DIY_EFI Digest Friday, 2 August 1996 Volume 01 : Number 218 In this issue: [admin] List services (automated monthly post) EGT for feedback Throttle switch Re: Fuel pump sucking air (was: Re: Proper Mixture) Re: Circuits for magnetic pickups Re: Proper Mixture. Re[2]: Proper Mixture. Digession on O2 Sensors Re: Circuits for magnetic pickups Re: Circuits for magnetic pickups Re[2]: Circuits for magnetic pickups Fred Miranda email address Re: EGT for feedback Re[2]: Fuel pump sucking air (was: Re: Proper Mixture) Re: DPM (was Proper Mixture) Re: EGT for feedback See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: jsg (John S Gwynne) Date: Thu, 1 Aug 1996 06:10:07 -0400 Subject: [admin] List services (automated monthly post) This message is post monthly as a reminder of the available list services. For help: Send "help" to Majordomo@xxx. To post: Send to "[list name]@xxx.edu" To subscribe: Send to Majordomo@xxx.edu subscribe [list name] [your email address *only* if different than your "From" address] To unsubscribe: Send to Majordomo@xxx.edu unsubscribe [list name] [your *registered* email address if different than your "From" address] The archive to each mailing list is available through the following sources: 1) WWW. http://efi332.eng.ohio-state.edu/ 2) ftp. ftp://efi332.eng.ohio-state.edu/ 3) Majordomo. Send "index [list name]" to Majordomo@xxx. You will find a file "archive_date_index" whose contents show the period covered by each of the archive files "archive_num_*". Digest mode is available for each mailing list. Send "lists" to Majordomo for a listing a mailing lists served. To switch to the digest mode, unsubscribe from the regular list and then subscribe to the digest version (i.e., diy_efi-digest). WWW sites: archive http://efi332.eng.ohio-state.edu/ diy_efi http://www.cpsc.ucalgary.ca/~fridman/diy_efi efi332 http://www.cim.swin.edu.au/~aden/web-docs/efi332/332_index.html Other related sites: http://devserve.cebaf.gov/~bowling/ http://spbted.gtri.gatech.edu:80/hpe/hpe.html Please send information to be added to this posting to jsg@xxx. John ------------------------------ From: "Michael T. Kasimirsky" Date: Thu, 1 Aug 1996 08:16:04 -0400 (EDT) Subject: EGT for feedback I'm new to the list and to the whole DIY-EFI thing in general. All the recent talk of O2 sensors has got me wondering about another source of combustion feedback. Has anyone tried using exhaust gas temperature for fine-tuning the intake mixture? It would seem to me that you could lean the mixture to increase EGT or richen to lower EGT. If you'd done some initial tuning with a gas analyzer to determine an optimum temp, this would work. Any thoughts? Michael T. Kasimirsky ----> mtk@xxx.edu Days: Staff Engineer or mk4u@xxx.edu ASTM Test Monitoring Center Phi Gamma Delta, Nights: 1992 Suzuki GSX-R750 Pilot NRA Life Member, AMA Member 1991 Suzuki GSF400 Bandit Mechanic DoD #1848 ------------------------------ From: Jens Knickmeyer Date: Thu, 1 Aug 1996 14:39:33 +0200 (MET DST) Subject: Throttle switch Hi all! In my Polo-G40, I found the idle throttle switch to open _before_ the throttle plate moved. When I had a friend of mine pressing down the accellerator pedal, I heared the click of the switch and shortly after that, the throttle started to open. I always thought it should be the other way round: the throttle opens a bit and then the switch opens its contacts? The reason for my question is a problem during warm-up. The engine starts perfectly, runs good during post-start enrichment, but then suddenly acts a bit reluctantly. When I press down the accellerator pedal only a little bit, the engine revs 100rpm below its normal idle rpm. Accelleration from idle rpms lets the engine tend to stall. These effects vanish when the engine is warmed up. I wonder if the idle switch is adjusted correctly. The VW service men said yes, but it would not be the first time they are wrong, so I thought I'd better ask the list members... Any help is apprciated, thanks in advance. Jens ('92 VW Polo-G40) - ------------------------------------ Jens Knickmeyer Technische Universitaet Braunschweig Mikroprozessorlabor 38106 Braunschweig near Wolfsburg knick@xxx.de - ------------------------------------ ------------------------------ From: Donald Whisnant Date: Thu, 01 Aug 1996 10:16:18 -0400 Subject: Re: Fuel pump sucking air (was: Re: Proper Mixture) > > From: FIScot@xxx.com > Date: Wed, 31 Jul 1996 22:54:33 -0400 > Subject: Re: Proper