DIY_EFI Digest Wednesday, 18 June 1997 Volume 02 : Number 207 In this issue: RE: Whipple (AutoRotor) Compressor RE: Whipple (AutoRotor) Compressor RE: Whipple (AutoRotor) Compressor GM TB injector questions, HELP! Re: GM TB injector questions, HELP! Re:Auto trans, was- Whipple (AutoRotor) Compressor Re: Whipple (AutoRotor) Compressor Re: GM TB injector questions, HELP! Re: GM TB injector questions, HELP! Re: GM TB injector questions, HELP! Re: GM TB injector questions, HELP! Re: Ignition Coil Drive Circuit Re: Ignition Coil Drive Circuit Re: Ignition Coil Drive Circuit RE: GM TB injector questions, HELP! RE: Ignition Coil Drive Circuit RE: GM TB injector questions, HELP! Fuel regulator to fit ACCEL Fuel rail Re: GM TB injector questions, HELP! See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: Frederic Breitwieser Date: Tue, 17 Jun 1997 06:46:19 -0400 Subject: RE: Whipple (AutoRotor) Compressor > Now Jim, this is obvious baiting here. I'm sure what he meant to say was > that reprogramming the valve body, increasing the line pressure, and Yes Jonny, that's exactly what I was thinking... however I sure didn't type it!!!! > sometimes you just have to read "intuitively" ;) Yes, that's true :) Frederic Breitwieser Homebrew Automotive Mailing List Website: http://members.aol.com/fjb203/index.htm Email: frederic.breitwieser@xxx.com Bridgeport, Connecticut ------------------------------ From: Frederic Breitwieser Date: Tue, 17 Jun 1997 06:45:35 -0400 Subject: RE: Whipple (AutoRotor) Compressor Hey Jim! > > make the vehicle shift "quicker", which reduces the catch time on the > > little dog clutches in the auto transmission, so they last longer. > I have never seen any of these little dog clutches. Please tell me more. A dog clutch is two metal plates that have mating "teeth", and when pushed together, they "mate" better than two flat surfaces. Detriot Lockers (I think) have them, not automatic transmissions. I was responding to your message while chugging coffee getting ready for the train. :) Frederic Breitwieser Homebrew Automotive Mailing List Website: http://members.aol.com/fjb203/index.htm Email: frederic.breitwieser@xxx.com Bridgeport, Connecticut ------------------------------ From: John Hess Date: Tue, 17 Jun 1997 09:26:09 -0500 Subject: RE: Whipple (AutoRotor) Compressor Hey, guys (and a doll or two)... This is not the whiffle supercharger group, nor is it the automatic transmission discussion group. Let's hear from someone with something to contribute regarding efi (the title of the group). - ---------- From: Frederic Breitwieser[SMTP:frederic.breitwieser@xxx.com] Sent: Tuesday, June 17, 1997 5:46 AM To: 'diy_efi@xxx.edu' Subject: RE: Whipple (AutoRotor) Compressor Hey Jim! > > make the vehicle shift "quicker", which reduces the catch time on the > > little dog clutches in the auto transmission, so they last longer. > I have never seen any of these little dog clutches. Please tell me more. A dog clutch is two metal plates that have mating "teeth", and when pushed together, they "mate" better than two flat surfaces. Detriot Lockers (I think) have them, not automatic transmissions. I was responding to your message while chugging coffee getting ready for the train. :) Frederic Breitwieser Homebrew Automotive Mailing List Website: http://members.aol.com/fjb203/index.htm Email: frederic.breitwieser@xxx.com Bridgeport, Connecticut ------------------------------ From: Greg Woods Date: Tue, 17 Jun 1997 10:56:22 -0500 Subject: GM TB injector questions, HELP! Well I finished my carb to TBI conversion on my 86 chevy 2.8l last night. Double checked everything and turned the key hoping to hear the engine spring to life. But alas, it was not to be... so now I have questions! I put a DMM (I have a cheesy little Radio shack analog meter) on the injector leads, cranked the starter and the meter seemed to move to about 2 Volts. I know that the injectors are pulse width modulated, and at start up I expected the reading to be closer to 12V. Their is a high pulse width at start up right? the DMM should integrate the signal and show around 12V, right??? The throttle body (w/ injectors) was purchased from a junkyard. I hosed the thing off good with carb cleaner and put a rebuild kit in. New seals and filter screens around the injectors. Could the injector solenoid be stuck? How common is it for these