From Diy_Efi-Owner Thu May 19 20:19:03 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA25241; Thu, 19 May 94 20:19:03 GMT Received: from wilgate.wiltel.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/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 AA25235; Thu, 19 May 94 16:18:59 -0400 Received: from hal01.wiltel.com by wilgate.wiltel.com with SMTP id AA11621 (5.67b/IDA-1.5 for ); Thu, 19 May 1994 15:20:50 -0500 Received: from atg by hal01.wiltel.com (NX5.67d/NX3.0S) id AA04820; Thu, 19 May 94 15:17:01 -0500 Received: from wtg7 by atg.wiltel.com (NX5.67d/NX3.0M) id AA21494; Thu, 19 May 94 15:17:00 -0500 From: Tony Johnson Message-Id: <9405192017.AA21494@atg.wiltel.com> Received: by wtg7 (NX5.67d/NX3.0X) id AA08505; Thu, 19 May 94 15:13:31 -0500 Date: Thu, 19 May 94 15:13:31 -0500 Received: by NeXT.Mailer (1.100.RR) Received: by NeXT Mailer (1.100.RR) To: DIY_EFI Subject: Info on EFI systems Next-Attachment: .tar.554.Info_on_EFI_systems.attach, 1776, 1/1, 2442, 0 Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI begin 666 .tar.554.Info_on_EFI_systems.attach M'YV0:=R0*8/'A1PZ9@`H7,BPH<.'$"-*G$BQ(HB+-FC0``'@8@P9,S9VO'@1 M!D>2*$'4H%'C8HT:-FS#32.(P'!XX=&'E^H4>"!;@!1%AMTK.7"&&^TH0!=355IY9589JGE MEEQVZ>678(8IYIADEFGFF6BFJ>::;+;IYIM%!32'=1*6(8=M909AD(#H/)`H``\4.@=0X21HD!VN@!'&VDHY"M M00@M5``X#KQ*@!)IM#%$0]TB46R@Y)J+KKKLFF$<'=;E":^\'$>A1,))<+46 M&T*82`?$MRH$#T>5)H"#$&'NT47$,Q1KX-H"UUBC;NF[74Z\JZ`/)+MLL=RZ4X:G!4+A#*0`+K.%& M&F>@00>T9T2M$`%@T!#VTDW7\30<=8C!ZBEAN_`&'&4(E(8<4$L]-1M60R%' M0&^Y<0;.#1$`10[@DIH$E%9!H3@:RW:UU:<2XS)(3Q4D,5`8G%X84!GK5GMM MMML>[438F&JJNW'SH4VWKN%"T#:S;#@K.K1RTT[W`*E#$$000T39QA1C?`[' MS0P(4ZYP5IV\AJQ!,6`[WV/#D8RD`+=T)`!P*(8=T,`$I:3!H$USFM1"*$+ MW&"&.=0`!S;8&*OFM;;E\2X,OH,?Z6`%!4"HD(5SL`$,93BU>X4K`@P"#]#$ MD``E#W#*IC:WRO.;X`RG.,=)SG(.!2=C ` end From Diy_Efi-Owner Thu May 19 21:17:27 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA25320; Thu, 19 May 94 21:17:27 GMT Received: from knuth.mtsu.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/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 AA25313; Thu, 19 May 94 17:17:13 -0400 Received: by knuth.mtsu.edu (Smail3.1.28.1 #17) id m0q4FSN-000AVPC; Thu, 19 May 94 16:16 CDT Message-Id: From: lusky@knuth.mtsu.edu (Jonathan R. Lusky) Subject: Re: Info on EFI systems To: DIY_EFI Date: Thu, 19 May 1994 16:16:43 -0500 (CDT) In-Reply-To: <9405192017.AA21494@atg.wiltel.com> from "Tony Johnson" at May 19, 94 03:13:31 pm X-Mailer: ELM [version 2.4 PL23] Content-Type: text Content-Length: 468 Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI Tony Johnson writes: > > begin 666 .tar.554.Info_on_EFI_systems.attach > M'YV0:=R0*8/'A1PZ9@`H7,BPH<.'$"-*G$BQ(HB+-FC0``'@8@P9,S9VO'@1 > M!D>2*$'4H%'C8HT:-FS MZ1XN!\W`X!+&S9PT3\V\<4.'CA@V7*2&G7,GS9PY()"486.G#)TT8\+LZ*.` What the heck was this? -- Jonathan R. Lusky -- lusky@knuth.mtsu.edu "Turbos are nice but I'd rather be blown!" 89 Jeep Wrangler - 258 / For Sale: $8000 obo 80 Toyota Celica - 20R / 5spd From Diy_Efi-Owner Thu May 19 21:17:51 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA25328; Thu, 19 May 94 21:17:51 GMT Received: from spsgate.sps.mot.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/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 AA25322; Thu, 19 May 94 17:17:47 -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 AA14130; Thu, 19 May 94 14:17:45 MST Received: from emailchd ([192.70.227.1]) by mogate (4.1/SMI-4.1/Email-2.0) id AA08030; Thu, 19 May 94 14:17:43 MST Received: by wdc.sps.mot.com (4.1/WDC-1.02) Thu, 19 May 94 14:15:42 MST Date: Thu, 19 May 94 14:15:42 MST From: Mark Shaw Message-Id: <9405192115.AA04779@wdc.sps.mot.com> To: DIY_EFI Subject: Roster? Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI Has anyone gathered a roster of the participants and listeners to this list? Also, what are the expertise and objectives? Mark From Diy_Efi-Owner Fri May 20 16:43:43 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA28774; Fri, 20 May 94 16:43:43 GMT Received: from wotan.compaq.