DIY_EFI Digest Wednesday, March 31 1999 Volume 04 : Number 202 In this issue: Shutting fuel off whie driving. Re: Chip for Northstar Re: Pre + Post O2s Re: Cam Suggestions for 4x4 Ford 429 Re: Chip for Northstar Re: diy flow bench Northstar VSS Re: Camshaft Selection Re: Shutting fuel off whie driving. Re: Pre + Post O2s Re: Chip for Northstar Re: Northstar VSS Re: Shutting fuel off whie driving. Re: Pre + Post O2s See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Wed, 31 Mar 1999 13:49:48 +1000 (EST) From: Benjamin Marsh Subject: Shutting fuel off whie driving. I want to build a circuit that will cut the fuel off to the engine when I have my foot off the accelerator. ie, when going down hills there is no throttle so cut fuel completely to save fuel. Basically it will look at revs and if >say 1500rpm and throttle switch is open to say 'no throttle' and to cut the fuel supply which I will probably do by use of a relay in the ECU injector input off the -ve side of the coil. Are there any problems associated with doing this? Are there really any fuel savings associated with it? Are there any commercially available units that do the same thing? Thanks for your help Ben ------------------------------ Date: Tue, 30 Mar 1999 20:20:06 PST From: "Chris Moore" Subject: Re: Chip for Northstar Paul, That sounds like a great idea. Now, how do I make a signal generator to make the pulses that I need? Or can I do it a different way? This sounds like the last bit of the puzzle that I need to get this thing running great. I would like to make a signal generator and have a switch to it to shut it off and on so I can have traction or not have it. This should be possible. How am I able to find the pulses per mile? What exactly do I need to get and do? Thanks Chris Moore >From: Paul Tholey >Reply-To: diy_efi@xxx.edu >To: diy_efi@xxx.edu >Subject: Re: Chip for Northstar >Date: Mon, 29 Mar 1999 17:44:48 -0500 > > >I thought I heard once that the Torque Mangmnt cuts out after 18 mph. SO >if you could trick it into thinking it is always over 18 mph via the VSS >this might be a simple solution to this problem. Any thoughts? > >Just my 2c > >Paul Tholey > >At 04:06 AM 3/29/99 PST, you wrote: >>Hi, >> I have a very unique car. I have a 1987 Fiero GT with a 1995 >>Cadillac Northstar. It runs great but it will not peel out. I only >>know of about 5 of these projects in the Nation and they all have this >>problem. My engine only has 16,000 miles on it. (just for you info). I >>think that it is the Torque Management located in the PROM. Torque >>Management was to make sure you do not peel out under a heavy load >>situation. It kills injectors and plays with the timing. It is all >>explained in the GM manual. I had Super Chip try to make a chip for me >>and they said that they could take care of the problem. It still did >>not fix it. I was wondering if you guys could help me out? Please let >>me know. Thank you. >> >>Chris Moore >>ASE Master Auto Tech >>Get Your Private, Free Email at http://www.hotmail.com >> > Get Your Private, Free Email at http://www.hotmail.com ------------------------------ Date: Tue, 30 Mar 1999 23:27:04 -0500 From: "Bruce Plecan" Subject: Re: Pre + Post O2s - -----Original Message----- From: Ord Millar To: diy_efi@xxx.edu> Date: Tuesday, March 30, 1999 10:59 PM Subject: Re: Pre + Post O2s Local gm store has different part numbers for front and rear. Different basic designs, too (from application to application). Grumpy >I am pretty sure that the pre and post O2 sensors are the same part on my >car - at least I can't tell any difference externally, and may have >accidentally swapped then at one time or another. > > >-----Original Message----- >From: Bruce Plecan >To: diy_efi@xxx.edu> >Date: Tuesday, March 30, 1999 9:08 PM >Subject: Pre + Post O2s > > >>As I understand things, the cat converters are a reducing chemical >reaction, >>so >>they consum calories to react. (True or False?). >> >>The rear O2 sensor would run cooler then the front. >> >>So, the rear O2 in order to measure the effectiveness of the cat would need >>to >>operate at least at the same temp as the front. So it would need a >"better" >>heater. >> >>Since