DIY_EFI Digest Monday, 15 April 1996 Volume 01 : Number 110 In this issue: Re: type of eprom Additional capacity for early L-Jetronic Re: Ignition questions & the Nat semi Injector driver Re: Ignition questions & the Nat semi Injector driver Nasties zapping our electronics HEI dizzy problem solved LPG/CNG octane rating Re: type of eprom Re: EEC-IV Questions Re: Ignition questions & the Nat semi Injector driver Re: LPG/CNG octane rating Re: Outboard Motor Coils Re: Ignition questions & the Nat semi Injector driver Just a note... Re: Outboard Motor Coils See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: "Grigoris Dimitriadis" Date: Sun, 14 Apr 1996 13:32:03 +0300 (EET) Subject: Re: type of eprom It's from a fiesta Rs turbo '90 Do you know the pinout? greg@xxx.gr ------------------------------ From: cmorris@xxx.com (Charles) Date: Sun, 14 Apr 1996 06:52:00 -0700 Subject: Additional capacity for early L-Jetronic Hello everyone... I'm new to this list, so I hope this isn't off-topic. I am modifying my '81 BMW 745i (factory intercooled turbo, L-Jetronic injection without an 02 sensor). Stock was 252 hp with the original 3.2 liter 6 cyl, and 7 psi boost. Injectors are 273 cc/min. Now I'm running 15 psi boost on a 3.5 liter engine, with a rising-rate (mechanical) fuel pressure regulator. Problem is, it takes 90-100 psi fuel pressure to support this much boost, and the injectors are not operating reliably. So - I would like to put bigger injectors on; readily available at about $50 each. From what I've read, though, the _minimum_ pulsewidth (idle) will become a limitation. If I put much larger injectors on, and stiffen the airflow meter spring, the ECU can't shorten the pulses enough at idle to avoid running rich. Any comments? The other solution is, additional injectors. Does anyone know of a reasonably priced injector controller? I'm about to make my own (30 psig pressure sensor from Omega, 8748 or PIC16xx microprocessor, LM1949 or CS452/3 injector driver chip) if I can't buy one first. - -Charles cmorris@xxx.com ------------------------------ From: Fred Miranda Date: Sun, 14 Apr 1996 07:59:46 GMT Subject: Re: Ignition questions & the Nat semi Injector driver Jim: 7-8yrs ago, before I knew too much about these things, I built an igniter box for my rotary pickup in which I had installed a mag pickup dist. I'm sure some will scoff at the simplicity of the output, but it did work and never blew in several years of use. I used a TIP152 400v 7.5 amp darlington. (and a balasted coil) Thats it. The TIP152 has an internal clamp for reverse voltages and I guess the transistor soaked up the positive spikes. Fred ------------------------------ From: John S Gwynne Date: Sun, 14 Apr 96 12:23:01 -0400 Subject: Re: Ignition questions & the Nat semi Injector driver - -------- | | General: When the field in the primary collapses (the +12V side of the coi | l) | there is a sudden induced voltage, duh... But is it true that the direction o | f | the voltage is the reverse of it's initial condition? No. Ideally, voltage equals inductance multiplied by the time derivative of current; regardless of the initial conditions. Assuming one side of the coil is attached to +12VDC and a transistor of some type drives the other side low to "charge" the coil, you will find a positive induced voltage relative to the 12VDC return. Your diagram has some sort of sign error. At idle on an automotive ignition system, I would expect a positive voltage on the primary of 40-60V during the duration of the spark. The primary is often clamped at or near 400V to de-energize a coil with an open secondary. You may fine it helpful to make some measurements of an existing electronic ignition system. John S Gwynne Gwynne.1@xxx.edu _______________________________________________________________________________ T h e O h i o - S t a t e U n i v e r s i t y ElectroScience Laboratory, 1320 Kinnear Road, Columbus, Ohio 43212, USA Telephone: (614) 292-7981 * Fax: (614) 292-7297 - ------------------------------------------------------------------------------- ------------------------------ From: jsturs@xxx.nl (Jim Sturcbecher) Date: Sun, 14 Apr 1996 21:06:55 -0100 Subject: Nasties zapping our electronics Since there has been some discussion recently about protecting the electronics against back emfs and other nastires I thought I would bring your attention to 3 application notes I found recently from SGS-Thomson. These are in PDF format (uses Adobe Acrobat to view and print). These ANs contain some interesting info about sources and types of signals that can not only give noise but also zap your carefully designed circuits unless you safeguard them. AN553/1292 - Protection Standards Applicable to