DIY_EFI Digest Saturday, March 4 2000 Volume 05 : Number 083 In this issue: weber-marelli ecu Re: weber-marelli ecu Re: ECT and voltage divider help? Frederic Breitwieser is famous!! (noefi) Re: ECT and voltage divider help? Re: Motorola chip and more Re: The EFI332 system and stuff the 8051 ;-) Hello from a new member. Hello from a new member. RE: Baud rate Re: The EFI332 system and stuff the 8051 ;-) Re: injector boss Angle vs time ... [none] anti-lag system Introduction / Test Post Re: See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Fri, 3 Mar 2000 05:06:43 -0800 (PST) From: max70@xxx.com Subject: weber-marelli ecu Hi everyone! I want to put a weber-marelli ecu (from a Lancia Integrale) in my Toyota Celica Alltrac. The problem is that the sensors for the phase are different. Has anyone tried to disassemble the eprom from the weber-marelli ecu? I have, obviously, the pointers to the ignition/iniection/boost map, but modify the code is not so simple.... Any help appreciated. Thanks Max _______________________________________________________ Get 100% FREE Internet Access powered by Excite Visit http://freeworld.excite.com - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 03 Mar 2000 06:39:20 -0800 From: Mike R Brown Subject: Re: weber-marelli ecu max70@xxx.com wrote: > > Hi everyone! > I want to put a weber-marelli ecu (from a Lancia Integrale) in my Toyota > Celica Alltrac. > The problem is that the sensors for the phase are different. > Has anyone tried to disassemble the eprom from the weber-marelli ecu? > I have, obviously, the pointers to the ignition/iniection/boost map, but > modify the code is not so simple.... > Any help appreciated. > Thanks > Max > Max, I've done some work with the weber-marelli ecm that is used in the Edelbrock Pro-Flo system. I don't think that what you have is the same as mine but what I've seen of the weber ECM's they all have some similarities. You might be able get a little more info on what you have by looking at mine. Of coarse the ignition trigger inputs are different on this system but the hardware is in place to use multiple magnetic inputs (trigger and phase). There are schematics and the complete dis-assembly of the code on these pages: http://www.sonic.net/~mikebr/main.html Good Luck, Mike mikebr@xxx.net - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 03 Mar 2000 07:18:53 -0800 From: Mike R Brown Subject: Re: ECT and voltage divider help? Bernd Felsche wrote: > > Daniel Houlton writes: > > >I'm working on a schmatic for a small controller for an electric > >radiator fan and I have some questions on reading the ECT sensor. > > >Doing some testing on my truck I found that the sensor is fed 5V from > >the ECM (measured with the wire dis-connected from the ECT), but > >connected it only reads 3V when cold. The voltage then drops to > >around .65 V at normal operating temp. > > Looks like nominal behaviour for any NTC device. You're probably > seeing the result of a constant-current supply being used to > determine the sensor's resistance - a constant current through a > variable resistance will give a variable voltage. > I don't think this he has a constant current source here. Most likely it is just what he describes below. The 5v reference sourcing a fixed internal resistance in series with the variable resistance of the thermistor in the sensor. The ADC is attached to the junction of the two resistive elements and reads the voltage. Probably a table just translates the voltage into a temperature value. > >It's not really important, but I was somewhat confused how hooking > >the wire to the ECT sensor caused the voltage to drop from 5V to 3V > >(or .7V or so when hot). After some research on the net, I found that > >it's set up as a voltage divider. > > Test the sensor in isolation; switch off the engine, unplug the > sensor and measure the resistance using a multi-meter. If the > resistance falls with increasing coolant temperature, then it's > probably an NTC resistor. > > >So, my question is, how do I switch something based on this voltage? > >Basically, I want to monitor the voltage to the ECT sensor and when it > >drops to around .4 or .5 V I want to trigger an output (that eventually > >drives a relay). Then, while the output is triggered and the voltage > Don't know what kind of thermistor is in your sensor but these guys can be (are) very nonlinear. The common GM sensors used in the system I'm running have very little delta_R/delta_T at the very temperature range a person is most interested in. You can see some graphs here where I put sensors in a thermal chamber and plotted their resistance: http://www.sonic.net/~mikebr/plots/mat_vs_res_adc.html What this boils down to is that the voltage ranges you are most likely dealing with can very small. The difference between the fan on and fan off voltages can be very small (in the order 10-100mv). Before I got into reverse engineering the EFI system in my car I built an analog circuit that would turn the fan on and off at certain set points. Problems you will run into is