injectors to go bad?? I see no evidence of fuel being sprayed into the throttle body when I crank the starter, I don't smell it or see a trace of it. Is it the injectors, or the computer... HELP!!:) TIA as usual Greg Woods gwoods@xxx.com austin, tx ------------------------------ From: cloud@xxx.edu (Tom Cloud) Date: Tue, 17 Jun 1997 11:47:05 -0500 Subject: Re: GM TB injector questions, HELP! >Well I finished my carb to TBI conversion on my 86 chevy 2.8l last night. >Double checked everything and turned the key hoping to hear the engine >spring to life. But alas, it was not to be... so now I have questions! > >I put a DMM (I have a cheesy little Radio shack analog meter) on the >injector leads, cranked the starter and the meter seemed to move to about 2 Volts. >I know that the injectors are pulse width modulated, and at start up I expected >the reading to be closer to 12V. Their is a high pulse width at start >up right? the DMM should integrate the signal and show around 12V, right??? you'd probably do better with the analog meter - you have a variable pulse width .... at full pulse width you should see 12 volts (this assumes you don't have a system that puts a large initial pulse to open the injector and then a smaller hold current), but at lower pulse widths, you can expect to see a lower joltage. - the meter will read from 0 to 100%, where 100% is 12 volts (that's how an analog tachometer works) -- (once again, this assumes your driver is putting out 12 volts or zero and not some other value like many do) - if you want to make it read 0 to 100% regardless of the type of injector driver you have, you need a "signal conditioner" circuit. You want something that senses when the injector is getting current -- any current -- and gives a digital, on or off signal as an output. A simple BJT or FET switch will do this. Then you can calibrate the output to drive your meter to full scale (or to a "1" or "10") on your meter for 100% so you can more easily read pulse width. >The throttle body (w/ injectors) was purchased from a junkyard. I >hosed the thing off good with carb cleaner and put a rebuild kit in. New >seals and filter screens around the injectors. Could the injector solenoid >be stuck? How common is it for these injectors to go bad?? > >I see no evidence of fuel being sprayed into the throttle body when >I crank the starter, I don't smell it or see a trace of it. Is it >the injectors, or the computer... HELP!!:) > >TIA as usual > >Greg Woods >gwoods@xxx.com >austin, tx dang Greg, you're here with me .... I'm at 223-4849 Tom Cloud ------------------------------ From: Aron Travis Date: Tue, 17 Jun 1997 11:48:45 -0700 Subject: Re:Auto trans, was- Whipple (AutoRotor) Compressor Johnny wrote: > I'm sure what he meant to say was > that reprogramming the valve body, increasing the line pressure, and > defeating the accumulator allows the bands and clutch packs to be > applied quicker, which usually reduces wear on those friction surfaces, And reduces heat, which will kill a autotrans. Increasing line pressure can reduce frothing of the oil too- bad lubricating properties of air and oil. - -Aron Travis- "always in a automotive frenzy" ------------------------------ From: Barney Ward Date: Tue, 17 Jun 1997 12:56:01 -0400 Subject: Re: Whipple (AutoRotor) Compressor John Hess wrote: > > Hey, guys (and a doll or two)... > > This is not the whiffle supercharger group, nor is it the automatic > transmission discussion group. Let's hear from someone with something > to contribute regarding efi (the title of the group). > > ---------- > From: Frederic Breitwieser[SMTP:frederic.breitwieser@xxx.com] > Sent: Tuesday, June 17, 1997 5:46 AM > To: 'diy_efi@xxx.edu' > Subject: RE: Whipple (AutoRotor) Compressor > > Hey Jim! > > > > make the vehicle shift "quicker", which reduces the catch time on > the > > > little dog clutches in the auto transmission, so they last > longer. > > > I have never seen any of these little dog clutches. Please tell me > more. > > A dog clutch is two metal plates that have mating "teeth", and when > pushed > together, they "mate" better than two flat surfaces. Detriot Lockers > (I > think) have them, not automatic transmissions. I was responding to > your > message while chugging coffee getting ready for the train. :) > > Frederic Breitwieser > Homebrew Automotive Mailing List > Website: http://members.aol.com/fjb203/index.htm > Email: frederic.breitwieser@xxx.com > Bridgeport, Connecticut I agree with Mr. Hess, let's discuss fuel injection, and besides, I would rather Have a Cat clutch. Detroit Redwings have these... ------------------------------ From: peter paul fenske Date: Tue, 17 Jun 1997 10:14:05 -0700 (PDT) Subject: Re: GM TB injector questions, HELP! Hi Greg Make sure ya got fuel pressure. You may have to prime the pump with the prime lead hangin from the relay or on the aldl connector. Let it run for a bit to circulate fuel.. A can or two of injector cleaner in the gas tank would prob also help. As the injectors might have been sitting too long and gotten lazy. If all else fails quickstart in moderation. Unplug the CTC if you really want to richen up the mix. Gl:peter At 10:56 AM 6/17/97 -0500, you wrote: >Well I finished my carb to TBI conversion on my 86 chevy 2.8l last night. >Double checked everything and turned the key hoping to hear the engine >spring to life. But alas, it was not to be... so now I have questions! > >I put a DMM (I have a cheesy little Radio shack analog meter) on the >injector leads, cranked the starter and the meter seemed to move to about 2 Volts. >I know that the injectors are pulse width modulated, and at start up I expected >the reading to be closer to 12V. Their is a high pulse width at start >up right? the DMM should integrate the signal and show around 12V, right??? > >The throttle body (w/ injectors) was purchased from a junkyard. I >hosed the thing off good with carb cleaner and put a rebuild kit in. New >seals and filter screens around the injectors. Could the injector solenoid >be stuck? How common is it for these injectors to go bad?? > >I see no evidence of fuel being sprayed into the throttle body when >I crank the starter, I don't smell it or see a trace of it. Is it >the injectors, or the computer... HELP!!:) > >TIA as usual > >Greg Woods >gwoods@xxx.com >austin, tx > > ------------------------------ From: peter paul fenske Date: Tue, 17 Jun 1997 10:15:28 -0700 (PDT) Subject: Re: GM TB injector questions, HELP! HI Again Greg.. In the TBI application also make sure you hooked up the start signal to the ecm. If you didn't you will get the symtoms you describe. CU:peter ------------------------------ From: Kurt Bilinski Date: Tue, 17 Jun 1997 10:25:21 -0700 Subject: Re: GM TB injector questions, HELP! At 10:56 AM 6/17/97 -0500, you wrote: >I put a DMM (I have a cheesy little Radio shack analog meter) on the >injector leads I'm impressed you got as far as you did with a pointer meter. I know you don't want to hear this but to work with EFI, you really should have a scope. Beg or borrow one. They are more useful then any meter. > Their is a high pulse width at start >up right? the DMM should integrate the signal and show around 12V, right??? > It does integrate but much too slowly to be of any use here. Get a scope. >The throttle body (w/ injectors) was purchased from a junkyard. I >hosed the thing off good with carb cleaner and put a rebuild kit in. New >seals and filter screens around the injectors. Could the injector solenoid >be stuck? How common is it for these injectors to go bad?? It's unlikely they all stuck at the same time. > >I see no evidence of fuel being sprayed into the throttle body when >I crank the starter, I don't smell it or see a trace of it. Is it >the injectors, or the computer... HELP!!:) Start at the beginning. What is the fuel pressure? Is it correct? Is gas getting to the injector inlets? Try pulsing (manually) the 12V to the injectors which should force them open. Do you get fuel? Just pulse them briefly as to not overheat them, and be darn careful of gasoline fumes. Boom! What triggers the injectors? Is the crank or distributer sensor working. Use the scope to varify. I gotta get back to work, good luck. Kurt ------------------------------ From: "steve ravet" Date: Tue, 17 Jun 1997 14:29:07 +0000 Subject: Re: GM TB injector questions, HELP! > Well I finished my carb to TBI conversion on my 86 chevy 2.8l last > night. Double checked everything and turned the key hoping to hear > the engine spring to life. But alas, it was not to be... so now I > have questions! > > I put a DMM (I have a cheesy little Radio shack analog meter) on the > injector leads, cranked the starter and the meter seemed to move to > about 2 Volts. I know that the injectors are pulse width modulated, > and at start up I expected the reading to be closer to 12V. Their > is a high pulse width at start up right? the DMM should integrate > the signal and show around 12V, right??? > > The throttle body (w/ injectors) was purchased from a junkyard. I > hosed the thing off good with carb cleaner and put a rebuild kit in. > New seals and filter screens around the injectors. Could the > injector solenoid be stuck? How common is it for these injectors to > go bad?? > > I see no evidence of fuel being sprayed into the throttle body when > I crank the starter, I don't smell it or see a trace of it. Is it > the injectors, or the computer... HELP!!:) Is the ECM alive at all? When you turn the key on, the check engine light should come on, then go off. If you short pins A&B on the diagnostic connector and turn the key on (not start) then you should at least see the check engine light flash a code 12, maybe some others. If that doesn't happen make sure the ECM is connected right, has power, etc. Then make sure you have fuel pressure. I think there's a schraeder valve somewhere (fuel rail?) that you can connect a pressure gauge to. Turn the key on, and push the deally in and see if fuel squirts out. If there's no gas then put your voltmeter on the line to the fuel pump. when you first turn the key on, you should see the ECM turn the pump on for a few seconds, then turn it off. It should come on again while you are cranking. If everything is ok up to this point your injectors may be bad. you can try jumpering them to 12v to see if they spray, but like someone else said be careful. If you want it to run for a few seconds, pour a little gas (1/2 cup or so) on the air filter and install it, then crank. That should allow it to start and run for a few seconds. good luck, I've got a DVM and I'm here in Austin if you want to borrow it. there is gas in the tank, right??? :-) - --steve ------------------------------ From: "David C. Carlson" Date: Tue, 17 Jun 1997 16:13:10 -0500 Subject: Re: Ignition Coil Drive Circuit I have observed that ignitions with transistor or mosfet drivers for the coil do not have a capacitor (condenser) in shunt with the driver like the old-fashioned points, condenser and coil system. I realize that the switching times would be slowed by the addition of the capacitor. I always thought the L-C resonance increased the spark energy and duration. Is the coil current collapse sufficient for spark generation? I am looking for comments. Dave ------------------------------ From: "Tony Bryant" Date: Wed, 18 Jun 1997 10:48:17 +1200 Subject: Re: Ignition Coil Drive Circuit > Date: Tue, 17 Jun 1997 16:13:10 -0500 > From: "David C. Carlson" > To: diy_efi@xxx.edu > Subject: Re: Ignition Coil Drive Circuit > Reply-to: diy_efi@xxx.edu > I have observed that ignitions with transistor or mosfet drivers for the > coil do not have a capacitor (condenser) in shunt with the driver like > the old-fashioned points, condenser and coil system. I realize that the > switching times would be slowed by the addition of the capacitor. I > always thought the L-C resonance increased the spark energy and > duration. Is the coil current collapse sufficient for spark generation? > > I am looking for comments. > > Dave Well the way I see it is: The energy in the cap is 1/2*C*V*V = 1/2*.22*10e-6*12*12= 16uJ Energy in coil is 1/2*L*I*I = 1/2*.01*3*3= .45J Assume coil primary L is 10mH (I can't remember exactly...), but the point (no pun intended) is that the cap contributes virtually nothing energy wise to the system. Its use in points, as far as I can see is to lower the peak of and slow down the inductive kick back, so the points don't arc. It could be used to help protect the transistor in a similar manner, but zeners do a more accurate job. Remember the higher you can let your coil primary (-ve terminal) get to, the higher the peak secondary voltage will be - they are proportinally related (k~=100 on normal coils). As for multi sparking, well maybe it'll help, but why not ensure it happens properly on the first try? BTW, has anybody experimented with building a say 12V->24V 10A dc convertor to power the coil with? Think of all that energy - arc weld with your spark plugs :-) The coil may need heatsinking though... 