Automobiles AN554/0393 - Choice of Protection in Automotive Applications AN555/0393 - Automotive Protection with the RBOxx Series. the URL is: http://www.st.com/STonLINE/books/pdf/alpha/an/index.html I have no connection with SGS-Thomson, just found these notes whilst browsing for automotive electronics components. Later, Jim Sturcbecher jsturs@xxx.nl ------------------------------ From: dzorde@xxx.au Date: Mon, 15 Apr 96 08:25:37 Subject: HEI dizzy problem solved Thanks everyone who contributed, Yes the problem turned out to be a bad tacho signal, the signal needed to be ac coupled and dc limited. I had to limit it to 12V otherwise it gets too hard to watch the signal on most tune-up equipment. Darrell N, you wrote about yours having a dizzy capacitor ac coupling your tacho signal, I'm a bit limited with books on US cars here in OZ, but what I have got makes no mention of this cap, so it seems like someones innovation. Dan dzorde@xxx.au ------------------------------ From: dzorde@xxx.au Date: Mon, 15 Apr 96 08:46:44 Subject: LPG/CNG octane rating A while ago, there was some discussion about the octane rating of LPG/CNG around the world, and as usual when you need that bit of mail you can't find it. Can some one refresh my memory of what it is in US, Canada, Australia, New Zealand, any other places. Much appreciated Dan dzorde@xxx.au ------------------------------ From: "Brian Warburton, c/o Turbo Systems Ltd" Date: Mon, 15 Apr 1996 02:27:16 Subject: Re: type of eprom >It's from a fiesta Rs turbo '90 >Do you know the pinout? > >greg@xxx.gr > Peter is right, it is a "unique-to-Ford" 32k EPROM. Just to expand on that a little more, when I say "unique-to-Ford", it was my understanding that normal EPROM programmers could not be configured to read/write them. Ford buy their EPROM programmers from Data-IO with special adapters which are not available to the general public, they are only available to Ford as are the devices themselves. I also seem to recall that the EPROMs have more little-tricks/differences inside than just non-standard power/GND pins. The Ford M-Bus is a wierd and wonderful beast, it must have been designed by committee ....... While consulting for Ford, I actually wrote the majority of the EEC-iv software that runs the RS-Fiesta Turbo. Out of interest, what are you trying to do ? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Brian Warburton, "Still searching for the perfect curve....." email: bwarb@xxx.net Advanced Automotive Electronics Ltd, Van-Nuys House, Scotlands Drive, Farnham Common, England. SL2-3ES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ------------------------------ From: "Brian Warburton, c/o Turbo Systems Ltd" Date: Mon, 15 Apr 1996 02:00:55 Subject: Re: EEC-IV Questions >A couple years ago, I calibrated some operating modes for the Mark >VIII so it would run without the MAS hookedup. I'm trying to remember >if we actually called it a limp-home mode or just a failure manage- >ment mode. Now that I think about it, I wound't really call that a >full limp home mode. It was more like a limp-without-the-MAS-mode, >something we needed in case the MAS broke or someone forgot to >hook it up after changing the air filter. What's the s/w? In Ford-speak the s/w is the strategy. LOS mode was entered when the EEC-iv software ceased to run. It is (or was) controlled entirely by hardware in the EEC-iv module, effectively the EEC became a hardware only ECU with no processor. LOS used to give a fixed fuel p/w (used to be around 3mSecs) fixed spark (used to be 10 deg BTDC) fixed ISC dutycycle (used to be around 50%) and so on, the values varied from engine to engine. I seem to remember some later modules had "programmable" LOS values instead of hard-wired in values. What I think you're talking about Ed is the FMEM system in the strategy which attempts to keep the engine running under software control when sensors and/or actuators fail. i.e. when MAF fails, start using TP instead for load, when ECT fails derive a substitute ECT value from the ACT sensor and time-since-start and so on ........ Mind you, it has been 16 months now, it's all getting a bit hazy. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Brian Warburton, "Still searching for the perfect curve....." email: bwarb@xxx.net Advanced Automotive Electronics Ltd, Van-Nuys House, Scotlands Drive, Farnham Common, England. SL2-3ES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ------------------------------ From: Doug Rorem Date: Sun, 14 Apr 1996 21:59:54 -0500 Subject: Re: Ignition questions & the Nat semi Injector driver Jim, Well this art isn't much better, but here's where you want to place your fast recovery diode (switches on from a reverse bias condition very quickly).. This provides a path for the current to keep flowing in the coil after the transistor turns off [the coil wants to keep current constant]. Without something like this, the coil can create very large voltages and cause the transistor to break down. +12 | |------ | | ----- c / \ o | | i --- l | | ------- | transistor switch | | gnd - -- Doug Rorem University of Illinois at Chicago (312)-996-5439 [voice] EECS Department RM 1120 (312)-413-1065 [fax] 851 S. Morgan Street (708)-996-2226 [pager] Chicago, IL 60607-7053 rorem@xxx.edu ------------------------------ From: Doug Rorem Date: Sun, 14 Apr 1996 22:20:53 -0500 Subject: Re: LPG/CNG octane rating > A while ago, there was some discussion about the octane rating of > LPG/CNG around the world, and as usual when you need that bit of mail > you can't find it. > > Can some one refresh my memory of what it is in US, Canada, Australia, > New Zealand, any other places. Dan, Here's two previous messages that dealt with CNG and octane.. Darrell A. Norquay Internet: dn@xxx.ca (wrote): Compressed Natural Gas (CNG) does have an octane rating somewhere near to 130 - you can run 25 degrees initial advance, and upwards of 35 total. It's cheap, (at least here in Canada), and it has VERY low emissions. Having said that, it is stored in tanks at up to 3000 PSI, which means they are big, heavy, and they don't hold much fuel. Typically, range is very limited. It's hard to find fuelling stations, (getting a bit easier) and it takes half an hour to fill up. Plumbing and installation is very expensive, all stainless hard tubing (no hoses allowed). Doesn't have as high a specific energy rating (per lb) as gasoline, making fuel consumption much higher. All in all rather impractical for a street vehicle. There's no reason you can't run turbos and high compression with CNG, it's just that nobody does... (Taxis, couriers, etc use it somewhat, and our local gas company's service vehicles are all CNG - it figures) Propane (LPG), however, has a pretty good octane rating(110-115), is also cheap, clean, and the tanks and plumbing are much lighter and less costly since you only have to deal with a couple of hundred PSI. Tanks also hold more fuel since it is in a liquid state instead of a gas, and you can get it anywhere. Ideal fuel for use with turbos and superchargers. All in all IT IS a good fuel for a street/high performance vehicle. Both fuels promote long engine life because of the cleaner combustion and the fact that these fuels are not solvents like gasoline and don't wash the lubricating oils off cylinder walls and valve guides, etc, thus prolonging their life substantially. Half a million miles is not too unusual between rebuilds on a propane engine, if it was built specifically for propane in the first place... Robert Dingli r.dingli@xxx.au (replied): While on the topic of CNG/LPG... There is a fleet of port injected CNG taxis running around in Brisbane, Australia as well as some in New Zealand. For our single fuel application, the compression ratio was raised from about 9:1 to well over 15:1, and the resulting peak efficiency increased from about 30% to over 40%. Natural gas in Melbourne is relatively consistent (but not available in CNG form) with a RON of 140-142. In Brisbane and NZ the methane ratio can be as low as 90% lowering the RON to about 130. To test various methane / propane ratios, we recently installed a second set of gas injectors with an adjustable pulsewidth proportional to the base injector pulse from the Ford EECV ECU. Could this be the ultimate dual fuel combination? The project was set back a little last week when the dyno drive shaft flex coupling decided to let go and hurl itself through the bell housing and steel safety cover, across the lab, through a window and into the car park onto an unoccupied Nissan. Luckily no one was hurt, but the mechanical casaulties include the drive shaft, engine crankshaft, dyno shaft, bell housing (now lots of little pieces of aluminium) and safety cover. LPG in Australia can have as much as 50% butane which lowers the octane rating to just under 100. Unfortunately this is little better than the leaded fuel that about half the cars on our roads still use. - -- Doug Rorem University of Illinois at Chicago (312)-996-5439 [voice] EECS Department RM 1120 (312)-413-1065 [fax] 851 S. Morgan Street (708)-996-2226 [pager] Chicago, IL 60607-7053 rorem@xxx.edu ------------------------------ From: Rob Skala Date: Mon, 15 Apr 1996 12:08:48 +0000 (WST) Subject: Re: Outboard Motor Coils > > Yes, these are NGK plugs on my boat. Now both two-strokes and rotaries have > more power 'strokes' than four-stroke motors. Is this significant? What > does it mean vis-a-vis