DIY_EFI Digest Wednesday, 12 August 1998 Volume 03 : Number 372 In this issue: 730 VSS Error?? L-Jet->LH-Jet Fuel Rails Re: Turbo Bypass Re: Fuel Rails RE: Supercharger info Re: 730 VSS Error?? Re: Supercharger info FI system on a SC rotory Re: 730 VSS Error?? Info on the GM 1228747 ECM Re: FI system on a SC rotory Re: Info on the GM 1228747 ECM Mech speedo revs per mile Re: Fuel Rails Re: Info on the GM 1228747 ECM RE: Supercharger info Re: FI system on a SC rotory RE: Supercharger info Re: Mech speedo revs per mile RE: Supercharger info RE: Supercharger info RE: Supercharger info RE: Supercharger info Re: Supercharger info Re: Final Verdict on 2 atta time bench ecms Re: Injector Driver Module RE: Supercharger info VSS Re: Final Verdict on 2 atta time bench ecms Re: Injector Driver Module Re: VSS Re: VSS Re: Info on the GM 1228747 ECM Re: Supercharger info Re: programming 101 and checksum Re: Mech speedo revs per mile Re: Motorola Phone Number See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: "Bruce Plecan" Date: Tue, 11 Aug 1998 16:32:31 -0400 Subject: 730 VSS Error?? Doesn't a 730 want a 12v-0 swing for VSS input at B10?.. I do that but no MPH displayed with scanner. The same signal works just fine on the 747........ Cheers Bruce ------------------------------ From: Jim Lill Date: Tue, 11 Aug 1998 17:04:29 -0400 (Eastern Daylight Time) Subject: L-Jet->LH-Jet Has anyone ever heard of an adapter that allows a LH-Jet Hotwire meter to replace a L-Jet flap type? - -Jim Lill http://www.vectorbd.com/users/jpl ------------------------------ From: Jim Lill Date: Tue, 11 Aug 1998 17:07:27 -0400 (Eastern Daylight Time) Subject: Fuel Rails many Bosch equipped cars have fuel-pressure regs. that pull into the fuel rails with oring seals. I'd like to put in an external regulator via AN fittings. Is there a "std trick" for dealing with the o-ring junction? - -Jim Lill http://www.vectorbd.com/users/jpl ------------------------------ From: bearbvd@xxx.net (Greg Hermann) Date: Tue, 11 Aug 1998 15:25:27 -0600 Subject: Re: Turbo Bypass >Does anyone have any thoughts or references to info on the type and >positioning of Turbocharger bypass valves? > >Things I'm wondering about... > >- bypass to compressor inlet vs. dump to atmosphere >- pre-intercooler vs, post-I/C dump point >- effects on A/F Ratio My first and best thought is AVOID USING BLOW OFF VALVEs IF YOU POSSIBLY CAN! How? Draw through a throttle body(s) into the compressor(s), and run the compressor(s) in vacuum at part throttle. No restriction points between compressor(s) and intake ports. Yep, you need to have the best compressor seal to do it this way, but it's well worth it. It becomes virtually impossible to put a properly selected compressor into surge, You will have much shorter spool up time (because the compressor will be spinning far faster as part throttle). You will have much lower exhaust back-pressure on the engine at part throttle, and consequently longer life and lower cruising BSFC (better mileage). As far as I'm concerned a throttle between compressor and intake only happened because factories wanted to add turbos with a minimum number of part revisions and cheap seals. Yes, some of the early porsche race turbo cars did it to get better throttle response with relatively primitive design turbos. This is just not that much of a factor any more, and those p cars were pretty much an efficiency be damned design. If you really want to chat about efficiency and turbos, get hold of me off list (this is a bit off mission) and we'll talk about using long tube headers with turbos. Regards :), Greg ------------------------------ From: James Weiler Date: Tue, 11 Aug 1998 15:05:34 -0700 (PDT) Subject: Re: Fuel Rails you could buy a short piece of D-section fuel rail and plug the O-ring into that. Then tap the ends of the rail with NPT threads. Then buy AN adapters that are NPT on one end and AN on the other. might look dorky though. Why not use the O-ring fitting in the stock rail? jw On Tue, 11 Aug 1998, Jim Lill wrote: > > many Bosch equipped cars have fuel-pressure regs. that pull into the fuel > rails with oring seals. I'd like to put in an external regulator via AN > fittings. Is there a "std trick" for dealing with the o-ring junction? > > > -Jim Lill http://www.vectorbd.com/users/jpl > > > > ------------------------------ From: bearbvd@xxx.net (Greg Hermann) Date: Tue, 11 Aug 1998 16:00:52 -0600 Subject: RE: Supercharger info >Dan Zorde wrote: > >> Thanks for the info