Mixture. > > I would not worry about what the ECM is doing..... What about running the > pump dry? > The ECM won't change dramatically in a couple seconds, and if you are on/off > the throttle, probably won't change at all. > > I would think that running the pump dry might shorten it's life. The Mike > Knell book on Chevrolet TPI and TBI Engine Swapping had a neat idea to stop > engine from dying in this situation. He made a little reservoir box to hold > fuel that fed the high pressure pump. A low pressure pump fed the box from > the tank. Requires two fuel pumps, but solves the problem if you can't get a > baffled fuel tank. > > Scot Sealander FIScot@xxx.com > Hmmm ... Some how I'm afraid the extra pump, its plumbing, and the extra wiring would end up costing more than getting a baffled tank at a junk yard .... Actually, I'm more concerned about a "sudden lean condition" in the engine than I am about running the pump dry. The pump (a rotary vain high pressure/velocity pump) doesn't seem to mind the short quick bursts of no fuel ... I wouldn't want to run it long that way, as it would overheat, but for the short bursts that only occasionally happen I don't think it is a problem... Thanks for the suggestion, though, I never thaught about using 2 pumps -- neat idea... Donald Whisnant dewhisna@xxx.com ------------------------------ From: Donald Whisnant Date: Thu, 01 Aug 1996 10:39:57 -0400 Subject: Re: Circuits for magnetic pickups > > From: "Oliver Scholz" > Date: Thu, 1 Aug 1996 09:24:35 +0200 > Subject: Re: Circuits for magnetic pickups > > Hi all, > > regarding the recent discussion of magnetic pickups I have a question: > > On older transmissions GM used a PM generator as the Vehicle Speed Sensor. > It outputs a sine wave and about 4000 pulses per mile. > > The later model transmissions (it is Getrags I am particularly interested > in) they use a hall sensor of some kind that is triggered by a slotted > disc on the axle. That signal is run to the ECM/PCM which drives the > speedo at the usual 4000ppm. > > Now, I would like to use the new transmission on an older car, so I > would have to run the Hall sensor signal into a microprocessor that > generates the proper speed signal from it. > > Now the question: Does anybody know the waveform of the signal? > Is it sine, square, ??? Which circuit would be recommended to buffer it? > Also, how many pulses does it generate per revolution of the drive wheel? > > Any help would be appreciated! > > Best regards, > > - -Oliver > :) I've recently had a tremendous amount of experience with this application, as I'm presently building a digital speedometer to go on my '85 Grand Prix for the '94 4L60E transmission I just put in (which has an electronic pickup -- versus the old mechanical gear/cable)... This is the same sensor used on 93-95 applications (and maybe even before that). It is basically a coil and magnet that generates an "AC" waveform that corresponds to the teeth on the output gear... These ECM/PCM systems typically used 2000 pulses per mile... The newer ones, as you mention, have switched to a hall-effect in place of the coil assembly (which eliminates not only an expensive [by comparison] coil but a buffer like the LM1815 or HIP9020, etc)... For higher resolution, these ECM/PCM systems have gone to using 4000 pulses per mile... HOWEVER, I don't think <-(key word here) they have changed the number of teeth on the output gear (if someone knows otherwise, please tell us) -- but on all the ones I've encountered, they have 40 teeth ... So for my circuit, with my tire size of 235/60R15 and diff ratio of 2.41 and given that you get 40 pulses (teeth) per revolution, I had to make a divider of 37.25 to get the 2000 ppm that my PCM needed (and it works very well) .... The signal the PCM, speedo, etc, wants to see is a 0 to 5v square wave. These are driven by OPEN COLLECTOR outputs in the divider circuit with pull-up resistors (the PCM has an internal pull-up to 5 volts) ... With the Hall-Effect, if it is like most hall effects, it already has an open-collector output -- SO, some of these PCMs don't even use an external divider (my 95 Formula Firebird is this way) -- it is all done inside the PCM ... However, on other vehicles, they still have the external divider... The typical hall-effect output looks like this: _____ Output (open collector) |/ H-E ----| |\>____GND Most hall-effects require a +5v power source, so typically 3 or 4 leads are used (+5V, Gnd, open-collector signal out, and optionally an extra "signal ground") ... This can go straight to the PCM (if the PCM has the internal dividers to handle the ratio)... On the older ones with the "generators", a buffer like the LM1815 and or HIP9020 is needed... There are only 2 wires from the sensor on these (signal and ground). Typically with this setup, they just make the "buffer circuit" into a "divider circuit" as well to handle the ratio conversions... (so the pcm doesn't have to know the tire sizes and gear ratios) ... And to complete the list, the older systems with the mechanical cable typically has an output gear that turns the "intermediate cable" -- The intermediate cable goes through a small gear box that via gear ratios does the division as needed for tire size, etc -- the output cable (that goes to the speedometer) turns at 1000 rotations per mile. On the back of the speedometer is a metal surface that has two "holes" evenly spaced... An LED interruptor is used for the ECM/PCM to pick up the speedometer cable turn... Since there are 2 holes and the cable turns at 1000 rot per mi, the result is 2000 pulses per mile -- with the output of the interruptor being the open-collector NPN driver transistor that all of the other setups use.... Hope this helps... If you need to make a "digital divider" circuit and don't know how to handle the fractions (assuming you want to -- I don't think GM even bothers with the fractions), let me know .. I've got several different circuits (both stand alone and cpu controlled) that can do divides down as far as 1/256 ... Donald Whisnant dewhisna@xxx.com ------------------------------ From: cloud@xxx.edu (tom cloud) Date: Thu, 1 Aug 1996 10:37:53 -0500 Subject: Re: Proper Mixture. >> A simple and effective indicator for O2 sensor is a DPM (digital >> panel meter) from Hosfelt Electronics. It is $14.95, their part >> number 39-165 (the part no. on the data says PM-128). It uses an >> Intersil ICL7106 DMM chip with a fairly standard wiring. There is >> one problem -- they have connected the supply voltage common with >> the input common, which can cause ground loop problems [snip] >This is a good meter but I am pretty sure the power supply ground and >the measuring circuit ground can not be the same. Thus can not run on >car voltage and still measure o2 volt which has the car gnd as common. >I have also used a 9 volt battery. That's why they are cheap. > > frank >> > I use these meters in a class I teach where the students build projects, and I have just finished scoping out the dilemma. The DPM in question uses the identical circuit recommended in the Intersil databook. I was wrong! The common and battery negative are not connected, but the reference voltage is derived from batt + with a voltage divider going to the DPM common, which is the "IN LO". Summary: the inputs are differential, but cannot go past either voltage rail (no problem -- the O2 sensor has one lead at ~ 0 and the other never exceeds ~ 1 volt). The ICL-7106 is spec'ed at 15 volts max, so the DPM "should" be OK being powered directly from the car system and should not have any problems with noise being induced into the sensor readings (certainly not enough so's one would notice). Frank .. if you've actually checked this out, would like to know. thanks, tom cloud ------------------------------ From: Gary W Harris Date: Thu, 01 Aug 96 08:26:00 PDT Subject: Re[2]: Proper Mixture. Text item: The best solution here is to get a complete gas tank assembly from a later model year vehicle that was OEM equipped with the in-tank pump. This tank will have the proper baffleing to prevent fuel starvation. the fuel return on these tanks also routs the fuel back to the baffled area, which helps maintain a constant fuel supply to the pump. Mike Knell's remote tank is a good solution if you can't get a "modern" fuel tank! Mike has a web page--http://www.jagsthatrun.com Regards, Gary In a message dated 96-07-31 10:42:31 EDT, you write: >My question is what effect does this have on the PCM and/or the engine? >For a little instance (unless the poppet valve just doesn't open at all >because of the air) the engine (at least a cylinder or too) would be >running very lean -- which over time, can't be good on it .. Also, how >will the PCM deal with it on the block learn??? I would not worry about what the ECM is doing..... What about running the pump dry? The ECM won't change dramatically in a couple seconds, and