DIY_EFI Digest Thursday, March 25 1999 Volume 04 : Number 193 In this issue: Re: valve overlap Re: O2 Sensor current? Re: OBDII to PC Re: valve overlap Re: PWM fuel pump Re: valve overlap Re: List Topics... Re: List Topics... RE: injector manifold design RE: injector manifold design Re: List Topics... Re: O2 Sensor current? Re: List Topics... See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Wed, 24 Mar 1999 18:24:20 -0800 (PST) From: Jim Davies Subject: Re: valve overlap On Thu, 25 Mar 1999, Matt Boland wrote: > silent50@xxx.com wrote: > > > Check out the lastest Muscle Mustangs, there is an article on solenoid > > activated valves. > > Where would I find the Muscle Mustangs ? > > Just check IBMs patent site, or the USPTO, there are hundreds of patents on this subject available to view. ------------------------------ Date: Wed, 24 Mar 1999 21:19:37 -0500 From: "Ord Millar" Subject: Re: O2 Sensor current? This is the standard way of telling if the O2 is at temperature yet... many systems will bias the sensor to .45 volts through a very high resistance (10 megaohms I believe). Once the sensor is at temperature, it does provide enough current to move the voltage away from the preset level. - -----Original Message----- From: Wen Yen Chan To: diy_efi@xxx.edu> Date: Wednesday, March 24, 1999 8:49 PM Subject: Re: O2 Sensor current? >Hello, > >A while back I tried to offset the reading from my O2 sensor with a simple >op-amp circuit. The circuit worked fine but the ECU always thought the >sensor was hot (even after a cold restart). It seems that the Honda ECU I >was playing with pulled a small current from the sensor to check if it was >lit. When my circuit was added the ECU saw the low output impedence of the >op-amp and just assumed the sensor was hot. > >Wen > > >On Wed, 24 Mar 1999 Teller.John@xxx.com wrote: > >> O2 Sensors do not draw current (excepting the heater in a heated 02 >> sensor), they are in fact a voltage source. Not only that, they are a high >> impedance voltage source and therefore do not put out much current at all. >> The voltage drop through a 10K resistor is going to be negligible due to >> the miniscule currents (less than a microAmp) involved. To figure the >> voltage drop accross your 10K resistor, use Ohm's law (E=I*R) where I = >> 0.0000002 Amps and R = 10000 Ohms for a voltage drop of 0.02 Volts. >> >> If you want to change the output voltage of one of these devices, you >> probably would be better off using an op amp circuit with a gain factor >> less than 1. Any loading of the output of these devices will at best >> provide erroneous readings and at worst destroy the sensor. See the >> Forrest M. Mims books which are (or at least used to be) available from >> Radio Shock for some examples of these circuits. >> >> >> > > ------------------------------ Date: Wed, 24 Mar 1999 21:26:07 -0500 From: "Ord Millar" Subject: Re: OBDII to PC Wow! What is the price for the kit with the software as shown on obd-2.com? That looks like exactly what I need right now. - -----Original Message----- From: xxalexx@xxx.com> To: diy_efi@xxx.edu> Date: Wednesday, March 24, 1999 6:12 PM Subject: Re: OBDII to PC Recomended circuits are in SAE J2201 and ISO-9141-2 publications. Consists of a comparator and a transistor. I can supply a kit for $22 Will post a schematic in near future. Alex C. Peper OBD-2 developer http://www.obd-2.com > Does anyone know where I can find a diy circuit to connect an OBDII ISO-9141 to the serial port of a PC ?. > > TIA > Wayne. > ------------------------------ Date: Wed, 24 Mar 1999 21:42:35 -0500 From: "Ord Millar" Subject: Re: valve overlap Most large magazine shops, some of the bigger bookstores. Also on the web at www.cskpub.com BTW, I looked in April issue, but could not find that article... what is the title? - -----Original Message----- From: Matt Boland To: diy_efi@xxx.edu> Date: Wednesday, March 24, 1999 9:28 PM Subject: Re: valve overlap >silent50@xxx.com wrote: > >> Check out the lastest Muscle Mustangs, there is an article on solenoid >> activated valves. > >Where would I find the Muscle Mustangs ? > > >-- > >Matt Boland m.boland@xxx.au >CSIRO Division of Exploration and Mining Phone: +61 7 3212-4482 >PO Box 883 Kenmore Fax: +61 7 3212-4455 >QLD 4069 Australia > > > > ------------------------------ Date: Wed, 24 Mar 1999 21:16:58 -0600 From: Tom Sharpe Subject: Re: PWM fuel pump Yes Wayne Macdonald wrote: > How fast could the fuel pump change pressure ?. > I was wondering if you could you use a PIC or HC11 to alter fuel pressure based on RPM and TPS to compensate for changes in the fuel requirements. > > Wayne. > > ------------------------------------------------------------------------ > > Part 1.2 Type: application/ms-tnef > Encoding: base64 ------------------------------ Date: Wed, 24 Mar 1999 22:20:46 -0500 From: goodall@xxx.com (Colin Goodall) Subject: Re: valve overlap All: > There was and article close to a year ago in AI about solenoid valves > and higher voltages which would go along way toward making it a > reality. I also worked with a ex tech from GM who was around the aurora > cam less prototype that is in the AI article. He said on advantage to > the engine beyond variable cam geometry was with plenty of valve > clearance and engine position they could open valves on seven cylinders > and start the engine with out a starter. Hey, go one step further. Two-stroke engines can be built with a "valve-train". How about an adaptive engine. Normal running its a four-stroke clean buring and all that "make the EPA happy" stuff. Then when you tromp the pedal it switches then engine to "two-stroke" mode for that extra shot of power. If you had one computer with that controlled both the EFI and the valves It wouldn't prove that