DIY_EFI Digest Thursday, 19 June 1997 Volume 02 : Number 208 In this issue: RE: plugs & hp increases RE: Ignition Coil Drive Circuit Re: GM TB injector questions, HELP! Re: plugs & hp increases Change the subject line! Re: plugs & hp increases Re[2]: Ignition Coil Drive Circuit Re: plugs & idle prob Re: plugs & hp increases Re: Change the subject line! GM TB injector questions, thank you! Recommend a good `scope for viewing injector pulses?? Re: Recommend a good `scope for viewing injector pulses?? Re: plugs & hp increases Re: Recommend a good `scope for viewing injector pulses?? 1986 z28 camero Data Sheets For 27C1028 (Subaru ECU EPROM) Memcal See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: "Gregory Chan" Date: Wed, 18 Jun 1997 08:07:51 EDT Subject: RE: plugs & hp increases > >Jeffrey: Another explaination for the HP increases you saw by changing > >plugs (and I've heard this attributed to Bosch Platinum plugs in '92 > >and later 3 series BMWs) is that with that plug you're getting some > >detonation and the knock sensor is dialing back the spark advance. > >I've used Bosch Platinum plugs in my VW Jetta, it really liked them, > >but it sounds like some cars don't like them for whatever reasons. > > > Japanese cars don't like Bosch plugs. I spent days figuring out an erratic idle problem which disappeared when I reverted to NGK. My buddy was also having the same problem with the same cure. I heard they work beautifully in German cars though. gchan@xxx.ca ------------------------------ From: cloud@xxx.edu (Tom Cloud) Date: Wed, 18 Jun 1997 07:47:12 -0500 Subject: RE: Ignition Coil Drive Circuit the MSD, Crane, Mallory and other aftermarket are CDI (cap discharge ignition) systems. The oem systems I'm familiar with are glorified point-type using BJT's or FET's instead of points. the problem with raising the joltage on the primary of a stock coil is you're gonna let the smoke out -- and it's smoke, not electrons that conduct current (if you don't beleaf me, try letting it out and see if the component works innimore) ;-) Some of the current (pun) oem coils are wound for much faster charging rates and the transistor circuit that drives them is basically a constant current circuit. this prevents the coil from overheating and driving all the little smokies out plus allowing less dwell time ("dwell" being a relic of the point age, actually we're talking the time required to build the magnetic field to a desired level -- maybe even near saturation). Re: using zener to clip rather than cap -- the cap is reactive. I.e. it doesn't dissipate or use any energy rather returns it to the circuit -- that's normally good. The zener just gets hot -- that's generally bad. Secondly, the cap/coil combo is a tuned circuit which lengthens the coil discharge time. So, I'd say, in general, you use a cap when you're tuning the coil (and that's precisely what it does in points-type systems -- though an artifact of that is that it slows the primary joltage rise time and suppresses arcing over the points), and you use a zener when you don't particularly care (like when you're getting your spark from applying the joltage and not from removing it -- as in point-type systems). **[part of the above is me blowing smoke -- i.e. conjecture. I know the electronic principles that apply, but I won't try to say that I know about every little trick of the trade - -- or why someone would misuse a component ;-) ] To summarize what I know ..... older points-type and transistor ignition systems used 8 to 10 volts (actually, the current) at typically 4A through the coil. This allowed it to work during starting and required a ballast (or dropping) resistor for running at 12V. The coil had, of necessity, magnetic field build-up times that were too long for hi-rpm operation. One way to overcome that was to use one coil for each cylinder (or for every two). Then along came CDI. It uses faster charging coils (though earlier units just pulsed oem coils -- but not with