From owner-diy_efi Fri Aug 5 18:44:21 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA11704; Fri, 5 Aug 94 18:44:21 GMT Received: from stdvax.gsfc.nasa.gov by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA11698; Fri, 5 Aug 94 14:44:18 -0400 Date: Fri, 5 Aug 1994 14:43:01 -0400 (EDT) From: OADDAB@STDVAX.GSFC.NASA.GOV (DIRK BROER) Message-Id: <940805144301.2861ca38@STDVAX.GSFC.NASA.GOV> Subject: Idle fuel mixture setting To: DIY_EFI X-Vmsmail-To: @EFI Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI General EFI question: On the mustang list - the question that came up is how the EFI sets the mixture at idle. For emission reasons I suspected that the EFI uses the O2 sensor to set the idle mixture at 14.7:1 Does anyone know if this is a hard and fast rule? I know some engines with radical cams like seeing more fuel at idle - but I always thought it was due to the exhaust contamination - you basically had to add more fuel to keep the ratio the same. The final ratio at the exhaust would still appear to be 14.7:1 by the O2 sensor. Can anyone shed some light on this? Dirk From owner-diy_efi Fri Aug 5 19:31:57 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA11815; Fri, 5 Aug 94 19:31:57 GMT Received: from gw1.att.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA11810; Fri, 5 Aug 94 15:31:55 -0400 Received: from uscbu.ih.att.com by ig2.att.att.com id AA11526; Fri, 5 Aug 94 15:30:39 EDT Received: by uscbu.ih.att.com (4.1/EMS-1.0.2 main.cf 1.37 10/5/93 (SMI-4.1/SVR4)) id AA07272; Fri, 5 Aug 94 14:30:19 CDT From: Bohdan.L.Bodnar@att.com Received: from usgp1.ih.att.com by uscbu.ih.att.com (4.1/EMS-1.0.2 main.cf 1.37 10/5/93 (SMI-4.1/SVR4)) id AA07268; Fri, 5 Aug 94 14:30:17 CDT Received: by usgp1.ih.att.com (5.0/EMS-1.1 client.cf 1/8/94 (SMI-4.1/SVR4)) id AA06654; Fri, 5 Aug 1994 14:30:17 +0600 Date: Fri, 5 Aug 1994 14:30:17 +0600 Message-Id: <9408051930.AA06654@usgp1.ih.att.com> Original-From: bohdan@uscbu.ih.att.com (Bohdan L Bodnar) To: DIY_EFI Subject: Re: Idle fuel mixture setting Content-Type: text Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI Dirk, et al., Idle actually runs richer than 14.7:1. There are several reasons for this (such as longer exhaust scavanging time at idle than off idle). I also know that some engines which do not use heated oxygen sensors run open loop at idle; this is because the O2 sensor will cool off and present incorrect readings to the computer which will then cause the engine to "hunt" as the air/fuel mixture varies wildly. I have some *good* auto mechanics books at home which cover this topic qualitatively; send me e-mail if you're interested in the titles, ISBN, etc. I think the particular book I have in mind also has a table listing approximate a/f ratios for various operating conditions. Regards, Bohdan bohdan.l.bodnar@att.com From owner-diy_efi Fri Aug 5 20:14:42 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA11947; Fri, 5 Aug 94 20:14:42 GMT Received: from knuth.mtsu.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA11942; Fri, 5 Aug 94 16:14:34 -0400 Received: by knuth.mtsu.edu (Smail3.1.28.1 #17) id m0qWVhJ-000MZPC; Fri, 5 Aug 94 15:16 CDT Message-Id: From: lusky@knuth.mtsu.edu (Jonathan R. Lusky) Subject: Re: Idle fuel mixture setting To: DIY_EFI Date: Fri, 5 Aug 1994 15:16:57 -0500 (CDT) In-Reply-To: <9408051930.AA06654@usgp1.ih.att.com> from "Bohdan.L.Bodnar@att.com" at Aug 5, 94 02:30:17 pm X-Mailer: ELM [version 2.4 PL23] Content-Type: text Content-Length: 953 Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI Bohdan.L.Bodnar@att.com writes: > Idle actually runs richer than 14.7:1. There are several reasons for > this (such as longer exhaust scavanging time at idle than off idle). I > also know that some engines which do not use heated oxygen sensors run > open loop at idle; this is because the O2 sensor will cool off and present > incorrect readings to the computer which will then cause the engine to > "hunt" as the air/fuel mixture varies wildly. Whoa, be careful with the blanket statements. I don't know about Fords, but GM stuff DEFINATELY tries to run closed loop at 14.7:1 at idle. I think your statment applies more to earlier attempts at closed loop fuel control than it does to modern systems. From an emissions standpoint, you'd want to be lean if anything at idle. -- Jonathan R. Lusky -- lusky@knuth.mtsu.edu "Turbos are nice but I'd rather be blown!" 