DIY_EFI Digest Monday, 9 September 1996 Volume 01 : Number 266 In this issue: Re: troubleshooting a taurus re: Re: hi compressions Re: troubleshooting a taurus Re: Injector Flow Variation Re: Water Injection Water Injection for power? Re: Ancient History Re: Water Injection for power? re: Manifold/throttle bodys-ED:-) Re: Ancient History re: Ancient History (now fuel economy) Http address RE: Sequential VS Batch fire systems RE: Re: hi compressions RE: Injector Flow Variation See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: "Tony Bryant" Date: Mon, 9 Sep 1996 08:36:07 +1200 Subject: Re: troubleshooting a taurus > From: "Mike Fahrion" > Organization: B&B Electronics Mfg. Co. > To: diy_efi@xxx.edu > Date: Fri, 6 Sep 1996 15:20:04 +0000 > Subject: troubleshooting a taurus > Priority: normal > Reply-to: diy_efi@xxx.edu > Sorry if this is a bit off subject. > > A coworker has paid an insane sum to a dealer to fix a problem which > hasn't gone away - and I believe that it should be a simple EFI > problem. > > The taurus has a very hard time starting after sitting overnite or > over perhaps 8-10 hours. Takes a large amount of cranking with no > firing, then stumbles slowly to life. Ambient temperature doesn't > seem to have any effect. Computer reveals no fault codes, pump and > filter are good. > > Isn't there a fuel accumulator which should maintain fuel pressure > when sitting? If this was faulty would it allow pressure to drop - > forcing the pump to charge the system again before it could start? > > Any insight would be appreciated > > TIA > -mike > mfahrion@xxx.com > Sounds like a marginal inductive (crank angle) pickup. These things produce a signal level proportional to the speed. Sounds like cold cranking is not producing enough signal. The computer probably expects some havoc while starting, so doesn't bother to report any bizarrities (since it runs fine when running) *********************************************************** * "Insanity is the only sane response to an insane world" * * >> bryantt@xxx.nz << * *********************************************************** ------------------------------ From: "Woodd, Michael" Date: Mon, 9 Sep 1996 08:20:00 +1200 Subject: re: Re: hi compressions Steve says... >This might be a dumb question, but why not non-circular valves? I guess >they wouldn't be able to spin. Is that a problem? I can see corners being >bad, but what about a nice oval shape? >- --steve It should be possible to use two valve stems to stop it spinning. What about making an oval valve with two stems at the, and machining an existing four valve head to have two oval valves? You could use the existing valve guides. Has this been tried before? Could be tricky to make the valves, with two stems and all, but not impossible. Mike Woodd (wooddm@xxx.nz) ------------------------------ From: Jonathan Lloyd Date: Sat, 7 Sep 1996 10:41:12 +0100 Subject: Re: troubleshooting a taurus In message , SRavet@xxx.com writes >"Mike Fahrion" Wrote: >| >| Sorry if this is a bit off subject. >| >| A coworker has paid an insane sum to a dealer to fix a problem which >| hasn't gone away - and I believe that it should be a simple EFI >| problem. What sort of EFI system? Any chance the idle or bypass system is not working thus not applying any throttle for starting cold. - -- Jonathan Lloyd john@xxx.uk ------------------------------ From: Jeffrey.Giberstein@xxx.EDU (Jeffrey Giberstein) Date: 08 Sep 96 18:50:34 EDT Subject: Re: Injector Flow Variation Both aftermarket suppliers and OEM's (where necessary) will flow injectors and match sets as best as possible. If, for instance, you were to order injectors from Kinsler, they'd do this for you. I learned this the hard way 'cause I had Ford send me some injectors for a Formula SAE EFI project and well into development, I decided to check flow and the injectors were grossly out of whack with eachother. JG ------------------------------ From: "William A. Sarkozy" Date: Sun, 08 Sep 1996 18:41:14 -0700 Subject: Re: Water Injection At 08:26 AM 9/6/96 -0600, you wrote: > >O.K., My daily driver (w/ 160k miles) is starting to knock unless I use >premium. I think I'll put in a water injection system, but have a few >questions. Can you dump in