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/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 AA28768; Fri, 20 May 94 12:43:37 -0400 Received: from twisto.eng.hou.compaq.com by wotan.compaq.com with smtp (Smail3.1.28.1 #6) id m0q4XV5-0002daC; Fri, 20 May 94 11:32 CDT Received: from bangate.compaq.com by twisto.eng.hou.compaq.com with smtp (Smail3.1.28.1 #8) id m0q4XV5-000pduC; Fri, 20 May 94 11:32 CDT Message-Id: Received: by bangate.compaq.com with VINES ; Fri, 20 May 94 11:32:44 CDT Date: Fri, 20 May 94 11:01:48 CDT From: Steve=Ravet%Prj=Eng%PCPD=Hou@bangate.compaq.com Subject: re: Info on EFI systems To: twisto.eng.hou.compaq.com!wotan!coulomb.eng.ohio-state.edu!Diy_Efi Cc: Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI Tony Johnson Wrote: | | | begin 666 .tar.554.Info_on_EFI_systems.attach | M'YV0:=R0*8/'A1PZ9@`H7,BPH<.'$"-*G$BQ(HB+-FC0``'@8@P9,S9VO'@1 Y'all can ignore this. It's a tarred, compressed, uuencoded postscript file, which when printed is a message asking to be signed up to the list. I say we sign him up, but send his mail the same way. :-) How could someone who knows how to compress, tar, and uuencode not know how to join a mailing list? ObEFI: What are possible algorithms for electronically controlled ignition? I think a closed loop system using feedback to continuously modify timing is a better solution than static lookup tables, but what do you use for feedback? Exhaust temp/composition? --steve From Diy_Efi-Owner Fri May 20 17:51:27 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA29002; Fri, 20 May 94 17:51:27 GMT Received: from knuth.mtsu.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/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 AA28995; Fri, 20 May 94 13:51:18 -0400 Received: by knuth.mtsu.edu (Smail3.1.28.1 #17) id m0q4Yih-000B2mC; Fri, 20 May 94 12:50 CDT Message-Id: From: lusky@knuth.mtsu.edu (Jonathan R. Lusky) Subject: Re: Info on EFI systems To: DIY_EFI Date: Fri, 20 May 1994 12:50:51 -0500 (CDT) In-Reply-To: from "Steve=Ravet%Prj=Eng%PCPD=Hou@bangate.compaq.com" at May 20, 94 11:01:48 am X-Mailer: ELM [version 2.4 PL23] Content-Type: text Content-Length: 871 Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI Steve=Ravet%Prj=Eng%PCPD=Hou@bangate.compaq.com writes: > ObEFI: What are possible algorithms for electronically controlled ignition? > Ithink a closed loop system using feedback to continuously modify timing is a > better solution than static lookup tables, but what do you use for feedback? > Exhaust temp/composition? Exhaust temp and composition vary widely with a bunch of factors besides spark timing, so I don't think either are appropriate. I think the only effective way to do closed loop spark is with a pressure sensor, a crank angle sensor, and calculating the location (degrees ATDC) of peak cylinder pressure. You'd still want to have a static map beneath this I think. -- Jonathan R. Lusky -- lusky@knuth.mtsu.edu "Turbos are nice but I'd rather be blown!" 89 Jeep Wrangler - 258 / For Sale: $8000 obo 80 Toyota Celica - 20R / 5spd From Diy_Efi-Owner Fri May 20 19:31:49 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA29545; Fri, 20 May 94 19:31:49 GMT Received: from wotan.compaq.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/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 AA29539; Fri, 20 May 94 15:31:44 -0400 Received: from twisto.eng.hou.compaq.com by wotan.compaq.com with smtp (Smail3.1.28.1 #6) id m0q4aGf-0002d7C; Fri, 20 May 94 14:30 CDT Received: from bangate.compaq.com by twisto.eng.hou.compaq.com with smtp (Smail3.1.28.1 #8) id m0q4aGe-000pdTC; Fri, 20 May 94 14:30 CDT Message-Id: Received: by bangate.compaq.com with VINES ; Fri, 20 May 94 14:30:03 CDT Date: Fri, 20 May 94 14:01:36 CDT From: Steve=Ravet%Prj=Eng%PCPD=Hou@bangate.compaq.com Subject: re: Re: Info on EFI systems To: twisto.eng.hou.compaq.com!wotan!coulomb.eng.ohio-state.edu!Diy_Efi Cc: Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI lusky@knuth.mtsu.edu (Jonathan R. Lusky) Wrote: | | | Steve=Ravet%Prj=Eng%PCPD=Hou@bangate.compaq.com writes: | > ObEFI: What are possible