68 Camaro Convertible - 350 / TH350 80 Toyota Celica - 20R / 5spd From owner-diy_efi Fri Aug 5 20:49:14 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA12015; Fri, 5 Aug 94 20:49:14 GMT Received: from quattro.corp.inmet.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA12010; Fri, 5 Aug 94 16:49:09 -0400 Received: by quattro.corp.inmet.com (5.0/SMI-SVR4) id AA26018; Fri, 5 Aug 1994 16:49:00 +0500 Date: Fri, 5 Aug 1994 16:49:00 +0500 From: walter@quattro.corp.inmet.com (Walter Meares) Message-Id: <9408052049.AA26018@quattro.corp.inmet.com> To: DIY_EFI Subject: Re: Idle fuel mixture setting X-Sun-Charset: US-ASCII Content-Length: 1188 Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI > Bohdan.L.Bodnar@att.com writes: > > Idle actually runs richer than 14.7:1. There are several reasons for > > this (such as longer exhaust scavanging time at idle than off idle). I > > also know that some engines which do not use heated oxygen sensors run > > open loop at idle; this is because the O2 sensor will cool off and present > > incorrect readings to the computer which will then cause the engine to > > "hunt" as the air/fuel mixture varies wildly. > > Whoa, be careful with the blanket statements. I don't know about Fords, but > GM stuff DEFINATELY tries to run closed loop at 14.7:1 at idle. I think > your statment applies more to earlier attempts at closed loop fuel > control than it does to modern systems. From an emissions standpoint, > you'd want to be lean if anything at idle. > I think the CIS-E on my Audi is closed loop at idle as well (85 4000S quattro). Can't remember offhand what A/F ratio it tries to hold there, but stoich would make the most sense. > -- > Jonathan R. Lusky -- lusky@knuth.mtsu.edu Walter -- Walter Meares Intermetrics, Inc. walter@inmet.inmet.com Information Systems 733 Concord Ave Cambridge MA 02138 (617) 661-1840 From owner-diy_efi Fri Aug 5 21:27:20 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA12287; Fri, 5 Aug 94 21:27:20 GMT Received: from spsgate.sps.mot.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA12282; Fri, 5 Aug 94 17:27:16 -0400 Received: from mogate (mogate.sps.mot.com) by spsgate.sps.mot.com (4.1/SMI-4.1/Email 2.1 10/25/93) id AA29175; Fri, 5 Aug 94 14:27:13 MST Received: from emailchd ([192.70.227.1]) by mogate (4.1/SMI-4.1/Email-2.0) id AA04778; Fri, 5 Aug 94 14:27:10 MST Received: by wdc.sps.mot.com (4.1/WDC-1.02) Fri, 5 Aug 94 14:27:00 MST Date: Fri, 5 Aug 94 14:27:00 MST From: Mark Shaw Message-Id: <9408052127.AA01634@wdc.sps.mot.com> To: DIY_EFI Subject: Re: Idle fuel mixture setting Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI > Bohdan.L.Bodnar@att.com writes: > > Idle actually runs richer than 14.7:1. There are several reasons for > > this (such as longer exhaust scavanging time at idle than off idle). I > > also know that some engines which do not use heated oxygen sensors run > > open loop at idle; this is because the O2 sensor will cool off and present > > incorrect readings to the computer which will then cause the engine to > > "hunt" as the air/fuel mixture varies wildly. Jonathan Lusky writes: > Whoa, be careful with the blanket statements. I don't know about Fords, but > GM stuff DEFINATELY tries to run closed loop at 14.7:1 at idle. I think > your statment applies more to earlier attempts at closed loop fuel > control than it does to modern systems. From an emissions standpoint, > you'd want to be lean if anything at idle. Double Whoa! The whole point of most post-1981 systems is to maintain the air-fuel ratio at stoichiometric (14.7) regardless