too much water? I plan on a winshield washer >pump, and to have it vaccum operated. I will monitor the map signal and >start pumping water when the engine gets below a certian vaccum. What >I could do with another op-amp and a 555 is have the water pump come in >at 50% duty cycle at one vaccum, and full on when it drops below another >vaccum. I don't think I'll get carried away with using a pic chip, >because I really don't know the relationship between engine load and >knock. > Would it be better to have the water controlled off throttle position? >Thanks for your time, >-Steven Ciciora > > Your 2-stage idea is good, but I would use 2 pumps.....1 at moderate vacuum and 1 at very low vacuum, each with its own regulating nozzle. The idea of modulating the motor speed (pump output) sounds good, but unless you have a closed loop motor speed control for the pump, you're in for a suprise. There are too many extraneous factors which will influence pump output (nozzle position, temperature, etc.) If you could call for a given motor speed with a certain voltage, it would be great, but you won't get 50 % motor speed by applying 50% voltage. And you won't get the response you want either. Also, I wouldn't key the water off throttle position....a given throttle position at heavy load can mean completely different operating characteristics that the same throttle position at light load and high speed. Good luck..... Bill ------------------------------ From: Thor Johnson Date: Sun, 8 Sep 1996 19:31:46 -0400 (EDT) Subject: Water Injection for power? I just looked at the current issue of "Midnight Engineering," and saw an article that may be of interest. The author suggested that, instead of the usual fan/radiator/et al, the cylinders be cooled by injecting water (diesel style) during the latter part of the power stroke. The H2O would flash into steam, thereby changing the heat (normally exhasted) into mechanical power. I, for one, would like to try this. How hard would it be to make an additional hole in the head for this purpose (I have little/no mechanical background), and would it have adverse effects on a HC engine (Honda F2)? Comments? Thor Johnson johnsont@xxx.edu http://falcon.mercer.peachnet.edu/~johnsont Have you seen the WarpMap lately? http://falcon.mercer.peachnet.edu/~johnsont/warpmap ------------------------------ From: Jonathan Lloyd Date: Sat, 7 Sep 1996 10:20:44 +0100 Subject: Re: Ancient History In message <9609061511.AB00164@xxx.or beng.com.au writes > >>cylinder contains free oxygen and free hydrocarbon radicals and the >>whole lot reacts at once. Bad news , knock , damage etc. > >Not exactly true. Combustion pressure, temperature and radiation are >required to initiate knock, which is where areas in the combustion >chamber auto-ignite causing several flame fronts to develop >uncontrolled. > As this is an EFI group I'll refrain from chatting about combustion but for anyone who does it is important to be very clear about the terms used i.e. ignition, flame etc. At basics the whole thing is a chemical reaction and the issues are what reactions and what drives them. There are many different and driven by different things. - -- Jonathan Lloyd john@xxx.uk ------------------------------ From: Jim Zurlo Date: Sun, 8 Sep 1996 19:40:53 -0500 Subject: Re: Water Injection for power? At 07:31 PM 9/8/96 -0400, you wrote: > >I just looked at the current issue of "Midnight Engineering," and saw an >article that may be of interest. The author suggested that, instead of >the usual fan/radiator/et al, the cylinders be cooled by injecting water >(diesel style) during the latter part of the power stroke. The H2O would >flash into steam, thereby changing the heat (normally exhasted) into >mechanical power. > Southwest Research Institute did this I think sometime in the '60s or early '70s. They could inject enough water to eliminate the radiator, but if memory serves me there was a problem with mineral build up inside the combustion chamber. It's all documented in an SAE paper. Jim Zurlo zurlo@xxx.com ------------------------------ From: Stuart Baly Date: Mon, 9 Sep 96 11:04:40 EST Subject: re: Manifold/throttle bodys-ED:-) >Does anyone know what would happen if you joined all the chokes >together on the down-stream side of each throttle, kind of like >forming a mini-plenum for improving balance robustness at low throttle >openings, but still allowing the correct runner design and plenum >volume up-stream of the blades for WOT performance? Yamaha also had another version of this apart from YDIS - I can't remember it's name but its used on the Yamaha V-Max. The engine is a 1200 V-4 with four downdraught carbs in the V. At high revs two butterflies open to join the intakes in pairs across the V. The idea is that the cylinders in each pair are drawing in air at separate times, so each cylinder can use two carbs rather than one. I don't know if it made that much difference to power, but a 145hp from a 1.2L engine is alright. Stuart P.S. All this talk of knock reminds me... One Sunday night recently I went for a ride in a Daihatsu Charade with a friend of mine. She said "Hey, listen to this!" and accelerated out of a 25mph corner at full throttle in top gear, knocking like a dog (the car, not the driver) all the way to about 50mph. She was laughing all the way, and said "It sounds like a truck!". I asked her how long she'd been doing that, and she said "Oh, most of the week."! These Daihatsus are tough little cars. ========================================================= Stuart Baly (S.Baly@xxx.au) '71 Datrat 1600, '89 Kawasaki GPz900R, '81 Yamaha RD350LC ========================================================= ------------------------------ From: Darrell Norquay Date: Sun, 8 Sep 1996 19:55:02 -0700 (PDT) Subject: Re: Ancient History At 12:45 AM 9/8/96 -0500, John Faubion wrote: >Whoa! As soon as you changed fuel (methane) you changed the stoichiometric >ratio! So your comparison of 28:1 on methane means absolutely nothing when >related to gasoline. Its an apples to oranges. In addition you wouldn't >want to lean out an engine to reach maximum power. Max power will occur >with a slightly richer than stoich mixture. While best efficiency will >occur leaner than stoich. Granted, the change of fuel makes a big difference, but the point was that 28:1 AFR is Very Lean, even for methane. I did not say it was making anywhere near maximum power at this AFR, again, it was making just enough power for it's intended (constant) load. >Mainly by reducing frictional losses at the lower RPM. This would be more of a factor with a big block, since it has higher frictional losses due to increased bore, stroke, stc. >Of course the ONLY rpm where torque, horsepower and VE could all peak at >the same time is at 5252 rpm. Not exactly most people's idea of a best >cruise speed! Now if your cam duration is short enough keep the engine >speed down, reducing the overall frictional losses (which are exponential >with regard to rpm) and then geared for this lower peak torque (at which VE >also peaks and usually BSFC) than you could have great mileage. I know this >is sort of what you were eluding to but just not getting there on the same >track. :) I wasn't aware of the magic number of 5252 RPM, how did you arrive at it? I can't see this applying to ALL internal combustion engines across the board... As far as best cruise RPM, depends if it's a Honda 750cc four or a 512ci Caddy, doesn't it? You're right, I shouldn't have included HP in that list, but the point was, that if all you're interested in is enough horsepower to cruise, it doesn't matter how much horsepower you can make at some other RPM. Horsepower is proportional to RPM, so in theory, the higher the RPM, the higher the horsepower. Of course, this is ultimately limited by engine design, VE, and a whole host of other things. regards dn dnorquay@xxx.com ------------------------------ From: RABBITT_Andrew@xxx.au Date: Mon, 9 Sep 1996 13:23:42 est Subject: re: Ancient History (now fuel economy) >Granted, the change of fuel makes a big difference, but the point was >that 28:1 AFR is Very Lean, even for methane. The biggest influence on fuel consumption is in pumping work (ie manifold pressure, or lack thereof). If you choose to run a 400+cid engine, then to produce the sort of power necessary for cruising (10-20 hp), you will be running relatively low manifold pressures compared to a smaller engine producing the same power. Remember, the