DIY_EFI Digest Saturday, 23 November 1996 Volume 01 : Number 358 In this issue: Re: Air Flow Measurement re: Air Flow Measurement Re: MAF response curve re: Air Flow Measurement Re: Air Flow Measurement Re: Air Flow Measurement Re: Gasoline FAQ Re: Diff between theory and practice FORSALE: Engine Management System, Haltech E6 new SuperFlow intertia/eddy current dyno? Re: Gasoline FAQ Subaru Fault Codes See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: kleenair@xxx.com Date: Fri, 22 Nov 1996 11:23:34 -0800 Subject: Re: Air Flow Measurement > reads the oxygen content of the combustion products and outputs a > voltage. But us California folks have this horrible pump that forces > air into the headers to cut emissions, so how can the O2 sensor give an > accurate reading??. Any comments anyone. > > Neil Powell Usually, air pumps are connected to the exhaust through a diverter (air bypass) valve. The computer simply redirects the air back to the air cleaner when in closed loop operation, so no excess oxygen is pumped to the exhaust. Alternatively, I saw a 1996 truck (I forget the brand), that pumped the air down stream of the O2 sensor. ------------------------------ From: Jan =?iso-8859-1?Q?W=E4nnman?= Date: Fri, 22 Nov 96 19:18 GMT+0100 Subject: re: Air Flow Measurement Move the sensor before the airpump or vice vers ... / Janne >> >I have been following the discussion on closed/open loop A/F and O2 >sensor readings with great interest. I understand that the O2 sensor >reads the oxygen content of the combustion products and outputs a >voltage. But us California folks have this horrible pump that forces >air into the headers to cut emissions, so how can the O2 sensor give an >accurate reading??. Any comments anyone. > >Neil Powell > > > ------------------------------ From: Todd King Date: Fri, 22 Nov 96 10:57:00 PST Subject: Re: MAF response curve <<< From: "Scot A. Sealander" Date: Thu, 21 Nov 1996 18:39:59 -0800 Subject: Re: Air Flow Measurement ... under control. I have never plotted the Raw MAF to gps tables to see what the actual curve looks like. It is very obvious that it is not linear. Maybe when I get some time..... >>> I did some plotting a while back of some of the MAF freq output vs ECM gps output I collected in the Buick. It was a second or third order looking curve; best curve fit I got was a third order but it was a crude pencil and paper effort. The MAF sensor output was 30'ish Hz to about 144Hz; but as the freq got close to 144 Hz the slope of the plot really went towards vertical in a hurry. As a result a tiny change in MAF frequency produced a big change in ECM output in the upper ranges so I would question the absolute accuracy here. Appears to work OK in practice though. For the person that asked- ALDL is a GM term for Assembly Line Diagnostic Link. This is the access port for ECM data, ie plug in your scantool there. Todd Todd_King@xxx.com ------------------------------ From: cloud@xxx.edu (tom cloud) Date: Fri, 22 Nov 1996 14:37:08 -0600 Subject: re: Air Flow Measurement >I have been following the discussion on closed/open loop A/F and O2 >sensor readings with great interest. I understand that the O2 sensor >reads the oxygen content of the combustion products and outputs a >voltage. But us California folks have this horrible pump that forces >air into the headers to cut emissions, so how can the O2 sensor give an >accurate reading??. Any comments anyone. > >Neil Powell I think we all have the 'horrible pump' -- don't know about your question. Tom Cloud ------------------------------ From: Niels Ezerman Date: Fri, 22 Nov 1996 22:12:26 +0100 Subject: Re: Air Flow Measurement SRavet@xxx.com (Steve Ravet) wrote: > TLA=Three Letter Abbreviation. > > or Three Letter Acronym, > but acronym isn't exactly correct since an acronym needs to actually be a > word, and TLA isn't a word... > > Most of these are at the tail end of the EFI_REF list. I'll post it again > later today to both lists. Watch for it, it's in two parts. Very informative list, I have also made a list with TLA's: http://www.cybernet.dk/users/nez/forkort.htm It can take a little time, it has diff. color and in a table. Niels Ezerman Denmark. ------------------------------ From: "Chuck Tomlinson" Date: Fri, 22 Nov 1996 16:28:06 -0500 Subject: Re: Air Flow Measurement > From: Neil Powell > > I have been following the discussion on closed/open loop A/F and O2 > sensor readings with great interest. I understand that the O2 sensor > reads the oxygen content of the combustion products and outputs a > voltage. But us California folks have this horrible pump that forces > air into the headers to cut emissions, so how can the O2 sensor give an > accurate reading??. Any comments