it might not track the front too well, then it's "range" would need >to >>be greater. >> >>Only have any documents to compare the above to, or does it make sense >>to someone other than me?. >>Bashful >> >> >> > ------------------------------ Date: Tue, 30 Mar 1999 21:30:51 -0700 From: "Brent W" Subject: Re: Cam Suggestions for 4x4 Ford 429 Birken asked: >I am building a Ford 429 for my 4-wheel drive truck. Basically the >major concern is maximum torque right off idle. Should I buy a >normal "torque" cam for the first stage of the build, and get a turbo >grind later? Also, I have been wondering about the suitability of an >automatic transmission with this type of power delivery. My major >intended use is super slow crawling. Would I need to change to a >different cam later if I turbocharge the engine? > Birken It would be difficult to beat the factory heavy duty truck application cam shaft for the Ford 429 engine since they were made specifically to have high low speed torque and used to pull heavy loads up steep hills. These cams were generally put into the 429 used with a 2-bbl carb and sometimes even with a speed governor for the super heavy duty trucks like the dump trucks and 2-5 ton trucks. The power curve was from 500-3500 rpm. It is a good low rpm cam which is optimized for low speed torque applications. Another option would be to use an aftermarket "torque" cam with a split duration with more duration for the exhaust and less for the intake. For a large cubic inch engine, you would want to look at a cam with the intake duration ranging from about 240 to 250 degrees with about 260 degrees exhaust duration. These cams are optimized for the 800-4000 rpm speed range. The reason that these types of cams are listed as "torque" cams is because they are designed for volumetric efficiency. This means that they try to fill the cylinders as much as possible without intermixing the intake charge with the exhaust gases and they try to extract the most power (BMEP or Brake Mean Effective Pressure) out of each combustion cycle. This is done at the expense of high rpm engine speed. These types of cams make the best cams for automatic transmissions also. These cams also do very well with turbochargers, and I wouldn't expect that you would have to change to a different cam if you decided to install a turbocharger on your engine at a later time. This advise only holds true for engines used in low rpm applications like off-roading where good low speed pulling is the predominant mode of operation of the engine. Although an on-road application where you desire good gas mileage and you travel at normal road speeds, then this same type of torque cam would be just fine also. If the engine is a small block engine, then you would want to choose a cam with a little less duration than that used in the big block engines. If you have a racing or on-road high speed application, one where you are wanting the most horsepower instead of the most torque, then you would want a different cam with longer duration and more overlap. Best of luck to you, Brent Wiscombe bwiscombe@xxx.com Mesa, AZ ------------------------------ Date: Tue, 30 Mar 1999 23:45:01 EST From: EFISYSTEMS@xxx.com Subject: Re: Chip for Northstar Me too,, - -Carl Summers In a message dated 99-03-30 12:43:36 EST, you write: << Subj: Re: Chip for Northstar Date: 99-03-30 12:43:36 EST From: romans@xxx.net (Mark Romans) Sender: owner-diy_efi@xxx.edu Reply-to: diy_efi@xxx.edu To: diy_efi@xxx.edu Yes and if anyone has the northstar docs they ought to be about 1000 pages. I would gladly pay the copying expense to get a copy too! Mark >> ------------------------------ Date: Tue, 30 Mar 1999 23:38:32 -0500 From: Shannen Durphey Subject: Re: diy flow bench ??? New info? As in... Shannen Don.F.Broadus@xxx.com wrote: > > Any new info on the flow bench ? > > > -----Original Message----- > > From: Shannen Durphey [SMTP:shannen@xxx.com] > > Sent: Wednesday, March 24, 1999 2:32 AM > > To: diy_efi@xxx.edu > > Subject: Re: diy flow bench > > > > Smokey Yunich talked about the MAF conversion in an issue of circle > > track around 92. 