DIY_EFI Digest Sunday, May 9 1999 Volume 04 : Number 271 In this issue: Re: FI pressure Sensors Re: Hessitation in Late Model Subarus Re: diesel pressures Re: Hessitation in Late Model Subarus Diesel Pressure - Wow!!! What chip is this?? Re: What chip is this?? Re: Hessitation in Late Model Subarus Re: Hessitation in Late Model Subarus Re: Hessitation in Late Model Subarus Re: diesel pressures RE: Hessitation in Late Model Subarus Re: What chip is this?? RE: Hessitation in Late Model Subarus Re: What chip is this?? Re: CFM Continued... Re: CFM Continued... Re: Hessitation in Late Model Subarus Re: Hessitation in Late Model Subarus Looking for a 1-psi Hobbes switch Re: Looking for a 1-psi Hobbes switch Re: What chip is this?? Re: What chip is this?? Re: diesel pressures Re: Looking for a 1-psi Hobbes switch Re: Looking for a 1-psi Hobbes switch Re: Looking for a 1-psi Hobbes switch Extra Inector Controller project Re: Hessitation in Late Model Subarus Re: What chip is this?? See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Sat, 08 May 1999 06:59:37 -0500 From: Steve Gorkowski Subject: Re: FI pressure Sensors Yes Bruce, Fords this year has no return line and replaced pressure regulator with a vacuum / fuel pressure sensor and electronically regulate fuel pump(I think by PWMing the pump) . I have the sensor and posted the information in incoming some time back. Steve. Bruce Plecan wrote: > There was a thread on this in the last few months, I think. > Anyway, as I recall some new Fords had something that looked good as I real. > Grumpy > Drs office magazine selection stunk. Way too M Stewart stuff > > > << I am trying to locate a fuel pressure sensor for my engine monitoring > > system > > I am wanting to build. I know Motorola made some custom sensors for > > someone, > > but their web page does not list numbers. > > Does anyone know what vehicles used a fuel pressure sensor and a > > differential > > fuel pressure sensor? A vehicle application or a part number would be > > appreciated. > > Thanks for any help provided! >> > > I am getting one for a digital guage from summit racing. > > James ------------------------------ Date: Fri, 7 May 1999 22:35:07 -0400 From: "Gary Derian" Subject: Re: Hessitation in Late Model Subarus A capacitor passes AC, an inductor blocks it. Or a resistor with a capacitor to ground on the sensor side of the resistor. Gary Derian > Hello, > > A lot of people have had a problem with a stuttering acceleration in > Subarus. I offered up an hypothesis along with a fix for the problem. > My hypothesis was first rejected by Subaru of America, then later > supported in a Technical Service Bulletin. > > Rather than go into detail here, I'll supply the URL for my website on > the matter. When you go there, scroll down for a lot of links. > http://home.earthlink.net/~hobiegary/hesitation.htm > > Well even though Subaru claims to have a fix for the problem via a new > ECU, I have yet to hear of anyone who could jump through all the > necessary hoops to get a new ECU *and* find out that the new one > actually cures the problem. So I am not holding my breath on that note. > > What I am doing however, is planning on an improvement on my primary > fix. The ECU is a OBD2 type with EPROM. It can be "reset," to loose > stored trouble logs, by disconnecting the battery for about a half > hour. I need to electronically dampen or trim or filter (or whatever it > is called!) the signal from the knock sensor to the ECU. > > What is happening is that the ECU is interpreting non detonation noises > as detonation and reacting accordingly. This leads to piss-poor > performance to say the least. I have gone the mechanical route, > buffering the signal by padding the mechanical interface between the > sensor and the engine block. > > What I would like to do is simply reduce the sensitivity of the sensor. > That is what I did mechanically and it seemed to work pretty good. The > problem though is that it is a little iffy and esoteric and problematic > and lacking consistency. It is not solid state enough to suit me. I'd > rather dampen the signal electrically. > > I tried hooking up a variable capacitor in parallel with it. I thought > that this would let any voltage spikes bleed (partially) to ground and > lessen the signal strength arriving at the ECU. I had trouble with this > method because as soon as I turned the capacitor a certain amount, I'd > get a trouble code and would have to shut down and restart. I'll guess > that the ECU sends a monitor current through the sensor and detects when > it is not at the proper impedance. It didn't seem to help either. I am > not convinced that I was doing the wrong thing either. I just could not > get any positive results. > > I