DIY_EFI Digest Tuesday, May 18 1999 Volume 04 : Number 290 In this issue: Re: O2 Volts Re: O2 Volts Re: O2 sensor and water Re: O2 Volts Re: BMFC, Tiiming, and Coatings Re: Variable Restrictiveness Exhaust - Meet Mr Helmholz Mercedes CLK 430 ECU Mods Mazda OBDII Re: O2 voltz Re: O2 Volts 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 23:42:39 -0400 From: Shannen Durphey Subject: Re: O2 Volts Bruce Plecan wrote: > > 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 Ahh... Now I see. Technically speaking, the O2 sensor should be called an O2 differential sensor. Or maybe a "lack of O2" sensor. ; ) No, the sensor doesn't make a voltage when there is oxygen on the sniffer side of the sensor. It makes a voltage when there is no oxygen on the sniffer side. Now the Argon thing, I'd like to know more about. IIRC, the ecm supplies a bias voltage to the sensor to prevent false readings like the ones you got in plain air. Shannen ------------------------------ Date: Mon, 17 May 1999 23:53:54 -0400 From: Shannen Durphey Subject: Re: O2 Volts G. Scott Ponton wrote: > > 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 So you're saying that some oxygen sticks to the sensor? It takes a gas with some "oomph" to push it away? Shannen ------------------------------ Date: Mon, 17 May 1999 01:57:15 -0400 From: Raymond C Drouillard Subject: Re: O2 sensor and water On Sun, 16 May 1999 23:56:56 +0200 "Nils Björkman" writes: >Hello > >Im working on an EFI project. The purpose of this project is converting >and modifying an Volvo B230F engine to be used in a boat. > >Now the turn has come to attach the O2 sensor. The following problems >occure: > >1. If the O2-sensor gets in contact with water (in the exhaust >manifold), will it be destryoed, how does it work and so on. Car exhaust is mostly water vapor. I have never heard of that bothering an O2 sensor. Liquid water might be another story, however. ___________________________________________________________________ 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 23:48:46 -0500 From: "G. Scott Ponton" Subject: Re: O2 Volts Shannen, That's one way of putting it. To get any more detailed about it I would have to get into the chemistry of the situation. I haven't used high level chemistry for 20 years so I have gone as far as I can go with that part of it. Mark Wilcutts posted a couple of URL's which do a very good job of explaining everything but they are still a little shy on the chemical details. Listening to what everyone seems to want leads to a 4 gas analizer built into the ECM/PCM. Not impossible to impliment just bulky and pricy. Scott ------------------------------ Date: Tue, 18 May 1999 01:04:37 EDT From: FHPREMACH@xxx.com Subject: Re: BMFC, Tiiming, and Coatings In a message dated 5/16/99 9:12:57 AM Pacific Daylight Time, nwester@xxx.org writes: << I have no faith in some kind of coating--just like I have no faith in Teflon additives...instead of coating the undersides of pistons, or coating the interior of an engine--polishing the interiors smooth would have a greater effect of oil return, and less oil "dwell". As far as piston ring manufacturers go--gapless piston rings and improper end gaps will always yield differing results. You can make anything look good on a dyno--depending on operator. Lyndon IPTECH -----Original Message----- >> Hi, I just wanted to add a bit to this idea. most research has noted that the "Leave it cast and paint it black" ideas of long ago still hold true. Oil is a strange beast at times. you want to cool it and drain it to the sump, but as it cools, it slows down the drainback. Rough surfaces increase the surface area and increase cooling. As for teflon, the jury is still out on the longterm results. Polishing the interior of motors has come in and out of use. and at one time, polishing the entire crankcase, crank, rod, and filling the balance holes in two strokes was supposed to lead to increased horsepower, but like stuffer plates, it seems to have lost favor. Coatings seem to come in and out of fashion. I do believe in coatings for certain areas, but am still looking into a couple of unorthodox ones. I will give results as they ocur. BTW, has anyone tried the carbide cylinder bore treatment that was in the threads a few months ago? I wondered about that with a Hard Anodized piston skirt might affect wear. Fred ------------------------------ Date: Tue, 18 May 1999 05:17:56 GMT From: bob@xxx.com (Robert Harris) Subject: Re: Variable Restrictiveness Exhaust - Meet Mr Helmholz The majordomo deleted portion proposed active acoustical tuning using a "microphone" or a sensitive pressure sensor well filtered and positioned near the valve to observe the exhaust acoustical pressure and in conjunction with a camshaft angle sensor, we would have the feedback mechanism to actively measure and time the arrival of the negative going pulse. While the Helmholz model may not be perfect, it gives us reasonable bounds to develope within without getting into magic. This model tells us that we can change the frequency of the resonance by changing the volume and the volume does not have to flow gas. Thus the slippy pipe. In reality, any reasonable way of varying the volume of a connected chamber will allow us to move the resonance to the current rpm. Multiple stubs connected by butterfly valves may work as well - depending on the broadness "Q" of the system. In the Helmholz model, the final tuning is done by the varying the length and area of the tuning pipe attached to the volume. This corresponds to the exhaust system past the collector "resonating" volume. Shortening the pipe by a "cutout" properly placed could shorten the effective length of the resonating pipe, raise the resonant frequency and thus extend the active bandwidth again. Again, with a Helmholz model, we can approximately predict the effect of changes either in the resonating volume or the tuning pipe. With the acoustical pressure vs camshaft angle measurement, we have a practical way of determining the effectiveness. For those that followed the link, you see how effective varying the temperature can be. Varying the temperature by water injection into the resonating volume works by varying the local speed of sound with the system. Since the sole purpose of the water is to vary the resonance by varying the temperature it becomes very interesting on how to administer the water. Probably the simplest is to vary the temperature of the gas in the collector. But would timed injection into the exhaust port just before the exhaust valve opens be more effective or just trailing the major pulse or perhaps even into the exhaust pulse itself. ???? Floors open. Date: Mon, 17 May 1999 22:00:40 -0500 From: Tom Sharpe Subject: Re: Variable Restrictiveness Exhaust - Meet Mr Helmholz Deleted Stuff >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 22:27:11 -0700 From: "John T. Luyster" Subject: Mercedes CLK 430 ECU Mods I have been following the threads on DIY-EFI and I am superchargering a '99 Mercedes CLK 430. I'm looking to modify the ECU. Is there anyone in this forum who would point me in the right direction? John T. ------------------------------ Date: Tue, 18 May 1999 01:54:25 EDT From: FHPREMACH@xxx.com Subject: Mazda OBDII Hi, Has anyone developed anything for accessing the OBDII ports on the 96 Mazda Protoge. I have one, and would like to learn the diagnostics and tuning of it. I realize is it a bit of a strange car for perfomance work, but it works and the systme might be adaptable to other projects. so far, finding a diagnostic tool has been fruitles around here. Fred ------------------------------ Date: Tue, 18 May 1999 02:05:25 EDT From: Regnirps@xxx.com Subject: Re: O2 voltz In a message dated 5/17/99 8:24:20 PM, markw@xxx.edu writes: >There are two papers up on my website: >http://vehicle.me.berkeley.edu/efi/SAE920289/ >http://vehicle.me.berkeley.edu/efi/SAE930352/ The server says they are not there. Charlie Springer ------------------------------ Date: Mon, 17 May 1999 23:52:03 -0700 From: Christopher J Beasley Subject: Re: O2 Volts CLsnyder wrote:snip > 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. > > Exactly, except the other way 'round, right? b ------------------------------ End of DIY_EFI Digest V4 #290 ***************************** 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".