DIY_EFI Digest Saturday, 20 September 1997 Volume 02 : Number 328 In this issue: Re: For Sale..Twin cam V-6 Re: DIY_EFI Digest V2 #326 Re: The 5th Injector RE: RE Volvo K-jet... Re: 5th Injector Circuit Injector calibration etc. Re: 5th Injector Circuit RE: 5th Injector Circuit carb vs. efi RE: 5th Injector Circuit Re: Injector calibration etc. Re: 5th Injector Circuit Re: DIY_EFI Digest V2 #326 honda eprom reprograming Re: Injector"spray"vs.evaporation Re: Holley ECM replacement Re[2]: 5th Injector Circuit Re: carb vs. efi Re[2]: I understand Q-jets re:carb vs. efi Question on Cold Starting re:carb vs. efi Re: 5th Injector Circuit RE: 5th Injector Circuit Re: Injector calibration etc. cold starting Re: Question on Cold Starting Re: Injector calibration etc. Re: Injector"spray"vs.evaporation Upgraded drivers Re: Injector calibration etc. See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: swagaero Date: Fri, 19 Sep 1997 05:04:04 -0700 Subject: Re: For Sale..Twin cam V-6 Paul Ruschman wrote: > > Complete Nissan 222 HP, 93' Twin Cam V-6 w/ 7000 mi., 5spd w/ 10,000mi, new clutch, all the EFI, harness, brain, Mass Air Flow. > Would make for a great Engine swap to the right person > > $3000 for all.. > > Serious inquires contact Dave Lum @xxx. > > > > davelum@xxx.com > > nice engine I converted one for an ad for Nissan Asia used in a E-Racer put crankfired ignition and a Map system fuel injection. worked good but on the heavy side. Steve - -- ----|------||------|---- --|------[]------|-- 0/ \0 www.flash.net/~swagaero ------------------------------ From: Jake Date: Fri, 19 Sep 1997 07:06:02 -0500 (CDT) Subject: Re: DIY_EFI Digest V2 #326 > I've seen a number of K-jet installations where the cold-start injector > has been disconnected to stop fuel dribble from it. Does the control > box not turn it off properly? > - -- > Chris Morriss > > Don't know? It seems to work just fine now. > BRAAP There is no computer in a K-jet car.. except the box which converts oxygen-sensor voltage to duty cycle for a single "injector" which regulates control pressure in the fuel distributor, which operates hydro-mechanically. The cold-start injector is triggered by the wire leading to the starter solenoid. the cold-start injector's negative side is connected not to ground but to the Thermal Time switch, which screws into the coolant jacket and provides a ground only below operating temperature. A heating coil causes it to "give up" if the cold start injector is activated for longer than ten seconds to prevent flooding, if the starter is cranked for too long. If for any reason the cold start injector doesn't get power, the car will NEVER start unless you spray carb cleaner in the intake. The "choke" which is a thermally-activated fuel pressure valve which changes the fuel delivery to airflow curve, but it doesn't change the fact that no fuel is delivered until the engine kicks over. The exception to this is that if the engine is warm, no cold start injection is needed and everything is "ready to go" meaning you can pop the clutch while rolling out of your driveway and your engine will start. Jake ------------------------------ From: Tom Cloud Date: Fri, 19 Sep 1997 07:28:12 -0500 Subject: Re: The 5th Injector >Anyway , between the moment you inject fuel using the 5th injector and >the moment you have some readings from the O2 sensor it's arround 0.5 >sec ( on my car ) . If the O2 sensor control the PW without delay ( >hysteresis ??? ) your system will go in a sort of oscillation . I was reading about various sensors last night ... said the zirconium dioxide (that's right, isn't it ??) sensor has marked different characteristics in things like Vout, Zout, and response time above and below about 350 C. Above 350 C, Zout drops, accuracy improves (Vout more meaningful) and the response time (as I remember) is about 50 mS from rich to lean and versa vice. Does anyone know the actual Zout of the EGO ?? Tom Cloud ------------------------------ From: clsnyde@xxx.net (Clare Snyder) Date: Fri, 19 Sep 1997 13:06:40 GMT Subject: RE: RE Volvo K-jet... >> >> >I've seen a number of K-jet