also wonder if I rather should be using a variable inductor in series > with the sensor. Wouldn't this choke a signal without greatly affecting > monitor current? I guess it would depend if the monitor is looking at > impedance with a/c or looking at resistance with d/c. > > Comments? Any other ways I should consider reducing the amplitude of > this signal? What about the ECU, is there anything I can do there to > help the situation? > > I thank you for your attention Fellows and thank you in advance for any > suggestions. > > -- > GARY mailto:hobiegary@xxx.net ------------------------------ Date: Sat, 08 May 1999 13:12:09 GMT From: charlesmorris@xxx.com (Charles) Subject: Re: diesel pressures On Fri, 7 May 1999 20:47:37 -0400, Greg wrote: >Type-------------Maximum rated pressure >M----------------400 bar (four hundred bar) My '73 220D has this type of pump. Injectors open at 140 or maybe 180 bar, if I remember right. Once they're open, I doubt the pressure rises as far as 400 bar though. BTW my "Diesel Engine and Fuel System Repair" textbook says the PE-P series can be used with nozzle opening pressures of 10,000 psi, usually on engines with more than 200 hp. - -Charles ------------------------------ Date: Sat, 8 May 1999 09:54:07 -0500 (CDT) From: Roger Heflin Subject: Re: Hessitation in Late Model Subarus On Fri, 7 May 1999, Bruce Plecan wrote: > That's not the problem as I see it. It's seeing a knock you don't want it > to see. > That is a problem with all these dumb acoustic sensors, only cure is going > to ionization kknock detection, please refer to the archives and search ION. > I don't actually believe there is anything wrong with the idea of a acoustic knock sensor, I really believe that most of the issues are with crude way they are doing it (simple filter). I believe using a acoustic sensor and DSP and some code using a better algorithm would do alot better in removing other noises. I would also think you could do miss detection using this method also, ie listen for each cylinder igintion and count the ones you missed. Now I just need to put a mic on my engine and collected and figure out how to process the data in such a way to get meaningful data. Roger ------------------------------ Date: Sat, 08 May 1999 15:36:30 GMT From: bob@xxx.com (Robert Harris) Subject: Diesel Pressure - Wow!!! The Mercedes / Bosch design used 1100 to 2000 psi - sort of a piss dribble to the diesel world - but at least 25 times better than standard port injection. But since you asked - a SWAG ( scientific wild ass guess ) - probably nothing much. Diesel is far easier to compression ignite than gasoline - centane vs octane - so gasoline should be far safer ( from pressure ). Lubrication would still be a problem, but with the piss that is the current low pollution diesel, its a problem anyway. But from combustion point of fuel - the mixing would be incredible. Course I could be full of it. - ------------------------------ > >Date: Fri, 7 May 1999 22:59:30 -0500 >From: "Jennifer and Brock Fraser" >Subject: Re: absurd pressures figures was: atomization enhancement > Deleted Stuff > > >Nobody postulated on what would happen if you tried to inject GASOLINE at >1800 BAR!!!!!!!!!!!!!!!!!!! > >- -Brock - ------------------------------ ------------------------------ Date: Sat, 08 May 1999 09:03:43 -0700 From: mike@xxx.com (Mike DiMeco) Subject: What chip is this?? I am a newbie to this group, and to FI in general. I have an ECM (16025321) from an '83 6 cyl. camaro. The PROM has a bunch of numbers after the DELCO 512K... 8317 3061 06630 CE1024. What PROM device is this? Also, this chip does not have a window like other EPROMS. I assume I can erase it with my device programmer just the same, or copy the bin to another EPROM, but I can't read it correctly until I know what device it is. Mike ------------------------------ Date: Sat, 08 May 1999 12:15:35 -0400 From: "David A. Cooley" Subject: Re: What chip is this?? At 09:03 AM 5/8/99 -0700, you wrote: >I am a newbie to this group, and to FI in general. > >I have an ECM (16025321) from an '83 6 cyl. camaro. >The PROM has a bunch of numbers after the DELCO 512K... > >8317 3061 06630 CE1024. > >What PROM device is this? Also, this chip does not have >a window like other EPROMS. I assume I can erase it with >my device programmer just the same, or copy the bin to >another EPROM, but I can't read it correctly until I >know what device it is. Mike, GM didn't use EEPROMS until recently, if it's an 83 and has no window, then it is a standard PROM (not EPROM) and is not eraseable. Not sure why it says 512K... nothing that early used that size prom... It's most likely an 82S181. How many pins does the prom chip have? =========================================================== David