DIY_EFI Digest Tuesday, August 24 1999 Volume 04 : Number 485 In this issue: Re:Update on the newbie question... Newbie question, slightly off topic. Injector Life. Idiot questions from lazy newby Help With Diacom-p See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Mon, 23 Aug 1999 17:52:03 -0400 From: "David A. Cooley" Subject: Re:Update on the newbie question... My Explorer autolocks as well... Don't need the disable system... I have a concealed carry permit and on any given day it's a toss up as to whether I'll have my 9mm glock or my .44 Magnum Taurus.... They aren't getting my vehicle. Now if an EEC-V just had an output to pull the trigger for ya... At 03:00 PM 8/23/99 -0400, you wrote: >Date: Mon, 23 Aug 1999 12:44:57 +0200 >From: Nic van der Walt >Subject: Update on the newbie question... > > > > > If the hijackers have guns, I would hope they get a couple of blocks > before > > the engine stops because they might not be happy with you if you foil > their > > plan. > > >If he doesn't have a gun I won't unlock the door and get out... Audi has >this nice feature in that it locks the doors when you drive off. Perfect >for a scatterbrain like me. =========================================================== 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: Mon, 23 Aug 1999 16:38:27 +1000 From: Christian Hack Subject: Newbie question, slightly off topic. > > I have been lurking around quite a while now, and though my > own EFI project won't start seriously for another month or > two I have a related question. > > The scenario is this. I installed a anti-hijack/tracking unit > in my car (Audi-EFI). The immobilizer relay (to disable the car > in event of an hijack) is connected in series with the booster > pumps' fuse, ie when the car is immobilized the main fuel pump > will run dry. > > When this happens what damage will be caused to the engine systems? > I'm quite willing to accept an amount of damage in return for recovering > my car, and the immobilizer will only be actived with my constent, > but knowing what will break would be nice.... ;-) > Well I can tell you that standard procedure for my car (an Australian VL Commodore with a Nissan engine) for depressurizing the fuel system is to idle the engine and pull out the fuel pump fuse. You then attempt to start the engine a few times to ensure all the pressure in the fuel system is gone. On my car it stutters and stalls after around 3 seconds and then is quite difficult to even start In a high load situation, not too much damage would occur I would guess. At worst, the engine will run lean (as the fuel pressure drops) for a second or so. Remember that under load a lot more fuel is injected than at idle The other thing that maybe of concern is running the main fuel pump dry. Some pumps rely on the fuel in order to cool them. Running them for too long dry could stuff things. > Does anyone know whether the fuel pump is switched off immediately when the > engine dies of fuel starvation? > In my car the ECU turns off the fuel pump essentially immediately the engine stops/stalls. It will turn the pump back on if/when the engine is cranking again. > Regards, > Nic van der Walt > South Africa > Christian Hack DESIGN ENGINEER christianh@xxx.au EDMI Pty Ltd Ph : (07) 3888 3066 FAX : (07) 3888 3583 ------------------------------ Date: Mon, 23 Aug 1999 19:06:59 -0700 From: "John Dammeyer" Subject: Injector Life. Hi all, I think, but I'm not sure if I am having an injector life problem. We'll know better tomorrow when the engine is cold but it seems like after a period of running the injectors will no longer open and close precisely. What happened today was that we ran the engine for about 30 minutes at full load and 5400RPM. Lot's of acceleration/decel etc. O2 sensor was reasonable and we achieved the max RPM expected considering prop load. We then brought the engine back down to an idle and let the temperature stabilize from 205 to 185. After that we turned the engine off. A few hours later, we did some more runs and suddenly found that the engine would barely idle. Pulse widths verses MAP etc. to the injectors were consistent with previous runs and the engine stumbled until about 2000RPM. To me it sounds like one or two stuck injectors because at idle the O2 sensor was off the scale as far as lean mixture was concerned. Pulling a plug from the high power run showed nice colouring and pulling a plug from the rough idle did not show carbon so I am assuming the O2 sensor was correct. Begs the question, what could be up with the injectors. They are stock Honda Injectors for the 1600CC engine, 11.5 Ohms roughly and we use a 7.5 Ohm resistor in series with them because we found that they wouldn't close fast enough to create a 1.25ms pulse which is about all we need at idle. Once we added the resistors in series with each injector we were able to easily get our low and high pulse rates. I don't have data sheets for the injectors used in Honda. Only what the after market information states which is that it's a 141.5 gm injector at 3 bar 11.6 ohms. If that number is the delivery rate at 80% duty cycle then I'm right on the money for fuel usage and timing calculations. If it's the delivery rate for a 100% duty cycle then I'll never get full power at 80% duty cycle but at the moment that's not my problem. Any ideas? Any place on the WEB that has injector specifications? Thanks, John ------------------------------ Date: Mon, 23 Aug 1999 22:20:15 -0700 (PDT) From: "Jon V." Subject: Idiot questions from lazy newby Hello, I've been trying to find the answers to these questions myself scanning through the list archive, but frankly there is just too much there for me to read, and if there is a FAQ I'm too wasted to find it... so I'm going to kill everyone's time with my silly questions. Please, feel free to flame me... but if you could throw in at least a token factoid. I appreciate it! :-) What I'm doing... I have an old "performance" car (early '70s, it is really an on POS, but hey, you work with what you've got..) that I play around with. The car has an OK engine, but it is early '70s technology... the most advanced piece of