installations where the cold-start injector >has been disconnected to stop fuel dribble from it. Does the control >box not turn it off properly? >-- >Chris Morriss > > Don't know? It seems to work just fine now. > > > BRAAP > >Attachment Converted: D:\TEMP\REREVolv. > They sometimes get sticky in their old age, and hang on after they are supposed to shut off. Some grease monkeys rap them with a hammer to shut them off, and pull the wire. First cold day, and the old beast won't start worth beans. At least, after it starts, it runs. ------------------------------ From: Tom Cloud Date: Fri, 19 Sep 1997 08:04:02 -0500 Subject: Re: 5th Injector Circuit > >Simon you link to your 5th injector DOC is not quite right. > >for those in a hurry it's: > >http://www.lincoln.ac.nz/ccb/techs/simon/5th_inj.doc > >Dean t'is true ..... but the content is still "garbage", and when I save it as "5th_inj.doc" and open it in Word, it crashes Word (97). Tom Cloud ------------------------------ From: clsnyde@xxx.net (Clare Snyder) Date: Fri, 19 Sep 1997 14:19:25 GMT Subject: Injector calibration etc. I have a strange project on the go - basically a dual throttle body injection on a 1.8 litre engine. It is a SOOB EA81 unit. I want to install one injector on each bank, just before the intake port on the head (where manifold connects) I have a couple throttle bodies from a snowmobile engine that accept ford type (multiport) injectors. What injector should come close to the right size? I figure a 400HP, or 7 litre v8 should be pretty close as a starting point, as each injector has to service 50 HP and 900 ccs of engine displacement. Also, the computer I have (not sure if I can use it) is set up for the low resistance injectors and resister pack. Can I substitute the high resistance (12 volt, 14 ohm +/-) type without damaging the drivers? Obviously I would be eliminating the resister pack. All I can think of is there would be a higher inductive kick-back when de-energized. Is there a way to add a Zener to handle this? Any other input appreciated. ------------------------------ From: clsnyde@xxx.net (Clare Snyder) Date: Fri, 19 Sep 1997 14:28:40 GMT Subject: Re: 5th Injector Circuit >> >>Simon you link to your 5th injector DOC is not quite right. >> >>for those in a hurry it's: >> >>http://www.lincoln.ac.nz/ccb/techs/simon/5th_inj.doc >> >>Dean > >t'is true ..... but the content is still "garbage", and when >I save it as "5th_inj.doc" and open it in Word, it crashes Word >(97). > >Tom Cloud > > DITTO ------------------------------ From: Kevin Timmerman Date: Fri, 19 Sep 1997 11:37:32 -0400 Subject: RE: 5th Injector Circuit On Friday, September 19, 1997 10:29 AM, Clare Snyder [SMTP:clsnyde@xxx.net] wrote: > >> > >>Simon you link to your 5th injector DOC is not quite right. > >> > >>for those in a hurry it's: > >> > >>http://www.lincoln.ac.nz/ccb/techs/simon/5th_inj.doc > >> > >>Dean > > > >t'is true ..... but the content is still "garbage", and when > >I save it as "5th_inj.doc" and open it in Word, it crashes Word > >(97). > > > >Tom Cloud > > > > > DITTO Hmmm... I just got the file and opened it with Word 97 without any problems. You wheren't using the browser's Save As.. where you ? That won't work, it corrupts the file. Grab it out of the cache. ------------------------------ From: blu@xxx.net (Greg) Date: Fri, 19 Sep 1997 12:06:33 -0500 (CDT) Subject: carb vs. efi I know I am kicking a dead horse here but Robert hit the jackpot, there are pros and cons to both injection and carbs. What is more important is your total vehicle setup and which one works for your application. I have three vehicles that I push to their limits, a '69 big block Vette that I have tried both efi and multiple makes of carbs and have found that they all work equally in their own settings. This vehicle has run 11.5 et's at 123mph at the strip with very little modification, but the best time was with a Quadrajet of all things because of the manifold design and closed chamber heads. Now I also autocross this vehicle and in that application the efi setup rules. I also have a '74 International Scout II half cab that has a 