so far. The intent is to generate as much >> boost as possible, which is why I'd like to know how much boost >> it can put out before it self destructs (or the engine), so it >> definitely won't be running slower. > >In theory you can get as much boost as you like by using different >crank:SC drive ratios. > >The problem you will have is that the thermal efficiency drops *way* >off as boost rises, pushing intake temps way up. That, plus the boost, >will usually push an NA engine into serious detonation unless the CR >is unusually low. An intercooler helps, water injection helps. (I have >to agree with the poster who said go turbo for max power or max boost. >A Roots SC is great for low end power though.) Not to mention the SC >will consume more and more crank HP as boost rises, and belt slip will >become a problem. > >HKS, Blitz and Cusco make *crank* pulleys for the 4A-GZE, they replace >the engine's crank pulley, not the SC pulley. (Yes, this spins the >water pump faster as well.) > >Supposedly the 1991+ Japan-spec SC12 had a smaller pulley on the SC >unit, also someone on the MR2 list looked into a custom job. Not too >hard if you didn't mind losing the clutch. > >There is also an SC14, which is ~1420 cc displacement. Since you're >looking at a total custom job, I'd get that instead. I didn't notice >that you're in Oz before (sorry), you may be able to get the SC14 >off a 1G-GZE. (We don't get that engine in the States.) It's also >a TRD bolt-on for the Previa engine. > >Word is that Eaton is the OEM for these units. Just a rumor I heard, >but maybe worth looking into. Also Eaton supposedly has newer >designs that are more efficient, and if you're already looking at a >full custom job, why not use a better unit? > > Chris C. > >Content-Type: application/ms-tnef > >Attachment converted: Bear's Den:RE- Supercharger info (????/----) (0000199E) If you're going total custom, talk to Whipple industries in Fresno, CA. They are the distributor for Opcon Autorotor screw compressors for supercharger applications, and have several different sized available. Also, they have performance curves which they will FAX you in order to get a proper match--not as simple a thing as one might assume. Screw compressors are FAR more efficient than Roots blowers, cuz part of the compression happens internally to the compressor. Regards, Greg ------------------------------ From: EFISYSTEMS@xxx.com Date: Tue, 11 Aug 1998 18:13:47 EDT Subject: Re: 730 VSS Error?? Hi Bruce, Can't tell you what the voltage requirements are but when you figure it out could you check to see if the injector pulse widths and/or ign timing moves when you show a speed vs no speed,,,,,thanks - -Carl Summers ------------------------------ From: Walter Petermann Date: Tue, 11 Aug 1998 17:38:37 -0500 Subject: Re: Supercharger info Chris Morriss wrote: > > > > It's difficult to use MAF on a simple analog system if you want to fire > the injectors once per crank revolution. Imagine that the engine is > loaded such that it requires the same amount of fuel per revolution at > 6000 rpm as it does at 2000 rpm. The MAF at 6000 rpm is going to be > roughly 3 times as much as at 2000, so if you fired once per rev, > without compensation, then you would be overfueling the thing grossly. > You need to divide the MAF by an amount proportional to rpm. ... Damn! I should have known that MAF alone sounded too good to be true. My turn to wear the cone shape hat. Walter ------------------------------ From: Robert Scott Winnicki Date: Tue, 11 Aug 1998 19:08:25 -0400 (EDT) Subject: FI system on a SC rotory I am building up a supercharged 1.3L rotory. I am in need of throtle body for the car. I am looking for something that will bolt to a holley square flange arangement. My supercharger is set up to run in a draw thru application. However the rotory block is set up to allow direct injection into the chambers for 2 injectors. Boost will be between 9 and 12 psi. I would like to run at least 4 injectors, maybe 6. I am looking at a wolf3d fuel/spark computer. But would be real open to cheaper/ or better ideas. thanks bob ------------------------------ From: peter paul fenske Date: Tue, 11 Aug 1998 16:13:12 -0700 Subject: Re: 730 VSS Error?? Hi Bruce A 730 can use three different inputs for VSS. One is digital, ie 12V on off with a pullup resistor in the ecm, on is magnetic pu.. and not sure the third I think it is CCM derived on the buss. Also there is a 2000 or 4000 pulse select. This is all set by one byte on powerup. later:peter At 04:32 PM 8/11/98 -0400, you wrote: >Doesn't a 730 want a 12v-0 swing for VSS input at B10?.. >I do that but no MPH displayed with scanner. >The same signal works just fine on the 747........ >Cheers >Bruce > > > ------------------------------ From: "Ross Myers" Date: Wed, 12 Aug 1998 09:25:06 +1000 Subject: Info on the GM 1228747 ECM Hi all, It seems from looking around EFI sites the GM 1228747 TBI ECU is the one everybody is trying to figure out. I was wondering if anybody has the stock PROM data out of one of these ECU's. from either the C15-25, 350 TBI auto w/OD or the K15-25, 350 TBI auto w/OD. Thanks Ross Myers ------------------------------ From: "Bruce Plecan" Date: Tue, 11 Aug 1998 19:43:18 -0400 Subject: Re: FI system on a SC rotory Subject: FI system on a SC rotory Might hunt some in it the archives, there has been mention of a similiar setup. Cheers Bruce > >My supercharger is set up to run in a draw thru application. Boost will be between 9 and 12 psi. I would like to run at >least 4 injectors, maybe 6. I am looking at a wolf3d fuel/spark computer. >But would be real open to cheaper/ or better ideas. >thanks >bob > > > > ------------------------------ From: "Bruce Plecan" Date: Tue, 11 Aug 1998 20:00:16 -0400 Subject: Re: Info on the GM 1228747 ECM - -----Original Message----- From: Ross Myers To: DIY_EFI@xxx.edu> Date: Tuesday, August 11, 1998 7:49 PM Subject: Info on the GM 1228747 ECM WHAT other sites??. Please do tell Cheers Bruce nacelp@xxx.net >Hi all, > >It seems from looking around EFI sites the GM 1228747 TBI ECU is the one >everybody is trying to figure out. > >I was wondering if anybody has the stock PROM data out of one of these >ECU's. from either the C15-25, 350 TBI auto w/OD or the K15-25, 350 TBI >auto w/OD. > >Thanks > >Ross Myers > > ------------------------------ From: Joe Boucher Date: Tue, 11 Aug 1998 18:57:31 -0500 Subject: Mech speedo revs per mile I was thinking about trying to use the mechanical input cruise control on the Suburban by using the electrical signal off the 700r4 tranny speed sensor into the box. But first, some experimentaion with the mechanical cable and a variable speed drill. Isn't a mechanical system set up for 1000 rev per mile? Joe Boucher '70 RS/SS Camaro '81 TBI Suburban ------------------------------ From: "WILMAN" Date: Wed, 12 Aug 1998 08:23:16 +0800 Subject: Re: Fuel Rails - ---------- > From: Jim Lill > To: diy_efi > Subject: Fuel Rails > Date: Wednesday, August 12, 1998 5:07 AM > > > many Bosch equipped cars have fuel-pressure regs. that pull into the fuel > rails with oring seals. I'd like to put in an external regulator via AN > fittings. Is there a "std trick" for dealing with the o-ring junction? > > > -Jim Lill http://www.vectorbd.com/users/jpl You will need a take-off adapter at the fuel rail. Have you seen FSE's Power Boost Valve installation on a Mi16? Wilman > > > ------------------------------ From: bearbvd@xxx.net (Greg Hermann) Date: Tue, 11 Aug 1998 19:04:29 -0600 Subject: Re: Info on the GM 1228747 ECM >-----Original Message----- >From: Ross Myers >To: DIY_EFI@xxx.edu> >Date: Tuesday, August 11, 1998 7:49 PM >Subject: Info on the GM 1228747 ECM > > >WHAT other sites??. >Please do tell >Cheers >Bruce nacelp@xxx.net YO! me too! please do tell what other sites!!! Regards, Greg> > >>Hi all, >> >>It seems from looking around EFI sites the GM 1228747 TBI ECU is the one >>everybody is trying to figure out. >> >>I was wondering if anybody has the stock PROM data out of one of these >>ECU's. from either the C15-25, 350 TBI auto w/OD or the K15-25, 350 TBI >>auto w/OD. >> >>Thanks >> >>Ross Myers >> >> ------------------------------ From: Dan Zorde Date: Wed, 12 Aug 1998 11:37:17 +0800 Subject: RE: Supercharger info Guess, I can always do it the slow way, just install it and play around with pulley sizes until the intake temp starts to increase to the point that its not worth it. Dan dzorde@xxx.au On Tuesday, 11 August, 1998 9:30 PM, Clive Apps Techno-Logicals 416 510 0020 [SMTP:clive@xxx.com] wrote: > > probably more > the greater retriction will cause more heat so the actual value will be > higher > there is also other pulleys available for this unit from TRD and HKS > gives about another 25% boost > Clive ------------------------------ From: bearbvd@xxx.net (Greg Hermann) Date: Tue, 11 Aug 1998 19:42:17 -0600 Subject: Re: FI system on a SC rotory There are several different "air doors" out there to fit a Holley square bore