark info wanted Shannen, I can print out the tables for the stock 94-95 PCM for you. The advance curves look different for the AUtomatic and Manual, which do you want? Is 94 - 95 a good year? I have the 96 Auto Image too, but I'll have to confirm that I have that table loction for the 96. Ken Shannen Durphey wrote: > > I'm looking for spark timing vs rpm, temp, map for an LT1 engine. > I've got the notion that this engine uses a large amount of advance at > cruise and would like to confirm it. Thanks. > Shannen ------------------------------ Date: Mon, 17 May 1999 09:58:41 -0400 From: WAYNE JOHNSON Subject: Re: I'm BACK...but NOW as a VENDOR Welcome back Gar. ___________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com/getjuno.html or call Juno at (800) 654-JUNO [654-5866] ------------------------------ Date: Mon, 17 May 1999 10:59:57 -0400 (EDT) From: pford@xxx.com Subject: 2.5L 730bins ?? Hi all: does anyone have a bin for a 7730 with a 2.5L manual trans? thanks for any help - -- Pat Ford email: pford@xxx.com QNX Software Systems, Ltd. WWW: http://www.qnx.com (613) 591-0931 (voice) mail: 175 Terrence Matthews (613) 591-3579 (fax) Kanata, Ontario, Canada K2M 1W8 ------------------------------ Date: Mon, 17 May 1999 10:13:13 -0500 From: DC Smith Subject: Re: switching eprom Anybody got any idea who the first person was to do this?? ... I heard of it and thought it'd be neat so I sat down and figured it out.. Anyhoo.. I've done this many times. I used 10K resistors to pull the extra address lines high and a binary pushwheel or thumbwheel switch to switch the different addresses (pull the line low). A dip switch setup will do the same thing. Just think in binary terms. :^) I load the buffer in my chip program with as many programs the prom I am using will hold using the (27256 = 8 cals to emulate a 2732, 27128 = (4) 4K programs) program (and set it to not clear the buffer before file load). (RomMax on a Pentium) I just offset the programs the file size +1 bit, when I load em. (I've got a PB-10 at work and find the RomMax more to my liking) On a software/programmability issue.. I don't think you can program the blocks individually using a .. say 27256 algorithm to emulate a 2732 (8 programs), since *my* programmer will write from FF's to 00's on any unused areas.. and it won't pass a blank check.. Maybe I can change this in the software setup, but I don't remember being able to do it. I can at least bypass the "blank check before programming" in the software. BTW, Hot Rod Power Tour is sposed to be at Gateway International Raceway (St. Louis) this thursday. I _hope_ to get my heads back on, motor back in, and be there, boosted and ready. This SFI'd ride ought to really honk after this little tune up. :^) Machine shop's still got the heads.. gonna be close.. Hope to pick em up in the morning after work.. I feel a cold comin on.. *********************************************************************** Dan Smith 84 Regal 12.13@112 GSCA# 1459 St.Charles, Missouri mailto:dcsmith@xxx.net http://www.tetranet.net/users/morepoweral *********************************************************************** ------------------------------ Date: Mon, 17 May 1999 11:08:18 -0500 From: steve ravet Subject: Re: KS Attenuation, or Dampening GARY wrote: > > > > > First of all, isn't the KS a piezo sensor? If so, I think DC resistance > > doen't really matter. > > Yes Ord, it is but the ECU freaks out if it notices that the KS circuit > is not present so I assume it is looking for a certain current flow with > an applied voltage. The knock sensor is a microphone essentially -- it produces voltage. It is not a driven sensor like a temp or TPS. Some GM ECMs test the knock sensor when certain requirements are met: Engine warmed up, throttle open a large amount, RPM low (high load condition). The ECM briefly advances spark and listens for knock. If it doesn't hear it it sets an ESC code (40 something). This test only happens once per startup, if it happens at all. This applies to 16136965 ECM ('91 Caprice, straight from the service manual), but probably applies to lots others. > > If you want to attenuate, you could build a divider > > around it - two resistors in series accross the element, leave one wire > > connected to the KS, connect the other to the junction of the resistors. > > > > If it is really damping that you want, instead of just attenuation, then you > > need to build a low pass filter. > > I am unclear on the deference between the two. Attenuation is reducing > the signal's amplitude (desired), dampening is reducing the signal's > magnitude? What's that? I don't know what I want! I want to see of > the ECU will stop retarding my timing every time the piezo reacts to a > non-detonation engine noise. A piezo sensor is very high impedance. In that sense it's like an O2 sensor, you have to be careful what kind of stuff you hang on it's output or you'll degrade the signal. If you build a voltage divider you'll have to use really large resistors, like 10x whatever the resistance of the sensor is. You can measure the sensor with a digital meter. I think piezo elements are in the megohm range. To hook it up get 2 big resistors and place them in series. Hook the knock sensor output to one end, ground the other end (at the block, close to the knock sensor), and hook the ECM/ESC module to the middle connection: R1 R2 KS output -----/\/\/-----/\/\/------gnd | |-------------to ECM If the resistors are large enough the attenuation is given by r2/(r2+r1). If you can find a high resistance potentiometer (again like 10x the KS resistance) it's even easier and adjustable. Connect the end terminals to KS and gnd as above, send the middle (variable) connector to the ECM. - --steve > > I don't quite follow your description of how to build the divider > either. Your help is appreciated! > > -- > GARY mailto:hobiegary@xxx.net - -- Steve Ravet steve.ravet@xxx.com Advanced Risc Machines, Inc. www.arm.com ------------------------------ Date: Mon, 17 May 1999 11:28:16 -0700 From: "Todd....!!" Subject: Re: horse power/acceleration ALSO, I've created a HP vs Veh Weight cross-reference spreadsheet at http://www.c-com.net/~atc347/dragtable.htm ... Don't remember if I posted the formula used to calc but I believe I may have... I normally do... Hope ya like.... There may be a mis calc(type-o in pasting the formulas in the spreadsheet) for the heavier vehicles... am workin on correcting... Later! Todd....!! Jeff W wrote: > > dear sir > I am writing to you because I am looking for the correct calculation/formula > for finding the approximate horse power conversion from vehicle weight and > acceleration curve. > I am presently in Vancouver community college, in Vancouver B.C and my > instructor (Dave William's) gave me your e-mail address feeling that you may > be of some help to me. > > vehicle weight + acceleration curve + some other things I don't know= > approximate HP@xxx. > thank you! > Jeff Weinberger > sierraj@xxx.com ------------------------------ Date: Mon, 17 May 1999 13:31:41 EDT From: ScottyCBoy@xxx.com Subject: Board group buy I'm in at Two boards Let me know where to send the check Scott ------------------------------ Date: Mon, 17 May 1999 10:39:36 -0700 (PDT) From: thergen@xxx.net Subject: Re: KS Attenuation, or Dampening On Mon, 17 May 1999, steve ravet wrote: > A piezo sensor is very high impedance. In that sense it's like an O2 > sensor, you have to be careful what kind of stuff you hang on it's > output or you'll degrade the signal. If you build a voltage divider > you'll have to use really large resistors, like 10x whatever the > resistance of the sensor is. You can measure the sensor with a digital > meter. I think piezo elements are in the megohm range. To hook it up > get 2 big resistors and place them in series. Hook the knock sensor > output to one end, ground the other end (at the block, close to the > knock sensor), and hook the ECM/ESC module to the middle connection: > > > R1 R2 > KS output -----/\/\/-----/\/\/------gnd > | > |-------------to ECM > > If the resistors are large enough the attenuation is given by > r2/(r2+r1). > > If you can find a high resistance potentiometer (again like 10x the KS > resistance) it's even easier and adjustable. Connect the end terminals > to KS and gnd as above, send the middle (variable) connector to the > ECM. > Don't some of the ecms look for a particular resistance to ground from the knock sensor input to ground (from memory, 3.9K Ohms for some sensors)? There's probably a range of resistance that will avoid setting a code. If R2 in parallel with R1+Rks is too high, will that cause a fault code? Thanks, Tom ------------------------------ Date: Mon, 17 May 1999 13:53:02 -0400 From: "Bruce Plecan" Subject: Re: O2 voltz Nope. Not backwards, I retried it several times with the same results. Bruce > > For the lack of anything else to do, I hooked the heated O2 up, and was > > looking at the voltage drop across a sensor resistor, I been thinking of > > using. > > As the heater warmed up, the voltage drop across the resistor changed, > > just meaning the heater was drawing less current. > > I had hooked the scope probe across the O2, and cold there was no output, > > to be expected, but as it warmed up the output swung toward, .2v. Just in > > atmospheric conditions. Ok, so then it should go way high in pure O2 right, > > nope went a little over .3, and stopped there. > I think you have got it backwards. The sensor should be reading a very low > voltage as there is no difference in the concentration of O2 on both sides > of the sensor. > Wen > > Did I need to load the sensor?. > > The heater doesn't go to a high enough temperature for the O2 to fully > > swing high?. > > Does the engine side need to see a slight amount of pressure to reference > > to?. > > Grumpy ------------------------------ Date: Mon, 17 May 1999 11:10:22 -0700 (PDT) From: Squash Subject: Re: Board group buy What is this for and how much is it? andy - --- ScottyCBoy@xxx.com wrote: > I'm in at Two boards > > Let me know where to send the check > > Scott > _____________________________________________________________ Do You Yahoo!? Free instant messaging and more at http://messenger.yahoo.com ------------------------------ Date: Mon, 17 May 1999 11:30:18 -0700 From: "Stowe, Ted-SEA" Subject: new auto scam http://portalmarket.com/force.html Formula Two Power Paks are specially formulated to follow Formula One Power Paks in application. Placed in your air intake path, their catalyst will help keep your engine at peak operating efficiency Each Performance Pak will be a uniquely effective combustion enhancer for 3 months or 3,000 miles. These 4 Performance Paks should last 12,000 miles or about a full year's normal driving. With continued use, they will enable you to experience all the power your engine was designed to deliver, protect your investment and enjoy new driving economy. ------------------------------ Date: Mon, 17 May 1999 14:34:53 -0400 From: "Bruce Plecan" Subject: Re: 2.5L 730bins ?? Is this wishing aloud?. I don't see this combination at all, anywhere, 2.5 anything with a 730.. If not a wish, a MY, or Platform? Bruce Subject: 2.5L 730bins ?? > Hi all: > does anyone have a bin for a 7730 with a 2.5L manual trans? > thanks for any help > -- > Pat Ford email: pford@xxx.com > QNX Software Systems, Ltd. WWW: http://www.qnx.com > (613) 591-0931 (voice) mail: 175 Terrence Matthews > (613) 591-3579 (fax) Kanata, Ontario, Canada K2M 1W8 ------------------------------ Date: Mon, 17 May 1999 11:56:28 -0700 (PDT) From: Orin Eman Subject: BOUNCE diy_efi@xxx.edu: Admin request of type /\buns\w*b/i at line 4 (fwd) This was bouncing due to a bad majordomo filter: > From: bob@xxx.com (Robert Harris) > To: diy_efi@xxx.edu > Subject: The missing part - before Mr Helmholz > Date: Mon, 17 May 1999 14:44:04 GMT > Organization: Bob - the Computer Guy > Message-ID: <37442ade.3820479@xxx.net> > X-Mailer: Forte Agent 1.5/32.451 > MIME-Version: 1.0 > Content-Type: text/plain; charset=us-ascii > Content-Transfer-Encoding: 7bit > In order to tune and use the acoustical pressure wave to our advantage, we > must first be able to detect it. Traditionally, dyno time has been used to > tune such acoustics - the math involved and the radically changing physicals > underneath it - are approaching unsolvable. Not that there is not programs > to do this ( and they are getting quite good - but consider selling your first > born to afford one ) but they rely on excellent data collection and feed back > to converge to an optimum solution - an extensive data collection effort that > may not be available to DIY > To measure the effect, we only need a camshaft angle sensors ( simpler to > determine which TDC we are looking at ) and a sensitive pressure sender. The > angular sensor tells us phase and the pressure tells us sign and amplitude. > The pressure sensor tells us pressure at the port. Flaw is that we need to > sense the pressure at the port and few affordable sensitive sensors can > withstand the temperature at the exhaust valve. The first proposed solution > is to us a small diameter tube from the collector to the sensor approximately > the same length as the runner. This delay line should place the acoustic wave > approximately the same at the sensor as at the valve. > We now can measure the desired effect - an acoustics pressure wave arriving at > the exhaust port. Now on to system concept to base our control mechanism on. ------------------------------ Date: Mon, 17 May 1999 16:15:46 -0400 (EDT) From: pford@xxx.com Subject: Re: 2.5L 730bins ?? Previously, you (Bruce Plecan) wrote: > > Is this wishing aloud?. > I don't see this combination at all, anywhere, 2.5 anything with a 730.. isn't a 92 cavalier(sp?) a 2.5? if not what is nearist to 2.25L > If not a wish, a MY, or Platform? may have been wishfull thinking 8-). all I know abut gms is what I've learned here and that they tend to leave cast iron on the road when I drive them 8)) I want to put a 730 into a 61 land rover ( get rid of lucas, and a cracked intake and carb) I missed a trail and drove off a 4' verticle drop and landed on a tree stump that pushed the motor up into the hood > Bruce > > Subject: 2.5L 730bins ?? > > Hi all: > > does anyone have a bin for a 7730 with a 2.5L manual trans? > > thanks for any help > > -- > > Pat Ford email: pford@xxx.com > > QNX Software Systems, Ltd. WWW: http://www.qnx.com > > (613) 591-0931 (voice) mail: 175 Terrence Matthews > > (613) 591-3579 (fax) Kanata, Ontario, Canada K2M 1W8 > > - -- Pat Ford email: pford@xxx.com QNX Software Systems, Ltd. WWW: http://www.qnx.com (613) 591-0931 (voice) mail: 175 Terrence Matthews (613) 591-3579 (fax) Kanata, Ontario, Canada K2M 1W8 ------------------------------ Date: Mon, 17 May 1999 16:42:41 -0400 From: "Bruce Plecan" Subject: Re: 2.5L 730bins ?? You have a choice of two bins, but both are automatics, (neither of which I happen to have), BTW was a 1227727. ASLW 16149591 ASLX 16150970 Maybe someone can turn something up Bruce > Previously, you (Bruce Plecan) wrote: > > Is this wishing aloud?. > > I don't see this combination at all, anywhere, 2.5 anything with a 730.. > isn't a 92 cavalier(sp?) a 2.5? if not what is nearist to 2.25L > > If not a wish, a MY, or Platform? > may have been wishfull thinking 8-). all I know abut gms is what I've learned > here and that they tend to leave cast iron on the road when I drive them 8)) > I want to put a 730 into a 61 land rover ( get rid of lucas, and a cracked > intake and carb) I missed a trail and drove off a 4' verticle drop and landed > on a tree stump that pushed the motor up into the hood > > Bruce > > Subject: 2.5L 730bins ?? > > > Hi all: > > > does anyone have a bin for a 7730 with a 2.5L manual trans? > > > thanks for any help > > > Pat Ford email: pford@xxx.com ------------------------------ Date: Mon, 17 May 1999 19:02:11 -0700 From: rr Subject: Re: switching eprom > > On a software/programmability issue.. > I don't think you can program the blocks individually using a .. say >27256 algorithm to emulate a 2732 (8 programs), since *my* programmer >will write from FF's to 00's on any unused areas.. and it won't pass a >blank check.. Maybe I can change this in the software setup, but I don't >remember being able to do it. I can at least bypass the "blank check >before programming" in the software. I keep forgetting about stuff like this. I wrote & built my own programmer so it's not a problem. With DOS, you can do a binary file copy and cat the 8 or so bins together. Use the /B switch and the + sign to do this: copy /b file1 + file2 + ... + file8 allfiles.out HTH BobR. >*********************************************************************** >Dan Smith 84 Regal 12.13@112 GSCA# 1459 >St.Charles, Missouri >mailto:dcsmith@xxx.net >http://www.tetranet.net/users/morepoweral >*********************************************************************** ------------------------------ Date: Mon, 17 May 1999 20:56:27 +0000 From: xxalexx@xxx.com Subject: Re: O2 voltz > At 04:02 PM 5/15/99 -0400, you wrote: > >For the lack of anything else to do, I hooked the heated O2 up, and was > >looking at the voltage drop across a sensor resistor, I been thinking of > >using. > > As the heater warmed up, the voltage drop across the resistor changed, > >just meaning the heater was drawing less current. > > I had hooked the scope probe across the O2, and cold there was no output, > >to be expected, but as it warmed up the output swung toward, .2v. Just in > >atmospheric conditions. Ok, so then it should go way high in pure O2 right, > >nope went a little over .3, and stopped there. > > Did I need to load the sensor?. > > The heater doesn't go to a high enough temperature for the O2 to fully > >swing high?. > > Does the engine side need to see a slight amount of pressure to reference > >to?. > > Bad thing about O2 sensors is they aren't truly O2 sensors... they are HC > sensors. > In pure O2, the sensor should keep a low voltage. In an environment rich > with HC (IE propane, unburnt fuel etc) they should go .9-1 Volt. Maybe ion sensors, the HC molecules can easily diassociate at high temperatures, probably more so with O2 helping. I'm not sure at what temp. 02 ionizes. Alex ------------------------------ Date: Mon, 17 May 1999 21:32:21 -0400 From: "Bruce Plecan" Subject: O2 Volts Per several off list letters I checked/doubled checked/thriple checked grounds and power for this bit of history. I noted the following, using a 4 wire heated O2 sensor. (General Motors) With no power to heater, 0.0v. For approximately 30secs 0.0, and then quickly rose to .1v, then then slowly climbed higher. When hot, there was a nominal voltage of .28v at the O2 sensor lead wire. Exposing this sensor to 97% O2 (Medical Grade O2, as tested this am) it drifted to .030.-.032v. Exposing this sensor to the Butane from a cigarette lighter that was unlit immediately responded with a display of .7v...... Your O2 sensor is a HC Sensor... Bruce and the staff at CSH, HQ ------------------------------ Date: Mon, 17 May 1999 18:49:10 -0700 (PDT) From: Mark Wilcutts Subject: Re: O2 voltz There are two papers up on my website: http://vehicle.me.berkeley.edu/efi/SAE920289/ http://vehicle.me.berkeley.edu/efi/SAE930352/ These two should answer most of your questions. On Sun, 16 May 1999, rr wrote: > P.S. A while back there was a link to an epa article posted, > interesting reading, I'll see if I can find it. ------------------------------ Date: Mon, 17 May 1999 21:40:56 -0400 From: Shannen Durphey Subject: Re: LT1 Spark info wanted Manual, 94-95 fine, much obliged. Shannen Ken Kelly wrote: > > Shannen, > I can print out the tables for the stock 94-95 PCM for you. > The advance curves look different for the AUtomatic and > Manual, which do you want? Is 94 - 95 a good year? I have > the 96 Auto Image too, but I'll have to confirm that I have > that table loction for the 96. > > Ken > > Shannen Durphey wrote: > > > > I'm looking for spark timing vs rpm, temp, map for an LT1 engine. > > I've got the notion that this engine uses a large amount of advance