DIY_EFI Digest Thursday, 23 May 1996 Volume 01 : Number 148 In this issue: Re: DIY_EFI Digest V1 #146 Re: Bosch ECU Schematic for 1981 BMW 528i Re: Bosch ECU Schematic for 1981 BMW 528i EPA study of O2 sensors Hiatus Parts? Re: Parts? See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: ehernan3@xxx.com (Edward Hernandez (R)) Date: Wed, 22 May 1996 08:27:05 +0500 Subject: Re: DIY_EFI Digest V1 #146 "I'd consider a bicycle first." Turbocharging a bicycle?! Wow, you guys really are DIY. And I thought I loved doing things the hard way:) ------------------------------ From: michael glidewell Date: Wed, 22 May 1996 12:32:00 -0400 Subject: Re: Bosch ECU Schematic for 1981 BMW 528i Werner: Thanks for taking the time for such a detailed answer. My L-jet has most of the same things you stated. I'm sure your right re. the multiport - I think I mean sequential vs batch. Per Fuel Injection book, forgot the author unfortunately, the L-jet is batch fired injectors and I believe 3 at a time ( half the charge each cam revolution). If I had a schematic I could better tell exactly what's going on. It has a lambda sensor and a new air flow meter. I had twiddled with the old flow meter so much (spring adjust) that I needed to go back to a baseline. Hope you don't mind thast I copied the newsgroup with your response - it was very good basic info. At 11:51 AM 5/19/96 -0600, you wrote: >Hi Michael > >I am a little confused. The L-Jetronic is a multi-port system usually. >Maybe I have my terms mixed up. I am not at all familiar with BMW's in >general, but here what I know about the L-Jetronic > > >* It is analog (not digital) for the early '80's and a few late '70's. A >few late versions were digital, but those are mostly the next generation of >EFI from Bosch. I know nothing about them. This is realy nice for us analog >guys that don't want to mess with burning in ROMs. > >* The L-Jetronic ECU, depending on options, has the following inputs > - trottle position input in digital (switch) form, idle, part open, >2/3 > open > - Analog (potentiometer) altitude input > - overboost cut out (by switch) > - enrichment input (by switch, same as > 2/3 trottle open > - Lambda sensor > - Air flap meter (with temperature input) or air mass meter on very few. > - coolent temperature input. > - the spark coil is the only input for timing the injectors > >* In the system, but not part of the ECU > - Cold start injector > - Fuel Pump relay that only operates when there is a spark coil signal > - Trottle bypass controlled electrically and by engine heat for extra > trottle when cold running. > >* The output is control of low impedance injectors. They are batch fired >(all fire at the same time) and they fire once for every revolution of the >crank. > >In terms of modification, I think there are only a couple of options. You >can upgrade to a later version with more features, ( go the lambda sensor >if you don't have one) or you can tune it for more power or torque if it is >running on the Oxygen sensor. But the gains are very small, because it >already enriches the mixture at wide open trottle. Still you can enrich >mixture a little. > >You can also increase the responsiveness by loosening the air meter spring >by about two notches. This gives it a little better 'accelerator pump >action' > > >If you need a schematic of how the L-Jetronic is hooked up, let me know. I >have one for a Fuego Turbo. They are all about the same. There are several >very good books that describe the operation and general hook up. > > >If anyone has a schematic, I sure would like to see it. Or maybe someone >has reverse engineered the L-Jetronic and can share some of the knowledge. >Let's hear from all those that have messed around with the L-Jetronic and >see what they have to say. I am sure both opinions and facts are welcome. >My experience is with an 1800cc engine, and MGB. And it works great but >doesn't give more noticeable power. > >I think the L-Jetronic works well and is easy as an upgrade from >carburettors, but to increase its performance beyond the designers intend, >you should go for something like the Tech II with an air mass meter and >some software to program it. > > >Werner > > > > > >______________________________ Reply Separator _________________________________ >Subject: Re: Bosch ECU Schematic for 1981 BMW 528i >Author: Non-HP-glide (glide@xxx.net) at HP-ColSprings,mimegw2 >Date: 5/17/96 2:29 PM > >Werner: > >Being a EE I look to EFI electronics where I might be able to improve things >without major cost impact. > >I wonder if it would be possible to turn the L-jet into a multiport >injection system by firing each injector individually and possibly improve >the city fuel consumption (its 12+ mpg). Or maybe I could bring out some of >the parameters and adjust for max performance/ economy. Maybe I could >repalce with a microprocessor and and do more calculations per second >resulting in smoother idle/ economy or performance. I guess I can't leave >things well enough alone also. - ---------------------------------------------- Michael Glidewell Boston, Massachusetts glide@xxx.net KE1CP BMW 528i BMWCCA http://www.shore.net/~glide/ ------------------------------ From: michael glidewell Date: Wed, 22 May 1996 12:32:04 -0400 Subject: Re: Bosch ECU Schematic for 1981 BMW 528i At 03:34 PM 5/19/96 -0700, you wrote: > >Michael Glidewell wrote: >>I wonder if it would be possible to turn the L-jet into a multiport >>injection system by firing each injector individually and possibly >improve>the city fuel consumption (its 12+ mpg). > > I think you mean "sequential" (vs. batch-fire). It is multiport. > > I'm not sure about your '81 2.8, but the late 70's 3.0 (i.e. 530i) >had horrible gas mileage because the emission control system was a >thermal reactor, not a catalyst. A thermoreactor requires about a >10-15% overrich mixture so that the exhaust is rich enough to burn. >Also the timing must be retarded to get a hot exhaust. These two >factors guarantee lousy mileage... >-Charles >('81 745i) > CHarles: Your'e right - I am interested in sequential firing vs multiport. Maybe sequential will improve the smoothness or idle.. Fortunately I do not a thermal reactor. I used to get 18mpg in LA and now in Mass I get maybe 11-12 mpg. Dealer says the HC, CO are perfect and thats what I should expect for city driving. I still don't believe. But I will change my driving habits a bit and see if that makes much of a difference. thanks for your help. - ---------------------------------------------- Michael Glidewell Boston, Massachusetts glide@xxx.net KE1CP BMW 528i BMWCCA http://www.shore.net/~glide/ ------------------------------ From: Frank Parker Date: Wed, 22 May 1996 15:03:17 -0600 (EDT) Subject: EPA study of O2 sensors There was a request a few days ago for the SAE paper on study of O2 sensors. The # is 920289. The paper talks @ how std O2 sensor can act as oxidation / reduction cell as well as std voltaic cell. A better paper describing the std sensor and its properties is 790143 done by 2 people @xxx. frank parker > ------------------------------ From: cmorris@xxx.com (Charles) Date: Wed, 22 May 1996 18:31:15 -0700 Subject: Hiatus I'm moving this weekend, and will be unsubscribing for now. (I won't actually be living in the new place for about 5-6 weeks, so the computer will be in storage for that time too). Anyway, I hope someone can benefit from my prototype injector controller design. Remember, this is just a quick and dirty example, for a starting point. I'll be checking E-mail periodically from friends' computers, so I may be able to respond to individual messages... Thanks, - -Charles ------------------------------ From: thoffman@xxx.net (Tim Hoffman) Date: Thu, 23 May 1996 06:29:27 GMT Subject: Parts? This isn't exactly an electronics question, but please bear with me. I'm in the final planning stages of my project, but I'm having trouble locating sources for the following parts: Injector connectors. These are the plastic kind with 2 contacts housed inside a female connector. Injector fuel rail stock. I could go ahead and fabricate something, but I KNOW that somewhere the extruded aluminum tubes are available. Injector mounting bosses. These are the things that the injector tip sits in. I've seend two kinds so far: one that actually clamps the injector body in place, and one that looks like a small aluminum tube. Once again, I could fabricate something, but I'd rather spend my time working on the microcontroller design... Thanks! Tim Please Note New Address: thoffman@xxx.net ------------------------------ From: pfenske@xxx.ca (peter paul fenske) Date: Thu, 23 May 1996 00:26:49 -0700 Subject: Re: Parts? > >Injector connectors. These are the plastic kind with 2 contacts housed >inside a female connector. > >>I believe GM stocks the injector connector as a repair replacement. >> >Injector fuel rail stock. I could go ahead and fabricate something, >but I KNOW that somewhere the extruded aluminum tubes are available. > >Injector mounting bosses. These are the things that the injector tip >orking on the microcontroller design... > >>A number of companies like DFI sell the rail and bosses. Another >>is fuel injection specialties. >>gl Peter >Thanks! >Tim >Please Note New Address: >thoffman@xxx.net > > ------------------------------ End of DIY_EFI Digest V1 #148 ***************************** 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".