Cooley N5XMT Internet: N5XMT@xxx.net Packet: N5XMT@xxx. Member #7068 Sponges grow in the ocean... Wonder how deep it would be if they didn't?! =========================================================== ------------------------------ Date: Sat, 8 May 1999 12:35:21 -0400 From: "Bruce Plecan" Subject: Re: Hessitation in Late Model Subarus OK, just for giggles, how do you tell a bad A/C compressor bearing that radiates a frequency of 25 Hz, from a knock "noise" of 25 Hz?. (Feel, free to change to any freg of noise) Repeat the above, with fan belt "noise", Alternator bearings, throw out bearings, rocker arm noise lifter noise etc, etc.. If you can do it, more power to you, but, I'll still stick with my original statement. As for miss detection, I'll rely on crank accleration rate changes thank, you. Bruce > > That's not the problem as I see it. It's seeing a knock you don't want it > > to see. > > That is a problem with all these dumb acoustic sensors, only cure is going > > to ionization kknock detection, please refer to the archives and search ION. > I don't actually believe there is anything wrong with the idea of a > acoustic knock sensor, I really believe that most of the issues are > with crude way they are doing it (simple filter). I believe using a > acoustic sensor and DSP and some code using a better algorithm would > do alot better in removing other noises. I would also think you > could do miss detection using this method also, ie listen for each > cylinder igintion and count the ones you missed. Now I just need > to put a mic on my engine and collected and figure out how to > process the data in such a way to get meaningful data. > Roger ------------------------------ Date: Sat, 8 May 1999 12:40:58 -0500 From: "G. Scott Ponton" Subject: Re: Hessitation in Late Model Subarus I have been following this thread for a while. There are other refferences to knock sensors and problems with "sensing" other engine noises in the arcives too. I have been running a old Pontiac with a custom distributor and ESC for several years (9). The engine has a solid grind cam and several other sources of "external" knocking. The only time I have ever had problems with the sensor picking up stray noises was went the oil pump drive broke. Although the rods weren't knocking audibly the ESC was retarding the timing. I think Gary is right with his assumtion that the Subaru computer is "too sensitve". As I have never checked I am not sure but I would guess that the GM ESC/EST has a built in filter to eliminate certain freqs and amplitudes below a point. When I first installed the system on this engine I was worried about the ESC retarding the timing because of the solid cam too. So I spent several hours with a 'scope checking the output from the sensor and checking to be sure the timing wasn't being retarded. The system worked/works perfectly. Now I can drive my old 11:1 pontiac anywhere on pump gas. Then if I want to race it I just fill it up with racing fuel and away I go. Scott ------------------------------ Date: Sat, 8 May 1999 14:22:23 -0400 From: "Bruce Plecan" Subject: Re: Hessitation in Late Model Subarus > I think Gary is right with his assumtion that the Subaru computer is > "too sensitve". As I have never checked I am not sure but I would guess that > the GM ESC/EST has a built in filter to eliminate certain freqs and > amplitudes below a point. In all the (gm)ESC modules, I tested each one responded to two different frequencies, and a threshold. Just out of curiousity what ecm are you running?. I've run a gm ESC for years also, in a "noisy environment", without a problem, but not with anything as sensitive as a OBDII system. Yes, you can use acoustic, but that doesn't mean there isn't a better answer. Some folks are perfectly happy with what they got, ie Cart, J+S (?) etc. Fun time starts when something goes wrong. Bruce > When I first installed the system on this engine I was worried about the > ESC retarding the timing because of the solid cam too. So I spent several > hours with a 'scope checking the output from the sensor and checking to be > sure the timing wasn't being retarded. The system worked/works perfectly. > Now I can drive my old 11:1 pontiac anywhere on pump gas. Then if I want to > race it I just fill it up with racing fuel and away I go. > Scott ------------------------------ Date: Mon, 10 May 1999 12:16:30 -0700 From: "Howard Wilkinson" Subject: Re: diesel pressures Charles: This I can buy..... 10,000 psi (690 bar) is not an unrealistically high pressure, but I find it unbelievable having worked with high pressure liquids that anybody would even consider 2050bar (almost 30,000 psi) as a realistic working pressure for a fluid in an