DIY_EFI Digest Wednesday, March 8 2000 Volume 05 : Number 091 In this issue: O2 sensor Voltage O2 sensor Voltage Re: AFM measurement/backpressure (was Turbo speed sensor) Re: O2 sensor Voltage Re: O2 sensor Voltage Re: O2 sensor Voltage Re: AFM measurement/backpressure (was Turbo speed sensor) Re: AFM measurement/backpressure (was Turbo speed sensor) Re: O2 sensor Voltage Re: AFM measurement/backpressure (was Turbo speed sensor) Re: AFM measurement/backpressure (was Turbo speed sensor) Re: AFM measurement/backpressure (was Turbo speed sensor) Re: AFM measurement/backpressure (was Turbo speed sensor) Turbo speed sensor Fuel Injector Bench - Rheostats Revisited re: Crank trigger Re: Fuel Injector Bench - Rheostats Revisited Re: AFM measurement/backpressure (was Turbo speed sensor) Re: AFM measurement/backpressure (was Turbo speed sensor) See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Wed, 08 Mar 2000 05:17:48 PST From: "Steve Leonard" Subject: O2 sensor Voltage I need to alter the voltage signal coming from a O2 sensor. I want to fool the ECU into a leaner condition. I am going to school, driving 110mi round trip. I want to see how much fuel mileage I can sqeeze out of my Geo Metro. Where can I get plans for a simple voltage "stepper". regards John ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.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: Wed, 08 Mar 2000 05:17:48 PST From: "Steve Leonard" Subject: O2 sensor Voltage I need to alter the voltage signal coming from a O2 sensor. I want to fool the ECU into a leaner condition. I am going to school, driving 110mi round trip. I want to see how much fuel mileage I can sqeeze out of my Geo Metro. Where can I get plans for a simple voltage "stepper". regards John ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.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: Wed, 08 Mar 2000 05:28:19 PST From: "mike mager" Subject: Re: AFM measurement/backpressure (was Turbo speed sensor) "Mike (Perth, Western Australia)" said: >I really would like to do a turbo speed sensor - so far no reply from >the emails I've sent out to distributors - not even a "we don't do it" :( Turbocharger RPM is also sensed via a variable-reluctance pickup at the compressor-wheel nut; that is the inlet side, so it won't be quite as hot as the outlet side (we hope). Mike ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.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: Wed, 08 Mar 2000 05:40:48 PST From: "mike mager" Subject: Re: O2 sensor Voltage "Steve Leonard" asked: > I need to alter the voltage signal coming from a O2 sensor. I want to fool the ECU into a leaner condition. > I am going to school, driving 110mi round trip. I want to see how much fuel mileage I can sqeeze out of my Geo Metro. Where can I get plans for a simple voltage "stepper". Uh, what's a 'Voltage "stepper"'? A simple single-supply operational amplifier could add an offset Voltage to the EGO Voltage, or could effect the EGO Voltage by a ratio. "How lean can you go", we wonder? Mike ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.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: Wed, 8 Mar 2000 08:52:05 -0500 From: "nacelp" Subject: Re: O2 sensor Voltage It really doesn't work that way. The ecm is going to try and maintain a 14.7:1 AFR, for emission purposes. So you really have two options, crack the code, and set it to run open loop, and recalibrate to run more effiecently (meaning changing timing/fuel/egr etc). Or finding some place in it's normal operating calibrations that is a sweet spot for mileage. Assuming this is for off road educational purposes, I'd try just installing a 500 ohm pot in the Coolant Temp Sensor, or Intake air temp sensor wiring, and try "fooling" the engine into thinking it's cooler then it actually is, HOWEVER, make sure that the temps aren't too low to disable say the Torque converter clutch or some other gotcha. You might try reading the tuning.doc or .txt at the FTP sometime, There is some info about setting cruise conditions there. I'd also, suggest you hit, www.tunercat.com and look at the hacs to see what in general your dealing with. There are lots of variable, and considerations. Grumpy > I need to alter the voltage signal coming from a O2 sensor. I want to fool > the ECU into a leaner condition. > I am going to school, driving 110mi round trip. I want to see how much > fuel mileage I can sqeeze out of my Geo Metro. Where can I get plans for a > simple voltage "stepper". > > regards > > John > > ______________________________________________________ > Get Your Private, Free Email at http://www.hotmail.