algorithms for electronically | controlled ignition? | > Ithink a closed loop system using feedback to continuously | modify timing is a | > better solution than static lookup tables, but what do you use | for feedback? | > Exhaust temp/composition? | | Exhaust temp and composition vary widely with a bunch of factors besides | spark timing, so I don't think either are appropriate. I think the only | effective way to do closed loop spark is with a pressure sensor, a crank | angle sensor, and calculating the location (degrees ATDC) of peak | cylinder pressure. You'd still want to have a static map beneath | this | I think. Well, how about this: it takes a certain amount of time for the fuel to completely burn. This should be relatively constant regardless of rpm. You want most of the burn to happen at max compression. So the timing has to be advanced with increasing rpm to give the burn a "head start" with respect to compression, which happens faster at higher rpms. This would imply that once you know how fast the flame front travels, you could calculate the advance for any rpm. But this doesn't take into account the type of fuel, etc. so there must be something else. Do higher octane fuels burn faster/slower? actually, re-reading your reply above is causing light to dawn. As the fuel burns, the pressure in the cylinder increases, right? for max torque, you want this pressure peak to occur at a certain angle atdc, right? so if you have a pressure sensor in the cylinder, you can measure pressure vs. crank angle, and vary the timing to keep the peak where you want it. is this basically correct? so are there pressure sensors that can survive in the cylinder, and from where can they be had? on another note, incoming mail is addressed to 'diy_efi@whatever' when i use reply, it gets addressed to 'diy_efi-owner@whatever', causing john much grief. if anyone has a suggestion for why this is happening, i'd like to fix it. --steve From Diy_Efi-Owner Fri May 20 19:44:10 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA29586; Fri, 20 May 94 19:44:10 GMT Received: from wotan.compaq.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/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 AA29580; Fri, 20 May 94 15:44:06 -0400 Received: from twisto.eng.hou.compaq.com by wotan.compaq.com with smtp (Smail3.1.28.1 #6) id m0q4aMO-0002dYC; Fri, 20 May 94 14:35 CDT Received: from bangate.compaq.com by twisto.eng.hou.compaq.com with smtp (Smail3.1.28.1 #8) id m0q4aMN-000pdTC; Fri, 20 May 94 14:35 CDT Message-Id: Received: by bangate.compaq.com with VINES ; Fri, 20 May 94 14:35:59 CDT Date: Fri, 20 May 94 14:35:19 CDT From: Steve=Ravet%Prj=Eng%PCPD=Hou@bangate.compaq.com Subject: ignition control.... To: diy_efi Cc: Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI lusky@knuth.mtsu.edu (Jonathan R. Lusky) Wrote: | | | Steve=Ravet%Prj=Eng%PCPD=Hou@bangate.compaq.com writes: | > ObEFI: What are possible algorithms for electronically | controlled ignition? | > Ithink a closed loop system using feedback to continuously | modify timing is a | > better solution than static lookup tables, but what do you use | for feedback? | > Exhaust temp/composition? | | Exhaust temp and composition vary widely with a bunch of factors besides | spark timing, so I don't think either are appropriate. I think the only | effective way to do closed loop spark is with a pressure sensor, a crank | angle sensor, and calculating the location (degrees ATDC) of peak | cylinder pressure. You'd still want to have a static map beneath | this | I think. Well, how about this: it takes a certain amount of time for the fuel to completely burn. This should be relatively constant regardless of rpm. You want most of the burn to happen at max compression. So the timing has to be advanced with increasing rpm to give the burn a "head start" with respect to compression, which happens faster at higher rpms. This would imply that once you know how fast the flame front travels, you could calculate the advance for any rpm. But this doesn't take into account