automotive application. Perhaps someday I'll see this VW with a 30K psi common rail pressure in real life.... but I doubt it..... not on this planet. H.W. - -----Original Message----- From: Charles To: diy_efi@xxx.edu Date: Saturday, May 08, 1999 8:10 AM Subject: Re: diesel pressures >On Fri, 7 May 1999 20:47:37 -0400, Greg wrote: > >>Type-------------Maximum rated pressure >>M----------------400 bar (four hundred bar) > > My '73 220D has this type of pump. Injectors open at >140 or maybe 180 bar, if I remember right. Once they're >open, I doubt the pressure rises as far as 400 bar though. > > BTW my "Diesel Engine and Fuel System Repair" textbook >says the PE-P series can be used with nozzle opening >pressures of 10,000 psi, usually on engines with more than >200 hp. > >-Charles > > ------------------------------ Date: Sat, 8 May 1999 14:20:19 -0500 From: Don.F.Broadus@xxx.com Subject: RE: Hessitation in Late Model Subarus Dr. Plecan is once again correct in the optimal knock/misfire detection system. Labeled as a magnetorestrictive sensor, this device measures the accle/decel (twist) of the crank. SAE has several papers on this type of sensor and research continues for incorporation into cars. A ring cast into the crank similar to a DIS timing ring is used to trigger the magnetorestictive sensor. Experiments could be conducted using this ring an possibly a modified mag pick up. So far it is claimed that cycle by cycle detection is possible for each cylinder. Don > -----Original Message----- > From: Bruce Plecan [SMTP:nacelp@xxx.net] > Sent: Saturday, May 08, 1999 11:35 AM > To: diy_efi@xxx.edu > Subject: Re: Hessitation in Late Model Subarus > > > OK, just for giggles, how do you tell a bad A/C compressor bearing that > radiates a frequency of 25 Hz, from a knock "noise" of 25 Hz?. (Feel, > free > to change to any freg of noise) > Repeat the above, with fan belt "noise", Alternator bearings, throw out > bearings, rocker arm noise lifter noise etc, etc.. > If you can do it, more power to you, but, I'll still stick with my > original statement. > As for miss detection, I'll rely on crank accleration rate changes thank, > you. > Bruce > > > > > That's not the problem as I see it. It's seeing a knock you don't > want > it > > > to see. > > > That is a problem with all these dumb acoustic sensors, only cure is > going > > > to ionization kknock detection, please refer to the archives and > search > ION. > > > I don't actually believe there is anything wrong with the idea of a > > acoustic knock sensor, I really believe that most of the issues are > > with crude way they are doing it (simple filter). I believe using a > > acoustic sensor and DSP and some code using a better algorithm would > > do alot better in removing other noises. I would also think you > > could do miss detection using this method also, ie listen for each > > cylinder igintion and count the ones you missed. Now I just need > > to put a mic on my engine and collected and figure out how to > > process the data in such a way to get meaningful data. > > Roger > ------------------------------ Date: Sat, 08 May 1999 13:10:20 -0700 From: mike@xxx.com (Mike DiMeco) Subject: Re: What chip is this?? David A. Cooley wrote: > > At 09:03 AM 5/8/99 -0700, you wrote: > >I am a newbie to this group, and to FI in general. > > > >I have an ECM (16025321) from an '83 6 cyl. camaro. > >The PROM has a bunch of numbers after the DELCO 512K... > > > >8317 3061 06630 CE1024. > > > >What PROM device is this? Also, this chip does not have > >a window like other EPROMS. I assume I can erase it with > >my device programmer just the same, or copy the bin to > >another EPROM, but I can't read it correctly until I > >know what device it is. > > Mike, > GM didn't use EEPROMS until recently, if it's an 83 and has no window, then > it is a standard PROM (not EPROM) and is not eraseable. > Not sure why it says 512K... nothing that early used that size prom... It's > most likely an 82S181. How many pins does the prom chip have? > =========================================================== > David Cooley N5XMT Internet: N5XMT@xxx.net > Packet: N5XMT@xxx. Member #7068 > Sponges grow in the ocean... Wonder how deep it would be if they didn't?! > =========================================================== It has 24 pins and it is set in the ECM with a large clear clip. Other numbers on the chip are.. 8566 ASH. Mike ------------------------------ Date: Sat, 8 May 1999 15:11:32 -0500 From: Don.F.Broadus@xxx.com Subject: RE: Hessitation in Late Model Subarus Being a Pontiac Fan I would like to hear more about your set up. I am working on a 1973 400 Pont with a HEI right now and your system sounds interesting. Thanks ,Don > -----Original Message----- > From: G. Scott Ponton [SMTP:gscottp@xxx.com] > Sent: Saturday, May 08, 1999 12:41 PM > To: diy_efi@xxx.edu > Subject: Re: Hessitation in Late Model Subarus > > I have been following this thread for a while. There are other refferences > to knock sensors and problems with "sensing" other engine noises in the > arcives too. I have been running a old Pontiac with a custom distributor > and > ESC for several years (9). The engine has a solid grind cam and several > other sources of "external" knocking. The only time I have ever had > problems > with the sensor picking up stray noises was went the oil pump drive broke. > Although the rods weren't knocking audibly the ESC was retarding the > timing. > I think Gary is right with his assumtion that the Subaru computer is > "too sensitve". As I have never checked I am not sure but I would guess > that > the GM ESC/EST has a built in filter to eliminate certain freqs and > amplitudes below a point. > When I first installed the system on this engine I was worried about > the > ESC retarding the timing because of the solid cam too. So I spent several > hours with a 'scope checking the output from the sensor and checking to be > sure the timing wasn't being retarded. The system worked/works perfectly. > Now I can drive my old 11:1 pontiac anywhere on pump gas. Then if I want > to > race it I just fill it up with racing fuel and away I go. > > Scott ------------------------------ Date: Sat, 8 May 1999 16:33:01 -0400 From: "Bruce Plecan" Subject: Re: What chip is this?? 83, V6, EFI.. That sounds odd, if carb'd then it's just a PROM, and not reprogramable. Large Clear Clip, is a new deal to me. Bruce > > >I am a newbie to this group, and to FI in general. > > >I have an ECM (16025321) from an '83 6 cyl. camaro. > > >The PROM has a bunch of numbers after the DELCO 512K... > > >8317 3061 06630 CE1024. > > >What PROM device is this? Also, this chip does not have > > >a window like other EPROMS. I assume I can erase it with > > >my device programmer just the same, or copy the bin to > > >another EPROM, but I can't read it correctly until I > > >know what device it is. > > Mike, > > GM didn't use EEPROMS until recently, if it's an 83 and has no window, then > > it is a standard PROM (not EPROM) and is not eraseable. > > Not sure why it says 512K... nothing that early used that size prom... It's > > most likely an 82S181. How many pins does the prom chip have? > > =========================================================== > > David Cooley N5XMT Internet: N5XMT@xxx.net > > Packet: N5XMT@xxx. Member #7068 > > Sponges grow in the ocean... Wonder how deep it would be if they didn't?! > > =========================================================== > It has 24 pins and it is set in the ECM with a large clear clip. > Other numbers on the chip are.. 8566 ASH. > Mike ------------------------------ Date: Sat, 8 May 1999 17:01:49 -0400 From: "Bruce Plecan" Subject: Re: CFM Continued... Er, this looks like it's assuming 100% VE, True?. If so wouldn't 130-140% be a tad closer? is there any intercooling? Sneezy > Then, the engine will be trying to breathe in 434 x 5400 x 0.5 x 1/1728 , > or 678 cfm at the highest speed you will be turning it. The runners to each > cylinder will be wanting to flow 1/8 of this much, or about 85 cfm each. > The trick is to size everything in the flow path so that you do not have > excessive pressure drop at any one point in the path at the amount of flow > the engine wants to draw in. What the guy talking to you is missing is that > with a pressurized intake--the pressure drop in the runners is proportional > to the density of the air flowing through them! > Of course--you will also have proportionally more pressure you can afford > to lose with the turbo motor, So whatever will work well with the same size > and speed range NA motor is pretty close for a turbo motor. Going maybe a > fuzz BIGGER than what you would use for a similar size/speed NA motor will > tend to lower backpressure from the turbo on the motor, and lower EGT's > some. > Going any smaller than what you would run on an NA 434 would hurt > performance some, and durability more. > Flow on the inlet side of the turbos will be the amount of air the engine > breathes times the manifold density ratio--a LOT more cfm. Everything on > the inlet side of the turbos should be sized accordingly, and also to have > VERY low pressure losses at this design flow The amount of back pressure > which the turbo(s) will put on the engine to make a given amount of boost > is EXTREMELY sensitive to losses in the inlet tract to the turbos!. > Regards, Greg > ------------------------------ Date: Sat, 8 May 1999 16:13:26 -0600 From: bearbvd@xxx.net (Greg Hermann) Subject: Re: CFM