that a car is a very electrically noisy environment. You need to pay attention to your input and supply filtering. Also watch out for ground loops. My battery is in the rear and the frame is the common return. When the fans came on (about 30 amps inrush current) a few millivolts would develop across the frame rails and that was more than the total hysteresis range I was dealing with so the relay and fans would start oscillating. Not trying to scare you away here because an analog design is really not that difficult but more to let you know that sometimes some weird and un-expected gotchas are out there looking for you. Knowing what I know now I would use the filtering and ADC in the ECM to control these things. A small PIC or something like Bernd suggest might be the way to go. > First; you need to isolate your circuit from the other one using the > same sensor. Using an op-amp is the easiest way of doing that - Op > amps have input impedances in the megaohm range. Isolating the > sensor gives you a buffered output signal - you might want to have a > small gain set up on the op-amp for convenience - else keep it at > unity. > > You can then feed the signal into a "comparator"; an op-amp can be > used for that as well. The comparator is basical a "switch" that has > a low output when the sensed input is less than the reference > voltage, and the output is high when the sense level is higher than > reference. Depending on the op-amp, you can then drive the relay > "directly" from the comparator output. > > >goes back up to around .7 V to turn the output back off. And I want > >to be able to fine-tune the on and off voltages with a couple pots. > > If you need hysteresis, then the circuit gets more complex. You'd need > another comparator and then combine outputs to set and reset the > corresponding driver output. There are dozens of ways of doing that; a > flip-flop is just one way - using the high-level comparator output as > the SET and the low-level comparator output to RESET the flip-flop. > > The reference levels of the comparator would be how you set the > on-off levels. Use the potentiometers in series to ensure that the > high reference level will always be higher than the low! > > >Any ideas how I can do this? I don't know a lot of the solid state > >devices. Would I be using a transitor, op-amp, etc? > > >Will tapping into the ECT wire to read voltage somehow screw up the > >reading to the ECM by acting as a sink or source? > > >Also, I'm including several inputs that can trigger the fan relay like > >the A/C clutch, air compressor clutch, and a couple extras as well as > >a manual on, manual off (which over-ride the other inputs) and an > >automatic setting. > > In that case, you may be better off with a small computer with an > analogue to digital converter and several digital inputs. You then > also have the ability to drive the radiator fan at a speed according > to the load by using a pulse-width-modulated drive instead of a relay. > > The computer (micro-controller) would eliminate all the small > relays and a heap of nested wiring. Flash-programmable computers are > very cheap - the micro-controller itself typically costs a few > dollars; the big bucks arise due to sophisticated output (mainly > driver transistors), housings and environmental requirements - heat > sinks, etc. > > In your application; if you're not worried about how it looks, you > should be able to throw something together for about $50 - assuming > you have access to a suitable desktop computer to write and compile > the programs; and then download them to the micro-controller. > > I know what the necessary circuits look like on my car when using > "conventional" setups that do the same sort of thing == UGLY. > > >My question is, that he low-amp signal relay (needs to handle about 200 > >mA max to trigger the fan relay coil) seems kinda big and bulky. Is > >there a solid state device that can replace this? Typically, a relay > >is used to drive a big load with a small signal, but I want to drive a > >small load with a small signal. Just wondering if there was some kind > >of small IC that would do that instead of a big relay. > > A high-power transistor. say a (MOS)FET - don't know how an IGBT would > handle being on all the time. > > >Oh yeah, one more thing. I've found sockets for different types of > >relays in Jameco and a couple other catalogs, but they aren't very > >high amperage and I'd rather use a common automotive 30A relay. I > >can't find board mounted sockets for these automotive relays though, > >just pigtail sockets with wire leads. Anybody know where I could find > >a board mount socket for these? > > Turn the problem upside-down. See if you can fit your logic circuits > into a relay case, find a relay plate and plug it in. A relay plate > is just a moulded plastic section designed for you to plug in a > relay - you clip a few together and wire the connections as needed > using conventional automotive spade connectors. > > Auto-electricians will never guess you have a computer in