manifold depression is un-recovered, therfore represents a power loss. The slower you spin the engine, then the higher the manifold pressure is for the same airflow (power), hence your pumping work (losses) is less. Dropping the axle ratio (numerically) will give you benefits in fuel consumption at the same (road) speed simply because you have your foot on the throttle harder (strange but true! :) Running lean does effectively the same thing, by running the same fuelling level, but higher airflow, the manifold depression is reduced, saving power. ------------------------------ From: "George Lerm" Date: Mon, 9 Sep 1996 08:01:55 GMT-2 Subject: Http address Hi Could anybody tell me if something is amiss with the efi332 page. Unable to get access at all. efi332 http://www.cim.swin.edu.au/~aden/web-docs/efi332/332_index.html Thanks George Lerm Clinical Engineering Red Cross Hospital Private Bag Rondebosch Cape Town South Africa 7700 ------------------------------ From: Mark Pitts Date: Fri, 20 Sep 1996 10:17:47 +-200 Subject: RE: Sequential VS Batch fire systems Well for a start, if you have ONE cylinder that wants to 'pink' you can = change the timing, and how much fuel you throw into one cylinder, and = keep all the others at 'normal'..... Just a thought Mark - ---------- From: Fred Francis[SMTP:Fred_Francis@xxx.us] Sent: Friday, September 06, 1996 5:03 PM To: diy_efi@xxx.edu Subject: Sequential VS Batch fire systems RABBITT Wrote:=20 .... All the applications that Robert J. Harris quoted in his original post = were high-speed, high power applications, and sequential fuelling is not = going to give you anything here. What sequential injection does give is better = low speed, part load combustion stability leading to better real-world = driveability. Would anyone like to comment on batch fire vs sequential injection = systems?=20 What are the real world advantages to each under specific circumstances? = GM went to sequential systems recently on the new camaros and corvettes, = WHY? Is anything really gained with a sequential system in terms of performance, efficiency or driveablility? ~~fred ------------------------------ From: Mark Pitts Date: Fri, 20 Sep 1996 09:32:12 +-200 Subject: RE: Re: hi compressions Problem comes, trying to work out the shims, so that both stems are = working together, and not trying to compress two valve springs, by only = pressing on one stem. Mark - ---------- From: Woodd, Michael[SMTP:wooddm@xxx.nz] Sent: Sunday, September 08, 1996 10:20 PM To: diy_efi Subject: re: Re: hi compressions Steve says... >This might be a dumb question, but why not non-circular valves? I = guess >they wouldn't be able to spin. Is that a problem? I can see corners = being=20 >bad, but what about a nice oval shape? >- --steve It should be possible to use two valve stems to stop it spinning. What about making an oval valve with two stems at the, and machining an existing four valve head to have two oval valves? You could use the existing valve guides. Has this been tried before? Could be tricky to make the valves, with two stems and all, but not impossible. Mike Woodd (wooddm@xxx.nz) ------------------------------ From: Mark Pitts Date: Fri, 20 Sep 1996 10:22:46 +-200 Subject: RE: Injector Flow Variation Is it worth testing them on the bench, flowing at 20%, 40% 60% and 80% = flows for a while, and actually seeing how much they flow, and putting = the adjustment into the code???? Comments please... as I've never really thought about this bit of = potentially disastrous mismatch. Mark - ---------- From: Greg Finnican[SMTP:f0247@xxx.net] Sent: Saturday, September 07, 1996 6:22 PM To: diy_efi@xxx.edu Subject: Injector Flow Variation What an injector's flow rating is and what it actually flows can vary=20 quite a bit. When we ultrasonicly clean them it does not always bring=20 them back in line. How much of this is manufacturing variation? After=20 seeing the variation in injectors I can'nt imagine using an untested set = in a performance application - certainly not a used set. I would like = to=20 hear others experience. greg@xxx.com ------------------------------ End of DIY_EFI Digest V1 #266 ***************************** 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".