258 straight six, it had a barn burning 1 barrel carb that I switched to a Clifford efi setup, best thing I ever did to the vehicle cause now I do have more power, reliability, and I don't have to be a trottle jockey on those cold winter mornings. I also have a '93 Escort with a 1.9 efi setup and again it rules in everyday commuting and the autocrossing I do with the vehicle. The moral of this story? Be knowledgable about your setup and goals for it, this forum is great for this. do not fall into that ever growing percentage that assumes efi=perfomance, this is not always the case. Now before I get flammed for my 2 cents worth understand that I love both, they both have their place and anyone who says one or the other is "the only" choice is limiting themselves to very small "Disney" world. I think we all have had the experience of knowing someone who put a "3/4 inch" racing cam and a big ol' "mega pumper" carb in his rust bucket and says it will blow the doors off anything on the road. thats when it does actually start and stays running long enough to back it out of the driveway! its the total combination of parts you put into the project, mismatch them and you get a real "dog". Do the homework and get a matching combination? Hold on 'cause your going to be doing the time warp again! Greg Don't tell me what I can't do, Be afraid of what I can! ------------------------------ From: Tom Cloud Date: Fri, 19 Sep 1997 13:08:50 -0500 Subject: RE: 5th Injector Circuit >On Friday, September 19, 1997 10:29 AM, Clare Snyder [SMTP:clsnyde@xxx.net] >wrote: >> >> >> >>Simon you link to your 5th injector DOC is not quite right. >> >> >> >>for those in a hurry it's: >> >> >> >>http://www.lincoln.ac.nz/ccb/techs/simon/5th_inj.doc >> >> >> >>Dean >> > >> >t'is true ..... but the content is still "garbage", and when >> >I save it as "5th_inj.doc" and open it in Word, it crashes Word >> >(97). >> > >> >Tom Cloud >> > >> > >> DITTO > >Hmmm... I just got the file and opened it with Word 97 without any >problems. You wheren't using the browser's Save As.. where you ? That >won't work, it corrupts the file. Grab it out of the cache. > didn't try that .... will, though Tom Cloud ------------------------------ From: swagaero Date: Thu, 18 Sep 1997 20:34:29 -0700 Subject: Re: Injector calibration etc. Clare Snyder wrote: > > I have a strange project on the go - basically a dual throttle body > injection on a 1.8 litre engine. It is a SOOB EA81 unit. > I want to install one injector on each bank, just before the intake port on > the head (where manifold connects) I have a couple throttle bodies from a > snowmobile engine that accept ford type (multiport) injectors. What injector > should come close to the right size? I figure a 400HP, or 7 litre v8 should > be pretty close as a starting point, as each injector has to service 50 HP > and 900 ccs of engine displacement. > > Also, the computer I have (not sure if I can use it) is set up for the low > resistance injectors and resister pack. Can I substitute the high resistance > (12 volt, 14 ohm +/-) type without damaging the drivers? Obviously I would > be eliminating the resister pack. All I can think of is there would be a > higher inductive kick-back when de-energized. Is there a way to add a Zener > to handle this? > > Any other input appreciated. is this the American ea-81 or the asian ea-81 ------------------------------ From: Paul Messinger Date: Fri, 19 Sep 1997 11:18:18 -0700 Subject: Re: 5th Injector Circuit Kevin Timmerman wrote: > > On Friday, September 19, 1997 10:29 AM, Clare Snyder [SMTP:clsnyde@xxx.net] > wrote: > > >> > > >>Simon you link to your 5th injector DOC is not quite right. > > >> > > >>for those in a hurry it's: > > >> > > >>http://www.lincoln.ac.nz/ccb/techs/simon/5th_inj.doc > > >> > > >>Dean > > > > > >t'is true ..... but the content is still "garbage", and when > > >I save it as "5th_inj.doc" and open it in Word, it crashes Word > > >(97). > > > > > >Tom Cloud > > > > > > > > DITTO > > Hmmm... I just got the file and opened it with Word 97 without any > problems. You wheren't using the browser's Save As.. where