DIY_EFI Digest Saturday, 16 January 1999 Volume 04 : Number 037 In this issue: Re: Low Pressure Transducers Re: 555 EFI Re: 555 EFI re: 555 EFI Re: Haltech E6GM Re: Low Pressure Transducers Re: Uploaded BIN to FTP Re: 555 EFI See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: bearbvd@xxx.net (Greg Hermann) Date: Fri, 15 Jan 1999 22:15:46 -0700 Subject: Re: Low Pressure Transducers >Joel, >Has anyone answered your post about low pressure transducers? > >I want to come up with a tool that will let me run tiny tubing to various >points on and in my truck, to locate and measure areas of hi and lo >aerodynamic pressure. Actual values are not too important - just pressure >at one location relative to another location. > >Would like to hear if you receive any leads. Mamac Systems--Minneapolis-(800) 843-5116 Model PR-274 or PR-275 have full scale ranges down to as low as 0--0.1" H2O for about $150. Sur they can be had in 24vdc supply, dunno about 12vdc tho. Ashcroft also goes down to about this range, choice of 0.25%, 0.5%, or 1% accuracy, depending on $$$, but reasonably competitive with Mamac. Dwyer is a third name. Regards, Greg > >Bud Todd >quest100@xxx.net ------------------------------ From: "Clarence L.Snyder" Date: Sat, 16 Jan 1999 00:22:53 -0500 Subject: Re: 555 EFI Bruce Plecan wrote: > > -----Original Message----- > From: Clarence L.Snyder > To: diy_efi@xxx.edu> > Date: Friday, January 15, 1999 11:57 PM > Subject: Re: 555 EFI > > >thergen@xxx.net wrote: > >> > >> Bruce, > >> > >> Are you thinking of a string of one-shots and using a varying > >> voltage on > >> the control pins to vary the output pulse width? If you're already going > >> to be using op-amps to scale the output of the sensors, you could > probably > >> add/subtract the outputs of multiple op-amps together through resistors > >> and run that into the control voltage pin of a smaller number of 555s. > >> > >question of clarification: > >what is the "control voltage" pin? My understanding of the 555 operation > >is the cap and resistance (cap between threshold {connected to discharge > >for monostable}and ground - resistor from B+ to threshold) were an RC > >"tank" circuit. The resistor controls the time required for the cap to > >reach 2/3 of B+ voltage. > > Pin 5 sets B+ as you discribe it. > Bruce > > What do I connect to pin 5, through what, to control this? On the info I have, this is the BYPASS pin and is tied to ground through a small cap to despike. How do I use it to control pulse width? What degree of adjustment is possible from this pin? Another question - What percentage pulse width change would be required from the MAP or TPS input? What percentage from engine temperature, assuming these were the only inputs you were going to use other than the trigger (tach sync)? ------------------------------ From: "Clarence L.Snyder" Date: Sat, 16 Jan 1999 00:48:15 -0500 Subject: Re: 555 EFI Clarence L.Snyder wrote: > > Bruce Plecan wrote: > > > > > > Pin 5 sets B+ as you discribe it. > > Bruce > > > > > What do I connect to pin 5, through what, to control this? On the info I > have, this is the BYPASS pin and is tied to ground through a small cap > to despike. How do I use it to control pulse width? What degree of > adjustment is possible from this pin? > > Another question - > What percentage pulse width change would be required from the MAP or TPS > input? What percentage from engine temperature, assuming these were the > only inputs you were going to use other than the trigger (tach sync)? The only other thing I have seen this pin used for is a very simple FM transmitter / signal generator where an audio signal is put onto an RF signal for tracing purposes. - FM radio then picks up the signal in an audible form. This is when used as astable. ------------------------------ From: "Robert W. Hughes" Date: Fri, 15 Jan 1999 23:52:14 -0600 Subject: re: 555 EFI > I've been thinking about a simple EFI using a string of 555s. > Just like the "Normal" math would be, ie first 555, base pulse, > second Coolant temp correction, third MAP, and so on for like > 6+ 555 all in series. Trouble is this gets me, an addition of > correction factors, instead of multipling them, is this a major > problem?. I realize this ain't gonna be as good as a oem, > ecm, but would like to get fairly close. Another approach - the switching point (pulse width) on the 555 is controlled by the voltage across the timing capacitor. When the voltage rises to a certain percentage of the supply votage, the 555 switches. If the capacitor value is constant and the resistor value is constant, the only thing controlling this timing is the voltage applied to the resistor. Obviously, this voltage must be high enough to trigger the 555 but it can be noticeably higher than the supply voltage. So, build an op-amp circuit to add together the MAP voltage, the coolant temp correction, perhaps even a function of engine speed vol eff curve) and produce an output voltage of 5 to n volts. Run the 555 on 5 volts and apply this voltage to the timing resistor. The timing resistor and capacitor would be chosen for a pulse width slightly shorter than that required for idle at 5 volts and the high voltage (n) would then be chosen to give the maximum pulse width desired. You would probably need a limiting circuit across the cap (like a 5v zener) to protect the 555 from the high voltage possible at high pulse widths and low speeds. The major problem here is dynamic range, the wider the ratio of min to max pulse width, the higher the voltage the op-amp circuit must produce. - -- Robert W. Hughes (Bob) BackYard Engineering Houston, Texas rwhughe@xxx.org ------------------------------ From: "Robert E. Yorke" Date: Fri, 15 Jan 1999 22:31:38 -0800 Subject: Re: Haltech E6GM Paul: If you found it to be so user friendly, why do you want to sell it? At any rate, what is your asking price? At 03:10 PM 1/16/1999 +1100, you wrote: >Hi There, > Maybe I can Help.I own a Haltech E6GM and an Autronic SMC >unit. >The E6GM has 22 fuel ranges every 500rpm up to 10500rpm or 17 fuel ranges >every 1000rpm up to 16000rpm and 32 load points per range. > These are the same for spark and fuel which gives a very precise >adjustment. >this is also interpolated to work out smaller increments. >This system is definately much more user friendly than the Autronic system. >Another great feature is the data logging but the laptop must be plugged in >for recording the info.I hope this info has been useful. >P.S my E6GM ecm is for sale but I live in Australia so someone else out >there may be interested. >PAUL. >---------- >> From: Charles Brooks >> To: diy_efi@xxx.edu >> Subject: Re: Haltech E6GM >> Date: Saturday, January 16, 1999 12:22 PM >> >> Is the E6GM capable of 500 RPM resolution? It's hard to tell >> from the Haltech page, and the post in the archives didn't >> elaborate. If so then I don't see any problem for my >> application. Hhmm, seems like I'm trying to talk myself into >> the Haltech unit, A 500 dollar difference is a persuasive >> argument :) >> >> Charles Brooks >> >> >> >> Bruce Plecan wrote: >> > >> > 1,000 rpm for a 12,000 rpm capacity calibration, 500 rpm resolution for >a >> > 6,000 rpm calibation. Meaning no correction over 6,000 rpm not >> > that the ecm wouldn't work at higher speeds. >> > Bruce ------------------------------ From: KD6JDJ@xxx.com Date: Sat, 16 Jan 1999 01:42:36 EST Subject: Re: Low Pressure Transducers Please ignore this post if it is way off base , I just came across it.and thought that I might suggest the use of a transparent tube with colored water in it so that you can see how the level of the water varies (monitored by eye ) , as the pressure at one open end varies , with respect the other open end. The system works. But it is likely not what you are seeking. It is sure less $$ than any other system . Jerry ------------------------------ From: Shannen Durphey Date: Sat, 16 Jan 1999 01:57:30 -0500 Subject: Re: Uploaded BIN to FTP It's right here. ftp://efi332.eng.ohio-state.edu/incoming/VS_BSTK1451%20%28V6%29.BIN I had to right click on it in netscape, but it downloaded. Shannen diy_efi@xxx.edu wrote: > > Ross, > I tried to download the bin file to have a look but it came up > with a url fault .....any ideas on how to download it???????? > PAUL. > > ---------- > > From: Ross Myers > > To: EFI List > > Subject: Uploaded BIN to FTP > > Date: Wednesday, January 13, 1999 6:20 PM > > > > Hi All, > > > > For those who are interested I've uploaded a BIN to the DIY_FTP /incoming > > dir. > > The file is called VS_BSTK1451 (V6).BIN > > > > It's from a 95/96 model VS Holden Commodore. > > PCM is a #16210672, 3.8L V6, 4Spd Electronic Auto, Memcal uses 27010 (32 > > pin) ROM. > > > > Regards > > > > Ross Myers ------------------------------ From: thergen@xxx.net Date: Fri, 15 Jan 1999 23:55:04 -0800 (PST) Subject: Re: 555 EFI Picture an op-amp with the non-iverting input connected to pin 6 and the inverting input connected to pin 5. Pin 5 is also connected to a resistor divider network that pulls it to 2/3 Vcc. There is probably a symbolic view on one of the semiconductor manufacturers sites. I'm looking at the cover of two different books that show this configuration. The 2/3 reference point can be yanked around to where you want by using pin 5. It can also affect the 1/3 reference for pin 2. The pin numbers above assume the 8 pin package. If you can't find an online reference, or it's still not clear, I could probably try some ascii art to show the configuration. Tom On Sat, 16 Jan 1999, Clarence L.Snyder wrote: > Bruce Plecan wrote: > > > > -----Original Message----- > > From: Clarence L.Snyder > > To: diy_efi@xxx.edu> > > Date: Friday, January 15, 1999 11:57 PM > > Subject: Re: 555 EFI > > > > >thergen@xxx.net wrote: > > >> > > >> Bruce, > > >> > > >> Are you thinking of a string of one-shots and using a varying > > >> voltage on > > >> the control pins to vary the output pulse width? If you're already going > > >> to be using op-amps to scale the output of the sensors, you could > > probably > > >> add/subtract the outputs of multiple op-amps together through resistors > > >> and run that into the control voltage pin of a smaller number of 555s. > > >> > > >question of clarification: > > >what is the "control voltage" pin? My understanding of the 555 operation > > >is the cap and resistance (cap between threshold {connected to discharge > > >for monostable}and ground - resistor from B+ to threshold) were an RC > > >"tank" circuit. The resistor controls the time required for the cap to > > >reach 2/3 of B+ voltage. > > > > Pin 5 sets B+ as you discribe it. > > Bruce > > > > > What do I connect to pin 5, through what, to control this? On the info I > have, this is the BYPASS pin and is tied to ground through a small cap > to despike. How do I use it to control pulse width? What degree of > adjustment is possible from this pin? > > Another question - > What percentage pulse width change would be required from the MAP or TPS > input? What percentage from engine temperature, assuming these were the > only inputs you were going to use other than the trigger (tach sync)? > ------------------------------ End of DIY_EFI Digest V4 #37 **************************** 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".