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 > - ---------------------------------------------------------------------------- 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: Wed, 8 Mar 2000 08:57:06 -0500 From: "nacelp" Subject: Re: O2 sensor Voltage > Uh, what's a 'Voltage "stepper"'? ie Voltage divider. > A simple single-supply operational amplifier could add an offset Voltage to > the EGO Voltage, or could effect the EGO Voltage by a ratio. "How lean can > you go", we wonder? It don't work that way in any gm ecm I've tinkered with. I'd think about 16:1 for a "normal" engine would be about it. Even going that lean, I'd for sure have an accurate AFR monitor (ie WB O2), and EGT. I'd hate to waste an engine over a couple pennies of mileage. By the time you try to cut too fine of line, you might spend more in tinkering then the difference in mileage gets you. > > Mike > ______________________________________________________ > Get Your Private, Free Email at http://www.hotmail.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 > - ---------------------------------------------------------------------------- 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: Wed, 08 Mar 2000 22:17:05 From: "Mike (Perth, Western Australia)" Subject: Re: AFM measurement/backpressure (was Turbo speed sensor) At 05:28 AM 8/03/2000 PST, you wrote: >"Mike (Perth, Western Australia)" said: > >>I really would like to do a turbo speed sensor - so far no reply from >>the emails I've sent out to distributors - not even a "we don't do it" :( > >Turbocharger RPM is also sensed via a variable-reluctance pickup at the >compressor-wheel nut; that is the inlet side, so it won't be quite as hot >as the outlet side (we hope). mmmmm OK, given the compressor speed I was of the opinion the VR type pickup would just plain saturate at high turbine speeds - whereas the optical one would give me more bandwidth. Also I would guess it would be problematic to mount a sensor close enough to the comp nut given its position, air flow restriction (perhaps minor) and care to avoid it falling into the comp on high flows etc As I haven't done anything on this so far I might have another look at the magnetic pickup then, do you have any ideas of component p/n's or do you consider the off the shelf VR pickups might be OK from a hobby outlet like Tandy's etc ? Tah for that - defintiely worth of another look - thanks :) I suppose when I next take the turbo out - I could install a small piece of ferrite into the rim of the comp wheel (rebalance it after of course), or would this be too risky given the rpm and centripetal forces ? Has anybody actually used an optical tacho to see what sort of rpm's the comp wheel does at idle ? And yes I know that getting access is a prob due to AFM being removed - I'm just asking since I did that on my system in 'limp' mode (AFM off) yet could idle car and run it (very rich) up to 2000rpm... At least it let me see if the turbo was OK spinning at idle after it was re-assembled... I've been told its around 300rpm - though I didn't have a optical tacho handy - it looked about the speed of a regular floppy drive though ~`:o Rgds ~`:o) Mike Massen Trading as "Network Power Systems" and "Network Computers" Perth, Western Australia Ph +61 8 9444 8961 Fx +618 9264 8229 (fax -> email) Products/Personal/Client web area at http://www.wantree.com.au/~erazmus (Current pics - trip to Malaysia to install equipment in jungle power site) Some say there is no magic but, all things begin with thought then it becomes academic, then some poor slob works out a practical way to implement all that theory, this is called Engineering - for most people another form of magic. - ---------------------------------------------------------------------------- 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: Wed, 8 Mar 2000 09:08:22 -0500 From: "nacelp" Subject: Re: AFM measurement/backpressure (was Turbo speed sensor) (the following ref street{able}cars, and probably most race stuff): While sorta interesting, I think your off on a tangent worring about the T/C shaft speed. In reference to back pressure, design a min backpressure exhuast of min volume, and be done with it. In the higher HP areas the T/C is more switched on and off by TPS changes then feathering into anyway. Using an accurate MAP/MAF is all that is needed, nice additional info is IAT, Water Injection, and better tuning. What would be neat is an auxillary method of driving up EGTs for T/C operation without being at the expense of engine components. But, for that you'd really even need to make it transistional so that when TPS changed there wasn't a drop, or the bog would put your nose against the windsheild. There are just some designs that reguire compromise. Grumpy > > >I really would like to do a turbo speed sensor - so far no reply from > >the emails I've sent out to distributors - not even a "we don't do it" :( > - ---------------------------------------------------------------------------- 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: Wed, 08 Mar 2000 22:27:35 From: "Mike (Perth, Western Australia)" Subject: Re: O2 sensor Voltage At 05:40 AM 8/03/2000 PST, "mike mager" wrote: >"Steve Leonard" asked: >A