at > > cruise and would like to confirm it. Thanks. > > Shannen ------------------------------ Date: Mon, 17 May 1999 21:37:55 -0700 From: rr Subject: Re: O2 voltz/epa article >This sounds correct, a lean (o2 rich), condition gives a low >reading, while too much fuel (no o2), gives a high reading. > >Run some propane over it to block out o2, and the reading >should go up. Don't know what I was thinking here, an unlite torch doesn't work, there's still o2 in it. Try a lite torch, works a treat. Goes right up to >900mV. >BobR. > >P.S. A while back there was a link to an epa article posted, >interesting reading, I'll see if I can find it. I found a referance to the article, but it's not there any more. If anyone has it, maybe contact Bruce. Thanks, BobR. - -- ------------------------------ Date: Mon, 17 May 1999 18:55:22 -0700 (PDT) From: Mark Wilcutts Subject: Re: O2 voltz Sorry that should be http://vehicle.me.berkeley.edu/~markw/efi/SAE920289/ http://vehicle.me.berkeley.edu/~markw/efi/SAE930352/ On Mon, 17 May 1999, Mark Wilcutts wrote: > There are two papers up on my website: > http://vehicle.me.berkeley.edu/efi/SAE920289/ > http://vehicle.me.berkeley.edu/efi/SAE930352/ > > These two should answer most of your questions. > > On Sun, 16 May 1999, rr wrote: > > > P.S. A while back there was a link to an epa article posted, > > interesting reading, I'll see if I can find it. > > > ------------------------------ Date: Mon, 17 May 1999 22:16:42 -0400 From: "CLsnyder" Subject: Re: O2 Volts - ----- Original Message ----- From: Bruce Plecan To: Sent: Monday, May 17, 1999 9:32 PM Subject: O2 Volts > Per several off list letters I checked/doubled checked/thriple checked > grounds and power for this bit of history. > I noted the following, using a 4 wire heated O2 sensor. (General Motors) > With no power to heater, 0.0v. For approximately 30secs 0.0, and then > quickly rose to .1v, then then slowly climbed higher. > When hot, there was a nominal voltage of .28v at the O2 sensor lead wire. > Exposing this sensor to 97% O2 (Medical Grade O2, as tested this am) it > drifted to .030.-.032v. > Exposing this sensor to the Butane from a cigarette lighter that was unlit > immediately responded with a display of .7v...... > Your O2 sensor is a HC Sensor... > Bruce and the staff at CSH, HQ > Try feeding it co2 and see what it does - same as butane. The sensor is an oxygen battery. If both electrodes are equal in oxygen you get 0 volts, more or less (let's say .25 from your open air heated test). If one (the one "outside" the exhaust is higher in O2 than the inner one, you get a higher voltage. If the inside is higher in O2 you get lower voltage. Use anything other than oxygen - CO2, Argon, Nitrogen, Butane, or Propane. This is the way the unit is designed - so this is how it SHOULD work. When running at stoich, there is little O2 in the exhaust. The voltage produced at this point is programmed into the ECU. If the voltage goes low, the ECU richens the mixture. When the voltage goes high it leans the mixture, and the ECU counts crossing points to determine if the system is correcting properly. > ------------------------------ Date: Mon, 17 May 1999 21:33:03 -0500 From: "G. Scott Ponton" Subject: Re: O2 voltz >Then why do I get any voltage reading when using the heater, and in free >air?. >Bruce The sensor isn't up to operating temp yet. The sensor needs to be above 600 F for it to operate properly. I don't know how hot the heaters get these things but it is very unlikely it is anywhere near 600 F. The purpose of the heater is to help the initial warm up time of the sensor from cold. After the exhaust is up to temp it is not needed. >So what you are saying is that what Bruce is doing wasting his time ? He can't >read AFR off the 14.7 value? If you could give me the range AFR numbers when >sensor is corrected for temp or are you saying this will not help expand the >range? Can you define very narrow range (numbers please)? >Have a great day >Steve No I'm not saying he is wasting his time. If