of the engine's steady-state condition (transients usually violate the rule). Otherwise, the three-way catalyst will go out of it's narrow band where it will both reduce NOx (slightly rich of stoich) and oxidize CO and HC (slightly lean of stoich). A few percent either way and the catalytic converter's efficiency falls rapidly. Only the more recent systems with UEGO sensors will try to operate to the lean side of stoichiometric. Operation at 14.7 is a necessary condition for 3-way cats. The problem with unstable idle is usually the result of a deteriorated O2 sensor whose response time is too slow at the lower idle temps or the sensor has been located too far from the exhaust ports. The only open-loop operation I have seen is during the warmup phase. At least this is the Bosch approach to fuel control. Mark From owner-diy_efi Mon Aug 8 12:51:04 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA16908; Mon, 8 Aug 94 12:51:04 GMT Received: from gw1.att.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA16903; Mon, 8 Aug 94 08:51:02 -0400 Received: from uscbu.ih.att.com by ig1.att.att.com id AA08778; Mon, 8 Aug 94 08:50:11 EDT Received: by uscbu.ih.att.com (4.1/EMS-1.0.2 main.cf 1.37 10/5/93 (SMI-4.1/SVR4)) id AA15207; Mon, 8 Aug 94 07:50:49 CDT From: Bohdan.L.Bodnar@att.com Received: from usgp1.ih.att.com by uscbu.ih.att.com (4.1/EMS-1.0.2 main.cf 1.37 10/5/93 (SMI-4.1/SVR4)) id AA15203; Mon, 8 Aug 94 07:50:49 CDT Received: by usgp1.ih.att.com (5.0/EMS-1.1 client.cf 1/8/94 (SMI-4.1/SVR4)) id AA21631; Mon, 8 Aug 1994 07:50:47 +0600 Date: Mon, 8 Aug 1994 07:50:47 +0600 Message-Id: <9408081250.AA21631@usgp1.ih.att.com> Original-From: bohdan@uscbu.ih.att.com (Bohdan L Bodnar) To: DIY_EFI Subject: Re: Idle fuel mixture setting Content-Type: text Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI Jonathan, You are correct that GM stuff tries to run closed loop at idle. Note that I wrote "some engines" (I had Ford's 2.3 liters engine in mind...) run open loop. Hence, this was not a "blanket statement." The statement about running richer at idle is, to the best of my knowledge, correct. This is done for several reasons (I mentioned the increased scavanging time -- roughly, this can be viewed as an increase in EGR). The 14.7/1 a/f ratio is required for NOx reduction, not HC, CO oxidation. At idle, there is little NOx formation and therefore the need for tight operating bounds is not as great. Cordially, Bohdan From owner-diy_efi Mon Aug 8 20:02:18 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA18479; Mon, 8 Aug 94 20:02:18 GMT Received: from knuth.mtsu.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA18474; Mon, 8 Aug 94 16:02:06 -0400 Received: by knuth.mtsu.edu (Smail3.1.28.1 #17) id m0qXavl-000MWJC; Mon, 8 Aug 94 15:04 CDT Message-Id: From: lusky@knuth.mtsu.edu (Jonathan R. Lusky) Subject: Re: Idle fuel mixture setting To: DIY_EFI Date: Mon, 8 Aug 1994 15:04:21 -0500 (CDT) In-Reply-To: <9408081250.AA21631@usgp1.ih.att.com> from "Bohdan.L.Bodnar@att.com" at Aug 8, 94 07:50:47 am X-Mailer: ELM [version 2.4 PL23] Content-Type: text Content-Length: 811 Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI Bohdan.L.Bodnar@att.com writes: > The statement about running richer at idle is, to the best of my knowledge, > correct. This is done for several reasons (I mentioned the increased > scavanging time -- roughly, this can be viewed as an increase in EGR). The > 14.7/1 a/f ratio is required for NOx reduction, not HC, CO oxidation. At > idle, there is little NOx formation and therefore the need for tight operating > bounds is not as great. Right, but if anything, you'd want to go lean at idle, not rich. I don't have any tables handy but CO generally goes thru the roof just rich of stoich and rapidly approaches nil on the lean side. -- Jonathan R. Lusky -- lusky@knuth.mtsu.edu "Turbos are nice but I'd rather be blown!" 68 Camaro Convertible - 350 / TH350 80 Toyota Celica - 20R / 5spd From owner-diy_efi Wed Aug 10 16:25:23 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA12678; Wed, 10 Aug 94 16:25:23 GMT Received: from gw1.att.