difficult. Just a little more food for thought.... Colin ------------------------------ Date: Wed, 24 Mar 1999 21:36:15 -0600 From: Tom Sharpe Subject: Re: List Topics... eclark@xxx.com wrote: > I agree, this has bothered me since I started reading the list. I dont > use a text based mail reader so html is useless. > How do you look at web sites? please get an html viewer like netscape. TomS ------------------------------ Date: Wed, 24 Mar 1999 23:07:09 -0500 From: "Clarence L.Snyder" Subject: Re: List Topics... > How do you look at web sites? please get an html viewer like netscape. > TomS > No, PLEASE turn off HTML. Many people cannot run Netscape or equivalent, and HTML is very wasteful of bandwidth, particularly for those who must pay by the megabyte for internet access. There is NO reason for using HTML mail for this type of mail-list. Also, archives of mail-lists with HTML grow EXTREMELY quickly. Whoever decided HTML MAIL was the way to go should be strung up. ------------------------------ Date: Wed, 24 Mar 1999 20:18:49 -0800 From: "Stowe, Ted-SEA" Subject: RE: injector manifold design interesting, I like this idea. I need to buy 2 injectors for this, are there any specific injectors that have adjustable mounts or any that would lend themselves to this idea ? thanks Howard. - -----Original Message----- From: AL8001@xxx.com] Sent: Wednesday, March 24, 1999 5:47 PM To: diy_efi@xxx.edu Subject: Re: injector manifold design On a engine with two valves per intake port and one inj per port, why not aim the injector towards the cylinder that's lean? Might not be directly towards the lean cyl, just slightly towards it. Make a 2 or 3 piece adjustable injector boss that will allow for the spray pattern to be adjusted left to right and up and down. The inj mounting would have bushing "A" drilled off center this would fit inside Bushing "B", "B" would be drilled diagonal bushing "C" would be welded to the intake. All bushings would have a O ring seal, set screw, and some way to turn the bushing. Another solution would be to have a o ring large enough to allow the inj to swivel. Harold ------------------------------ Date: Wed, 24 Mar 1999 20:22:58 -0800 From: "Stowe, Ted-SEA" Subject: RE: injector manifold design sorry make that thanks Harold. uh, duh. - -----Original Message----- From: Stowe, Ted-SEA Sent: Wednesday, March 24, 1999 8:19 PM To: 'diy_efi@xxx.edu' Subject: RE: injector manifold design interesting, I like this idea. I need to buy 2 injectors for this, are there any specific injectors that have adjustable mounts or any that would lend themselves to this idea ? thanks Howard. - -----Original Message----- From: AL8001@xxx.com] Sent: Wednesday, March 24, 1999 5:47 PM To: diy_efi@xxx.edu Subject: Re: injector manifold design On a engine with two valves per intake port and one inj per port, why not aim the injector towards the cylinder that's lean? Might not be directly towards the lean cyl, just slightly towards it. Make a 2 or 3 piece adjustable injector boss that will allow for the spray pattern to be adjusted left to right and up and down. The inj mounting would have bushing "A" drilled off center this would fit inside Bushing "B", "B" would be drilled diagonal bushing "C" would be welded to the intake. All bushings would have a O ring seal, set screw, and some way to turn the bushing. Another solution would be to have a o ring large enough to allow the inj to swivel. Harold ------------------------------ Date: Wed, 24 Mar 1999 21:30:49 -0800 (PST) From: Jim Davies Subject: Re: List Topics... On Wed, 24 Mar 1999, Tom Sharpe wrote: > > > eclark@xxx.com wrote: > > > I agree, this has bothered me since I started reading the list. I dont > > use a text based mail reader so html is useless. > > > > How do you look at web sites? please get an html viewer like netscape. > TomS > I dont know about others, but I do have netscape and use it for some things, but it is too slow and unwieldy for large volumes of email, I find. Cant beat good old pine and plain ASCII, IMO. Also, HTML uses lots of extra space so it slows things down. Last point is ASCII goes everywhere, whereas other things are specific to certain software. That is why many [all?] of the listservs I know of ask for things in plain ASCII. ------------------------------ Date: Wed, 24 Mar 1999 22:45:19 -0800 (PST) From: Orin Eman Subject: Re: O2 Sensor current? > This is the standard way of telling if the O2 is at temperature yet... many > systems will bias the sensor to .45 volts through a very high resistance (10 > megaohms I believe). Once the sensor is at temperature, it does provide > enough current to move the voltage away from the preset level. I seem to remember the bias resistors in my ecu were 768k. The O2 sensor's impedance isn't _that_ high or you could never get sensible results looking at it with a regular 1M impedance scope! I beleive it's in the 10 to 100k range when hot. Orin. ------------------------------ Date: Wed, 24 Mar 1999 22:48:55 -0800 (PST) From: Orin Eman Subject: Re: List Topics... > > > I agree, this has bothered me since I started reading the list. I dont > > > use a text based mail reader so html is useless. > > > > > > > How do you look at web sites? please get an html viewer like netscape. > > TomS > > > I dont know about others, but I do have netscape and use it for some > things, but it is too slow and unwieldy for large volumes of email, I > find. Cant beat good old pine and plain ASCII, IMO. Also, HTML uses lots Prefer elm myself... anyway, enough of this subject. Let's get back to efi. Orin, list admin. ------------------------------ End of DIY_EFI Digest V4 #193 ***************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. 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