the temp of the exhaust stream is known it makes it very easy to build a table which allows you to temp compensate the sensor reading. The problem is even with temp compensation a "normal" sensor doesn't have a great enough range to be useful for "power" tuning. Even a "wide band" sensor is limited for power tuning. Because of the way it work an HEGO sensors range can be "extended" to the point of reading A/F ratios greater than ( or less than depending on your view) 13:1 But you still have the same problem. It needs to be temperature compensated. Also the "outside" current pump control has to be calibrated to known values for the richer A/F ratios before it can be used as most seem to want to use it. Narrow range is from about 15.5:1 to 14.0:1. Have any on the list tried using a O2 sensor to adjust the idle A/F on a carberated engine? Long before you get to even a 10% misfire rate in the lean direction the sensor reads >.2 volt. The same is true in the rich direction. Back the mixture screw out 1/4 to 1/2 a turn from lean best idle and the sensor goes abovr .85 v. But as I pointed out in a earlier post the sensor doesn't read on a linear basis. It's not because the sensor isn't linear. It's because combustion and O2 content in the exhaust stream aren't linear. From ~ 9.0:1 to ~ 15:1 the sensor reads .90 v. or greater. At ~ 8:1 and richer the sensor will drop again to >.20 v. as rich misfire is induced. On the other hand ar most A/F ratios of > ~15:1 the sensor will read >.20 v. >> I had hooked the scope probe across the O2, and cold there was no output, >> to be expected, but as it warmed up the output swung toward, .2v. Just in >> atmospheric conditions. Ok, so then it should go way high in pure O2 right, >> nope went a little over .3, and stopped there. >I think you have got it backwards. The sensor should be reading a very low >voltage as there is no difference in the concentration of O2 on both sides >of the sensor. In pure O2 the sensor should read low. The design of the sensor doesn't allow it to "reverse" the process. In other words , if there is more O2 on the exhaust side than the air side it won't read higher. If you isolate the tip and flood the air side with pure O2 then the reading will climb. Scott P.S. Please excuse the typos. I get in a hurry and sometimes correct them in my head when I reread them. ------------------------------ Date: Mon, 17 May 1999 22:28:13 -0400 From: Shannen Durphey Subject: Re: O2 voltz Bruce Plecan wrote: > > Nope. Not backwards, I retried it several times with the same results. > Bruce Think he meant predicted results, not actual. I haven't picked up on the split in information, but traditional teaching has it that less O2 on sensor side=higher output voltage. Try putting just the wire side in O2 and see if voltage climbs by a tenth or two. Shannen > > > > For the lack of anything else to do, I hooked the heated O2 up, and was > > > looking at the voltage drop across a sensor resistor, I been thinking of > > > using. > > > As the heater warmed up, the voltage drop across the resistor changed, > > > just meaning the heater was drawing less current. > > > I had hooked the scope probe across the O2, and cold there was no > output, > > > to be expected, but as it warmed up the output swung toward, .2v. Just > in > > > atmospheric conditions. Ok, so then it should go way high in pure O2 > right, > > > nope went a little over .3, and stopped there. > > > I think you have got it backwards. The sensor should be reading a very low > > voltage as there is no difference in the concentration of O2 on both sides > > of the sensor. > > > Wen > > > > Did I need to load the sensor?. > > > The heater doesn't go to a high enough temperature for the O2 to fully > > > swing high?. > > > Does the engine side need to see a slight amount of pressure to > reference > > > to?. > > > Grumpy ------------------------------ Date: Mon, 17 May 1999 21:38:50 -0500 From: "G. Scott Ponton" Subject: Re: O2 Volts Exposing the sensor to butane cut off the oxygen