'Course Smokey being a perfectionist figured it > > would take more time than it's worth to calibrate it, but thought it > > would be technically possible. Don't think he looked at the ECM > > aspect of things. Now that's a guy with an original DIY flow bench. > > Shannen > > > > Bruce Plecan wrote: > > > > > > -----Original Message----- > > > From: Shannen Durphey > > > To: diy_efi@xxx.edu> > > > Date: Tuesday, March 23, 1999 9:37 PM > > > Subject: Re: diy flow bench > > > > > > He also, references the PHR articles. > > > As a second thought: > > > get an old MAF, and matching ecm, hack the diagnostics, so that it > > doesn' > > > use any default values, and hook a diacom to it. Instant accurate > > > gram/second flow rates. > > > Then if your real good you could set the MAP filtering rates. > > > Since your just doing one port the "smaller" the better (ie jus an old 4 > > > cylinder). > > > Makes me want to build one now, well maybe after I finish the ecm bench > > LOL. > > > Bruce > > > > > > >I'll bet this guy has a pretty good idea of what it takes. > > > >http://www.htrd.com/kem/flowbench/ > > > > > > > >I found the link in the archives. > > > >Shannen > > > > > > > >Matt Boland wrote: > > > >> Does anybody know if anybody has built a diy flowbench ? I had an > > idea > > > >> that you could use an electric motor with an air pump on it and > > measure > > > >> the current drawn by the motor. You could use it uncalibrated in just > > a > > > >> good, better mode or maybe you could calibrate it by flowing known > > > >> items. It would be easy to hook up a PC and have a proffesional > > looking > > > >> display. The bench part would be easy to build and you could mount > > the > > > >> motor/pump underneath. Any thoughts? ------------------------------ Date: Wed, 31 Mar 1999 00:02:59 -0500 From: Paul Tholey Subject: Northstar VSS CM, okay this is where my knowledge runs out. I am sure the rest of our friends will correct me if I am wrong. It sounds like the solution you are looking for is the one that is cheap an effective. Keeping in mind the goal is to fool the ecm that the car is running at or above 18 mph at all times, could the "wrong" VSS be used in this car? What I am imagining is...say the Caddy sees 2000 pulse per mile. if a 4000 ppm were used, might this be a simple solution. I speculate the answer to be "NO" since at 30 mph the ecm would think the car was traveling much faster, next thing you know your hitting th 112 mph fuel cutoff. Common guys, what do you think? Paul At 08:20 PM 3/30/99 PST, you wrote: >Paul, > > That sounds like a great idea. Now, how do I make a signal generator >to make the pulses that I need? Or can I do it a different way? This >sounds like the last bit of the puzzle that I need to get this thing >running great. I would like to make a signal generator and have a >switch to it to shut it off and on so I can have traction or not have >it. This should be possible. How am I able to find the pulses per >mile? What exactly do I need to get and do? Thanks > >Chris Moore > > >>From: Paul Tholey >>Reply-To: diy_efi@xxx.edu >>To: diy_efi@xxx.edu >>Subject: Re: Chip for Northstar >>Date: Mon, 29 Mar 1999 17:44:48 -0500 >> >> >>I thought I heard once that the Torque Mangmnt cuts out after 18 mph. >SO >>if you could trick it into thinking it is always over 18 mph via the >VSS >>this might be a simple solution to this problem. Any thoughts? >> >>Just my 2c >> >>Paul Tholey >> >>At 04:06 AM 3/29/99 PST, you wrote: >>>Hi, >>> I have a very unique car. I have a 1987 Fiero GT with a 1995 >>>Cadillac Northstar. It runs great but it will not peel out. I only >>>know of about 5 of these projects in the Nation and they all have this >>>problem. My engine only has 16,000 miles on it. (just for you info). >I >>>think that it is the Torque Management located in the PROM. Torque >>>Management was to make sure you do not peel out under a heavy load >>>situation. It kills injectors and plays with the timing. It is all >>>explained in the GM manual. I had Super Chip try to make a chip for >me >>>and they said that they could take care of the problem. It still did >>>not fix it. I was wondering if you guys could help me out? Please >let >>>me