Continued... >Er, this looks like it's assuming 100% VE, True?. >If so wouldn't 130-140% be a tad closer? >is there any intercooling? >Sneezy It wuz--just using round numbers to try to give him the idea. Bear > >> Then, the engine will be trying to breathe in 434 x 5400 x 0.5 x 1/1728 , >> or 678 cfm at the highest speed you will be turning it. The runners to >each >> cylinder will be wanting to flow 1/8 of this much, or about 85 cfm each. > >> The trick is to size everything in the flow path so that you do not have >> excessive pressure drop at any one point in the path at the amount of flow >> the engine wants to draw in. What the guy talking to you is missing is >that >> with a pressurized intake--the pressure drop in the runners is >proportional >> to the density of the air flowing through them! >> Of course--you will also have proportionally more pressure you can afford >> to lose with the turbo motor, So whatever will work well with the same >size >> and speed range NA motor is pretty close for a turbo motor. Going maybe a >> fuzz BIGGER than what you would use for a similar size/speed NA motor will >> tend to lower backpressure from the turbo on the motor, and lower EGT's >> some. >> Going any smaller than what you would run on an NA 434 would hurt >> performance some, and durability more. >> Flow on the inlet side of the turbos will be the amount of air the engine >> breathes times the manifold density ratio--a LOT more cfm. Everything on >> the inlet side of the turbos should be sized accordingly, and also to have >> VERY low pressure losses at this design flow The amount of back pressure >> which the turbo(s) will put on the engine to make a given amount of boost >> is EXTREMELY sensitive to losses in the inlet tract to the turbos!. >> Regards, Greg > >> ------------------------------ Date: Sat, 08 May 1999 18:03:00 -0500 From: dave.williams@xxx.us (Dave Williams) Subject: Re: Hessitation in Late Model Subarus - -> OK, just for giggles, how do you tell a bad A/C compressor bearing - -> that radiates a frequency of 25 Hz, from a knock "noise" of 25 Hz?. - -> (Feel, free to change to any freg of noise) Amplitude. Even my wife can recognize it when the engine pings. Real detonation can be recognized by drivers in nearby cars. You have to decide what you're looking for here. If you're trying to listen through all the rumble to find erratic igntion events so you can fiddle with the advance or mixture, you're trying to do something even most OEMs don't try to do. If all you want is to know when the engine is in danger of damage, almost anything will do - I have a Carter EKE box (add on knock eliminator, sold for $75 back in the '80s) that works just fine, and it's just a handful of discrete analog components. ==dave.williams@xxx.us====================================== I've got a secret / I've been hiding / under my skin / | Who are you? my heart is human / my blood is boiling / my brain IBM | who, who? =================================== http://home1.gte.net/42/index.htm ------------------------------ Date: Sat, 8 May 1999 20:37:19 -0400 From: "Bruce Plecan" Subject: Re: Hessitation in Late Model Subarus >From reading his post and URL, it seems that the ecm is having it's knock detection system triggered. There was no mention of any audible, knocking type sounds. SOA has a cure that involves replacing the ecm. The assumption on their (original poster's) part is that this is a false signal. In a prior post I mentioned some things to check. Then work can begin at looking at things, Least that's the way I'd do it. GM has had problems for a long time with trace ping, and tip in ping, that can be non-audible, but triggering the KS.. Just putting a pot in the system to turn down the amplitude, is a down and dirty thing to do, without examining what the true problem is in my book. Yes a knock detector circuit probably could be just a 741, and $1 worth of other stuff, but that is just a threshold noise detector. Which would probably be fine for many ecms. But, I would tend to think a OBDII box is smarter than those. Meaning when it goes thru it's self diagnostics, and listens for a response, when doing the ESC test. > -> OK, just for giggles, how do you tell a bad A/C compressor bearing > -> that radiates a frequency of 25 Hz, from a knock "noise" of 25 Hz?. > -> (Feel, free to change to any freg of noise) > Amplitude. ?. A stethoscope, and microphone?. Or are you looking at this as an audible knock?. What a dual trace scope, and one lead to the KS trigger line, and one to another piezio electric device, and compare each bearings noise, to find a similiar trace?. > Even my wife can recognize it when the engine pings. Real detonation > can be recognized by drivers in nearby