10A * 24V * .5 duty cycle = 120W - ouch! $$$ MAKE CAR FAST $$$ bryantt@xxx.nz ------------------------------ From: Sandy Date: Tue, 17 Jun 1997 17:35:11 -0700 Subject: Re: Ignition Coil Drive Circuit I was thinking of something similar, but decided that I would try to focus on finishing off the EFI system first. A good place to start for 12V to What ever supplies are in some of the mid priced Auto audio amps that has a nice PWM supply, they put out a bunch of power, and have a nice case. I have seen some pretty small ones in a magazine, that did something like 58 volts at 8 amps. It was not very large and looked prety simple. Sandy At 10:48 AM 6/18/97 +1200, you wrote: >BTW, has anybody experimented with building a say 12V->24V 10A >dc convertor to power the coil with? Think of all that energy - arc >weld with your spark plugs :-) > >The coil may need heatsinking though... 10A * 24V * .5 duty cycle = >120W - ouch! ------------------------------ From: Frederic Breitwieser Date: Tue, 17 Jun 1997 19:41:51 -0400 Subject: RE: GM TB injector questions, HELP! Hey George! > At 10:56 AM 6/17/97 -0500, you wrote: > >I put a DMM (I have a cheesy little Radio shack analog meter) on the > >injector leads A meter, digital or analog has a sampling time associated with it. DMM's are typically a few times a second, and analog meters depend on how much the needle/pointer weighs. The only realy way to do this is with an occilloscope, spelling not included. I bought one used a few years back for $20, which only goes to 5Mhz, which is great for automotive applications. Computers, Nah. > > Their is a high pulse width at start > >up right? the DMM should integrate the signal and show around 12V, > >right??? Yes, but its still too fast for any kind of meter... an occiliscope will help you out tremendously. For example, at 1000 RPM, each cylinder fires twice, which means you have 500 pulses per minute divided by six cylinders, which translates to 125 pulses per minute. Meters just don't cut it... still way to fast. That's assuming the injectors are open during the intake cycle, and not modulated, which someone else could answer better than I. If its modulated, you have several sharp pulses per cycle. > >solenoid > >be stuck? How common is it for these injectors to go bad?? Did you check all of them? Or just the cylinder closest to you? What's the chances of six being bad? I have heard that injectors that sit for long periods of time after use tend to corrode somewhat. Its my understanding that the gasoline, as obnoxious as it is, keeps them clean. > >I see no evidence of fuel being sprayed into the throttle body when > >I crank the starter, I don't smell it or see a trace of it. Is it > >the injectors, or the computer... HELP!!:) I would check the crank sensor, which on your engine (and mine) is a magnetic hall sensor, if you rotate the engine with a large pry bar and socket on the flywheel, it should pulse several times per rotation. Also, make sure the computer is getting 12-13V, excessive cranking kills the battery quickly as you know, and computers generally don't work well in undervoltage situations. Next, I would measure voltages along the spark plug wires (wear gloves), just to double check that has voltage too... make sure all your grounds are good, and your computer is grounded as well. Lastly, make sure your fuel is getting into the injector rail, and there is no air sitting around. I went through some of this stuff when I started my 3.8L on the engine crane. But I got it. My issue was the computer wasn't grounded correctly. Frederic Breitwieser Homebrew Automotive Mailing List Website: http://members.aol.com/fjb203/index.htm Email: frederic.breitwieser@xxx.com Bridgeport, Connecticut ------------------------------ From: "Michael F. Sargent" Date: Wed, 18 Jun 97 01:51:01 UT Subject: RE: Ignition Coil Drive Circuit MSD ignitions put out over 400 volts to the primary of the coil (really!). Nice hot spark! Make arm move very fast! Mike - ---------- From: owner-diy_efi@xxx.edu on behalf of Sandy Sent: Tuesday, June 17, 1997 20:35 PM To: diy_efi@xxx.edu Subject: Re: Ignition Coil Drive Circuit I was thinking of something similar, but decided that I would try to focus on finishing off the EFI system first. A good place to start for 12V to What ever supplies are in some of the mid priced Auto audio amps that has a nice PWM supply, they put out a bunch of power, and have a nice case. I have seen some pretty small ones in a magazine, that did something like 58 volts at 8 amps. It was not very large and looked prety simple. Sandy At 10:48 AM 6/18/97 +1200, you wrote: >BTW, has anybody experimented with building a say 12V->24V 10A >dc convertor to power the coil with? Think of all that energy - arc >weld with your spark plugs :-) > >The coil may need heatsinking though... 