you ? That > won't work, it corrupts the file. Grab it out of the cache. I have a word viewer linked to netscape and cannot load anything but garbage either. There is no way for me to get around this short of deleting the plugin. I also have word 95 as the word 97 it too buggy for me. Seems like the way to post files is in a common format that all can read. Paul ------------------------------ From: Orin Eman Date: Fri, 19 Sep 1997 11:47:04 -0700 (PDT) Subject: Re: DIY_EFI Digest V2 #326 > > I've seen a number of K-jet installations where the cold-start injector > > has been disconnected to stop fuel dribble from it. Does the control > > box not turn it off properly? > > - -- > > Chris Morriss > > > > Don't know? It seems to work just fine now. > > BRAAP > There is no computer in a K-jet car.. except the box which converts > oxygen-sensor voltage to duty cycle for a single "injector" which > regulates control pressure in the fuel distributor, which operates > hydro-mechanically. The cold-start injector is triggered by the wire > leading to the starter solenoid. the cold-start injector's negative side > is connected not to ground but to the Thermal Time switch, which screws > into the coolant jacket and provides a ground only below operating > temperature. A heating coil causes it to "give up" if the cold start > injector is activated for longer than ten seconds to prevent flooding, if > the starter is cranked for too long. Not necessarily true. 80's Audi turbo cars are K-jet and they control the cold-start injector from same computer that controls the frequency valve for mixture etc... The cold-start valve is however, well known for leaking, however it is activated! Orin. ------------------------------ From: Tunerguy@xxx.com Date: Fri, 19 Sep 1997 14:46:03 -0400 (EDT) Subject: honda eprom reprograming Does anybody know anything about reprograming import car eproms. There is a lot of aftermarket people out there that do this, but I want to create my own fuel map programs. Alan tunerguy@xxx.com ------------------------------ From: "B.E. Herron" Date: Fri, 12 Sep 1997 15:17:33 -0700 Subject: Re: Injector"spray"vs.evaporation Re: Holley ECM replacement - -----Original Message----- From: Dean To: diy_efi@xxx.edu> Date: Wednesday, September 17, 1997 5:26 AM Subject: Re: Injector"spray"vs.evaporation Re: Holley ECM replacement >(if >my >> > feeble memory serves me correctly) about (150 HP and 50 mpg) >> >> ( three-cylinder sprint engine.) >Steve if you want a copy of this ( 3 pages ) I could scan it in the next >few days >you post your circuit described below: > > I mentioned my memory was feeble (Brian), but I'm glad to see some others have heard of this engine. Too bad he couldn't get it developed into a SAFE design. I would like a copy of the article also. I don't think you'll be able to post it here due to the 40k limit, but I would appreciate it if you could e-mail directly to me. BEH '66 Mustang Fastback '73 Camaro RS ------------------------------ From: Terry Sare Date: 19 Sep 97 14:11 CDT Subject: Re[2]: 5th Injector Circuit In netscape, press the shift key while clicking on the link. Netscape will display a download area to save the file. This overrides plugins. ts - --- Kevin Timmerman wrote: > > On Friday, September 19, 1997 10:29 AM, Clare Snyder [SMTP:clsnyde@xxx.net] > wrote: > > >> > > >>Simon you link to your 5th injector DOC is not quite right. > > >> > > >>for those in a hurry it's: > > >> > > >>http://www.lincoln.ac.nz/ccb/techs/simon/5th_inj.doc > > >> > > >>Dean > > > > > >t'is true ..... but the content is still "garbage", and when > > >I save it as "5th_inj.doc" and open it in Word, it crashes Word > > >(97). > > > > > >Tom Cloud > > > > > > > > DITTO > > Hmmm... I just got the file and opened it with Word 97 without any > problems. You wheren't using the browser's Save As.. where you ? That > won't work, it corrupts the file. Grab it out of the cache. I have a word viewer linked to netscape and cannot load anything but garbage either. There is no way for me to get around this short of deleting the plugin. I also have word 95 as the word 