one of > those tiny relay cases. :-) > > -- > Real Name: Bernd Felsche > Email: nospam.bernie@xxx.au > http://www.perth.dialix.com.au/~bernie - Private HP > ---------------------------------------------------------------------------- > To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) > in the body of a message (not the subject) to majordomo@xxx.org - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 3 Mar 2000 10:55:41 -0500 From: John_Calabrese@xxx.COM Subject: Frederic Breitwieser is famous!! (noefi) Just wanted all of you to know that Frederic Breitwieser (a member of this list) is in the April 2000 issue of MOPAR ACTION. They are did a story of online parts searching for mopars, and on of the pictures shows a message board with Frederic's name as on of the posts!! Talk about a small world!! It is on page27, and his name is actually circled. Pretty cool, Fred, your famous :) - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 03 Mar 2000 07:52:02 -0800 From: Ludis Langens Subject: Re: ECT and voltage divider help? Daniel Houlton wrote: > > After some math, I found the internal ECM resistor is > around 1765 ohms, confirmed by both hot and cold readings. What brand of ECM is this? GM likes to switch between two different pullup resistor values. One for cold, one for hot. Measuring the voltage on the sensor won't work unless your trip point is far away from the ECM's resistor switching temperature. > Any ideas how I can do this? I don't know a lot of the solid state > devices. Would I be using a transitor, op-amp, etc? You need a voltage comparator. A comparator is similar to an op-amp, except the amplifier gain is non-linear. The output is designed to switch between on and off. Generally speaking, a comparator will need an external pullup resistor on the output because the output stage is just an open collector transistor. > Will tapping into the ECT wire to read voltage somehow screw up the > reading to the ECM by acting as a sink or source? Wire the ECT to the comparator through a high resistance - say 100K or 1M. This will cause no problems. > My question is, that he low-amp signal relay (needs to handle about 200 > mA max to trigger the fan relay coil) seems kinda big and bulky. Is > there a solid state device that can replace this? Typically, a relay > is used to drive a big load with a small signal, but I want to drive a > small load with a small signal. Just wondering if there was some kind > of small IC that would do that instead of a big relay. A transistor would work fine. You can also get driver ICs that are essentially a transistor and the circuitry to control it. - -- Ludis Langens ludis (at) cruzers (dot) com Mac, Fiero, & engine controller goodies: http://www.cruzers.com/~ludis/ - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 03 Mar 2000 08:26:29 -0800 From: Ludis Langens Subject: Re: Motorola chip and more Carl Summers wrote: > > Supposedly uncrackable once > programmed(yeah but they said that about the 68332 when it came out too) Why would the 68332 be uncrackable? AFAIK, it contains no ROM (other than the TPU ROM). Thus there is nothing to crack. On the other hand, a newer chip with onboard ROM/FLASH and no external bus would be uncrackable in the conventional reverse engineering sense. Cracking would require finding security holes in the communications protocols, or by attacking the chip with an electron microscope and so on. - -- Ludis Langens ludis (at) cruzers (dot) com Mac, Fiero, & engine controller goodies: http://www.cruzers.com/~ludis/ - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 03 Mar 2000 08:19:56 -0800 From: Ludis Langens Subject: Re: The EFI332 system and stuff the 8051 ;-) > Nicholas Parker wrote: > > 2. Is it correct that the TPU can run the engine under static > conditions.? Without any help from the cpu except to supply what > ? coil load time, ign angle , pulse width, pulse start angle, & > injector on delay compensation. No angles. The TPU will want those values expressed as time durations. - -- Ludis Langens ludis (at) cruzers (dot) com Mac, Fiero, & engine controller goodies: http://www.cruzers.com/~ludis/ - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 03 Mar 2000 11:44:52 -0500 From: Keith Mezzina Subject: Hello from a new member. Hello, folks. Just subscribed to this list today. As you can see in my sig, I'm building a pretty serious race motor. Going to be in the 600+ HP range. I was wondering if anyone has any experience with EFI on such a beast. Also, what do you folks think of the Edelbrock Pro-Flow system? According to the Edelbrock Techs, if I change the injectors, it should work. My question concerns the air flow capabilities of the intake, and how well the electronics work. - - - - - - - 1973 Dodge Challenger (340/727/3.91SG/NOS) 13.01 @xxx.2 @ 112 (NOS) 1985 Z-28 Backhalf Race car (356/TH400/5.56) 1977 Suburban (Daily Beater) - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 03 Mar 2000 11:50:52 -0500 From: Keith Mezzina Subject: Hello from a new member. Hello, folks. Just subscribed to