DIY_EFI Digest Saturday, May 8 1999 Volume 04 : Number 270 In this issue: Re: Turbo Parts Re: Espen's Reed Valves Re: Hessitation in Late Model Subarus Re: Espen's Reed Valves Re: Hessitation in Late Model Subarus Re: Espen's Reed Valves Re: Jeep 4.0 Liter MPI (circa 1987-1991) Re: Espen's Reed Valves Re: absurd pressures figures was: atomization enhancement Re: 730edit program Re: Hessitation in Late Model Subarus Re: Espen's Reed Valves Re: FI pressure Sensors Re: Espen's Reed Valves Re: Espen's Reed Valves See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Fri, 07 May 1999 21:07:45 -0400 From: Shannen Durphey Subject: Re: Turbo Parts Bill Shaw wrote: > > Just thought I'd mention if anyone is looking for turbo parts (or Corvette > parts) for a project, you might find something interesting at Callaway's > garage sale. Go to www.callawaycars.com and click on garage sale. > > bs > > "By the time their numbers had dwindled from 50 > to 8, the other dwarves began to suspect 'Hungry'" Boy, this really is a garage sale. there's 32 of these: Bosch Fuel Injector. flows 8.95 grams/sec @xxx. Price is $46 dollars each. I recommend checking the site out.... Shannen ------------------------------ Date: Fri, 07 May 1999 20:43:00 -0700 From: rr Subject: Re: Espen's Reed Valves Yeah, and them' thar' yaamies' go like stink too... BobR. who ain't get'n rid of his. Bruce wrote: >What application is folks talking about?. >F1 or motorcycles?. >Big Problem with the reeds is do to inertia the basiclly stay open at more >than 2,000 rpm, in say a Yamahahah 350 2 stroke motorcycle. They will stop >reversion at low speed but not at higher speeds >Bruce > > > >> > > We tried this on some race bikes years ago. Reeds reduced the airflow and > > added length to the inlet tract that changed the tuned length. If it bore > any > > real use, the F1 guys would be all over it. > > Fred > The F1 guys dont cruise their cars do they?Torque at 2000rpm is not an isue > for F1 guys. > Reeds could be bypassed at high rpm.I dont have any proof that a good > engineered reed setup would work great I just belive it, when Im thinking > about it a two walve engine with high mass valve train would bennefit the > most , > because of the small dynamic range of system.If you are conserned of reed > reduction of airflow, think what a regular valve is doing at high rpms. > Espen ------------------------------ Date: Fri, 7 May 1999 22:06:47 -0400 From: "CLsnyder" Subject: Re: Hessitation in Late Model Subarus - ----- Original Message ----- From: GARY To: EFI DIY mailing list Sent: Friday, May 07, 1999 6:33 PM Subject: Hessitation in Late Model Subarus > 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 > Have you thought about a high resistance pot set up as a voltage divider on the sensor? Cut the output down to about 80% and see if it still false triggers. Then take it back up to the point where the performance "just" starts to deteriorate. I have not tried this, but as the sensor is just a microphone, I figure a volume control should do the trick. ------------------------------ Date: Fri, 7 May 1999 22:09:27 -0400 From: "CLsnyder" Subject: Re: Espen's Reed Valves - ----- Original Message ----- From: Bruce Plecan To: Sent: Friday, May 07, 1999 7:01 PM Subject: Re: Espen's Reed Valves > What application is folks talking about?. > F1 or motorcycles?. > Big Problem with the reeds is do to inertia the basiclly stay open at more > than 2,000 rpm, in say a Yamahahah 350 2 stroke motorcycle. They will stop > reversion at low speed but not at higher speeds > Bruce > All the idea of using reed valves would do is improve the low end torque - exactly what we want, while staying open at high speeds to reduce obstruction - which we also want. If they lock open at 2000 RPM on a 2 stroke you should get some effect up to about 4000 RPM on a 4 stroker - which sounds pretty good to me. ------------------------------ Date: Fri, 7 May 1999 23:11:28 -0400 From: "Bruce Plecan" Subject: Re: Hessitation in Late Model Subarus >>The ECU is a OBD2 type with EPROM. > > What I would like to do is simply reduce the sensitivity of the sensor. 