cars. OK, if the ecm has a limit for the amount of retard and that doesn't take care of the detonation, then it will be audible. But, if the knock limit is 7 degrees and 5 degrees retard takes care of it, performance will be down, and you won't hear any detonation. If it is false knock it will run the KS right up to the 7 degree max, and just ruin performance.. > You have to decide what you're looking for here. And the long term effects of what you do. >If you're trying to > listen through all the rumble to find erratic igntion events so you can > fiddle with the advance or mixture, you're trying to do something even > most OEMs don't try to do. My interuption of the 99 vette ecm is that it will do individual cylinder knock/miss detection, and try to cure it with mix/timing changes. In one shop manual they mention that, but in the training manual there is no mention, but that is from a yet to be updated manual. Bruce > If all you want is to know when the engine > is in danger of damage, almost anything will do - I have a Carter EKE > box (add on knock eliminator, sold for $75 back in the '80s) that works > just fine, and it's just a handful of discrete analog components. ==dave.williams@xxx.us====================================== ------------------------------ Date: Sat, 08 May 1999 20:53:52 -0400 From: Ed Subject: Looking for a 1-psi Hobbes switch Here's what I'm doing. I'd like to mount a switch on an intake manifold that'll work once there is positive pressure (boost). Such a switch exist? A part # would be most appreciated too. - -Ed ------------------------------ Date: Sat, 8 May 1999 21:18:19 EDT From: DemonTSi@xxx.com Subject: Re: Looking for a 1-psi Hobbes switch In a message dated 5/8/99 5:54:18 PM Pacific Daylight Time, EdDSP@xxx.com writes: << Here's what I'm doing. I'd like to mount a switch on an intake manifold that'll work once there is positive pressure (boost). Such a switch exist? A part # would be most appreciated too. >> The lowest psi activated switch I've ever seen was a 3psi unit...that goes for like 125 bucks! You can get an adjustable hobbs one (sold for use with nos systems) that activates at 5psi for like under 10 bucks. Then you can use a regulator or other restrictor inline and adjust it to show the switch the psi you need. Van ------------------------------ Date: Sat, 08 May 1999 21:26:02 -0400 From: Shannen Durphey Subject: Re: What chip is this?? Bruce Plecan wrote: > > 83, V6, EFI.. > That sounds odd, if carb'd then it's just a PROM, and not reprogramable. > Large Clear Clip, is a new deal to me. > Bruce > Prom carrier in my 83 Camaro ECM is clear. Going by a BCC of ASH/8556 I get 1983 F body, 2.8 longitudinal, 2bbl carb, California emissions, THM 200 trans. Heh heh... It's been too long since you've worked on the oldies. : ) Shannen ------------------------------ Date: Sat, 8 May 1999 21:53:25 -0400 From: "Bruce Plecan" Subject: Re: What chip is this?? Heck, I caught it was a carbby, and just got thrown by clip instead of holder, so that ain't to bad (or was it) Bruce > > 83, V6, EFI.. > > That sounds odd, if carb'd then it's just a PROM, and not reprogramable. > > Large Clear Clip, is a new deal to me. > > Bruce > Prom carrier in my 83 Camaro ECM is clear. Going by a BCC of ASH/8556 > I get 1983 F body, 2.8 longitudinal, 2bbl carb, California emissions, > THM 200 trans. > Heh heh... It's been too long since you've worked on the oldies. : ) > Shannen ------------------------------ Date: Sat, 08 May 1999 21:59:54 -0400 From: Shannen Durphey Subject: Re: diesel pressures Howard Wilkinson wrote: > > Charles: > This I can buy..... 10,000 psi (690 bar) is not an unrealistically > high pressure, but I find it unbelievable having worked with high > pressure liquids that anybody would even consider 2050bar (almost > 30,000 psi) as a realistic working pressure for a fluid in an > automotive application. Perhaps someday I'll see this VW with a 30K > psi common rail pressure in real life.... but I doubt it..... not on > this planet. H.W. > Howard, if these guys knew that "owly" is Montana slang for stubborn and disagreeable, they might be better prepared for your frame of mind. ; ) Shannen ------------------------------ Date: Sat, 8 May 1999 20:35:54 -0600 From: bearbvd@xxx.net (Greg Hermann) Subject: Re: Looking for a 1-psi Hobbes switch >In a message dated 5/8/99 5:54:18 PM Pacific Daylight Time, >EdDSP@xxx.com writes: > ><< Here's what I'm doing. I'd like to mount a switch on an intake manifold > that'll work once there is positive pressure (boost). Such a switch > exist? A part # would be most appreciated too. >> > >The lowest psi activated switch I've ever seen was a 3psi unit...that goes >for like 125 bucks! You can get an adjustable hobbs one (sold