know. Thank you. >>> >>>Chris Moore >>>ASE Master Auto Tech >>>Get Your Private, Free Email at http://www.hotmail.com >>> >> > >Get Your Private, Free Email at http://www.hotmail.com > ------------------------------ Date: Wed, 31 Mar 1999 00:13:35 EST From: EFISYSTEMS@xxx.com Subject: Re: Camshaft Selection Hi Gwyn, What RPM do you usually tow at?????? - -Carl Summers In a message dated 99-03-15 10:31:58 EST, you write: << Subj: Camshaft Selection Date: 99-03-15 10:31:58 EST From: mgr@xxx.com (Gwyn Reedy) Sender: owner-diy_efi@xxx.edu Reply-to: diy_efi@xxx.edu To: sixtiestrucks-l@xxx.org (Sixties Truck List), diy_efi@xxx.org (CK Series List), chevelle@xxx.com (Chevelle List) I have the 402 BBC out of my 72 Cheyenne pickup torn down for a rebuild. Dang oil pump inlet fell off and the bearings got fed a mixture of oil and air... The engine is not very badly damaged. Taking the crank in today to see what it needs done to it, but it doesn't look very bad at all. The cam shows a lot of wear. Looks like the original cam with 70k miles on it. Some of the lifters are starting to get concave a bit too. The truck is used for running errands around town, and from time to time pulling a heavy trailer. The trailer is 6000 lbs empty and up to 14000 loaded. 3.08 posi rear end and THM-400. Wondering what cam to put in it. This is an oval port (passenger car type heads) with a low profile Quadrajet manifold, standard cast iron exhaust manifolds. Need low end torque, not horsepower. I'm wondering if any of these 'bottom-end torque for 4x4 off road use' cams might be a good choice or should I just put a replacement factory cam back in it? Gwyn Reedy Brandon, Florida mailto:mgr@xxx.com '72 Cheyenne half ton (driver) '69 El Camino SS396 (rebuilder) >> ------------------------------ Date: Wed, 31 Mar 1999 00:32:30 EST From: ECMnut@xxx.com Subject: Re: Shutting fuel off whie driving. Hi Ben, most efi systems do this. They 'blip' the injectors once in a while to keep the cat fed (meow) but coast down usually results in ijectors being shut off at rpms above 1500 or so. HTH. MV > I want to build a circuit that will cut the fuel off to the engine > when I have my foot off the accelerator. > ie, when going down hills there is no throttle so cut fuel completely > to save fuel. ------------------------------ Date: Wed, 31 Mar 1999 00:39:02 -0500 From: Shannen Durphey Subject: Re: Pre + Post O2s Been scratchin' at the brain... Pretty sure that pre and post O2 sensors on the 96 pickups had different part nos., and different connectors. Will try to verify in the next few days. Not saying all cars are the same. If so, may imply something. Not much of a chemist...but end product has lower HC reading, lower "fuel" content, would say lower calorie content. As far as temp of exiting gasses being lower, not sure I agree. Heh heh... call it the "burned arms" data collection system.:) Rear O2 readings are very much like tired pre-cat O2 readings. Whether or not sensor is accurate, larger peak to peak differences are a sign of a failing converter. We're not looking for stoich, just activity. Just some O2 sense worth ; ) Shannen Ord Millar wrote: > > I am pretty sure that the pre and post O2 sensors are the same part on my > car - at least I can't tell any difference externally, and may have > accidentally swapped then at one time or another. > > -----Original Message----- > From: Bruce Plecan > To: diy_efi@xxx.edu> > Date: Tuesday, March 30, 1999 9:08 PM > Subject: Pre + Post O2s > > >As I understand things, the cat converters are a reducing chemical > reaction, > >so > >they consum calories to react. (True or False?). > > > >The rear O2 sensor would run cooler then the front. > > > >So, the rear O2 in order to measure the effectiveness of the cat would need > >to > >operate at least at the same temp as the front. So it would need a > "better" > >heater. > > > >Since it might not track the front too well, then it's "range" would need > to > >be greater. > > > >Only have any documents to compare the above to, or does it make sense > >to someone other than me?. > >Bashful > > > > > > ------------------------------ Date: Wed, 31 Mar 1999 00:51:46 -0500 From: Shannen Durphey Subject: Re: Chip for Northstar Chris Moore wrote: > > Paul, > > That sounds like a great idea. Now, how do I make a signal generator > to make the pulses that I need? Or can I do it a different way? This > sounds like the last bit of the puzzle that I need to get this thing > running great. I would like to make a signal generator and have a > switch to it to shut it off and on so I can have traction or not have > it. This should be possible. How am I able to find the pulses per > mile? What exactly do I need to get and do? Thanks Exactly you need to count how many teeth are on the reluctor ring, and remember the number. Then you need to mark a line on your tire, and a corresponding line on the asphalt. Roll the car until the tire makes one complete revolution, then make another corresponding mark on the asphalt. Measure this distance to get your tire's (or tires') "rolling circumference". Measure in inches for accuracy. : ) Remember this number. There are 5,280 feet in a mile, which is 63,360 inches. Divide 63360 by your rolling circumference which will result in tire revolutions per mile. Multiply tire revs/mi and # of teeth on reluctor ring to get speed sensor pulses per mile. Exactly. Shannen > > Chris Moore > > >From: Paul Tholey > >Reply-To: diy_efi@xxx.edu > >To: diy_efi@xxx.edu > >Subject: Re: Chip for Northstar > >Date: Mon, 29 Mar 1999 17:44:48 -0500 > > > > > >I thought I heard once that the Torque Mangmnt cuts out after ------------------------------ Date: Wed, 31 Mar 1999 01:13:32 -0500 From: Shannen Durphey Subject: Re: Northstar VSS Some of the thread is missing from this post, and it wasn't clear anyway, but signal may come from wheel speed sensors for ABS, which are much higher resolution than VSS. ABS signals are usually sent to an ABS controller (well, usually is a relative term), but Cadillac is known to follow their own path, so to speak. However, one of the pitfalls of subbing signals is exactly what you're describing. In this case, if 4,000 ppm VSS is subbed for WSS, speeds will look very slow, so no problem with high speed cutoff. Big question is... is one module responsible for all portions of traction control? (I'm really unfamiliar with this Caddy system, but may be able to dig out a book tomorrow.) Shannen Paul Tholey wrote: > > CM, > okay this is where my knowledge runs out. I am sure the rest of our > friends will correct me if I am wrong. It sounds like the solution you are > looking for is the one that is cheap an effective. Keeping in mind the > goal is to fool the ecm that the car is running at or above 18 mph at all > times, could the "wrong" VSS be used in this car? > What I am imagining is...say the Caddy sees 2000 pulse per mile. if a > 4000 ppm were used, might this be a simple solution. I speculate the > answer to be "NO" since at 30 mph the ecm would think the car was traveling > much faster, next thing you know your hitting th 112 mph fuel cutoff. > > Common guys, what do you think? > > Paul > > At 08:20 PM 3/30/99 PST, you wrote: > >Paul, > > > > That sounds like a great idea. Now, how do I make a signal generator > >to make the pulses that I need? Or can I do it a different way? This > >sounds like the last bit of the puzzle that I need to get this thing > >running great. I would like to make a signal generator and have a > >switch to it to shut it off and on so I can have traction or not have > >it. This should be possible. How am I able to find the pulses per > >mile? What exactly do I need to get and do? Thanks > > > >Chris Moore > > > > > >>From: Paul Tholey > >>Reply-To: diy_efi@xxx.edu > >>To: diy_efi@xxx.edu > >>Subject: Re: Chip for Northstar > >>Date: Mon, 29 Mar 1999 17:44:48 -0500 > >> > >> > >>I thought I heard once that the Torque Mangmnt cuts out after 18 mph. > >SO > >>if you could trick it into thinking it is always over 18 mph via the > >VSS > >>this might be a simple solution to this problem. Any thoughts? > >> > >>Just my 2c > >> > >>Paul Tholey > >> > >>At 04:06 AM 3/29/99 PST, you wrote: > >>>Hi, > >>> I have a very unique car. I have a 1987 Fiero GT with a 1995 > >>>Cadillac Northstar. It runs great but it will not peel out. I only > >>>know of about 5 of these projects in the Nation and they all have this > >>>problem. My engine only has 16,000 miles on it. (just for you info). > >I > >>>think that it is the Torque Management located in the PROM. Torque > >>>Management was to make sure you do not peel out under a heavy load > >>>situation. It kills injectors and plays with the timing. It is all > >>>explained in the GM manual. I had Super Chip try to make a chip for > >me > >>>and they said that they could take care of the problem. It still did > >>>not fix it. I was wondering if you guys could help me out? Please > >let > >>>me know. Thank you. > >>> > >>>Chris Moore > >>>ASE Master Auto Tech > >>>Get Your Private, Free Email at http://www.hotmail.com > >>> > >> > > > >Get Your Private, Free Email at http://www.hotmail.com > > ------------------------------ Date: Wed, 31 Mar 1999 16:29:13 +1000 (EST) From: Benjamin Marsh Subject: Re: Shutting fuel off whie driving. Does this happen in an L-JET? Is there a way I can test the injector output while driving to see if they are being fired at coast? Ben On Wed, 31 Mar 1999 ECMnut@xxx.com wrote: > Hi Ben, > most efi systems do this. They 'blip' the injectors once in > a while to keep the cat fed (meow) but coast down usually > results in ijectors being shut off at rpms above 1500 or so. > HTH. MV > > > I want to build a circuit that will cut the fuel off to the engine > > when I have my foot off the accelerator. > > ie, when going down hills there is no throttle so cut fuel completely > > to save fuel. > ------------------------------ Date: Wed, 31 Mar 1999 02:19:48 -0500 From: Chris Conlon Subject: Re: Pre + Post O2s At 07:28 PM 3/30/99 -0500, Bruce Plecan wrote: >As I understand things, the cat converters are a reducing chemical >reaction, so they consum calories to react. (True or False?). The cat basically finishes up any incomplete burning that should have happened in the cylinder. The catalytic part of it makes the reaction(s) proceed even without an ignition source or flame. Because of this the cat produces heat, exactly like burning does, just not as much heat. (Hopefully.) Chronic misfire is hard on cats (or so I hear) because the cat has to burn up much more air/fuel than usual, and may overheat, melt, etc. A 3-way cat can react an oxidizing agent (O2 or NOx) with a reducing agent (HC or CO), hopefully yielding just CO2, H2O and N2. Or at least this is my understanding. (I'm not clear where the "3-way" comes from; I think it has to do with the exact reactions the cat can and cannot catalyze. The end result is, it "finishes up" the combustion.) Also it supposedly has a limited sponge-like storage ability to hold small amounts of excess CO, HC, O2 or NOx, so that the exhaust mixture does not have to be perfectly stoich at every moment, it just has to average out to stoich over a second or 2. Thus the whole closed loop operation we know and love. The above I'm pretty clear on, the rest of this is wild-guess land: I would think that the post-cat O2 sensor wants to see a perfectly stoich reading, or very close to it, whenever the engine ought to be in closed loop. If it shows rich or lean, I think that would indicate a rich or lean condition beyond the cat's ability to clean up, due to it being too far off stoich for too long. How far, how long, I dunno. As EGT pre and post... the cat generates some heat, maybe a *lot* in some apps. Of course it also sheds a lot too! If combustion in the cylinder was perfect, and you were stoich, the cat would generate no additional heat since there would be no fuel left over to burn. I guess it comes down to heat generated vs. heat lost, I won't even guess at that one. I agree that a really precise setup should measure EGT pre and post cat, to correct the O2 sensor readings. Let me know if anyone actually does. ;) And since I can never resist spouting, how long til we see OEs using ceramic coated manifolds to speed up cat warm up time and reduce coldstart emissions? Who's running the betting pool? ;) Chris C. ------------------------------ End of DIY_EFI Digest V4 #202 ***************************** 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".