the type of fuel, etc. so there must be something else. Do higher octane fuels burn faster/slower? actually, re-reading your reply above is causing light to dawn. As the fuel burns, the pressure in the cylinder increases, right? for max torque, you want this pressure peak to occur at a certain angle atdc, right? so if you have a pressure sensor in the cylinder, you can measure pressure vs. crank angle, and vary the timing to keep the peak where you want it. is this basically correct? so are there pressure sensors that can survive in the cylinder, and from where can they be had? on another note, incoming mail is addressed to 'diy_efi@whatever' when i use reply, it gets addressed to 'diy_efi-owner@whatever', causing john much grief. if anyone has a suggestion for why this is happening, i'd like to fix it. --steve From Diy_Efi-Owner Fri May 20 21:22:10 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA29934; Fri, 20 May 94 21:22:10 GMT Received: from mn.ecn.purdue.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/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 AA29928; Fri, 20 May 94 17:22:06 -0400 Received: from mn.ecn.purdue.edu (armfield@localhost) by mn.ecn.purdue.edu (8.6.8/3.4davy) id QAA02791; Fri, 20 May 1994 16:22:04 -0500 Message-Id: <199405202122.QAA02791@mn.ecn.purdue.edu> Date: Fri, 20 May 1994 16:22:04 -0500 From: Jeffrey S Armfield To: DIY_EFI Subject: Pressure Sensors Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI You can buy quartz pressure sensors from PCB and Kistler but these tend to be pricey and more oriented toward research. You also need a charge amp to go with the pressure sensor. Bosch just published an SAE paper (940379) that describes a new pressure sensor that they use for misfire detection , knock control , ignition control , etc. I have a feeling that you may be seeing these in pass. cars in the not too distant future. Still some signal processing circuitry required but the price has to be better than a PCB or Kistler unit. Jeff Armfield From Diy_Efi-Owner Fri May 20 23:37:13 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA00241; Fri, 20 May 94 23:37:13 GMT Received: from knuth.mtsu.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/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 AA00234; Fri, 20 May 94 19:36:52 -0400 Received: by knuth.mtsu.edu (Smail3.1.28.1 #17) id m0q4cYH-000BlyC; Fri, 20 May 94 16:56 CDT Message-Id: From: lusky@knuth.mtsu.edu (Jonathan R. Lusky) Subject: Re: Re: Info on EFI systems To: DIY_EFI Date: Fri, 20 May 1994 16:56:21 -0500 (CDT) In-Reply-To: from "Steve=Ravet%Prj=Eng%PCPD=Hou@bangate.compaq.com" at May 20, 94 02:01:36 pm X-Mailer: ELM [version 2.4 PL23] Content-Type: text Content-Length: 3097 Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI Steve=Ravet%Prj=Eng%PCPD=Hou@bangate.compaq.com writes: > | > Ithink a closed loop system using feedback to continuously > | modify timing is a > | > better solution than static lookup tables, but what do you use > | for feedback? > | > Exhaust temp/composition? > | Exhaust temp and composition vary widely with a bunch of factors besides > | spark timing, so I don't think either are appropriate. I think the only > | effective way to do closed loop spark is with a pressure sensor, a crank > | angle sensor, and calculating the location (degrees ATDC) of peak > | cylinder pressure. You'd still want to have a static map beneath > | this I think. > Well, how about this: it takes a certain amount of time for the fuel to > completely burn. This should be relatively constant regardless of rpm. > You want most of the burn to happen at max compression. So the timing > has to be advanced with increasing rpm to give the burn a "head start" with > respect to compression, which happens faster at higher rpms. This would > imply that once you know how fast the flame front travels, you could > calculate the advance for any rpm. But this doesn't take into account > the type of fuel, etc. so there must be something else. Do higher octane > fuels burn faster/slower? Actually, while