this list today. As you can see in my sig, I'm building a pretty serious race motor. Going to be in the 600+ HP range. I was wondering if anyone has any experience with EFI on such a beast. Also, what do you folks think of the Edelbrock Pro-Flow system? According to the Edelbrock Techs, if I change the injectors, it should work. My question concerns the air flow capabilities of the intake, and how well the electronics work. - - - - - - - 1973 Dodge Challenger (340/727/3.91SG/NOS) 13.01 @xxx.2 @ 112 (NOS) 1985 Z-28 Backhalf Race car (356/TH400/5.56) 1977 Suburban (Daily Beater) - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 3 Mar 2000 08:52:47 -0800 From: "Al Lipper" Subject: RE: Baud rate Good thinking, Daniel. You may be right. In the latest version, we are trying 4800 baud and it seems to be working pretty well. Perhaps give the slower baud rate a try. Al > -----Original Message----- > From: Daniel [mailto:duagu@xxx.com] > Sent: Thursday, March 02, 2000 7:32 PM > To: Al Lipper > Subject: Baud rate > > > Hi al, > bear with me for a minute. i poked a bit around the fload.asm and was > wondering if the 9600 baud rate could be causing the errors. I > checked with > the original hex loader and it was set at 2400. I also downloaded a baud > rate calculator for a dallas equivalent of the 87C51. At 12mhz, > they stated > the error is about 7%. I'm not too sure what this means but at > 2400, it was > just 0.2% > I'm not sure how to change the baud on the fload.asm. I think its from > BaudLoad equ -39 ;9600 at 12MHz > binary = 111001 > to > BaudLoad equ -3b > binary = 111011 > I'm also not sure about how it would affect the other timings in the > program. > could you advise on this? > thanks a lot for your help. > Daniel > > - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 03 Mar 2000 12:05:48 -0500 From: "John S. Gwynne" Subject: Re: The EFI332 system and stuff the 8051 ;-) In message <38BFE61A.EAA1C5B@xxx.com>, you write: | > Nicholas Parker wrote: | > | > 2. Is it correct that the TPU can run the engine under static | > conditions.? Without any help from the cpu except to supply what | > ? coil load time, ign angle , pulse width, pulse start angle, & | > injector on delay compensation. | | No angles. The TPU will want those values expressed as time durations. That depends on which TPU code you are using. Nicholas is correct for the engine management TPU code on our web page. It does use angles... more specifically spark angle, dwell, inject pulse width, and either stop or stop injector angle (don't remember which). Once given these parameters, The TPU risk processor does the rest without the core CPU32 intervention. john gwynne - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 3 Mar 2000 19:37:45 EST From: WLundquist@xxx.com Subject: Re: injector boss The top inside of the intake runner is the high pressure area, yes, grind down the boss for smooth flow. It will also allow the injector to spray its' proper pattern. Wayne - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Sat, 4 Mar 100 09:35:05 +0800 (WST) From: Bernd Felsche Subject: Angle vs time ... John S. Gwynne writes: > In message <38BFE61A.EAA1C5B@xxx.com>, you write: >| > Nicholas Parker wrote: >| > >| > 2. Is it correct that the TPU can run the engine under static >| > conditions.? Without any help from the cpu except to supply what >| > ? coil load time, ign angle , pulse width, pulse start angle, & >| > injector on delay compensation. >| No angles. The TPU will want those values expressed as time durations. >That depends on which TPU code you are using. Nicholas is correct for >the engine management TPU code on our web page. It does use >angles... more specifically spark angle, dwell, inject pulse width, and >either stop or stop injector angle (don't remember which). Once given >these parameters, The TPU risk processor does the rest without the >core CPU32 intervention. I haven't been able to figure out why a spark angle is used. AFAIK spark angles date back to mechanical distributors and their advance mechanisms. That's not to say that this specific use of angle is incorrect - if your timing base in angle, then that may be appropriate. The spark timing is the critical condition - and oddly enough, this is actually amenable to computer control with a constant clock timing. The spark under static conditions is always a constant clock offset before TDC because the _time_ to light the mixture is constant, as is the required dwell. Now, when you get to injection, you do have to be aware of the start and end angles because of the camshaft imposing a mechanical constraint - it's not generally a good idea to squirt as the valve opens as the scavenging process during overlap might exhaust precious fuel. (Haven't yet figured out why squirting on a closing valve is such a problem - valve seats maybe?) The actual injection time is however determined by the fuel requirements - which don't vary with crank or camshaft angle. (Ignoring stratified charging!) - -- Real Name: Bernd Felsche Email: nospam.bernie@xxx.au