10A * 24V * .5 duty cycle = >120W - ouch! ------------------------------ From: "Michael F. Sargent" Date: Wed, 18 Jun 97 01:58:41 UT Subject: RE: GM TB injector questions, HELP! Hey Fred! Your reality cheque bounced. :-) Yes, but its still too fast for any kind of meter... an occiliscope will help you out tremendously. For example, at 1000 RPM, each cylinder fires twice, which means you have 500 pulses per minute divided by six cylinders, which translates to 125 pulses per minute. Meters just don't cut it... still way to fast. That's assuming the injectors are open during the intake cycle, and not modulated, which someone else could answer better than I. If its modulated, you have several sharp pulses per cycle. OK. At 1,000 RPM, the crank rotates 1,000 times per minute. On a four stroke engine each cylinder fires every second revolution, so there will be 500 power strokes per minute per cylinder. Since this is a six cylinder engine, that means there will be 3,000 ignition events per minute (or 50 per second). Determining how many injection events per minute will require knowing what type of EFI system it is (i.e., gang injection would probably fire each injector 1,000 times per minute, while sequential would only fire 500 times per minute (per cylinder). Mike ------------------------------ From: triad@xxx.net (William Moffitt) Date: Tue, 17 Jun 1997 11:18:06 -0700 Subject: Fuel regulator to fit ACCEL Fuel rail Greetings All, A question for anyone who might be using the "D" shaped aluminum fuel rail sold by ACCEL. Has anyone successfully mounted a fuel regulator directly to the rail? Did you have to make brackets or is there something out there in auto land that can be purchased. Many thanks, Bill ------------------------------ From: pantera@xxx.com (David Doddek) Date: Tue, 17 Jun 1997 23:22:58 -0500 (CDT) Subject: Re: GM TB injector questions, HELP! Greg wrote: >Well I finished my carb to TBI conversion on my 86 chevy 2.8l last night. >Double checked everything and turned the key hoping to hear the engine >spring to life. But alas, it was not to be... so now I have questions! > >I put a DMM (I have a cheesy little Radio shack analog meter) on the >injector leads, cranked the starter and the meter seemed to move to about 2 Volts. This would be a normal voltage to see. as the are actually only on for a short period of time at cranking or any other speed. The only time you would actually see 12 volts would be at full throttle at max revs. And NO, the volt meter does not integrate, it does an Average. >I know that the injectors are pulse width modulated, and at start up I expected >the reading to be closer to 12V. Their is a high pulse width at start >up right? the DMM should integrate the signal and show around 12V, right??? > >The throttle body (w/ injectors) was purchased from a junkyard. I >hosed the thing off good with carb cleaner and put a rebuild kit in. New >seals and filter screens around the injectors. Could the injector solenoid >be stuck? How common is it for these injectors to go bad?? > >I see no evidence of fuel being sprayed into the throttle body when >I crank the starter, I don't smell it or see a trace of it. Is it >the injectors, or the computer... HELP!!:) > >TIA as usual > >Greg Woods >gwoods@xxx.com >austin, tx > > Injectors from junk yards tend to sit around a lot. I have bought throttle bodies before from the yards and had the injectors stuck. Using very carefull methods of pressing on the pintle tip or using a rod to press on the injector disk. Also make sure you are getting fuel pressure at the injector. For throttle body it should be around 17psi. David Doddek pantera@xxx.com/~pantera 217-422-3722 69 EFI Fairlane, 89 T-bird SC, 74 Twin turbo NOS EFI Pantera #6825 If you are going to go fast, go real fast. ------------------------------ End of DIY_EFI Digest V2 #207 ***************************** 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".