four-stroke engines? > > > Regards, > > John > I think the reason for these types of plugs, is not because of the power strokes but rather that both types of engines consume oil design. It is obvious with the two-strokes, but with the rotaries, oil is injected into the engine to lubricate the apex seals and provide some degree of gas sealing. For this reason, at low-speed operation, standard plugs would tend to foul from the oil during operation. Using these types of plugs will allow more reliable operation at low-speeds since there is more electrode surface area. I hope this makes sense. By the way, the NGK SD-xx plugs used in the rotaries are fired by standard high energy igntion systems, not CDI systems, so they can be used in a normal engine provided you can find the right heat-range for your application. As an aside I once used one of these plugs in a 150cc McCulloch chainsaw and it ran really well.....much better than with the factory recommended plug !!!! Regards, Rob Robert D Skala Materials Research Group School of Physical Science Curtin University of Technology GPO Box U1987 Perth 6001 WESTERN AUSTRALIA Telephone: +61 9 351 2331 Fax: +61 9 351 2377 email: skala_rd@xxx.au ------------------------------ From: "Jim Staff" Date: Mon, 15 Apr 1996 07:15:52 GMT Subject: Re: Ignition questions & the Nat semi Injector driver > > I used a TIP152 400v 7.5 amp darlington. (and a balasted coil) > Thats it. The TIP152 has an internal clamp for reverse voltages > and I guess the transistor soaked up the positive spikes. > The balast was put there to act as a currecnt limiter correct? I Don't have access to something like that... I have access only to more normal electronic parts.. What kind of Volts and Amps could i expect? I can get resistors that are very heavy duty, also I found a diode that could block the mississippi, from haris. 1000V @ 150amps!!!! Also SGS thomson has automotive ignition transistors, that are 400V @ 15amps, and carry internal protection. About the tip 120, I've got a good supply. (Radio shack 1 mile away) It also carries internal protection for reverse voltage and high voltage (It's only 60V max), of course I maybe able to slide by on luck and a handfull in case I blow one! Jim Staff ------------------------------ From: Hoa T Nguyen Date: Mon, 15 Apr 1996 01:07:38 -0700 (PDT) Subject: Just a note... Thanks much to all for the Heywood references. I place my order tomorrow. Saab has been using individual coils per cylinder for quite a while. The Trionic engine management system has the ability to monitor the current flow through the coils, thus to the plug, to analize the combustion quality. The system can then make changes to the spark / fuel on a cylinder by cylinder basis. Basicly the same stuff being discussed on the 332 list. Saab did a neat demo where they pumped exhaust from an old two-stroke car into the new 900 turbo (I think) where it was again used. The cool part was it came out cleaner than it went in. On the topic of spark plugs... has anyone seen the info on the new Saab plug. Engineers replaced the standard plug with a single isolated electrode then built up a special piston with a peak in the middle. The peak acts as the ground, causing a spark to jump across the combustion chamber. By changing timing they can change the effective plug gap as well. Sounds like the best plug to date. Thanks again to everyone else for the interest - - Mike Kent ------------------------------ From: Bruno! Date: Mon, 15 Apr 1996 18:45:59 +1000 (EST) Subject: Re: Outboard Motor Coils On Mon, 15 Apr 1996, Rob Skala wrote: > By the way, the NGK SD-xx plugs used in the rotaries are fired by > standard high energy igntion systems, not CDI systems, so they can be > used in a normal engine provided you can find the right heat-range for > your application. As an aside I once used one of these plugs in a 150cc > McCulloch chainsaw and it ran really well.....much better than with the > factory recommended plug !!!! with what you've said in mind, i was told, from a friend of mine who used to own a rotary, that these spark plugs are also priced proprtional to the exponential of the wizardry these things are compared to normal plugs. I was told about A$90 each. They'd better last a long time!! Couldn't the same effect be achieved by cutting the tip of the spark plug off a normal plug? It may sound excessive. I know it works at 1 bar, not sure at comb. chamber pressures though. Bruno. (u933234@xxx.au) "A sewer rat might taste like pumpkin pie, but I wouldn't know cos I don't eat the filthy muthaf***a" ------------------------------ End of DIY_EFI Digest V1 #110 ***************************** 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".