I believe thats the typical non-technical explanation of why spark advance is necessary, its very wrong according to Heywood (someone posted a summary of the correct explanantion of rec.autos.tech within the past few days... I really ought to pick up a copy of Heywood sometime). Burn rate increases with RPM, but ignition time remains constant, thats why you need advance. For a feedback system, you aren't really concerned with the details I don't think, you just want to make sure peak pressure is at the appropriate place (~19deg ATDC???) and that the area under the pressure vs crankangle? curve is maximized. > actually, re-reading your reply above is causing light to dawn. As the fuel > burns, the pressure in the cylinder increases, right? for max torque, you > want this pressure peak to occur at a certain angle atdc, right? so if you > have a pressure sensor in the cylinder, you can measure pressure vs. crank > angle, and vary the timing to keep the peak where you want it. is this > basically correct? so are there pressure sensors that can survive in the > cylinder, and from where can they be had? Yep, that exactly what I meant. There are sensors designed for this, but I'm not sure of their cost or durability. > on another note, incoming mail is addressed to 'diy_efi@whatever' > when i use reply, it gets addressed to 'diy_efi-owner@whatever', > causing john much grief. if anyone has a suggestion for why > this is happening, i'd like to fix it. Sounds like your mail program is ignoring the Reply-To: line in the header and sending replies to the address in the From: line. -- Jonathan R. Lusky -- lusky@knuth.mtsu.edu "Turbos are nice but I'd rather be blown!" 89 Jeep Wrangler - 258 / For Sale: $8000 obo 80 Toyota Celica - 20R / 5spd From Diy_Efi-Owner Sun May 22 07:01:08 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA02986; Sun, 22 May 94 07:01:08 GMT Received: from eigen.ee.ualberta.ca by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo/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 AA02980; Sun, 22 May 94 03:00:54 -0400 Message-Id: <9405220700.AA02980@coulomb.eng.ohio-state.edu> Received: by eigen.ee.ualberta.ca (1.37.109.4/15.6) id AA15848; Sun, 22 May 94 01:00:51 -0600 From: Dale Ulan Subject: Re: 68HC11F1 To: DIY_EFI Date: Sun, 22 May 94 1:00:49 MDT In-Reply-To: <9405191857.AA24920@coulomb.eng.ohio-state.edu>; from "John S Gwynne" at May 19, 94 2:57 pm Mailer: Elm [revision: 70.85] Sender: Diy_Efi-Owner Precedence: bulk Reply-To: DIY_EFI > > 65%... I'm impressed. Do you think there is enough "head room" (extra memory > and CPU cycles) to write all the software in C? > Not the C compilers I've seen (the free ones). Maybe the commercial compilers would work better. I'm sticking to assembler for my stuff because I can't afford a big commercial compiler... > Could you share with us your general I/O configuration? Sure. Here goes: Timer Ports: IC1: camshaft position encoder (not presently used) IC2: crank position # 1 IC3: crank position # 2 OC2,3,4,5: fuel injector control OC1: ignition control Ports: PD2: ignition route select (#1/#2) PD3: stepper controller (idle) STEP PD4: stepper controller (idle) DIRECTION PD5: stepper controller (idle) LOWPOWER Port G: CSPROG used to select a 27C512 EPROM chip, although I used a 27C256. CSIO1 used to select a 74HC574 latch for output. The remaining 6 port G lines are used as inputs: A/C request in, Start Signal in, PS Pump pressure, Neutral/ingear/clutch, 2 spares. All 8 outputs from my 74HC574 go to MTP3055EL MOSFETs, which drive: fan relay oil cooler fan relay fuel pump relay check engine lamp A/C clutch output and 3 spares. the serial port has two modes: a 19200 mode which is used for my own use, and it actually generates 166 baud data for the old GM scan tools if you're hooked on to one. The hardware of the spark system has a built-in 'bypass' mode, where the timers are left on, and sparks occur when the spark steering output changes. This is for cranking and the first few seconds of running. after this, the CPU starts running OC1. -Dale