for use with >nos systems) that activates at 5psi for like under 10 bucks. Then you can use >a regulator or other restrictor inline and adjust it to show the switch the >psi you need. > >Van How about the switch normally used on oil pressure to actuate the oil pressure idiot light--aren't they set at about 4 or 5 psi?? Greg ------------------------------ Date: Sat, 8 May 1999 22:52:44 EDT From: DemonTSi@xxx.com Subject: Re: Looking for a 1-psi Hobbes switch In a message dated 5/8/99 7:38:47 PM Pacific Daylight Time, bearbvd@xxx.net writes: << How about the switch normally used on oil pressure to actuate the oil pressure idiot light--aren't they set at about 4 or 5 psi?? >> Ouch...if they wait till your oil pressure drops to 4-5 before setting off the idiot light....... :) Van - - http://members.xoom.com/BADROC ------------------------------ Date: Sun, 9 May 1999 00:47:55 EDT From: Cameano@xxx.com Subject: Re: Looking for a 1-psi Hobbes switch In a message dated 5/8/99 9:40:14 PM Pacific Daylight Time, DemonTSi@xxx.com writes: << << How about the switch normally used on oil pressure to actuate the oil pressure idiot light--aren't they set at about 4 or 5 psi?? >> Ouch...if they wait till your oil pressure drops to 4-5 before setting off the idiot light....... :) Van - http://members.xoom.com/BADROC >> This is why I like to replace my stock switch with an Autometer 15psi unit. They can be found fairly cheap from Summit and other places. Autometer makes them for their oil pressure "Pro Light". They also come in 25psi. Darren (new list member) Waipahu, HI ------------------------------ Date: Sun, 09 May 1999 01:49:15 -0400 From: Jeff Smith Subject: Extra Inector Controller project Hi all, I know then subject of "EICs" has been covered, as I've scanned through the archives already and found a lot of good info. I do have a couple of questions regarding this, however. First of all, I have seen a lot of mention of the Cherry or Motorola drivers (they appear to be identical) and the National LM1949, however ST Micro makes something called an L584 that also looks interesting (more like the 1949 than the Cherry parts, it requires an external Darlington to turn the injectors on and off). Has anyone had any experience with this part? Other than the requirement of external parts, what are the pros and cons that have been found with any of these parts relative to the others? My second question has more to do with the timing of the injector pulses. I will most likely be using the ignition coil as the interrupt used to fire the injectors, but is there a more appropriate time to do it? Is there a delay that I should wait after the coil fires, or is there some other interrupt, which would provide a more optimal firing time? TIA, jds ------------------------------ Date: Sun, 9 May 1999 01:16:34 -0500 From: "G. Scott Ponton" Subject: Re: Hessitation in Late Model Subarus In all the (gm)ESC modules, I tested each one responded to two different frequencies, and a threshold. Just out of curiousity what ecm are you running?. I've run a gm ESC for years also, in a "noisy environment", without a problem, but not with anything as sensitive as a OBDII system. Yes, you can use acoustic, but that doesn't mean there isn't a better answer. Some folks are perfectly happy with what they got, ie Cart, J+S (?) etc. Fun time starts when something goes wrong. Bruce Honestly I can't tell you which ECM it is. I'm pretty sure it came out of a Chevy P/U mid 80,s variety. It has been under my dash for 9 years and I have never had a problem with it. The vehicle isn't a daily driver anylonger. I suppose I could go to storage and pull it out and look. Some of us are never "happy" with what we have. Why do you think I went through the trouble to manufacture a distributor and install the system on my 67 Pontiac. Sometimes you have to work with what the world gives you to work with. At the time I installed this system there wasn't anything "better" which a "normal" person could afford. Scott ------------------------------ Date: Sat, 08 May 1999 23:47:29 -0700 From: mike@xxx.com (Mike DiMeco) Subject: Re: What chip is this?? Shannen Durphey wrote: > > Bruce Plecan wrote: > > > > 83, V6, EFI.. > > That sounds odd, if carb'd then it's just a PROM, and not reprogramable. > > Large Clear Clip, is a new deal to me. > > Bruce > > > Prom carrier in my 83 Camaro ECM is clear. Going by a BCC of ASH/8556 > I get 1983 F body, 2.8 longitudinal, 2bbl carb, California emissions, > THM 200 trans. > > Heh heh... It's been too long since you've worked on the oldies. : ) > Shannen Thanks! Mike ------------------------------ End of DIY_EFI Digest V4 #271 ***************************** 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".