http://www.perth.dialix.com.au/~bernie - Private HP - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 3 Mar 2000 17:24:20 -0800 (PST) From: dennis Subject: [none] - -------------------------------------------------------------------------------- Has anyone on this list tried to make, or used, an anti-lag system? For those not familiar with this term, some of the rally cars and other cars in big dollar classes that use a larger and more difficult to spool turbo use these systems to decrease lag. This system allows a car to come out of a corner on a track already in boost after lifting and breaking, without left foot breaking it and shortening pad/rotor life. Or to launch at the dragstrip with a manual transmission, and have boost built up already. Some say they can get substantial amounts of boost at idle with these systems. Once activated, it is a system where when the throttle is closed, ignition timing is retarded and additional fuel is added to the engine. When the throttle is opened again, everything returns to normal. I think it requires a slighly greater amount of airflow too. This could be accomplished with the idle speed motor. There may be more to this than what I've gathered. If anyone knows more, let me know it too. Some systems add more fuel through the stock injectors, while others use a mechanical style injector in the exhaust manifold to inject fuel there. When the timing is retarded, combustion takes place later in the cycle and a large portion of the explosion that pushes the piston down is expelled out of the exhaust valve, increasing exhaust pulse pressure, and so driving the turbine wheel to a higher speed. The extra fuel helps this by causing backfires in the exhaust manifold that also hit the turbine pretty hard. This also makes pretty flames come out the exhaust tip. Intimidating. Cool! Maybe not so cool for that guy tailgating you. Some aftermarket programmable engine management systems, like Motec for example, offer this as part of their programming. I would imagine that you could build a stand-alone system that does this cheaply using an additional injector, some means of easily retarding timing(MSD?), a switch that comes on when the throttle is released, and an activation switch. You wouldn't want it on all of the time, just when racing(or maybe when being tailgated). I also think you might be able to feed the map sensor signal wire some votage(on a 2bar system), say just above 2.5 where it would think it's in boost, while tricking the 02 so it doesn't freak out, to get the ECM to do this for you. That way the computer would think you're making boost and respond, hopefully, with increased injector pulsewidth and retarded timing. And since the car would be running rough, the idle speed would automatically increase to keep it running. Has anyone got a reason this MAP/O2 trick wouldn't work? All this may come at the expense of shorter lived exhaust gaskets, manifolds, and turbos. Not to mention emissions. I would also expect plug fouling issues if the fuel is injected through the intake. Stuff breaks when you try to make it do what it wasn't designed for. Oh well, parts are cheap-let it eat! ;) I'd like to hear from anyone that has any ideas or thoughts on this subject. TIA for your thoughts and suggestions, dennis _____________________________________________________________ AutoSpeed - The World's Best High Performance Online Magazine http://www.autospeed.com - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Sat, 4 Mar 100 10:47:25 +0800 (WST) From: Bernd Felsche Subject: anti-lag system dennis writes: >Has anyone on this list tried to make, or used, an anti-lag system? Two options come to mind immediately .... read on. >For those not familiar with this term, some of the rally cars and >other cars in big dollar classes that use a larger and more >difficult to spool turbo use these systems to decrease lag. >This system allows a car to come out of a corner on a track already >in boost after lifting and breaking, without left foot breaking it >and shortening pad/rotor life. Or to launch at the dragstrip with a >manual transmission, and have boost built up already. >Some say they can get substantial amounts of boost at idle with >these systems. Fuel consumption isn't a big problem under race conditions. :-) >Once activated, it is a system where when the throttle is closed, >ignition timing is retarded and additional fuel is added to the >engine. When the throttle is opened again, everything returns to >normal. I think it requires a slighly greater amount of airflow >too. This could be accomplished with the idle speed motor. There >may be more to this than what I've gathered. If anyone knows >more, let me know it too. That causes the fuel to burn in the exhaust manifold as combustion cannot be completed - the expanding gases in the exhaust manifold cause the turbine to spool up. Note that your CO and HC emissions go through the roof when you do this. A catalytic convertor is likely to melt under prolonged exposure due to those conditions. The HC emissions