great success) and hits them with a high joltage pulse -- typically 300 volts. These have more parts and cost more to build -- wonder why we don't see them on oem products ??? Then came the oem answer to "standard" xstor ignition -- the current-controlled charging circuit. One way to think of this might be to say .... imagine taking a coil designed for 3 volts at 12A and just build a 12A constant current circuit (that's a BJT/FET with a resistor in the emitter/source ... pretty simple/cheap). This would charge the coil faster, as it would put the full 12 volts (or whatever) on the 3V coil at the beginning and then decrease the joltage to keep the current constant. Still not as efficient as the CDI (lotsa heat lost in the xstors), but cheeper! >>>MSD ignitions put out over 400 volts to the primary of the coil (really!). >>> >>>Nice hot spark! Make arm move very fast! >>> >> >>I was thinking of something similar, but decided that I would try to focus >>on finishing off the EFI system first. A good place to start for 12V to >>What ever supplies are in some of the mid priced Auto audio amps that has a >>nice PWM supply, they put out a bunch of power, and have a nice case. I >>have seen some pretty small ones in a magazine, that did something like 58 >>volts at 8 amps. It was not very large and looked prety simple. >> > >BTW, has anybody experimented with building a say 12V->24V 10A >dc convertor to power the coil with? Think of all that energy - arc >weld with your spark plugs :-) > >The coil may need heatsinking though... 10A * 24V * .5 duty cycle = >120W - ouch! Tom Cloud ------------------------------ From: cloud@xxx.edu (Tom Cloud) Date: Wed, 18 Jun 1997 07:56:39 -0500 Subject: Re: GM TB injector questions, HELP! >>I put a DMM (I have a cheesy little Radio shack analog meter) on the [ snip ] > .... . . . .. . . .. . And NO, >the volt meter does not integrate, it does an Average. David, just for fun, I'm gonna argue with you on this one ;-) an analog meter does average (and I guess I missed it, I thought he was trying to look at the injector duty cycle .... and an analog meter / tachometer-type setup would be perfect for this, IMHO, if only a simple xstor switch were put in front of it). every digital DMM I know of uses "dual-slope integration". It actually does integrate (or else I've been lying to my students for the last 19 years). Tom Cloud ------------------------------ From: Barney Ward Date: Wed, 18 Jun 1997 10:12:16 -0400 Subject: Re: plugs & hp increases Gregory Chan wrote: > > > >Jeffrey: Another explaination for the HP increases you saw by changing > > >plugs (and I've heard this attributed to Bosch Platinum plugs in '92 > > >and later 3 series BMWs) is that with that plug you're getting some > > >detonation and the knock sensor is dialing back the spark advance. > > >I've used Bosch Platinum plugs in my VW Jetta, it really liked them, > > >but it sounds like some cars don't like them for whatever reasons. > > > > > > Japanese cars don't like Bosch plugs. I spent days figuring out an > erratic idle problem which disappeared when I reverted to NGK. > My buddy was also having the same problem with the same cure. > I heard they work beautifully in German cars though. > > gchan@xxx.ca Please explain how the nationality of the car affects plug type. Do they use different materials in the cylinder heads? This seems like saying "my Pinto runs good on Amoco, but my Vega likes Shell." What's the correlation? Barney Ward ------------------------------ From: Mark Eidson Date: Wed, 18 Jun 97 08:17:00 PDT Subject: Change the subject line! Text item: We have discussed the effects of supercharging on fuel delivery and how that effects the EFI algorythms, i.e., acceleration enrichment, etc. So let's not stifle discussion in this forum. There is a lot to learn! Maybe we need to change the the subject line rather than just hit reply when the topic migrates from the initial message. me ______________________________ Reply Separator _________________________________ Subject: RE: Whipple (AutoRotor) Compressor Author: owner-diy_efi-outgoing@xxx.edu at SMTPGATE Date: 6/17/97 9:26 AM Hey, guys (and a doll or two)... This is not the whiffle supercharger group, nor is it the automatic transmission discussion group. Let's hear from someone with something to contribute regarding efi (the title of the group). - ---------- From: Frederic Breitwieser[SMTP:frederic.breitwieser@xxx.com] Sent: Tuesday, June 17, 1997 5:46 AM To: 'diy_efi@xxx.edu' Subject: RE: Whipple (AutoRotor) Compressor Hey Jim! > > make the vehicle shift "quicker", which reduces the catch time on the > > little dog clutches in the auto transmission, so they last longer. > I have never seen any of these little dog clutches. Please tell me more. A dog clutch is two metal plates that have mating "teeth", and when pushed together, they "mate" better than two flat surfaces. Detriot Lockers (I think) have them, not automatic transmissions. I was responding to your message while chugging coffee getting ready for the train. :) Frederic Breitwieser Homebrew Automotive Mailing List Website: http://members.aol.com/fjb203/index.htm Email: frederic.breitwieser@xxx.com Bridgeport, Connecticut 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 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 X-Mailer: Microsoft Exchange Server Internet Mail Connector Version 4.0.994.63 Date: Tue, 17 Jun 1997 09:26:09 -0500 Subject: RE: Whipple (AutoRotor) Compressor To: "'diy_efi@xxx.edu>, "'Frederic Breitwieser'" From: John Hess Message-ID: Received: by exchange1.ixc-comm.net with SMTP (Microsoft Exchange Server Interne t Mail Connector Version 4.0.994.63) id <01BC7B00.7324F6B0@xxx.net>; Tue, 17 Jun 1997 09:25:52 -0 500 Received: from unknown(192.1.52.1) by ixc_fw0.ixc-comm.net via smap (V3.1.1) id xma027529; Tue, 17 Jun 97 09:19:09 -0500 Received: by ixc_fw0.ixc-comm.net; id JAA27591; Tue, 17 Jun 1997 09:19:34 -0500 (CDT) Received: from ixc_fw0.ixc-comm.net by coulomb.eng.ohio-state.edu via ESMTP (940 816.SGI.8.6.9/940406.SGI) for id KAA28941; Tue, 17 Jun 1997 10:2 3:04 -0400 Received: by coulomb.eng.ohio-state.edu (940816.SGI.8.6.9/940406.SGI) for diy_efi-outgoing id OAA28946; Tue, 17 Jun 1997 14:23:07 GMT Received: from coulomb.eng.ohio-state.edu by thalia.fm.intel.com (8.8.4/10.0i); Tue, 17 Jun 1997 15:54:01 GMT Received: from thalia.fm.intel.com (thalia.fm.intel.com [132.233.247.11]) by chm ail.ch.intel.com (8.8.5/8.7.3) with ESMTP id IAA19494 for ; Tue, 17 Jun 1997 08:49:35 -0700 (PDT) Return-Path: owner-diy_efi-outgoing@xxx.edu ------------------------------ From: "Gregory Chan" Date: Wed, 18 Jun 1997 11:32:03 EDT Subject: Re: plugs & hp increases > Date: Wed, 18 Jun 1997 10:12:16 -0400 > From: Barney Ward > To: diy_efi@xxx.edu > Subject: Re: plugs & hp increases > Reply-to: diy_efi@xxx.edu > Gregory Chan wrote: > > > > > >Jeffrey: Another explaination for the HP increases you saw by changing > > > >plugs (and I've heard this attributed to Bosch Platinum plugs in '92 > > > >and later 3 series BMWs) is that with that plug you're getting some > > > >detonation and the knock sensor is dialing back the spark advance. > > > >I've used Bosch Platinum plugs in my VW Jetta, it really liked them, > > > >but it sounds like some cars don't like them for whatever reasons. > > > > > > > > > Japanese cars don't like Bosch plugs. I spent days figuring out an > > erratic idle problem which disappeared when I reverted to NGK. > > My buddy was also having the same problem with the same cure. > > I heard they work beautifully in German cars though. > > > > gchan@xxx.ca > Please explain how the nationality of the car affects plug type. Do they > use different materials in the cylinder heads? This seems like saying > "my Pinto runs good on Amoco, but my Vega likes Shell." What's the > correlation? > Barney , I had a problem with an erratic idle speed where the car would cut out at the lights. I spent quite a while on this problem and