flange. Give me a whistle off list if you need info. Like anything else, some are pretty good, others are not so good. Regards, Greg >I am building up a supercharged 1.3L rotory. I am in need of throtle body >for the car. I am looking for something that will bolt to a holley square >flange arangement. > >My supercharger is set up to run in a draw thru application. However the >rotory block is set up to allow direct injection into the chambers for 2 >injectors. Boost will be between 9 and 12 psi. I would like to run at >least 4 injectors, maybe 6. I am looking at a wolf3d fuel/spark computer. >But would be real open to cheaper/ or better ideas. > > >thanks >bob ------------------------------ From: Dan Zorde Date: Wed, 12 Aug 1998 11:44:38 +0800 Subject: RE: Supercharger info I'd like around 100hp at the rear wheels (don't know if the gearbox will handle it though). Low down torque is the most essential part, as the car will mainly be doing motorkhana events (at least 6/year), some hill climbs (possibly 2/year) and the odd sprint around the race track (3/year) and on the 1/4 mile (1/year). So as you can see the low down torque is required for the majority of events. I had thought of just using the Abarth setup like the OT2000, but I figured I'd try something no one else in the club has done yet. Dan dzorde@xxx.au On Tuesday, 11 August, 1998 9:30 PM, Francois Dion [SMTP:francois@xxx.org] wrote: > > How much hp do you think you can squeeze? How much would you really > like? For what kind of application are you preparing your 850? I have a > Fiat 850 myself and the tought of a Fiat Uno Turbo engine has crossed my > mind... (I know one person who did a conversion like that and is found > from time to time in a Fiat x1/9 and even in a 127). Stock, that engine (1.3 > and roughly the same weight as the 1L Fiat/Lancia Fire engine) puts out > a very conservative 110hp and 15 kgm due to a non agressive boost. A > proper boost management system (right now on the Peugeot turbo list, > we are investigating different options, including the Saab APC) would let > you go higher on the boost and you would be putting out some serious > power. Abarth did put a 1.1 that was stroked/bored to 1.3 in an 850 OTR > so it's not a sacrilege. > > Ciao, > Francois Dion (francois@xxx.org) > -- > Member: FLU #1722, PCNA > http://www.fortunecity.com/silverstone/zagato/101/launch.html > Alfa Romeo, Fiat, Lancia, Peugeot, Volvo, Solex ------------------------------ From: "Bruce Plecan" Date: Tue, 11 Aug 1998 21:58:34 -0400 Subject: Re: Mech speedo revs per mile - -----Original Message----- From: Joe Boucher To: diy_efi@xxx.edu> Date: Tuesday, August 11, 1998 8:25 PM Subject: Mech speedo revs per mile >I was thinking about trying to use the mechanical input cruise control on >the Suburban by using the electrical signal off the 700r4 tranny speed >sensor into the box. The speedo signal used for the ecm in many 700r4's is actually generated in the speedometer head. The speedo cable rotates at 1000 revoltions per mile. I'm not totally sure that answers your guestion. Cheers Bruce > >But first, some experimentaion with the mechanical cable and a variable >speed drill. Isn't a mechanical system set up for 1000 rev per mile? >Joe Boucher >'70 RS/SS Camaro '81 TBI Suburban > ------------------------------ From: Dan Zorde Date: Wed, 12 Aug 1998 11:48:16 +0800 Subject: RE: Supercharger info Reminds me of the episode when the toolman did his lawnmover. By the way this little unit (not cheap by my standards), I've managed to pick up for A$200. Dan dzorde@xxx.au On Tuesday, 11 August, 1998 10:39 PM, Greg Hermann [SMTP:bearbvd@xxx.net] wrote: > > Me too. I'v got an IH Cub tractor (60 CID flathead 4 banger) which has been > crying for a supercharger so that it can even be able to move itself and > turn a belly-mower at 7250 feet MSL. I've been looking for a blower for it > for a while from an economical source (read cheap). More info on this Ota > unit would be welcome. > Regards, Greg ------------------------------ From: Dan Zorde Date: Wed, 12 Aug 1998 11:58:40 +0800 Subject: RE: Supercharger info I'm not too worried about the clutch, in fact I was just going to lock it up to have constant boost. This SC12 came of a jap import engine. As I'll need to change the pulley system on the engine anyway, I may even move everything to tooth pulleys as I have a mate that sells them. I was told that in OZ the MR2 people use the crank pulley of the the Ford EA falcon as this is slightly larger