simple single-supply operational amplifier could add an offset Voltage to >the EGO Voltage, or could effect the EGO Voltage by a ratio. "How lean can >you go", we wonder? Correct me if I'm wrong (can't recall rich/lean direction) but if the output voltage goes low(er) to indicate richer, then all you need is a voltage divider or even (if the o/p impedance of the sensor is high) a series resistor. If its the other way around - higher voltage = richer then all you need is a small pullup resistor to a convenient supply rail to 'lift' the sensor voltage - a series resistor to the sensor would be a small protection and it also depends on the O2 output impedance. In essence with a bit of investigation easier then an opamp, though admittedly an opamp does have a nice high i/p impedance and a single trim pot can make the offset go +ve/-ve from span to span with some cal for checks. Rgds ~`:o) Mike Massen Trading as "Network Power Systems" and "Network Computers" Perth, Western Australia Ph +61 8 9444 8961 Fx +618 9264 8229 (fax -> email) Products/Personal/Client web area at http://www.wantree.com.au/~erazmus (Current pics - trip to Malaysia to install equipment in jungle power site) Some say there is no magic but, all things begin with thought then it becomes academic, then some poor slob works out a practical way to implement all that theory, this is called Engineering - for most people another form of magic. - ---------------------------------------------------------------------------- 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: Wed, 8 Mar 2000 09:13:25 -0500 From: "nacelp" Subject: Re: AFM measurement/backpressure (was Turbo speed sensor) The speed varies alot, meaning from barely moving to several hundred rpm. On, some big stuff (436 CID, turbo set up for 60 PSI od boost), you often can count it's vanes moving, by. On a turbo buick is just fast enough at times to blur. Oil temp., EGT are what spins the turbo. Grumpy > Has anybody actually used an optical tacho to see what sort of rpm's > the comp wheel does at idle ? And yes I know that getting access is a prob > due to AFM being removed - I'm just asking since I did that on my system > in 'limp' mode (AFM off) yet could idle car and run it (very rich) up > to 2000rpm... At least it let me see if the turbo was OK spinning at idle > after it was re-assembled... > I've been told its around 300rpm - though I didn't have a optical tacho > handy - it looked about the speed of a regular floppy drive though ~`:o - ---------------------------------------------------------------------------- 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: Wed, 08 Mar 2000 06:22:34 PST From: "mike mager" Subject: Re: AFM measurement/backpressure (was Turbo speed sensor) The quotations are getting complicated here (or I just need some sleep?). >From: "Mike (Perth, Western Australia)" >Reply-To: diy_efi@xxx.org >To: diy_efi@xxx.org >Subject: Re: AFM measurement/backpressure (was Turbo speed sensor) >Date: Wed, 08 Mar 2000 22:17:05 > >At 05:28 AM 8/03/2000 PST, you wrote: > >"Mike (Perth, Western Australia)" said: > > > >>I really would like to do a turbo speed sensor - so far no reply from > >>the emails I've sent out to distributors - not even a "we don't do it" >:( > > > >Turbocharger RPM is also sensed via a variable-reluctance pickup at the > >compressor-wheel nut; that is the inlet side, so it won't be quite as >hot > >as the outlet side (we hope). > >mmmmm OK, given the compressor speed I was of the opinion the VR type >pickup would just plain saturate at high turbine speeds - whereas the >optical one would give me more bandwidth. Excellent point!; I have read of it, but I don't know what type of VR sensor they had. >Also I would guess it would be problematic to mount a sensor close >enough to the comp nut given its position, air flow restriction (perhaps >minor) and care to avoid it falling into the comp on high flows etc > >As I haven't done anything on this so far I might have another look at >the magnetic pickup then, do you have any ideas of component p/n's or >do you consider the off the shelf VR pickups might be OK from a hobby >outlet like Tandy's etc ? > >Tah for that - defintiely worth of another look - thanks :) > >I suppose when I next take the turbo out - I could install a small piece >of ferrite into the rim of the comp wheel (rebalance it after of course), >or would this be too risky given the rpm and centripetal forces ? Wow! A shot-peener spins more slowly than a compressor! A radial mounting would do, but that would be a permanently drilled hole. I mainly just wondered why nobody had mentioned that, with certain (I don't remember which) books mentioning it; the application may have been laboratory only. Definitely sounds interesting, at the least. Aircraft engines have turbine tachometers, BTW. Mike >Has anybody actually used an optical tacho to see what sort of rpm's >the comp wheel does at idle ? And yes I know that getting access is a prob >due to AFM being removed - I'm just asking since I did that on my system >in 'limp' mode (AFM off) yet could idle car and run it (very rich) up >to 2000rpm... At least it let me see if the turbo was OK spinning at idle >after it was re-assembled... > >I've been told its around 300rpm - though I didn't have a optical tacho >handy - it looked about the speed of a regular floppy drive though ~`:o > > > > >Rgds ~`:o) > >Mike Massen Trading as "Network Power Systems" and "Network >Computers" >Perth, Western Australia Ph +61 8 9444 8961 Fx +618 9264 8229 (fax -> >email) >Products/Personal/Client web area at http://www.wantree.com.au/~erazmus > (Current pics - trip to Malaysia to install equipment in jungle power >site) > >Some say there is no magic but, all things begin with thought then it >becomes >academic, then some poor slob works out a practical way to implement all >that >theory, this is called Engineering - for most people another form of magic. > >---------------------------------------------------------------------------- >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 > ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.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: Wed, 08 Mar 2000 22:45:53 From: "Mike (Perth, Western Australia)" Subject: Re: AFM measurement/backpressure (was Turbo speed sensor) At 09:08 AM 8/03/2000 -0500, you wrote: >(the following ref street{able}cars, and probably most race stuff): > >While sorta interesting, I think your off on a tangent worring about the T/C >shaft speed. In reference to back pressure, design a min backpressure >exhuast of min volume, and be done with it. mmm yes good point, an associate on a nissan's user group is making up a 3.5" dump pipe and dump to cat pipe, should get it sent over in twoweeks. Trouble is a freeer flowing exhaust may give more propensity for overspeed, especially since I have a very basic bleed valve arrangement without a proper waste-gate boost controller. So knowing what it does at all - helps. Regardless of the practical need/outcome - I'd still be interested to see what sort of revs the damn thing actually does :) Not having much practical experience with turbos so far other then playing with bleeds etc. > In the higher HP areas the T/C is more switched on and off by TPS changes >then feathering into anyway. Using an accurate MAP/MAF is all that is >needed, nice additional info is IAT, Water Injection, and better tuning. Sorry - whats IAT ? > What would be neat is an auxillary method of driving up EGTs for T/C >operation without being at the expense of engine components. But, for that >you'd really even need to make it transistional so that when TPS changed >there wasn't a drop, or the bog would put your nose against the windsheild. Sorry again - EGT ? - Equivalent to Exhaust Gas Recirculation (Transfer ?) > There are just some designs that reguire compromise. Yeah true, though with 1GigaHertz DSP's from TI and other smarts, ones wish lists of avoiding compromises gets longer and longer but at the expense of our pockets - we can still speculate (fancy name for dream ;-) Tah, Rgds ~`:o) Mike Massen Trading as "Network Power Systems" and "Network Computers" Perth, Western Australia Ph +61 8 9444 8961 Fx +618 9264 8229 (fax -> email) Products/Personal/Client web area at http://www.wantree.com.au/~erazmus (Current pics - trip to Malaysia to install equipment in jungle power site) Some say there is no magic but, all things begin with thought then it becomes academic, then some poor slob works out a practical way to implement all that theory, this is called Engineering - for most people another form of magic. - ---------------------------------------------------------------------------- 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: Wed, 8 Mar 2000 09:38:45 -0500 From: "nacelp" Subject: Re: AFM measurement/backpressure (was Turbo speed sensor) > Trouble is a freeer flowing exhaust may give more propensity for overspeed, > especially since I have a very basic bleed valve arrangement without a > proper waste-gate boost controller. So knowing what it does at all - helps. You ain't gonna overspeed one on any street car. Overheat, underlubricate, yes. > Regardless of the practical need/outcome - I'd still be interested to > see what sort of revs the damn thing actually does 60K to 120K rpm > > In the higher HP areas the T/C is more switched on and off by TPS changes > >then feathering into anyway. Using an accurate MAP/MAF is all that is > >needed, nice additional info is IAT, Water Injection, and better tuning. > Sorry - whats IAT ? Intake Air Temp.. > > What would be neat is an auxillary method of driving up EGTs for T/C > >operation without being at the expense of engine components. But, for that > >you'd really even need to make it transistional so that when TPS changed > >there wasn't a drop, or the bog would put your