electronics on the thing is... well, the HET point replacement I installed in a BFE parking lot so I could make it home after the distributor started filling with oil every 20 miles. It is a 2L engine and they are pulling about 140HP out of it, but it is capable of a lot more. (Re-carbing alone is said by the engine manufacturer to add about 20HP.) So I am going to "performance enhance" the engine. Actually, the engine has some life left in it and I like driving the car, so I went ahead and bought a second engine (same type) and I'm going to screw *it* up... then when I finally break a timing belt or whatever I'll have a new engine to throw in. Which brings me to the list-relevant parts. I think it'd be pretty snazzy to implement a fuel injection and ignition controller for the old rattletrap... but before I go and get myself sold on the idea, I need a reality check. I had intended to ask a bunch of leading questions at this point, filled with all sorts of "gems" of knowledge to show that I'm really in with the EFI scene, but I decided that since I don't know a my ASS from my EGO and I get weird shrinking feelings when people say things like 'Lambda' I figure I'll take a different approach. Assume that I have an IQ at least 20% higher than this email indicates... no, that's too open... assume that I have an IQ of at least 100. Assume that I know how to do something besides waste everyone's time... say maybe some software development (high level languages, some assembly) experience and a little bit of HW (enough to run screaming), and that I know which end of a wrench the little spinny things hook up to. Assume that I have two FI VW engines just sitting around waiting to sacrifice their existence to the gods of experimentation. A selection of spare computers ranging from 386/33Mhz to Cyrix 6x86 or Alpha 166Mhz that can be reassigned. Familiarity+ with Linux. A selection of basic electronic tools (VOM, Oscilliscope, device programmer, scientific calculator) and an occasional window of access to even better tools (aka real electrical engineers that owe me favors). Assume a fairly modest performance envelope. Redline ~7K, maybe a little higher, naturally aspirated, <9:1 compression. I expect 160HP, if I'm lucky 180HP. I'll need to do a distributorless ignition at the same time. Assume that I am what I sound like, a dirt poor crazyperson. Oh, and if it is no bother, assume that I have the ultimate source of PIC 16C65A OTP PLCC parts... people I work with chew through them like popcorn and the company policy is "engineering begets engineering." IOW they encourage projects.... up to and including the time the one of the EEs fitted flashing LEDs on all the snails he could find around the building... but I digress. Given all of those assumptions, what is the slickest way to get started? I don't like duplicating effort (but I don't want to buy... logically inconsistent) unless I need to... I certainly don't want to need to duplicate basic research. Should I find a junkyard GM computer and work on reprogramming it? Should I jimmy up some IO for a PC motherboard and start with that? My OS preference is Linux these days, but I have worked long enough to know that preference don't mean jack when there is a job to do. What *I'd* like to do is set up a system that uses the PICs as IO controllers... say one PIC per sensor, with all the code to refine the sensor data and bounce it (on a serial bus) to a central processor. IOW there would be a HET sensor on a cam pulley connected to a PIC which abstracts the data into RPM and bounce it out each time Cly #1 is TDC... Set up a sensor/PIC pair for everything (EGO, MAF, CP, TP, RPM, MAT, EGT, ECT, TLA, TLA, LFLA, ETC, ETC.) which just transmits its data based on some sensor specific criteria (the RPM might be sent each time the engine is TDC, the EGO every 10th of a second, TPS whenever it changes) to a central computer which can log the data, and control the injectors, ignition, etc. The extended idea is that because everything is bussed together you could have actuator/PIC pairs (e.g. an injector) that act a lot like the sensors. For example, the CPU configures each injector with timing information (MS from TDC to open, MS from TDC to close) and a common sync pulse (engine TDC) is constantly issued. At that point if the CPU got behind for a few revs the engine would just sort of "hold" until things were caught up. The stretched idea is that everything is really bussed together, and the sensors just share their data, and the actuators just take the data and act on it... and the CPU just oversees the process and makes sure that everybody is talking. See, now that's exactly what I said I wasn't going to do... damn these fingers. All of that is, as you are saying to yourself, sky high dreaming, and I agree, I should pull my head out, but it has been lodged in there for so long that my spine has set. Whatever I do, I'd like it to be educational, but not in the bad way that people mean when they say "it was educational". I want to be educational AND work. It doesn't have to work the first time, but it needs to do better than the carbs someday. I don't really want to buy a ready built solution... both because it seems like a waste of a good hobby project, and because if this works I've got several other engines ranging from a 700+ CID industrial/truck engine to 1100CC motorcycle engine that I'd like to look at too. So, can anyone politely ignore the utopian "all the little computers working together" part and tell me how much a project like this is going to cost, and will it work better than carbs? FWIW, recarbing with the "performance" carbs would probably cost about $900. TIA -Jon The eagle may soar, but the weasel never gets sucked into a jet engine. ------------------------------ Date: Tue, 24 Aug 1999 02:25:08 EDT From: Fisystems@xxx.com Subject: Help With Diacom-p I can't seem to find a Vin # to link Diacom-p to a 93 Vette 9280 ECM. Will Diacom-p work on a 93 Vette ECM? Ken Murillo fisystems@xxx.com ------------------------------ End of DIY_EFI Digest V4 #485 ***************************** 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".