97 it too buggy for me. Seems like the way to post files is in a common format that all can read. Paul ------------------------------ From: Sandy Date: Fri, 19 Sep 1997 12:46:17 -0700 Subject: Re: carb vs. efi Man Greg, sounds like part of my life story, I had the 69' 427, ran it with a couple of thrashed motors, used it as a daily driver too, ran the best on the street with my worked over Q-Jet (Best carb made....) Had the IH Scout too, had one with the ND Turbo Diesel, swapped that for a destroked chevy 400, I'm now thrashing an old 323 Alpina BMW that just wont stop running. Just glad to see that I'm not the only one with really strange things going on!! Sandy At 12:06 PM 9/19/97 -0500, you wrote: >I know I am kicking a dead horse here but Robert hit the jackpot, there are >pros and cons to both injection and carbs. What is more important is your >total vehicle setup and which one works for your application. >I have three vehicles that I push to their limits, a '69 big block Vette >that I have tried both efi and multiple makes of carbs and have found that >they all work equally in their own settings. This vehicle has run 11.5 et's >at 123mph at the strip with very little modification, but the best time was >with a Quadrajet of all things because of the manifold design and closed >chamber heads. Now I also autocross this vehicle and in that application [SNIP] ------------------------------ From: michaels@xxx.com (Michael Skolones) Date: Fri, 19 Sep 1997 12:55:08 -0700 Subject: Re[2]: I understand Q-jets - --IMA.Boundary.426007478 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part I think the point was that the Quadrajet couldn't take a high-pressure electric fuel pump due to needle valve restrictions, whereas the Holley units can take a stronger valve and therefore a higher pressure from an electric pump. Apparently the mechanical pumps don't put out enough fuel to keep either carb's bowl(s) filled, though I have my doubts about this. A pump is a pump, it's only a matter of size. Of course, there's nothing saying you couldn't have a lower pressure, higher flow pump with fatter fuel lines on a Quadrajet. That would get around the valve problem. The whole question is silly anyways; I'm sure that if you tried hard enough you could get equal performance out of Q-Jets or Holley carbs if they are rated the same CFM and sufficient fuel were supplied. And likewise I doubt that "all" hot rodders "couldn't" understand Q-Jets. For some people, performance mods are influenced by style, advertising, your buddy's opinion, etc, and "Holley" or "Edelbrock" logos look a lot neater on your car and clothes than 'Rochester Quadrajet". ______________________________ Reply Separator _________________________________ Subject: Re: I understand Q-jets Author: diy_efi@xxx.edu at Internet Date: 9/18/97 12:48 PM Paul: If the mechanical fuel pump can't keep one bowl filled, how can it keep 2 bowls filled (assuming same rate of consumption & still only one fuel pump)? Thanks - Daniel > > > >> There is a school of thought that the racers used to replace the > >> Rochester QuadraJets with Holleys because they couldn't understand the > >> QuadraJets! > > To be more correct the reason the Holley carb is used over a Q-jet > is because the Q-jet has a single fuel bowl in the center to feed both the > primaries and secondaries. Mechanical fuel pumps cannot keep this bowl > filled, and electric fuel pumps that can keep an average carb filled run at > a pressure that will blow past the Q-jet needle and seat, wich are only good > to 7 lbs. > The Holley has two fuel bowls, one on each end, which can be > extended to hold even more fuel. Their needle and seats also hold 9 lbs. > and can be replaced with ones that hold up to 12 lbs. > I am not trying to start an argument, but there are people who > subscribe to this list that run Holleys, and it is not because we can't > figure out a Q-jet. > > Paul Tholey > pft101@xxx.edu > - -- Daniel Grambihler danielg@xxx.com '87 328 GTS '95 D90 #3064 '96 900SS/CR - --IMA.Boundary.426007478 Content-Type: text/plain; charset=US-ASCII; name="RFC822 message