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA12673; Wed, 10 Aug 94 12:25:21 -0400 Received: from uscbu.ih.att.com by ig1.att.att.com id AA07631; Wed, 10 Aug 94 12:24:27 EDT Received: by uscbu.ih.att.com (4.1/EMS-1.0.2 main.cf 1.37 10/5/93 (SMI-4.1/SVR4)) id AA11661; Wed, 10 Aug 94 11:25:07 CDT From: Bohdan.L.Bodnar@att.com Received: from usgp1.ih.att.com by uscbu.ih.att.com (4.1/EMS-1.0.2 main.cf 1.37 10/5/93 (SMI-4.1/SVR4)) id AA11652; Wed, 10 Aug 94 11:25:06 CDT Received: by usgp1.ih.att.com (5.0/EMS-1.1 client.cf 1/8/94 (SMI-4.1/SVR4)) id AA05052; Wed, 10 Aug 1994 11:25:07 +0600 Date: Wed, 10 Aug 1994 11:25:07 +0600 Message-Id: <9408101625.AA05052@usgp1.ih.att.com> Original-From: bohdan@uscbu.ih.att.com (Bohdan L Bodnar) To: DIY_EFI Subject: servicing ref books Content-Type: text Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI As promised, here is the pertinent information about the books I mentioned on auto servicing: ENGINE PERFORMANCE DIAGNOSIS AND TUNE-UP, 2nd ed., Chek-Chart Publications, Harper-Collins, pub., 1989 ISBN 0-06-45018-9. This is a set of two books: a classroom manual and a shop manual. Chapter titles (in order): Engine Operating Principles Engine Air-Fuel Requirements Engine Lubrication Cooling and Exhaust Systems Introduction to Emission Controls What is a Tune-up? The Battery, Charging, and Starting Systems The Ignition Primary Circuit and Components The Ignition Secondary Circuit and Components Ignition Timing and Spark Advance Control Solid-State Electronic Ignition Systems Fuel System Operation Basic Carburetion and Manifolding Electronic Fuel Metering Control Electronic Engine Control Systems Gasoline Fuel Injection Systems Supercharging and Turbocharging Positive Crankcase Ventilation Air Injection Exhaust Gas Recirculation Catalytic Converters The book is divided into several section with each section comprised of several chapters (incidently, the second chapter has some Chevrolet graphs which CLEARLY show a/f mixture is richer at idle than at cruising speed). Keep in mind that this set of books is for service technicians. Therefore, much of the presented data is of a qualitative nature. For people who are primarily interested in ensuring that their car passes local emission tests (BIG grin!) or who are interested in a good general background book set, this is probably an excellent LOW COST (around $25) investment. BTW, Chek-Chart also has an excellent book set on braking systems (including some stuff on antilock brakes), one on engine rebuilding (I've seen it, but don't own it) and, possibly, a few more. Feel free to send me e-mail (bohdan.l.bodnar@att.com) if you're interested in details. Cordially, Bohdan From owner-diy_efi Wed Aug 10 23:07:46 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA14916; Wed, 10 Aug 94 23:07:46 GMT Received: from student4.cl.msu.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA14911; Wed, 10 Aug 94 19:07:43 -0400 Received: by student4.cl.msu.edu (AIX 3.2/UCB 5.64/MSU-2.08A) id AA71477; Wed, 10 Aug 1994 19:07:47 -0400 From: Loelle S Poneleit Message-Id: <9408102307.AA71477@student4.cl.msu.edu> Subject: co% To: DIY_EFI Date: Wed, 10 Aug 1994 19:07:47 -0400 (EDT) X-Mailer: ELM [version 2.4 PL22] Content-Type: text Content-Length: 165 Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI does anyone have a table that compares CO readings to air/fuel ratios. Iam trying to use a O2 sensor to set the CO on a bosch l-jetronic inj.system. John C Haley From owner-diy_efi Thu Aug 18 20:25:37 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA13879; Thu, 18 Aug 94 20:25:37 GMT Received: from relay.hp.