nose against the windsheild. > Sorry again - EGT ? - Equivalent to Exhaust Gas Recirculation (Transfer ?) Exhuast Gas Temperature > > There are just some designs that reguire compromise. > Yeah true, though with 1GigaHertz DSP's from TI and other smarts, ones > wish lists of avoiding compromises gets longer and longer but at the > expense of our pockets - we can still speculate (fancy name for dream ;-) Processor speed ain't an issue. An engine is sooo slowww in operating speed. Even slower is the human mechanism operating the whole deal. Wounldn't it be more productive thou to think about what can be improved upon, rather then worring about say making something with some something that doesn't exist?. ie, a zero mass set of "wheels" for a turbo. Grumpy - ---------------------------------------------------------------------------- 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: Thu, 09 Mar 2000 16:37:25 +0200 From: Nic van der Walt Subject: Turbo speed sensor > > >I agree that measuring the turbo speed and backpressure is best ,if you > >know the speed and accleration of the turbo you know where its heading > >in advance. > > I really would like to do a turbo speed sensor - so far no reply from > the emails I've sent out to distributors - not even a "we don't do it" :( What could work for a turbo speed sensor is strapping a microphone to it and listening to the frequency it screams at. A wideband knock sensor would work well. On my bike I can clearly hear the turbo sweeping through the frequencies as it speeds up. N. - ---------------------------------------------------------------------------- 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: Wed, 8 Mar 2000 07:49:16 -0700 From: "Andrew Hunter" Subject: Fuel Injector Bench - Rheostats Revisited Has anyone on the list built this bench? My question is that there is a discrepancy between the schematic and the parts list with respect to what rheostats to use. The schematic shows 20w rheostats for the injector controls but the parts list shows 12.5w rheostats. I just want to make sure I use the correct ones. Any help would be greatly appreciated. Andrew - ---------------------------------------------------------------------------- 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: Wed, 8 Mar 2000 08:50:05 -0600 From: "Clint S." Subject: re: Crank trigger This is a multi-part message in MIME format. - ------=_NextPart_000_0015_01BF88DB.4C8D3080 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Thank you to those who responded . I should have been a bit clearer when posting question . I have the = nissan turbo motor originally equipped with a 3 pickup Hall sensor and = (3) 120deg signal teeth and (90) 1 degree signal teeth . Rather than = adapting this to my Accel DFI, I put in a normal magnetic pickup = distributor and used a 1988 chev truck 4 wire EST igntion control module = . The module hooked right up to the DFI and registered rpm . At this = point the ignition and fuel should work, crank trigger is not used at = this point . Later on I want to go to Coil Packs and use the original crank trigger . = I have been reading up on the Buick GN systems and they use a simular = system on the MPFI . It uses the (3) 120deg signals, and uses 1 tooth to = set up TDC . It looks like the Nissan had way better resolution, I don't = know if the old ECU could react that fast . If read Clay's post = correctly I need the (3)120deg signals and the (1) TDC synchronizing = signal from the crank sensor .=20 Thank you for the help, my ears are open on this subject . Clay nailed it on the head, wrote <<<<<< Oh, you're referring to the crank sensor. And wondering about converting = an Accel DFI/dizzy combo to DIS? (if I read you're post right). I think your = Accel brain only wants the 120 degree signals. Sequential FI requires cam position, = but DIS will be happy with the TDC signal from the wide pulse from the crank = trigger. Waste spark coils firing on exhaust anyway. You'll still need to sort = the ignition output from the Accel into a 3 channel signal, and drive coils. Many OEM = "modules" do this, I mention the Ford EDIS because it is common here in the US, = and easily adaptable. Not sure if I'm speaking to your question, or not. - - - Clay <<<<<<<<<<< =20 - ------=_NextPart_000_0015_01BF88DB.4C8D3080 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Thank you to those who responded .
I should have been a bit clearer when posting = question . I=20 have the nissan turbo motor originally equipped with a 3 pickup Hall = sensor and=20 (3) 120deg signal teeth and (90) 1 degree signal teeth . Rather than = adapting=20 this to my Accel DFI, I put in a normal magnetic pickup distributor and = used=20 a 1988 chev truck 4 wire EST igntion control module . The module = hooked=20 right up to the DFI and registered rpm . At this point the ignition and = fuel=20 should work, crank trigger is not used at this point .