if you are on/off the throttle, probably won't change at all. I would think that running the pump dry might shorten it's life. The Mike Knell book on Chevrolet TPI and TBI Engine Swapping had a neat idea to stop engine from dying in this situation. He made a little reservoir box to hold fuel that fed the high pressure pump. A low pressure pump fed the box from the tank. Requires two fuel pumps, but solves the problem if you can't get a baffled fuel tank. Scot Sealander FIScot@xxx.com Text item: External Message Header The following mail header is for administrative use and may be ignored unless there are problems. ***IF THERE ARE PROBLEMS SAVE THESE HEADERS***. Reply-To: diy_efi@xxx.edu Precedence: bulk Sender: owner-diy_efi@xxx.edu Subject: Re: Proper Mixture. To: diy_efi@xxx.edu Message-ID: <960731225016_446775473@xxx.com> Date: Wed, 31 Jul 1996 22:54:33 -0400 Received: by emout14.mail.aol.com (8.6.12/8.6.12) id WAA26810 for diy_efi@coulom b.eng.ohio-state.edu; Wed, 31 Jul 1996 22:54:33 -0400 From: FIScot@xxx.com Received: from emout14.mail.aol.com by coulomb.eng.ohio-state.edu via ESMTP (940 816.SGI.8.6.9/940406.SGI) for id WAA03805; Wed, 31 Jul 1996 22:5 2:32 -0400 Received: by coulomb.eng.ohio-state.edu (940816.SGI.8.6.9/940406.SGI) id CAA03810; Thu, 1 Aug 1996 02:52:35 GMT Received: from coulomb.eng.ohio-state.edu (coulomb.eng.ohio-state.edu [128.146.9 0.150]) by ormail.intel.com (8.7.4/8.7.3) with SMTP id VAA20616 for ; Wed, 31 Jul 1996 21:11:44 -0700 (PDT) Received: from ormail.intel.com (ormail.intel.com [134.134.248.3]) by relay.jf.i ntel.com (8.7.4/8.7.3) with ESMTP id VAA12587 for ; Wed, 31 Jul 1996 21:11:53 -0700 (PDT) Return-Path: owner-diy_efi-outgoing@xxx.edu ------------------------------ From: ptimmerm@xxx.GOV Date: Thu, 1 Aug 1996 09:15:45 -0700 Subject: Digession on O2 Sensors >Everybody should keep in mind that the (so called) lambda sensor is not >measuring O2 or A/F at all. What it is is a galvanic cell which (at >temperature) will generate a voltage from EACH and EVERY component of the >exhaust gases. The voltage contribution of each of these is proportional to >their partial pressures, as well as some constants relating to their size >(permittivity of the sensor), and their electronegative potential. All though not an electrochemist (no pHd) I do play one on TV. Most of what you say above is correct, but you may be headed the wrong way with it. The ceramic used is a solid oxide that conducts oxygen at high temperatures. I doubt anything else is is transported across the oxide. This would effectively remove all other gases from the couple. I could be wrong, but I don't think so. paul timmerman electrochemcial system group jet propulstion labs pasadena ca ------------------------------ From: Tim Drury Date: Thu, 1 Aug 1996 13:17:17 -0400 Subject: Re: Circuits for magnetic pickups >If anyone get a good pickup going (no extra pulses) that uses the simple >op-amp, let me know. I would love to remove the lm1815 from the design. I am >far into the routing of the board, but I have a couple of extra amps in the >LMC6494 that I am using for O2 buffers. So I you guys get some good thig >working, shoot me some mail. Sandy, I always got good noise immunity by doing this: |-------- gain ---------- | | [pickup]----------------- + | | opamp >--------- --------------------- - | | GND This circuit uses an op-amp like a comparator (high pos-feedback). But what is important is using the other lead from the pickup as a ground reference and feeding it into the negative side of the op-amp. Any noise in the system (eg. ignition) will appear on both leads of the pickup and be cancelled out inside the op-amp. Here is something to consider: Does it matter where you ground the lead? At the sensor, or at the op-amp? - -tim ------------------------------ From: peter paul fenske Date: Thu, 01 Aug 1996 10:27:05 -0700 Subject: Re: Circuits for magnetic pickups Hi Oliver >On older transmissions GM used a PM generator as the Vehicle Speed Sensor. >It outputs a sine wave and about 4000 pulses per mile. This tends to give a sine wave whose frequency is proportional to speed oliver. It ranges from about half a volt to ten volts depending on vehicle speed. Magnetic field and all that > >The later model transmissions (it is Getrags I am particularly interested >in) they use a hall sensor of some kind that is triggered by a slotted >disc on the axle. That signal is run to the ECM/PCM which drives the >speedo at the usual 4000ppm. Hall effect devices generally deliver a square wave either five volts or 12 volts in amplitude. > >Now, I would like to use the new transmission on an older car, so I >would have to run the Hall sensor signal into a microprocessor that >generates the proper speed signal from it. I would just use a resistor network to slightly attenuate the hall output and perhaps a low pass filter(parallel cap) and a series cap to generate a zero crossing for the ECM. >Any help would be appreciated! > >Best regards, > >-Oliver Well oliver there are prob better answers out there. but dats all my sens GL: peter ------------------------------ From: Terry Sare Date: 1 Aug 96 14:25 CDT Subject: Re[2]: Circuits for magnetic pickups To cancel the voltage induced in both line you would probably need to ground the sensor side. Use a twisted pair to the sensor to have a balance line, otherwise common mode noise cancellation will not be as effective. You should also have some degree of hystresia in this as it is a high input impedance and will pickup non common mode voltage and oscillate. TS ______________________________ Reply Separator _________________________________ Subject: Re: Circuits for magnetic pickups Author: owner-diy_efi-outgoing@xxx.edu at dell_unix Date: 8/1/96 1:23 PM >If anyone get a good pickup going (no extra pulses) that uses the simple >op-amp, let me know. I would love to remove the lm1815 from the design. I am >far into the routing of the board, but I have a couple of extra amps in the >LMC6494 that I am using for O2 buffers. So I you guys get some good thig >working, shoot me some mail. Sandy, I always got good noise immunity by doing this: |-------- gain ---------- | | [pickup]----------------- + | | opamp >--------- --------------------- - | | GND This circuit uses an op-amp like a comparator (high pos-feedback). But what is important is using the other lead from the pickup as a ground reference and feeding it into the negative side of the op-amp. Any noise in the system (eg. ignition) will appear on both leads of the pickup and be cancelled out inside the op-amp. Here is something to consider: Does it matter where you ground the lead? At the sensor, or at the op-amp? - -tim ------------------------------ From: Doug Robson Date: Fri, 02 Aug 1996 07:06:04 +1100 Subject: Fred Miranda email address Whos got Freds email please - -- |===============================================================| | When I die, | | I want to go in my sleep, like my grandfather, | | not screaming like the passengers in his car. | |---------------------------------------------------------------| | Doug Robson mailto:doug@xxx.au | | Sydney, Australia http://www.cia.com.au/doug | |---------------------------------------------------------------| | Club Car Racing Register of NSW | Thank God | | 1992/93 Under 2 litre State Champion | for | | http://www.cia.com.au/doug/ccrrnsw.html | Gravity | |===============================================================| ------------------------------ From: "Stuart Woolford" Date: Fri, 2 Aug 1996 09:39:19 +1100 Subject: Re: EGT for feedback > I'm new to the list and to the whole DIY-EFI thing in general. All the > recent talk of O2 sensors has got me wondering about another source of > combustion feedback. Has anyone tried using exhaust gas temperature for > fine-tuning the intake mixture? It would seem to me that you could lean > the mixture to increase EGT or richen to lower EGT. If you'd done some > initial tuning with a gas analyzer to determine an optimum temp, this > would work. Any thoughts? I believe the local jet boat racers use that, on custom comupters (well, at least my bosses brother, who races jetboats, does..) - you would not BELIEVE what they paid to have this system designed (theres a sucker born.....) however, I believe it works well, and is fast, and it easyish to run 1 per cylinder. The biggest problem is the EGT sensors designed for this application cost a fortune! - I would just re-package standard TC wire (type-N, probably..) in a through-drilled bolt to hold it.. - ---------------------------------------------------------------------- Stuart Woolford, stuart@xxx.nz >>>>In VI Where Available<<<< - ---------------------------------------------------------------------- ------------------------------ From: dzorde@xxx.au Date: Fri, 02 Aug 96 08:27:36 Subject: Re[2]: Fuel pump sucking air (was: Re: Proper Mixture) I built a small 5L