headers" Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part Content-Disposition: inline; filename="RFC822 message headers" Received: from coulomb.eng.ohio-state.edu (128.146.90.150) by mailserver.mail1.com with SMTP (IMA Internet Exchange 2.1 Enterprise) id 0009DA0E; Thu, 18 Sep 97 13:47:17 - -0700 Received: by coulomb.eng.ohio-state.edu (940816.SGI.8.6.9/940406.SGI) for diy_efi-outgoing id TAA14003; Thu, 18 Sep 1997 19:43:47 GMT Received: from nz1.netzone.com by coulomb.eng.ohio-state.edu via ESMTP (940816.SGI.8.6.9/940406.SGI) for id PAA13998; Thu, 18 Sep 1997 15:43:44 - -0400 Received: (from danielg@xxx.9) id MAA09842 for diy_efi@xxx.edu; Thu, 18 Sep 1997 12:48:13 -0700 (MST) From: Daniel Grambihler Message-Id: <199709181948.MAA09842@xxx.com> Subject: Re: I understand Q-jets To: diy_efi@xxx.edu Date: Thu, 18 Sep 1997 12:48:12 -0700 (MST) In-Reply-To: <199709122333.TAA35112@xxx.edu> from "Paul Tholey" at Sep 12, 97 07:33:52 pm X-Mailer: ELM [version 2.4 PL24] Content-Type: text Sender: owner-diy_efi@xxx.edu Precedence: bulk Reply-To: diy_efi@xxx.edu - --IMA.Boundary.426007478-- ------------------------------ From: blu@xxx.net (Greg) Date: Fri, 19 Sep 1997 16:30:53 -0500 (CDT) Subject: re:carb vs. efi hey I live by the only car bible I know...........RUN WHATCHA BRUNG! I've got a freind who is putting a chev 400 into a '73 Scout and he is looking for some input, cool if I slide him your email address? Don't tell me what I can't do, Be afraid of what I can! ------------------------------ From: Ric Rainbolt Date: Fri, 19 Sep 1997 17:00:38 -0500 Subject: Question on Cold Starting I'm trying to tune a custom EFI system that I've developed and I'm having trouble with the cold start. By cold I mean room temp, which in my garage lately has been about 70-80 F. I've tried many settings from moderately rich to "pig" rich and nothing at all happens until I squirt some Carb cleaner into the manifold. Once I do that, the engine will hit and then may start (or may not). One or two shots of Carb cleaner more and it starts and runs (at which point my warm up cycle takes over and seems to work OK). More info: 8 cylinders with port injection Injectors well matched to engine output No cold start injector 250 RPM cranking speed nominal Good spark, new plugs Hot re-starts work OK Does anyone have any info on good "start" algorithms? One that I have not tried yet is a rapidly decaying very rich to a little rich scenario. Say, 2x to 3x the normal amount of fuel for the first few revs and then back off to 125% over a 20 rev range. What do "factory" systems do? Ric Rainbolt ricrain@xxx.net ------------------------------ From: Sandy Date: Fri, 19 Sep 1997 16:38:15 -0700 Subject: re:carb vs. efi Sure can, too bad, he could have bought my for the cost of the install! Sandy At 04:30 PM 9/19/97 -0500, you wrote: >hey I live by the only car bible I know...........RUN WHATCHA BRUNG! > >I've got a freind who is putting a chev 400 into a '73 Scout and he is >looking for some input, cool if I slide him your email address? > >Don't tell me what I can't do, > Be afraid of what I can! > > > ------------------------------ From: Paul Messinger Date: Fri, 19 Sep 1997 18:28:18 -0700 Subject: Re: 5th Injector Circuit Terry Sare wrote: > > > In netscape, press the shift key while clicking on the link. Netscape will > display a download area to save the file. This overrides plugins. That worked great but word vuer and word 95 both crash when trying to read the file. Any Ideas? Thanke for the great tip Paul ------------------------------ From: clsnyde@xxx.net (Clare Snyder) Date: Sat, 20 Sep 1997 01:41:36 GMT Subject: RE: 5th Injector Circuit >On Friday, September 19, 1997 10:29 AM, Clare Snyder [SMTP:clsnyde@xxx.net] >wrote: >> >> >> >>Simon you link to your 5th injector DOC is not quite right. >> >> >> >>for those in a hurry it's: >> >> >> >>http://www.lincoln.ac.nz/ccb/techs/simon/5th_inj.doc >> >> >> >>Dean >> > >> >t'is true ..... but the content is still "garbage", and when >> >I save it as "5th_inj.doc" and open it in Word, it crashes Word >> >(97). >> > >> >Tom Cloud >> > >> > >> DITTO > >Hmmm... I just got the file and opened it with Word 97 without any >problems. You wheren't using the browser's Save As.. where you ? That >won't work, it corrupts the file. Grab it out of the cache. > > > how? ------------------------------ From: clsnyde@xxx.net (Clare Snyder) Date: Sat, 20 Sep 1997 01:57:51 GMT Subject: Re: Injector calibration etc. >Clare Snyder wrote: >> >> I have a strange project on the go - basically a dual throttle body >> injection on a 1.8 litre engine. It is a SOOB EA81 unit. >> I want to install one injector on each bank, just before the intake port on >> the head (where manifold connects) I have a couple throttle bodies from a >> snowmobile engine that accept ford type (multiport) injectors. What injector >> should come close to the right size? I figure a 400HP, or 7 litre v8 should >> be pretty close as a starting point, as each injector has to service 50 HP >> and 900 ccs of engine displacement. >> >> Also, the computer I have (not sure if I can use it) is set up for the low >> resistance injectors and resister pack. Can I substitute the high resistance >> (12 volt, 14 ohm +/-) type without damaging the drivers? Obviously I would >> be eliminating the resister pack. All I can think of is there would be a >> higher inductive kick-back when de-energized. Is there a way to add a Zener >> to handle this? >> >> Any other input appreciated. >is this the American ea-81 or the asian ea-81 > Standard north american issue, 1987 Chaser hatchback ------------------------------ From: eric schumacher Date: Fri, 19 Sep 1997 19:08:06 -0700 Subject: cold starting Hi ric Obviously you are not getting enough of the right kind of fuel. By that I mean not atomized enough. There is a curve in one of the bosch books on how much fuel it takes to start a cold engine. It is unbelievable the large amount required. A lot of the fuel is wasted of course because of poor atomization. Bosch discusses this as a design feature of their cold start injectors. An interesting and related point is the VW experience with Warm engines. On CIS engines they of course have a cold start injector that squirts when the engine is cold and the engine is cranking. Worked great when the engine was cold, But when the car was driven a short distance like a mile or two and left to sit for a half hour the things would not start no way. This condition was most frequently encountered in cars that were a year or so old. The factorys solution,after ignoring the problem for a few years, was to add a "cold start pulse relay" In addition to the previous stuff this relay gives the cold start injector one quick goose every time the starter engages, regardless of temp. Presto mo more problem. On my DIY EFI based on Bosch stuff the cold start algorithm I use is when air is flowing into the engine and the cylinder heads (air cooled engine) are cold I squirt fuel into the manifold. The squirting is duty cycle modulated at a fixed rate with the duration determined by a pot and cylinder head temp. The pot setting is empirically determined Lotsa Luck Eric 85 GTI with VR6 power ------------------------------ From: clsnyde@xxx.net (Clare Snyder) Date: Sat, 20 Sep 1997 02:08:37 GMT Subject: Re: Question on Cold Starting > >I'm trying to tune a custom EFI system that I've developed and I'm having >trouble with the cold start. By cold I mean room temp, which in my garage >lately has been about 70-80 F. I've tried many settings from moderately >rich to "pig" rich and nothing at all happens until I squirt some Carb >cleaner into the manifold. Once I do that, the engine will hit and then may >start (or may not). One or two shots of Carb cleaner more and it starts and >runs (at which point my warm up cycle takes over and seems to work OK). > >More info: > 8 cylinders with port injection > Injectors well matched to engine output > No cold start injector > 250 RPM cranking speed nominal > Good spark, new plugs > Hot re-starts work OK > >Does anyone have any info on good "start" algorithms? One that I have not >tried yet is a rapidly decaying very rich to a little rich scenario. Say, >2x to 3x the normal amount