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. > > 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. OK, once you get it dampened how ya know it really works when you need it?. Ya just listen for it?. I'd be a heck of alot more curious about the cause for it, what gas are you using. operating temp., spark plug heat range/style. If you've already addressed these fine, but you didn't mention them. I just don't beleive in automatically disabling parts of the ecm. How about the self diagnostics of OBDII, what are it's parameters, and what effect would it have on it. > > 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 thank you for your attention Fellows and thank you in advance for any > > suggestions. > > GARY mailto:hobiegary@xxx.net > > Have you thought about a high resistance pot set up as a voltage divider > on the sensor? Cut the output down to about 80% and see if it still false > triggers. Then take it back up to the point where the performance "just" > starts to deteriorate. I have not tried this, but as the sensor is just a > microphone, I figure a volume control should do the trick. ------------------------------ Date: Fri, 7 May 1999 23:18:58 -0400 From: "Bruce Plecan" Subject: Re: Espen's Reed Valves 4,000 on a 175cc per cylinder engine (4 stroke). As the air flow goes up your gonna need large reeds, inertia goes up, and they drop in max rev effectiveness. Or go to LOTS of little one, and then port volume goes to h---. Again, the is just on th Yamahaha, and old info, but I haven't head of any manufacturer going to reeds lately for auto use.... Grumpy > > What application is folks talking about?. > > F1 or motorcycles?. > > Big Problem with the reeds is do to inertia the basiclly stay open at more > > than 2,000 rpm, in say a Yamahahah 350 2 stroke motorcycle. They will > stop > > reversion at low speed but not at higher speeds > > Bruce > All the idea of using reed valves would do is improve the low end torque - > exactly what we want, while staying open at high speeds to reduce > obstruction - which we also want. If they lock open at 2000 RPM on a 2 > stroke you should get some effect up to about 4000 RPM on a 4 stroker - > which sounds pretty good to me. ------------------------------ Date: Thu, 6 May 1999 22:44:42 -0600 From: "Programmer" Subject: Re: Jeep 4.0 Liter MPI (circa 1987-1991) James, These things used to have problem with oil contamination of the sensor (rearward of the engine) responsible for cam position to the ECU. Causes extended cranking, and eventually ends up as a no start. Another fault of these things was cranking speed. Hall effect sensors can run low speed sensing quite well--AC output type need a higher RPM to get the signal high enough for reference. If you're 100% sure on the fuel pressure, fuel filter and ignition secondary--check out that sensor. Lyndon IP TECH - -----Original Message----- From: Simpson, James H To: diy_efi@xxx.edu> Date: Tuesday, May 04, 1999 5:13 PM Subject: Jeep 4.0 Liter MPI (circa 1987-1991) >Hi, > >I have a 1987 Jeep Cherokee 4.0 Liter MPI engine installed in a 1982 Jeep >CJ7. I have discovered that AMC used a Renault (Renix?) computer system in >the 1987-1991 Cherokees, and that information on this computer system is, so >far, impossible to obtain. I'm having some troubles starting the engine; it >cranks for several seconds (15-30) before it starts, if it starts at all. >I've been through all of the static tests (sensor resistance/function, fuel >pressure, etc.) and everything looks OK. I've been looking for information >on computer codes and commands with no success. > >Q. Does anyone have information on the Renix computer system? > >Q. Is it possible to retrofit a different computer system to this engine? >Has anyone done this? I guess GM would be my first choice. > >Thanks for any help you might be able to give! > >Jim Simpson > > ------------------------------ Date: Sun, 9 May 1999 20:17:27 -0700 From: "Howard Wilkinson" Subject: Re: Espen's Reed Valves Bruce: You wrote: >What application is folks talking about?. >F1 or motorcycles?. >Big Problem with the reeds is do to inertia the basiclly stay open at more >than 2,000 rpm, in say a Yamahahah 350 2 stroke motorcycle. They will stop >reversion at low speed but not at higher speeds >Bruce > Let me point out that in a 4 cycle engine reversion is only a problem at low RPM .... that RPM depends on camming and the inertia of the air column in the intake (intake design). A properly designed reed valve that stayed open above a specific RPM might therefore be a real asset in a 4 cycle engine. H.W. ------------------------------ Date: Fri, 7 May 1999 22:59:30 -0500 From: "Jennifer and Brock Fraser" Subject: Re: absurd pressures figures was: atomization enhancement > do however find it highly improbable that a fuel injection system > could have a pressure range of 1600bar with a breaking pressure of a > small fraction of that number..... I have yet to see any injector > breaking pressures listed which suggest line pressures of this > magnitude. That such pressures could be associated with a common rail > system is simply beyond belief....... What you are failing to realize is that (unit pump, HEUI, EUI, or common rail) electronic Diesel injectors are much more than just poppet valves. There's no such thing as a popping pressure on an electronic injector, so the very fact the "local pump shop" that was mentioned went looking for maximum popping pressures shows that they had a feeble grasp on what the current state of injection technology was. It's likely that they might not even be servicing any of these systems yet. Good 'ole electrons control when the injector opens and closes, not a mechanical pop pressure. There's no mistake, no decimal place error, no magazine mix-ups, or anything like that. The more pressure you have, the shorter you can make the ignition event, and the better mixture quality you can achieve. You can run more holes in the nozzle tip, allowing a lower swirl ratio. It's a systems approach. With electronic control of the injector, you can rate shape and do pilot injection... mostly for the sake of noise but also to help NOx formation and cold starting. Somebody related the tensile strength of aluminum to the pressures present in these types of systems. That's why the rail on a common rail system is usually made of forged steel! Cast materials typically won't work because the porosity is too high. Lines don't have to be that exotic, because the ID is so small that even though the pressure is very high, the area being acted upon is not. The line OD is very big compared to the ID. Ratios of 4:1 or 5:1 are typical. The Cummins ISB and ISC engines (at least most of their applications) use Bosch VP44 pumps, which is basically a warmed over version of the good ole rotary pump, but will full electronic authority over timing and delivery. They are headed for common rail. You have to understand that emissions regs drive these changes, and Tier 2 isn't being phased in for "off-road" until 2002 for the most popular of rated power ranges. VP44's still use poppet valves, and are NOT particularly high pressure systems (1000-1100 BAR), although they do a better job than something like a Stanadyne or Lucas rotary pump. Stanadyne or Lucas rotary pumps, as I mentioned before, are only good for about 600-700 BAR. We fondly call these "drip pumps" or even "gravity injection". Possibly this will help illustrate the frame of reference. Most high pressure systems (common rail is the most popular) are being made by Lucas, Bosch, or Denso. They are cost competitive with full-authroity rotary distributor pumps, because distributor pumps still cost WAY more to manufacture than a simple high pressure supply pump. The rail isn't too bad, and the injectors still aren't expensive enough to eat up the pump cost advantage. EUI's are "high-dollar", not only for the injectors but also the massive cam that's required. They do have an advantage over common rail as far as rate shaping, however. Greg's spot-on about the relative danger of split injection lines. You can't build high hydraulic pressure with a leaky line. Our R&D lines that have been instrumented with pressure transducers routinely develop leaks, and believe me, nobody is getting their arms and legs cut off... at least not on a daily basis. :>) Nobody likes a good debate better than me, but I just couldn't take the disbelief any longer. Nobody postulated on what would happen if you tried to inject GASOLINE at 1800 BAR!!!!!!!!!!!!!!!!!!! - -Brock ------------------------------ Date: Fri, 7 May 1999 21:19:34 -0600 From: "Programmer" Subject: Re: 730edit program How'r you making out with your program ?? Lyndon IP TECH - -----Original Message----- From: Squash To: diy efi Date: Friday, April 23, 1999 3:34 PM Subject: 730edit program >I've begun work on the 730 AUJP editor. > >If you would like a copy of the VERY immature version, >e-mail me. I'll be posting updates on a website soon. > >I only have the