anyone. My Chevy as an electric air pump. It only runs during warm-up, before the engine first enters closed-loop. - -- Chuck Tomlinson ------------------------------ From: "John Faubion" Date: Fri, 22 Nov 1996 17:59:31 -0600 Subject: Re: Gasoline FAQ > I can not recall who sent the address, but does anyone have the url for the > "gasoline FAQ" which was tossed about a few months ago? My old server has > gone down and I lost all my addresses :( Its at http://www.vtr.org/maintain/gasoline-faq.html. ------------------------------ From: David Chambers Date: Sat, 23 Nov 1996 11:42:01 +1000 Subject: Re: Diff between theory and practice The difference on this motor could be due to the motor involved. With these 4AG toyota motors the inlet tract length is changed by the TVIS system. Removing these butterflies will change the torque point. Toyoto use this system to spread the tourque curve. It is a common racing change in australia to remove the butterflies which then gives you more torque at higher revs than before. With this modified motor the torque peak could well be occuring at 6000 rpm as the injector duty cycle implies. Regards David Chambers ------------------------------ From: Jeremy Pronk Date: Sat, 23 Nov 1996 14:11:55 +1100 (EST) Subject: FORSALE: Engine Management System, Haltech E6 I am considering selling the EMS system installed in my alfa. I would love to keep it, but if someone offers me enough, I need the money! (And will have to go back to carbies). The system is a Haltech E6, some specs (out of manual) are below: Outputs - -Controls 1-8 multipoint injectors - -IAC - -Ignition drive out - -Programmable general purpose output (NOS etc) - -Fuel pump power Input - -MAP - -Programmable general purpose input - -Coolant and intake air temp's - -TPS - -Engine speed pickup - -Optional EGO Adjustable features - -Fuel and ignition control - -Programmable general purpose output - -Real time emulation (Haltech can be programmed while engine is running) - -Fuel cut on decel - -Datalog - -Closed loop - -rpm limiter - -Idle speed strategy - -Adjustable accelerator pump - -Engine warm up cycles You need an ibm-pc (eg laptop with serial port) to program the ecu, it also comes with the software, manual and all the sensors (no EGO, I need that) fuel pumps, 4 injectors, ignition thing, pressure regulator etc. The system cost ~$4000 (including throttle bodies), but I am willing to let it go for around $1700AUS. I may also be interested in selling without the injectors/pumps or something. Just make me an offer! btw, this system supposably has one of the "easiest" to tune software programs on the market (bar charts, and quickmap functions rather than tables of numbers). regards, Jeremy, Sydney AUSTRALIA http://www.st.nepean.uws.edu.au/~jpronk/ '83 AlfaSud Ti (Haltech E6 efi) ------------------------------ From: "Frank/G.speed" Date: Fri, 22 Nov 1996 19:13:20 -0800 (PST) Subject: new SuperFlow intertia/eddy current dyno? Anyone of comment about this new dyno? My buddy is getting one (been waiting for a while, it's overdue by couple of quarters). I was curious if there were anything else out there. My buddy is raving about what he'll be able to do even though he don't have the darn thing yet... hehehe. I'm thinking about buying a ROM tuning system from Japan and do custom ROM programming for Japanese imports. - -- Frank M. Lin | G.speed - Z.Speed Trust HKS DC-Sports Razo/Carmate Soei fmlin@xxx.html EG2, 15.3 @xxx.info" u ssim I enirehtaC | Wanna try road racing with your car? http://am.net/nasa ------------------------------ From: Frank Mallory Date: Fri, 22 Nov 1996 23:36:13 -0800 Subject: Re: Gasoline FAQ John Brewer wrote: > > I can not recall who sent the address, but does anyone have the url for the > "gasoline FAQ" which was tossed about a few months ago? My old server has > gone down and I lost all my addresses :( > > John Brewer It is published periodically on rec.autos.tech. Suggest you go to that newsgroup and ask where to get it. > > "Any man who would trade liberty for security deserves neither." > Benjamin Franklin Thanks for the correct attribution. ------------------------------ From: firkins@xxx.au (John Firkins) Date: Sat, 23 Nov 1996 16:59:22 +1000 Subject: Subaru Fault Codes Hi all Does anyone have any idea on where to find out about the fault codes from a Subaru B2 cpu? It was originally fitted to a quad cam EJ20 motor & was working well in my Kombi until this morning. Now the ignition is momemtarily cut at revs above 4k & the led on the cpu is flashing 3 long,3 short,1long,2 short. TIA John Firkins ------------------------------ End of DIY_EFI Digest V1 #358 ***************************** 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".