of fuel for the first few revs and then back off >to 125% over a 20 rev range. > >What do "factory" systems do? > >Ric Rainbolt >ricrain@xxx.net > > when cold, first ignition pulse triggers a "prime " pulse on all injectors. This is a common setup, used by GM and others. Easy enough to implement, I would think, even as an addon.just a oneshot triggered by the ignition pulse, and not retriggerable. ------------------------------ From: swagaero Date: Fri, 19 Sep 1997 19:33:46 -0700 Subject: Re: Injector calibration etc. Clare Snyder wrote: > > >Clare Snyder wrote: > >> > >> I have a strange project on the go - basically a dual throttle body > >> injection on a 1.8 litre engine. It is a SOOB EA81 unit. > >> I want to install one injector on each bank, just before the intake port on > >> the head (where manifold connects) I have a couple throttle bodies from a > >> snowmobile engine that accept ford type (multiport) injectors. What injector > >> should come close to the right size? I figure a 400HP, or 7 litre v8 should > >> be pretty close as a starting point, as each injector has to service 50 HP > >> and 900 ccs of engine displacement. > >> > >> Also, the computer I have (not sure if I can use it) is set up for the low > >> resistance injectors and resister pack. Can I substitute the high resistance > >> (12 volt, 14 ohm +/-) type without damaging the drivers? Obviously I would > >> be eliminating the resister pack. All I can think of is there would be a > >> higher inductive kick-back when de-energized. Is there a way to add a Zener > >> to handle this? > >> > >> Any other input appreciated. > >is this the American ea-81 or the asian ea-81 > > > Standard north american issue, 1987 Chaser hatchback I will tell you monday what size injctor you need take a look at my web site for where to mount them if you want it to work correctly as the input port has to much cross flow to use 2 injectors the asian is even worse. Steve - -- ----|------||------|---- --|------[]------|-- 0/ \0 www.flash.net/~swagaero ------------------------------ From: MaxBoost@xxx.com Date: Fri, 19 Sep 1997 22:54:06 -0400 (EDT) Subject: Re: Injector"spray"vs.evaporation In a message dated 97-09-18 02:53:19 EDT, you write: << Obviousy, he didn't. They hadn't even invented the Suziki/Geo engine when Smokey was tinkering with his "hot vapor engine". I have no idea what engine he was using, it was 'bout 20 years befor the Geo engine was invented. >> If memory serves me correctly, it was a dodge omni that he used. There was an article in HOT ROD in 1984 by C. J. Baker. There also was an article in Circle Track 7/90 that talks about his hot vapor engine and adiabatic engines in general. You should be able to look them up a major library. Max ------------------------------ From: TMatthe@xxx.com Date: Sat, 20 Sep 1997 00:23:04 -0400 (EDT) Subject: Upgraded drivers Is there any way to upgrade the injector drivers in a GM computer to drive the low impedence injectors? I've heard the stockers will burn out driving a L Imp. pinjector, but they are so much cheaper than the ACCEL H Imp. injectors. Tom ------------------------------ From: clsnyde@xxx.net (Clare Snyder) Date: Sat, 20 Sep 1997 05:30:26 GMT Subject: Re: Injector calibration etc. > > >I will tell you monday what size injctor you need take a look at my web >site for where to mount them if you want it to work correctly as the >input port has to much cross flow to use 2 injectors the asian is even >worse. > >Steve >-- > > ----|------||------|---- > --|------[]------|-- > 0/ \0 > > > >www.flash.net/~swagaero > >What about throttle bodies - act just like a pair of Bings, with the nozzles about 3 " up from the head surface? the cross flow should not affect this too much, should it? The factory manifold has a little flow divider "dam" in it, supposedly to help fuel distribution. | | | | | \ | | \ | inj> \ | Throttle body diagram, kinda' | | | | | | | | - ------J L--------- Head & Intake <<<<< >>>>>>> flow ------------------------------ End of DIY_EFI Digest V2 #328 ***************************** 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".