to the element. This is what caused the reading to go high. This is something I started to touch on in yesterdays post. It has to do with the molecular weight of the gas being used to flush the exhaust side of the sensor. If the gas used doesn't have enough "weight" to "push" the oxygen out of the way the reading doesn't change. Scott ------------------------------ Date: Mon, 17 May 1999 21:49:21 -0500 From: "G. Scott Ponton" Subject: Re: O2 voltz Very good papers!!!! Scott ------------------------------ Date: Mon, 17 May 1999 22:00:40 -0500 From: Tom Sharpe Subject: Re: Variable Restrictiveness Exhaust - Meet Mr Helmholz All well states... If you missed it, go thru your trash and read it again! Robert Harris wrote: > To review the basics A Helmholtz resonant intake consists of a largish > diameter intake pipe, a resonating volume (plenum) and individual cylinder > runners. The individual cylinder runners are length/diameter tuned to the > highest power rpm desired and the helmholz resonator extends the rpm range > downward. > > Reverse it. Individual cylinder runners, resonating volume ( collector ) and > a largish tunable pipe. Size the exhaust cylinder runners for the high rpm > diameter and length. Fire them into a collector and then out a pipe. > > or using a vacuum > headlight actuator to vary the length of a slippy pipe stub coupled to the > collector. Robert, I really like the slippy pipes... could you figure out the length from the sound produced? Sort of a knock sensor approach... or use lookup tables like fuel, spark, exhaust position?? Just trying to simplify the process.. Do we need a stepper motor headlight actuator.... Tom S ------------------------------ Date: Mon, 17 May 1999 23:10:14 -0400 From: Shannen Durphey Subject: Re: 2.5L 730bins ?? pford@xxx.com wrote: > > Previously, you (Bruce Plecan) wrote: > > > > Is this wishing aloud?. > > I don't see this combination at all, anywhere, 2.5 anything with a 730.. > > isn't a 92 cavalier(sp?) a 2.5? if not what is nearist to 2.25L No. 2.5 and Cavalier were never offered together. 92 Cav shows up with 16134847 ecm, and 2.2l engine. Shannen ------------------------------ Date: Tue, 18 May 1999 03:31:02 GMT From: "The Punisher" Subject: RE: BMFC, Tiiming, and Coatings >here's a thought, has anyone ever given any thought to painting the inside >of an engine ? before you hit delete, consider how easy it is for dirt etc >to stick to the inside of the block, under a microscope the surface must be >like velcro. I suspect oil would return a little quicker to the pan. just a >thought, you can flame me now. > I paint ALL My engines that I build. I DO NOT use standard engine paint for the inside however. I use electric motor insulation paint, the stuff they paint the windings with. It is very tough and maintains a slick surface even after several years of use. The oil in my engines just run off the stuff and hardly even leave any film behind. They usualy have this stuff at electric motor rebuilding shops. I have used it on the exterior too, but it does not seem to have the same durability. I have NEVER yet seen any signs of peeling or flaking inside the engine. >Has anyone run any "independent" testing on these barrier coatings for what >they actually have seen as an improvement pre+post coating?. > Has any one run any endurance tests?. >Do I need mention that this might need a complete recal to get right. >Bruce I have also used thermal barrier on piston domes,combustion chambers, valves and exhause ports. It sure seems to work for me. I have built some small blocks that were similar but the ones with the thermal coatings seem less prone to detonation. Another advantage (especialy on the street), is the piston expands less, therefore you can run a tighter piston/bore clearence, which means less blow-by,less wear, less leakage which all adds up to a better engine. _______________________________________________________________ Get Free Email and Do More On The Web. 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