than the standard unit. Does anyone know if Eaton has an email address, if so I'll drop them a line and see how helpful they are. Dan dzorde@xxx.au On Wednesday, 12 August, 1998 12:22 AM, Chris Conlon [SMTP:synchris@xxx.net] wrote: > > HKS, Blitz and Cusco make *crank* pulleys for the 4A-GZE, they replace > the engine's crank pulley, not the SC pulley. (Yes, this spins the > water pump faster as well.) > > Supposedly the 1991+ Japan-spec SC12 had a smaller pulley on the SC > unit, also someone on the MR2 list looked into a custom job. Not too > hard if you didn't mind losing the clutch. > > There is also an SC14, which is ~1420 cc displacement. Since you're > looking at a total custom job, I'd get that instead. I didn't notice > that you're in Oz before (sorry), you may be able to get the SC14 > off a 1G-GZE. (We don't get that engine in the States.) It's also > a TRD bolt-on for the Previa engine. > > Word is that Eaton is the OEM for these units. Just a rumor I heard, > but maybe worth looking into. Also Eaton supposedly has newer > designs that are more efficient, and if you're already looking at a > full custom job, why not use a better unit? > > Chris C. begin 600 WINMAIL.DAT M>)\^(BH#`0:0" `$```````!``$``0>0!@`(````Y 0```````#H``$(@ <` M& ```$E032Y-:6-R;W-O9G0@xxx.;W1E`#$(`0V ! `"`````@`"``$$ MD 8`$ (```$````0`````P``, (````+``\.``````(!_P\!````80`````` M``"!*Q^DOJ,0&9UN`-T!#U0"`````&1I>5]E9FE 969I,S,R+F5N9RYO:&EO M+7-T871E+F5D=0!33510`&1I>5]E9FE 969I,S,R+F5N9RYO:&EO+7-T871E M+F5D=0`````>``(P`0````4```!33510`````!X``S !````(@```&1I>5]E M9FE 969I,S,R+F5N9RYO:&EO+7-T871E+F5D=0````,`%0P!`````P#^#P8` M```>``$P`0```"0````G9&EY7V5F:4!E9FDS,S(N96YG+F]H:6\M5]E M9FE 969I,S,R+F5N9RYO:&EO+7-T871E+F5D=0````(!]U\!````80`````` M``"!*Q^DOJ,0&9UN`-T!#U0"`````&1I>5]E9FE 969I,S,R+F5N9RYO:&EO M+7-T871E+F5D=0!33510`&1I>5]E9FE 969I,S,R+F5N9RYO:&EO+7-T871E M+F5D=0`````#`/U?`0````,`_U\``````@'V#P$````$`````````NEX`02 M`0`6````4D4Z(%-U<&5R8VAA`' ``0```!8```!213H@4W5P97)C:&%R9V5R M(&EN9F\````"`7$``0```!L````!O<5$'^@OZ 6),0@1TJ]?[+T$P0```!@$ M#Z `'@`># $````%````4TU44 `````>`!\,`0```!4```!D>F]R9&5 R`H!]"H (R" [\0EO,C4U%!\*8 * "H%L=6,`4 L#8Q%2"\0@0$DG;2!N M;P5 =#!O;R!W!; (@60@AP&@"& 8D6AE(&,*0))T$# L( N (&8`T!4%0$D8 MX&$$(&IU1LP>1IP&Q `P'TC$&4=4 .@!& =425AR)E$$(!ZQ8"A9!Y#[2*(OLG +@"EC28]$M1LP_R-@!< BP" @&K$C407 &T%R=RDQ M+BE/+T-/1%M3=QS0(# 0<&0P01G2/M$QV"L@2A_@`' M3I %D/\>U!! &5$C M( # (N%0XBU$_R.T'N!3ST2U,@xxx.2(Z4KDB_P&Y$)`+YO M1I 94 N '"$?L&,;@=,#8$X8A%E_7T2U$$%=<1^0,X!U-K!I]3V0 M)P5 ;0N &5 )``"0_QOR&>L5M3`Y$>X30:<'>W M'J 0,"^B?F=P& %C5R"_87!.D$E"!X ",!Y@4PN ^TE@82(G%8!DST2U72(; MXG\H\1^P&+ !D ,@7@@DX2?_&5 B4!FR*L,C436 'F ;$/]A=1AQ09!J;TJ( M*/%J%"KCW46P8@$0!; 9\"@V0!D0_'DI&G!A,B4BU]D;T1;?EH!6@!N"?1^P`$(0`0```# ````\,#%"1$,U,C(N0S9&-S4U13! ;6``: "" &``````# M````````1@````!4A0```0````4````X+C R``````,`!X (( 8``````, ` M``````!&``````&%````````"P`0@ @@!@``````P ```````$8`````#H4` M```````#`!& "" &``````# ````````1@`````0A0````````,`$H (( 8` M`````, ```````!&`````!&%`````````P`5@ @@!@``````P ```````$8` M````&(4````````>`"6 "" &``````# ````````1@`````VA0```0````$` M````````'@`F@ @@!@``````P ```````$8`````-X4```$````!```````` M`!X`)X (( 8``````, ```````!&`````#B%```!`````0`````````>`#T` :`0````4```!213H@``````,`#33]-P``\E:% ` end ------------------------------ From: Dan Zorde Date: Wed, 12 Aug 1998 12:03:14 +0800 Subject: RE: Supercharger info Thought there had to be something wrong (sounded too easy when I wrote the email in the first place), is the anything wrong with just firing at a constant frequency ? Obviously this will still have to increase as rpm increases, won't it ? Dan dzorde@xxx.au On Wednesday, 12 August, 1998 2:12 AM, Chris Morriss [SMTP:crsm@xxx.uk] wrote: > > Of course, if you were prepared to fire the injectors at a constant > frequency, irrespective of rpm, then you could easily relate the > injector on-time to the MAF. > -- > Chris Morriss ------------------------------ From: Dan Zorde Date: Wed, 12 Aug 1998 12:05:43 +0800 Subject: RE: Supercharger info O-ringed, sleeved offset bores, Honda pistons, stroked, wish I had the money. Hopefully the supercharger will be a cheap way of getting more hp. Dan dzorde@xxx.au On Tuesday, 11 August, 1998 8:47 AM, xxalexx@xxx.com [SMTP:xxalexx@xxx.com] wrote: > > Nice car to hang out the tail, I used to blow a few head gaskets > (stock engine) running in redline, you might look into o-rings. > alex > ------------------------------ From: Mike Morrin Date: Wed, 12 Aug 1998 11:40:33 +1200 Subject: Re: Supercharger info >Chris Morriss wrote: >> Imagine that the engine is >> loaded such that it requires the same amount of fuel per revolution at >> 6000 rpm as it does at 2000 rpm. The MAF at 6000 rpm is going to be >> roughly 3 times as much as at 2000, Are you saying that the air/fuel ratio is varying in proportion to RPM? smells fishy to me... regards, Mike Morrin ------------------------------ From: ECMnut@xxx.com Date: Tue, 11 Aug 1998 22:55:52 EDT Subject: Re: Final Verdict on 2 atta time bench ecms This is 'sort of' on the same track.. If I needed the crank sensor's output for a 2nd injector system, is it possible to split one hall effect sensor into two separate outputs? Thanks, Mike V. In a message dated 8/11/98 3:57:43 PM Eastern Daylight Time, nacelp@xxx.net writes: > Don't bother trying to share inputs between two ecms. Maybe if > doing two of the same type, but otherwize bzzzzt, wrong for gms. > For whatever differences in pull down resistors, and power/grnd > issues, it's not worth the headache, IMHO. > This is in reference to the CTS, MAT, TPS, MAP. > Cheers ------------------------------ From: bearbvd@xxx.net (Greg Hermann) Date: Tue, 11 Aug 1998 20:50:33 -0600 Subject: Re: Injector Driver Module Hi again, guys, This switched power supply business sounds promising for injector drivers. Be aware: With 8 sequence fired injectors on an 8 cylinder motor sized for an 83% duty cycle at WOT you are going to have either 6 or 7 of them open and drawing current at one time at WOT. That's how it is. If the duty cycle went above 87.5% at WOT, you would have either 7 or 8 of them open at any given time at WOT. It really would also be nice to avoid the parasitic power use that would go along with dissipating the power rather than controlling it. It really would be a beautiful thing if the injector power supply were set up so that the peak current, the length of the peak current pulse, and the hold current were all three able to be controlled through software and stabilized by the ecu at the software set values. Perhaps a common injector power supply on the plus side (voltage adjustable through software) and then individual drivers on the ground side capable of either going saturated or letting through only the hold current after a set (software adjustable) peak pulse time (without having to dissipate a lot of power)? You tell me=--pwm with filtering, switched power supplies, whatever. The common power supply on the plus side would even be a good idea for driving saturated coil injectors. Especially if it were capable of boosting system voltage when required (cold starts?) or knocking system voltage down for those fools among us who want to run a 24v electric system. I'm not really a fool for wanting 24v. i'm doing an enormous motor project for a motorhome, and intend to mount a Leece-Neville 195 amp @xxx. alternator on it, and use a 4KW Trace inverter to run things in the coach when going down the road. Trying to run 12v. would verge on the ridiculous in a case like this. Want to bet that the stories out of Canada about saturated coil injectors not working too well in cold weather originate out of what happens when battery voltage is low from -40 or whatever, and gets lower when cranking? Like low to the point that the injectors won't open when cranking? Sorry, GM has sold lots of #$%^ that don't work--remember the Vega motor? early Corvairs? And I even liked the 348!! A voltage boost capability in the common injector power supply would likely cure such syndromes. It's really impossible to overemphasize how important absolute precision, repeatability, and tunability is to operating the injectors for good performance. See Passini's words about Weber's secrets, quoted elsewhere. This is the place where it is worthwhile and will be rewarding beyond your dreams to spend both design effort and money on hardware. I know I'm preaching here, but have a little faith, and be rewarded! I would even bet that one could run so-called saturated coil injectors with a reduced hold-open current (with the type of drivers I'm talking about) and make them run better and longer. Have fun with the ideas! Regards, Greg >Don, thanks for your reply. > > I am going to fire them sequentially, like you indicate below. Yes, I >also see that the factory heatsinks on the driver transistors are not big, >and that is what surprises me. > The only explanation I have so far is that the injectors used by the OEM >modules are the saturated type (16 ohms, and