spark table section complete at this >time. I should have all the VE and the high-end spark >done this weekend. > >As for ALL of the rest of the switches and tables, i >plan on adding them all over the next week or 2. > >The biggest challenge for me is converting the data to >something readable (i.e. 39H to 20 degrees advance). > >See ya > >Andy > >_________________________________________________________ >Do You Yahoo!? >Get your free @xxx.com > ------------------------------ Date: Fri, 7 May 1999 21:15:48 -0600 From: "Programmer" Subject: Re: Hessitation in Late Model Subarus Gary, Knock sensor torque is "extremely" important. Overtorque is going to make the sensor over "sensitive" to any noises. From your post it sounds like you've tried the retorque thing--tried mounting with teflon tape ? Another fix is to isolate the source of the engine noises--ever try a synthetic lube ? Problem with motor mounts ? Driveline noise being translated through to the knock sensor ? I'll have to check the TSB list at the shop for their "fix". Lyndon IP TECH LWester@xxx.com - -----Original Message----- From: GARY To: EFI DIY mailing list Date: Friday, May 07, 1999 7:02 PM Subject: Hessitation in Late Model Subarus >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, 8 May 1999 00:29:37 -0400 From: "Bruce Plecan" Subject: Re: Espen's Reed Valves > Bruce: > You wrote: > >What application is folks talking about?. > >F1 or motorcycles?. > >Big Problem with the reeds is do to inertia the basiclly stay open at > more > >than 2,000 rpm, in say a Yamahahah 350 2 stroke motorcycle. They > will stop > >reversion at low speed but not at higher speeds > >Bruce > Let me point out that in a 4 cycle engine reversion is only a problem > at low RPM .... that RPM depends on camming and the inertia of the air > column in the intake (intake design). A properly designed reed valve > that stayed open above a specific RPM might therefore be a real asset > in a 4 cycle engine. H.W. Reversion can happen at many different rpm levels. Manifolding has alot to do with it, a dual plane V-8 is about impossible. Single planes get worse. Independent runners can be a PITA. Take something like a Fiat X1/9 engine and hang some 45 DCOEs on it. Due to the manifolding the runners are kinda long so the Air horns get to be real short. So the reversion, pushes the fuel into stand off very easily. You could slowly rev the engine and watch the stand off start and stop. It had 3 ranges as I recall (This was a healthy one that ran to 8,500rpm). ------------------------------ Date: Sat, 8 May 1999 00:43:46 -0400 From: "Bruce Plecan" Subject: Re: FI pressure Sensors 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, 07 May 1999 20:24:00 -0500 From: dave.williams@xxx.us (Dave Williams) Subject: Re: Espen's Reed Valves - -> Big Problem with the reeds is do to inertia the basiclly stay open at - -> more than 2,000 rpm, in say a Yamahahah 350 2 stroke motorcycle. - -> They will stop reversion at low speed but not at higher speeds ...which is exactly what you want when running a big cam on the street, right? ------------------------------ Date: Sat, 8 May 1999 02:49:18 -0400 From: "Bruce Plecan" Subject: Re: Espen's Reed Valves I've had some MAF stuff read like it was suffern from reversion. In little narrow bands the grams/sec would jump up. I've read that these blips are do to reversion. The problem with MAFS is that they measure flow, and don't care in which direction. So this is somewhat of a problem on big cammed motors, and MAF. Which would only explain that the problem can occur at higher rpm.. This experimenting/problems were early in my EFI tinkering, so may be full of errors just that's what I found.. I really haven't seen a problem with EFI, and reversion at low rpm. Carbs yes, maybe if using a carb to EFI conversion manifold, with TBI. But, for a MAP Port system just ain't seen it, maybe it was there, but not as a problem. Bruce > -> Big Problem with the reeds is do to inertia the basiclly stay open at > -> more than 2,000 rpm, in say a Yamahahah 350 2 stroke motorcycle. > -> They will stop reversion at low speed but not at higher speeds > ...which is exactly what you want when running a big cam on the street, > right? ------------------------------ End of DIY_EFI Digest V4 #270 ***************************** 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".