get so high that the unburnt fuel will spontaneously ignite near the exit of the exhaust system. >Some aftermarket programmable engine management systems, like Motec >for example, offer this as part of their programming. I would >imagine that you could build a stand-alone system that does this >cheaply using an additional injector, some means of easily >retarding timing(MSD?), a switch that comes on when the throttle is >released, and an activation switch. You wouldn't want it on all of >the time, just when racing(or maybe when being tailgated). I also >think you might be able to feed the map sensor signal wire some >votage(on a 2bar system), say just above 2.5 where it would think >it's in boost, while tricking the 02 so it doesn't freak out, to The O2 won't just freak... it'll die under those conditions. OK if you have the ability to change sensors every couple of races, not so good on the road. Also, drivability suffers - the very rich mix can make the engine die - you can flood an engine after starting. Especially when you change the AFR from around 18:1 to about 3:1. >get the ECM to do this for you. That way the computer would think >you're making boost and respond, hopefully, with increased injector >pulsewidth and retarded timing. And since the car would be running >rough, the idle speed would automatically increase to keep it >running. It's a mistake IMHO to put too much fuel into the cylinder in the first place. That leads to a high-maintenance engine. >Has anyone got a reason this MAP/O2 trick wouldn't work? It might work; for a while. Two options - as I said before... 1. Electric air pump to add air into the exhaust manifold - a simple check-valve ensures that you don't get any blow-back when you open the throttle and the valve sets the pressure you want in the exhaust manifold. [This idea is adapted from the now common practice of pumping air into a cat to optimise the conversion under less-than-ideal conditions (i.e. quite often).] By sensing the position of the check-valve (either directly or through a pressure switch/sensor), you can run an injector to add fuel to the additional air. The ECU should check that the engine is hot before injecting the fuel though - just to be sure that it'll ignite spontaneously. What's also important is how and where you inject. You definitely want to avoid a back-fire through the auxiliary air system! Use the existing O2 sensor to ensure correct mixture when off-boost. You probably don't need the pre-boost spool after being off-boost for more than say 3 seconds, and certainly not at idle. That allows you to stabilise the idle mixture and saves some fuel. The driver can always blip the throttle to activate the pre-boost spool. 2. Get a different turbocharger - Garret make one with integral electric drive to keep it spinning when off-boost. The electric drive can also be used yto re-charge your battery - so it saves on a big alternator (a small one is advisable as a fail-safe). - -- Real Name: Bernd Felsche Email: nospam.bernie@xxx.au http://www.perth.dialix.com.au/~bernie - Private HP - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Fri, 03 Mar 2000 23:19:37 -0500 From: Matt Cramer Subject: Introduction / Test Post Hello everyone! My name is Matt Cramer, and I've got a '66 Dodge Dart with a 225 cubic inch slant six that I've been looking into the possibility of converting to EFI, preferably multi-point. I've joined this list to get a feel for what's involved and what it's likely to cost me. This is hopefully going to be something I can incorporate into a design project that I'm going to have to do to get my degree in mechanical engineering, so I should at least have access to a decently well equipped machine shop. This also means I'm going to have to design some significant part of the system - I figure I can probably come up with some kind of exotic tuned runner intake manifold for it. Anyway, I really don't have much of an idea of what's likely to be involved in such a conversion. Would it be as simple as getting the electronics and injectors off a donor car with a similarly sized engine (I'm thinking Ford 3.8, Buick 3.8, or Jeep 4.0), finding a way to attach the fuel injectors and supply them with enough fuel pressure, finding ways to install the sensors into the engine, and wiring it all up? Or is it something a lot more involved? Matt Cramer - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ Date: Sat, 4 Mar 2000 00:09:01 EST From: MdntRdr1@xxx.com Subject: Re: Well, not familiar with the anit-lag, but my father-in-law just recently had his 92 Dodge 3/4 4x4 turbo Cummins in the shop and it came back out without any turbo lag and a new exhaust. I can ask him on how the system works. - ---------------------------------------------------------------------------- To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes) in the body of a message (not the subject) to majordomo@xxx.org ------------------------------ End of DIY_EFI Digest V5 #83 **************************** 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".