the driver is not working on >the linear region, but saturated, and hence very little power is >dissipated there). Unfortunately, I need to drive peak-and-hold injectors >(1.5..2.3 ohms). > Over the 360 crank degrees, the injectors will be fired approximately >like this: >#1 (0 degrees), #8 (45 deg), #4 (90), #3 (135), #6 (180), #5 (225), #7 >(270), #2 (315). > > Every driver would be on up to 85% of the time, so no matter what the >timing sequence is, every power driver will conduct the Hold current (1 >amp) for 85% of the time, so the average power dissipated on the driver >module box is: > [ (Battery Voltage)-(Hold Current)*(Coil Resistance) ]*(Hold >Current)*(Duty Cycle)*(number of injectors) = > so assuming worst case (Maximum battery voltage): > [ (16)-(1)*(1.5) ]*(1)*(0.85)*(8) = 98.6W! > > How much power is being dissipated in your module? > >>>> 08/10/98 10:47AM >>> >I'm working on an injector driving module also. If you are going to fire >the injectors sequentially, then one injector would be on at a time in the >firing order sequence (1-8-4-3-6-5-7-2 GM V-8) If you are going to batch > ------------------------------ From: bearbvd@xxx.net (Greg Hermann) Date: Tue, 11 Aug 1998 21:12:54 -0600 Subject: RE: Supercharger info Toolman's lawnmower or not, Right is usually more economical than cheap. Been there, tried both. Kind of like women, you tend to learn what works best for you. If doing O-rings, try using .043" diam. 347 SS mig wire instead of safety wire--much harder, and immune to (intergranular) corrosion. With a copper head gasket. Greg >O-ringed, sleeved offset bores, Honda pistons, stroked, wish I had the money. > Hopefully the supercharger will be a cheap way of getting more hp. > >Dan dzorde@xxx.au > >On Tuesday, 11 August, 1998 8:47 AM, xxalexx@xxx.com >[SMTP:xxalexx@xxx.com] wrote: >> >> Nice car to hang out the tail, I used to blow a few head gaskets >> (stock engine) running in redline, you might look into o-rings. >> alex >> ------------------------------ From: "Bruce Plecan" Date: Tue, 11 Aug 1998 23:26:10 -0400 Subject: VSS OK, on the bench ecms. No matter what memcal, the scanner sees no MPH, and the TCC is always on. Gear switch doesn't change it or 4th gear apply switch. Sounds like a bad ecm, maybe?. Any thoughts?, I've checked the wiring several times and everything appears right.. Kelp Bruce ------------------------------ From: "Bruce Plecan" Date: Tue, 11 Aug 1998 23:36:36 -0400 Subject: Re: Final Verdict on 2 atta time bench ecms - -----Original Message----- From: ECMnut@xxx.com> To: diy_efi@xxx.edu> Date: Tuesday, August 11, 1998 11:25 PM Subject: Re: Final Verdict on 2 atta time bench ecms >This is 'sort of' on the same track.. If I needed the crank sensor's output >for a 2nd injector system, is it possible to split one hall effect sensor into >two separate outputs? Yes, that's easy.. I toggles high to low. Bruce >Thanks, >Mike V. > >In a message dated 8/11/98 3:57:43 PM Eastern Daylight Time, nacelp@xxx.net >writes: >> Don't bother trying to share inputs between two ecms. Maybe if >> doing two of the same type, but otherwize bzzzzt, wrong for gms. >> For whatever differences in pull down resistors, and power/grnd >> issues, it's not worth the headache, IMHO. >> This is in reference to the CTS, MAT, TPS, MAP. >> Cheers > ------------------------------ From: Lawrence King Date: Wed, 12 Aug 1998 00:27:11 -0400 Subject: Re: Injector Driver Module Hmmm... Why go to all of the trouble to switch the injectors from +14V. This would be a very tricky switch mode power supply design. Why not simply lower the drive voltage. If you drive the injectors from a lower voltage (say +5V) then your power dissipation will drop to a mangeable level. National Semiconductor builds chips which are switch mode power supplies (I think the family is called "simple-switcher") or you can buy a commercial module (try PowerTrends http://www.powertrends.com/ ) to drop the voltage. This also solves the problem of not having enough volts to fire the injectors while cranking. - -- Lawrence King lawrence@xxx.net Ottawa Ontario Canada 70 Buick Wildcat, 71 Lotus Elan, 92 Nissan NX2000 I am a three car family (four if you count the Buick as two cars) ------------------------------ From: Richard Wakeling Date: Wed, 12 Aug 1998 14:21:58 +1100 Subject: Re: VSS Hi Bruce, What ECU are you testing below. Is it the 808 or 747? If it is the 808, could it be that your scanner is giving you the wrong info. What scanner are you useing on the 