eventually bit the bullet and took it to a shop. The guy checked the plugs and quoted me the price of a new set of plugs and half an hours labour. I said OK and he replaced the plugs and the problem went away, the car's idle was rock steady. Of course I have a lot of aftermarket parts in this car. The guy then proceeded to tell me that through experience he had determined that those plugs don't work that well in these cars. My buddy with an Integra was having the same problem and after changing back to the original plugs his problem went away. Other than that they performed OK and no, I can't explain why that happens. You can draw your own conclusions from this but when my buddy changed his plugs and his erratic idle went away that convinced me. BTW my car is a Corolla GTS. gchan@xxx.ca ------------------------------ From: Mark Eidson Date: Wed, 18 Jun 97 08:39:00 PDT Subject: Re[2]: Ignition Coil Drive Circuit Text item: I found that ignition is critical to EFI tuning. It is probably best to do one at a time using a proven good ignition system and timing while setting up the EFI and then once the EFI is running well look at doing the ignition changes or control from the EFI unit. me ______________________________ Reply Separator _________________________________ Subject: Re: Ignition Coil Drive Circuit Author: owner-diy_efi-outgoing@xxx.edu at SMTPGATE Date: 6/17/97 5:35 PM I was thinking of something similar, but decided that I would try to focus on finishing off the EFI system first. A good place to start for 12V to What ever supplies are in some of the mid priced Auto audio amps that has a nice PWM supply, they put out a bunch of power, and have a nice case. I have seen some pretty small ones in a magazine, that did something like 58 volts at 8 amps. It was not very large and looked prety simple. Sandy At 10:48 AM 6/18/97 +1200, you wrote: >BTW, has anybody experimented with building a say 12V->24V 10A >dc convertor to power the coil with? Think of all that energy - arc >weld with your spark plugs :-) > >The coil may need heatsinking though... 10A * 24V * .5 duty cycle = >120W - ouch! 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 Content-Type: text/plain; charset="us-ascii" Mime-Version: 1.0 Subject: Re: Ignition Coil Drive Circuit From: Sandy To: diy_efi@xxx.edu Date: Tue, 17 Jun 1997 17:35:11 -0700 X-Mailer: Windows Eudora Pro Version 3.0 (32) X-Sender: sganz@xxx.net Message-Id: <3.0.32.19970617173510.00964220@xxx.net> Received: from bullwinkle (du296-pcap-nca01.wgn.net [207.213.6.42]) by mail.wgn. net (8.8.5-q-beta3/8.6.9) with SMTP id RAA05672 for ; Tue, 17 Jun 1997 17:32:00 -0700 Received: from mail.wgn.net by coulomb.eng.ohio-state.edu via ESMTP (940816.SGI. 8.6.9/940406.SGI) for id UAA00746; Tue, 17 Jun 1997 20:3 2:50 -0400 Received: by coulomb.eng.ohio-state.edu (940816.SGI.8.6.9/940406.SGI) for diy_efi-outgoing id AAA00751; Wed, 18 Jun 1997 00:32:55 GMT Received: from coulomb.eng.ohio-state.edu by thalia.fm.intel.com (8.8.4/10.0i); Wed, 18 Jun 1997 01:34:58 GMT Received: from thalia.fm.intel.com (thalia.fm.intel.com [132.233.247.11]) by chm ail.ch.intel.com (8.8.5/8.7.3) with ESMTP id SAA26206 for ; Tue, 17 Jun 1997 18:30:32 -0700 (PDT) Return-Path: owner-diy_efi-outgoing@xxx.edu ------------------------------ From: Fred Miranda Date: Wed, 18 Jun 1997 11:24:20 -0500 (CDT) Subject: Re: plugs & idle prob Greg, Those were Bosch plugs? How many miles on them? I've heard of those causing problems becouse that tiny center electrode receeds into the insulator over time. Not that easy to spot at first glance either. Fred > I had a problem with an erratic idle speed where the >car would cut out at the lights. I spent quite a while on this >problem and eventually bit the bullet and took it to a shop. The guy >checked the plugs and quoted me the price of a new set of plugs and >half an hours labour. I said OK and he replaced the plugs and the >problem went away, the car's idle was rock steady. Of course I have a >lot of aftermarket parts in this car. The guy then proceeded to tell >me that through experience he had determined that those plugs don't >work that well in these cars. My buddy with an Integra was having the >same problem and after changing back to the original plugs his >problem went away. Other than that they performed OK and no, I >can't explain why that happens. > >You can draw your own conclusions from this but when my buddy changed >his plugs and his erratic idle went away that convinced me. BTW my >car is a Corolla GTS. > >gchan@xxx.ca > > ------------------------------ From: cloud@xxx.edu (Tom Cloud) Date: Wed, 18 Jun 1997 11:27:10 -0500 Subject: Re: plugs & hp increases >> > >Jeffrey: Another explaination for the HP increases you saw by changing >> > >plugs (and I've heard this attributed to Bosch Platinum plugs in '92 >> > >and later 3 series BMWs) is that with that plug you're getting some >> > >detonation and the knock sensor is dialing back the spark advance. >> > >I've used Bosch Platinum plugs in my VW Jetta, it really liked them, >> > >but it sounds like some cars don't like them for whatever reasons. >> > > >> > >> Japanese cars don't like Bosch plugs. I spent days figuring out an >> erratic idle problem which disappeared when I reverted to NGK. >> My buddy was also having the same problem with the same cure. >> I heard they work beautifully in German cars though. >> >> gchan@xxx.ca >Please explain how the nationality of the car affects plug type. Do they >use different materials in the cylinder heads? This seems like saying >"my Pinto runs good on Amoco, but my Vega likes Shell." What's the >correlation? if the platinums run hotter then, if the system were at it's limit, it'd start to detonate or pre-ignite (can't get that straight 8^) .... and combustion chamber design affects things like that, so different types of engines could conceivably not like platinum plugs ..... just a thought Tom Cloud ------------------------------ From: Aron Travis Date: Wed, 18 Jun 1997 12:30:51 -0700 Subject: Re: Change the subject line! Mark Eidson wrote: > > We have discussed the effects of supercharging on fuel delivery and how > that effects the EFI algorythms, i.e., acceleration enrichment, etc. So > let's not stifle discussion in this forum. There is a lot to learn! > Maybe we need to change the the subject line rather than just hit reply > when the topic migrates from the initial message. me I agree! To tie in the auto trans subject to EFI, it seems that many modern cars, to emission conform, upshift at a much earlier point (ie lower RPM). If you tinker with the EFI, you could very well change the torque curve, therefore you should try to change the shift points too. Plus we're seeing computer controlled shifting nowdays, soon one ECU will do all automotive functions, so if you modify one thing like EFI you will have to modify many others too. - -Aron Travis- "always in a automotive frenzy" ------------------------------ From: Greg Woods Date: Wed, 18 Jun 1997 14:28:06 -0500 Subject: GM TB injector questions, thank you! thanks to everyone who helped with suggestions for my TBI problem. I took the injectors out last night, soaked them with carb cleaner and gently pressed on the pintle (sp?) to make sure they weren't stuck. Then as I was placing the 2 injectors back into the throttle body I noticed something. The injectors have 3 fuel flow holes spaced 120 degrees near the base. I noticed that their is a hole of the approximate same size in the throttle body which fuel flows out of where the injectors are seated. I lined up one of the injector holes with the throttle body hole, tightened everything down and cranked it over and it started! So I'm not sure if the injectors were stuck, or if I put them in wrong when I rebuilt the throttle body. but it's workin now! I'm quite the happy camper:) thanks again for all the replies this list is great! especially for newbies like me. greg woods gwoods@xxx.com austin, tx Jeep Cherokee