 
Later on I want to go to Coil Packs and use the = original=20 crank trigger . I have been reading up on the Buick GN systems and = they =20 use a simular system on the MPFI . It uses the (3) 120deg signals, and = uses=20 1 tooth to set up TDC . It looks like the Nissan had way better=20 resolution, I don't know if the old ECU could react that fast=20 . If read Clay's post correctly I need the (3)120deg signals and = the (1)=20 TDC synchronizing signal from the crank sensor .
 
Thank you for the help, my ears are open on this = subject=20 .
 
Clay nailed it on the head, wrote=20 <<<<<<
Oh, you're referring to the crank sensor. And = wondering about=20 converting an Accel
DFI/dizzy combo to DIS? (if I read you're post = right). I=20 think your Accel brain
only wants the 120 degree signals. Sequential = FI=20 requires cam position, but DIS
will be happy with the TDC signal from = the=20 wide pulse from the crank trigger.
Waste spark coils firing on = exhaust=20 anyway. You'll still need to sort the ignition
output from the Accel = into a 3=20 channel signal, and drive coils. Many OEM "modules"
do this, I = mention the=20 Ford EDIS because it is common here in the US, and=20 easily
adaptable.

Not sure if I'm speaking to your question, = or=20 not.

- -=20 Clay
<<<<<<<<<<<
  - ------=_NextPart_000_0015_01BF88DB.4C8D3080-- - ---------------------------------------------------------------------------- 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: Wed, 8 Mar 2000 09:59:33 -0500 From: "nacelp" Subject: Re: Fuel Injector Bench - Rheostats Revisited Have I built the bench, no. However, tinkering with electronics as I do, I'd always go for the higher wattage devise, so that in the future, it's not a limiting factor. Never can tell where paths are going to lead you Grumpy > Has anyone on the list built this bench? My question is that there is a discrepancy between the schematic and the parts list with respect to what rheostats to use. The schematic shows 20w rheostats for the injector controls but the parts list shows 12.5w rheostats. I just want to make sure I use the correct ones. > Any help would be greatly appreciated. > > Andrew > -------------------------------------------------------------------------- - -- > 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: Wed, 08 Mar 2000 23:38:10 From: "Mike (Perth, Western Australia)" Subject: Re: AFM measurement/backpressure (was Turbo speed sensor) At 09:38 AM 8/03/2000 -0500, you wrote: >You ain't gonna overspeed one on any street car. Overheat, underlubricate, >yes. OK - hope so - but I was interested in injecting water in the exh manifold as an anti-lag measure, without some feedback and flakey bleed valve I'd just be unsure where I'm heading etc. >> Regardless of the practical need/outcome - I'd still be interested to >> see what sort of revs the damn thing actually does > >60K to 120K rpm mmm OK :) >> Yeah true, though with 1GigaHertz DSP's from TI and other smarts, ones >> wish lists of avoiding compromises gets longer and longer but at the >> expense of our pockets - we can still speculate (fancy name for dream ;-) > >Processor speed ain't an issue. Well I think it is - for a reliable realtime o/s and scheduler its helpful to have lots of grunt - given the typical overhead a really good o/s introduces into the overall responsiveness. With a faster processor there are so many more exception conditions you can operate on in dynamic conditions. Sure lazy AFM to injector translation with correction from engine temp etc doesn't need a 10Mhz cpu - a simple 1Mhz 68705R3 will do nicely - but once you start adding high speed sensors or at least expect to provide cleverer filtering algorithms - such as kalman filters and all the related conditions then the faster the processor the reduced chance you have of a scheduling bind at really high rpms. > An engine is sooo slowww in operating >speed. Even slower is the human mechanism operating the whole deal. Yeah sure, I also had in mind that such a high speed processor might provide extensions not normally found in embedded EFI's or not at all practical at moment due to such lack of memory and cpu speed. >Wounldn't it be more productive thou to think about what can be improved >upon, rather then worring about say making something with some something >that doesn't exist?. Keh ? a. I'm not actually embarking on any design to use a 1Gig DSP CPU If however you were looking at a high end commercial product then now would be the time to consider what *will* be available in mass production within your development timeframe 6 to 12months. b. Actually theres a 2400 mips engine (1.5v) available (samples now) rising to 5000 mips (at least the roadmap says so;) by year end. Besides there's nothing wrong with thinking ahead. You and others should start getting worried if I ask about stripline transmission from my AFM to individual injector CPUs and Firewire to the dash instruments ;-) *grin* :) Mike - ---------------------------------------------------------------------------- 