808? Cheers Richard Bruce Plecan wrote: > > OK, on the bench ecms. No matter what memcal, the scanner sees > no MPH, and the TCC is always on. Gear switch doesn't change it > or 4th gear apply switch. > Sounds like a bad ecm, maybe?. > Any thoughts?, I've checked the wiring several times and everything appears > right.. > Kelp > Bruce ------------------------------ From: "TBK" Date: Tue, 11 Aug 1998 22:10:10 -0700 Subject: Re: VSS Hi Bruce, TCC on always has been a manual tranny memcal for me. Hummmm TK - -----Original Message----- From: Richard Wakeling To: diy_efi@xxx.edu> Date: Tuesday, August 11, 1998 9:57 PM Subject: Re: VSS >Hi Bruce, > What ECU are you testing below. Is it the 808 or 747? >If it is the 808, could it be that your scanner is giving you the wrong >info. What scanner are you useing on the 808? >Cheers Richard > >Bruce Plecan wrote: >> >> OK, on the bench ecms. No matter what memcal, the scanner sees >> no MPH, and the TCC is always on. Gear switch doesn't change it >> or 4th gear apply switch. >> Sounds like a bad ecm, maybe?. >> Any thoughts?, I've checked the wiring several times and everything appears >> right.. >> Kelp >> Bruce > > ------------------------------ From: Shannen Durphey Date: Tue, 11 Aug 1998 23:21:55 -0600 Subject: Re: Info on the GM 1228747 ECM Ross Myers wrote: > > Hi all, > > It seems from looking around EFI sites the GM 1228747 TBI ECU is the one > everybody is trying to figure out. > > I was wondering if anybody has the stock PROM data out of one of these > ECU's. from either the C15-25, 350 TBI auto w/OD or the K15-25, 350 TBI > auto w/OD. > > Thanks > Ross Myers I've got k2500 454 thm400 aftermarket chip, and v3500 350 4 spd manual factory. Looking for others... Shannen ------------------------------ From: Walter Petermann Date: Wed, 12 Aug 1998 00:38:50 -0500 Subject: Re: Supercharger info Mike, I think what he's saying is this: Say the MAF output is read as kg/min of air then kg/min (air)*14.7= kg/min (fuel) but what's needed is kg/rev of fuel to get injector on time. Deviding kg/min (fuel) by rpm gives kg/rev (fuel). Or, MAF reading needs to be devided by rpm. Walter Mike Morrin wrote: > > >Chris Morriss wrote: > >> Imagine that the engine is > >> loaded such that it requires the same amount of fuel per revolution at > >> 6000 rpm as it does at 2000 rpm. The MAF at 6000 rpm is going to be > >> roughly 3 times as much as at 2000, > > Are you saying that the air/fuel ratio is varying in proportion to RPM? > smells fishy to me... > > regards, > > Mike Morrin ------------------------------ From: Ludis Langens Date: Tue, 11 Aug 1998 23:23:27 -0800 Subject: Re: programming 101 and checksum Vance Rose wrote: > > >>Also, > >>this location in 8747 ecm contains the value $4F. Is it > >>safe to assume this is checksum enable for this ecm? > > If ya have time - just disassemble code. The checksum is usually early in > program section. Being a novice it was one of my first finds for 165 ecm. That'll be a bit difficult to do for the 1228747 - the EPROM doesn't contain all the program code. Specifically, the checksum code won't be in the EPROM. - -- Ludis Langens ludis (at) cruzers (dot) com Mac, Fiero, & engine controller goodies: http://www.cruzers.com/~ludis/ CSH field operatives have discovered an allergy to sharp metal. Symptoms are similar to the broken glass allergy. Will ask HQ for cone shaped shin guards. ------------------------------ From: mrvette Date: Wed, 12 Aug 1998 03:13:44 -0400 Subject: Re: Mech speedo revs per mile it's 1000 rpm is 60 mph......GENE - -- ____________ Fun under the sun in //~~~~~~~~~~~~\\ Jacksonville, Fl. :-))) //______________\\ /~~~---~ | | ~---~~~\ /| /______\____/______\ |\ (( | / | | \ | )) Mako 'Vettes | \============================/ | Shift better with |\ \\[ ] |mrvette| [ ]// /| Automatics | \/+========================+\/ | |~==============================~| |_____| |_____| - ------------------------------------------------------------------- ------------------------------ From: dave.williams@xxx.us (Dave Williams) Date: Tue, 11 Aug 1998 15:11:00 -0500 Subject: Re: Motorola Phone Number - -> Uhh... You do know that you can just cut and paste right of - -> Adobe's acrobat reader don't you?? Select the little icon on the All I got was gibberish when I tried that, but it's been several versions of Acrobat ago. ------------------------------ End of DIY_EFI Digest V3 #372 ***************************** 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".