TBI'd! ------------------------------ From: Chris Wilson Date: Wed, 18 Jun 1997 20:35:07 +0100 Subject: Recommend a good `scope for viewing injector pulses?? Can someone recommend a good cheap,worldwide brand (we are in the UK) scope for viewing EFI injector pulse width? I just need something with reasonable resolution,that is cheap to buy and easy to use. Has anyone any experiences with these cards for computers that allow one to use them as a scope,together with grabbing the screen picture and / or storing the information? Thanks for any help. - -- Best Regards, Chris Wilson http://www.maximum-bhp.u-net.com mailto:chris@xxx.com ------------------------------ From: "David C. Carlson" Date: Wed, 18 Jun 1997 16:15:33 -0500 Subject: Re: Recommend a good `scope for viewing injector pulses?? The Tektronix TDS210 is less than $1000 US and is a great buy for the money. It has a 1GS/s sample rate and a 60MHz bandwidth. It has a very good back-lit LCD. The unit is small and light weight. After the first unit we purchased 4 more and plan to buy one for every engineer. P.S. I do not work for Tek. Dave ------------------------------ From: "Steve Meade" Date: Wed, 18 Jun 1997 14:50:25 -0700 Subject: Re: plugs & hp increases > Please explain how the nationality of the car affects plug type. Do they > use different materials in the cylinder heads? This seems like saying > "my Pinto runs good on Amoco, but my Vega likes Shell." What's the > correlation? I think there are several major factors to consider: * Different cyclinder head materials and design * Different heat ranges * Different ignition systems Oh, my Dodge Intrepid will pretty much run on any crap you can pour into the tank but my BMW runs bad on Mobil yet runs excellent on Shell. I'm citing the difference in fuel injection systems as the reason. > Barney Ward =-=-=-=-=-=-=-=-=-=-= Steve Meade smeade@xxx.com ------------------------------ From: cloud@xxx.edu (Tom Cloud) Date: Wed, 18 Jun 1997 16:12:24 +0000 Subject: Re: Recommend a good `scope for viewing injector pulses?? >Can someone recommend a good cheap,worldwide brand (we are in the UK) >scope for viewing EFI injector pulse width? I can understand the desire to look at the pulse shapes, but can anyone tell me why measuring the pulse widths isn't adequate -- and why measuring with a tachometer-like analog (or digital) meter isn't really better ?? The circuit could be as simple as taking an actual tachometer and modifying the scale to read 0 to 100% or using a BJT with a trimpot to set the meter to "100" with full "on" and a cap to keep the meter from jiggling. Tom Cloud ------------------------------ From: Mike Fiorillo Date: Wed, 18 Jun 1997 17:47:31 +0000 Subject: 1986 z28 camero I was wandering if you had any information about the effect of cutting off a cadlydic converter from a 86 z28 with tpi fuel injection??? Mainly wandering if it will effect my car's computer.(o2 censor is before the converter) If you have any additional info please contact me at fiorillo@xxx. ------------------------------ From: avos@xxx.au Date: Thu, 19 Jun 97 09:14:51 EST Subject: Data Sheets For 27C1028 (Subaru ECU EPROM) I am after information about the Fujitsu 27C1028 EPROM that is nolonger available, but is used by my JECS Subaru ECU for external EPROM chip installation. Can anyone provide me with information about where I can get Data sheets, or can I email anyone directly who can answer questions about it. Adrian Vos avos@xxx.au ------------------------------ From: Jennifer Rose Date: Wed, 18 Jun 1997 22:36:32 -0700 (PDT) Subject: Memcal Hi All Since i've been learning the code from the eprom. Wondered about the two other chips? My two memcals have different numbers on the chips. Any one know ? Thanks Vance PS: anyone come up with a way to convert Peter's tango schematic to a bmp or gif file? ------------------------------ End of DIY_EFI Digest V2 #208 ***************************** 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".