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: Thu, 9 Mar 100 00:01:04 +0800 (WST) From: Bernd Felsche Subject: Re: AFM measurement/backpressure (was Turbo speed sensor) Mike writes: >At 08:15 PM 7/03/2000 +0100, you wrote: >>What I tryed to say was that the AFM cant give info for the retard of >>ignition advance that the backpressure is indicating. >OK - I understand now, the backpressure affects ignition timing but the >AFM still manages to report actual air flow - over time as it were. >I suppose in those conditions a simple pressure sensor off the exhaust >before the turbo would be OK. >ie Short (cooled) piece of pipe to carefully mounted sensor. Most pressure sensors will handle only about 180C. Cooling the pipe reduces the pressure as far as I know; you need to know the amount of cooling (temperature sensors?) to determine the actual backpressure. That's a bit more number crunching than you might want to do. Even then, the pressure you determine will be the pressure at some time in the past - that might be as long as 10 milliseconds ago. You almost certainly will not see the pulsations resulting from the opening and closing of valves. >The speed wouldn't be much of an issue for this reason. Once its installed >and calibrated then the conditions which lead to a immediate ignition >retard can be 'pre-emptive' ie. a differentiator off the pressure sensor >could initiate an interrupt for immediate retard by a set number of >degrees - or even better, the differentiator sets the interrupt pulse >width depending on rate of 'upward' change of pressure in exh before turbo. The condition which is being avoided is that of knock. A knock sensor is apparently out of the question to aid in learning the engine's response under a range of conditions. It is theoretically possible that a single knock event can destroy a fragile engine. However, you don't need to run the engine to severe knock conditions, and once you've learnt the response, you can use that to avoid the knock condition by a safe, but minimal margin. An alternative may be to build pressure sensors into the head of the engine; those devices must exist (presumably you could buy them if you had the money). Another option may be to monitor the speed of deflection of the crankshaft - the knock pressure will cause the angular velocity to exhibit a characteristic "jitter". You won't be able to measure that easily at the flywheel end - the inertia will "squelch" the jitter, but a measurement at the other end could be worthwhile if there are no inertial loads there. A PLL-type logic could be used to detect the jitter from a "crank-angle" sensor if the resolution were high enough. Of course, that's an empirical approach... The exhaust backpressure determines the internal exhaust gas recirculation and hence the remaining displacement to be filled with fresh mixture. That's the air-fuel ratio - remembering that the two differ by about 400C (if not more) in temperature, making for a more volatile mixture (hence the need to retard with more EGR). At high speed, we can consider the two gas mixtures to be stratified; they won't change significantly in volume, nor will they mix to a significant degree. We can measure "exactly" how much fresh mixture enters the cylinder by measuring the flow through the inlet tract, but only if the exhaust valve has already closed. What we need for that is a high-speed differential pressure sensor and two pressure taps ahead of the inlet valve. The inlet temperature is fairly constant and we should already know what this is for calculating the amount of fuel to inject... If there's an exhaust valve overlap with inlet, and we don't know the exhaust backpressure, then we must measure if the overlap causes exhaust to be drawn back into the cylinder, or if a significant portion of the fresh mixture is being "scavenged" into the exhaust. Enter your trusty O2 sensor. You need it to react fast enough to detect a rise in O2 after the exhaust valve to indicate scavenging, or to remain "level" indicating only exhaust gases downstream of the exhaust valve (obtaining such a sensor's a problem for higher engine speeds). Even knowing the mean exhaust backpressure wouldn't be sufficient on it's own to determine the degree of EGR. Flow dynamics of the exhaust valve closing will often result in a disproprotionately-high exhaust flow for the closing valve as the columns of exhaust gas "sucks" harder through the diminishing opening. Any exhaust gases actually drawn back will add to the base EGR of the engine and will be "cancelled out" by a reduced fresh mixture intake. We can still calculate the AFR based on our knowledge of volumetric efficiency of the engine. Prior testing with the engine will indicate appropriate ignition timing to avoid knock at a particular AFR for a specific load/boost. - -- 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 ------------------------------ End of DIY_EFI Digest V5 #91 **************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. 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