surge tank to fit in my boot. It was close to a half days work soldering up a copper tank out of a large pipe and some plate, add 4 small pipes for high pressure in and out and low pressure in and out. Buy an ordinary cheap electric fuel pump (no need for high pressure or high volume) and you are there. All up about AU$60. If you build it correctly (taller rather than wide) it'll be way better than any new baffled tank you can find. Dan dzorde@xxx.au ______________________________ Reply Separator _________________________________ Subject: Re: Fuel pump sucking air (was: Re: Proper Mixture) Author: diy_efi@xxx.edu at INTERNET Date: 8/1/96 11:28 PM > > From: FIScot@xxx.com X-ccAdmin: postmaster@guardia > Date: Wed, 31 Jul 1996 22:54:33 -0400 > Subject: Re: Proper Mixture. > > I would not worry about what the ECM is doing..... What about running the > pump dry? > The ECM won't change dramatically in a couple seconds, and if you are on/off > the throttle, probably won't change at all. > > I would think that running the pump dry might shorten it's life. The Mike > Knell book on Chevrolet TPI and TBI Engine Swapping had a neat idea to stop > engine from dying in this situation. He made a little reservoir box to hold > fuel that fed the high pressure pump. A low pressure pump fed the box from > the tank. Requires two fuel pumps, but solves the problem if you can't get a > baffled fuel tank. > > Scot Sealander FIScot@xxx.com > Hmmm ... Some how I'm afraid the extra pump, its plumbing, and the extra wiring would end up costing more than getting a baffled tank at a junk yard .... Actually, I'm more concerned about a "sudden lean condition" in the engine than I am about running the pump dry. The pump (a rotary vain high pressure/velocity pump) doesn't seem to mind the short quick bursts of no fuel ... I wouldn't want to run it long that way, as it would overheat, but for the short bursts that only occasionally happen I don't think it is a problem... Thanks for the suggestion, though, I never thaught about using 2 pumps -- neat idea... Donald Whisnant dewhisna@xxx.com ------------------------------ From: Darrell Norquay Date: Thu, 1 Aug 96 19:14 PDT Subject: Re: DPM (was Proper Mixture) At 10:37 AM 8/1/96 -0500, you wrote: >Summary: the inputs are differential, but cannot go past either >voltage rail (no problem -- the O2 sensor has one lead at ~ 0 and the >other never exceeds ~ 1 volt). The ICL-7106 is spec'ed at 15 volts >max, so the DPM "should" be OK being powered directly from the car system >and should not have any problems with noise being induced into the >sensor readings (certainly not enough so's one would notice). The automotive electrical system can have voltages as high as 16-18 volts steady state, and transient voltages a LOT higher than that. In my experience with DPM's, the 9V powered models artificially produce a ground halfway between the supply rails, so you cannot connect INLO to the - supply lead. Nor can you measure the voltage of the battery with the meter that it is powering, for the same reasons. Better off just to stick with the battery... regards dn dnorquay@xxx.com ------------------------------ From: garfield@xxx.com (Garfield) Date: Fri, 02 Aug 1996 01:12:43 GMT Subject: Re: EGT for feedback On Thu, 1 Aug 1996 08:16:04 -0400 (EDT), Michael T. Kasimirsky wrote: >All the >recent talk of O2 sensors has got me wondering about another source of >combustion feedback. Has anyone tried using exhaust gas temperature for >fine-tuning the intake mixture? It would seem to me that you could lean >the mixture to increase EGT or richen to lower EGT. I suppose many in this list know that this is exactly what is done on aviation engines, manually. With just a tach, the mixture is leaned to max RPM and then richened back 50 rpm, say. With an EGT, a thermocouple is stuck in the gas flow through a hole drilled in the exhaust stack of what is expected to be the hottest running jug just after the header, and again mixture is leaned to peak EGT and then enriched to 50-100deg drop, say, (much dependent on the engine). This manual procedure is still about the only option even in modern times, because the O2 sensors really get messed up by the ton of lead that is still in 100LL aviation fuel, the most common fuel used in 95% of all GA aircraft. Garfield ------------------------------ End of DIY_EFI Digest V1 #218 ***************************** 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".