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA13864; Thu, 18 Aug 94 16:25:19 -0400 Received: from hpmwtd.sr.hp.com by relay.hp.com with SMTP (1.37.109.8/15.5+ECS 3.3) id AA06093; Thu, 18 Aug 1994 13:25:17 -0700 Received: from eagle.sr.hp.com by hpmwtd.sr.hp.com with SMTP (15.11.1.6/15.5+ECS 3.3) id AA17062; Thu, 18 Aug 94 13:25:14 -0700 Received: by eagle.sr.hp.com (1.37.109.8/15.5+ECS 3.3) id AA25664; Thu, 18 Aug 1994 13:25:04 -0700 From: Craig Eid Message-Id: <9408182025.AA25664@eagle.sr.hp.com> Subject: FORD EEC_IV control systems To: DIY_EFI Date: Thu, 18 Aug 1994 13:25:04 -0800 (PDT) X-Mailer: ELM [version 2.4 PL21] Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Length: 438 Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI I'm starting to tinker with my EEC-IV system and wondered if anyone has done any in-depth mods to the computer. I've heard of a couple of bootleg computers that are floating around (modifications of EEC's out of wrecked cars) but haven't been able to substantiate this info. Does anyone have any leads? Craig -- Craig Eid Manufacturing Development Engineer Microwave Instruments Division, Hewlett Packard e-mail address craige@sr From owner-diy_efi Thu Aug 18 21:27:20 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA14217; Thu, 18 Aug 94 21:27:20 GMT Received: from stdvax.gsfc.nasa.gov by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA14211; Thu, 18 Aug 94 17:27:15 -0400 Date: Thu, 18 Aug 1994 17:26:06 -0400 (EDT) From: OADDAB@STDVAX.GSFC.NASA.GOV (DIRK BROER) Message-Id: <940818172606.2b00c27a@STDVAX.GSFC.NASA.GOV> Subject: Re: Ford EEC_IV control systems To: DIY_EFI X-Vmsmail-To: @EFI Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI >I'm starting to tinker with my EEC-IV system and wondered if anyone has >done any in-depth mods to the computer. I've heard of a couple of >bootleg computers that are floating around (modifications of EEC's out >of wrecked cars) but haven't been able to substantiate this info. Does >anyone have any leads? Could you post some specifics - like what processor and what chips are on the board. I understand the ford system has the prom solder in place - and maybe even potted. Could a standoff be solder in its place? Are we talking surface mount or .100 lead spacing stuff? (I think they started them in 1982ish - kinda early for surface mount no? I can look up the chips myself. The reason I'm interested is that the ford unit was always sequential fuel injected - and got all its firing signal from the distributer. Sounds like a neat system if you want a quick / complete computer to test out algorithms. Dirk PS. does anyone have any info on the LT1 computer (chevy corvette, new firebird / camaro) It is also a MAF sensor / sequential injection. From owner-diy_efi Thu Aug 18 21:41:49 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA14253; Thu, 18 Aug 94 21:41:49 GMT Received: from grolsch-2.cs.ubc.ca by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA14248; Thu, 18 Aug 94 17:41:45 -0400 Received: (from ean@localhost) by grolsch.cs.ubc.ca (8.6.9/8.6.9) id OAA16651 for DIY_EFI@coulomb.eng.ohio-state.edu; Thu, 18 Aug 1994 14:41:42 -0700 X400-Received: by mta cs.ubc.ca in /PRMD=/ADMD=/C=/; Relayed; Thu, 18 Aug 1994 14:41:40 UTC-0700 X400-Received: by /PRMD=ca/ADMD=/C=/; Relayed; Thu, 18 Aug 1994 14:41:40 UTC-0700 Date: Thu, 18 Aug 1994 14:41:40 UTC-0700 X400-Originator: rodb@cs.ubc.ca X400-Recipients: non-disclosure:; X400-Content-Type: P2-1984 (2) X400-Mts-Identifier: [/PRMD=ca/ADMD=/C=/;940818144140] Content-Identifier: 1533 Conversion: Prohibited From: Rod Barman To: DIY_EFI In-Reply-To: <940818172606.2b00c27a@STDVAX.GSFC.NASA.GOV> Message-Id: <"1533*rodb@cs.ubc.ca"@MHS> Subject: Re: Ford EEC_IV control systems Mime-Version: 1.0 (Generated by Ean X.400 to MIME gateway) Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI If you are interested in ford fi check out the new bentley book by probst. It is full of info although it doesn't go into the low-level hardware in any great detail. Both this book and the bosch bentley book are great. The two bosch handbooks are also great references. --rod. -- Rod Barman, IRIS NCE @ Laboratory for Computational Intelligence, University of British Columbia rodb@cs.ubc.ca