DIY_EFI Digest Thursday, 17 October 1996 Volume 01 : Number 316 In this issue: Re: Gm Controllers Re: GM EGR carbon buildup in intake plenum? Re: Bosch Technical Info Re: Injector Fuel Flow More GM EGR GM Controllers Excellent Gasoline FAQ Re: More GM EGR Re: GM Controllers Re: Excellent Gasoline FAQ See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: txhartma@xxx.com (Terry Hartman) Date: Wed, 16 Oct 1996 07:51:22 -0500 Subject: Re: Gm Controllers > From: peter paul fenske > When a TPI vehicle is run without a cat, perhaps souped up a bit with headers > it will tend to run lean in open loop modes. These are wot and start, and warmup > modes. If you want to fix this you can enrichen the mix by increasing the > fuel pressure to about 50 PSI. Closed loop should easily handle this with > the block learn. This is EXACTLY what I had to do (set the FP to 50psi). I just had my car rear-wheel-dyno'd on a DynoJet chassis dyno and I went in with the FP set to 47. Just by turning the FP up to 50 I gained 10lb/ft of torque and like 8-10 hp.... Power was up accross the band as well... T. - -- Terry Hartman voice:(972) 519-2920 txhartma@xxx.com "Question authority, but raise your hand first." ------------------------------ From: txhartma@xxx.com (Terry Hartman) Date: Wed, 16 Oct 1996 07:47:21 -0500 Subject: Re: GM EGR > > From: Jennifer Rose > > EGR valve in this system is a negative back pressure valve. Believe EGR > depends on back pressure from exhuast system to work correctly. Since my pu > is dual exhuast with out cats, back pressure probaly nil. Just need to > increase back pressure :( or fiqure how to change valve. So don't throw your > valve away yet. I haven't looked up the code 32 yet, but on your EGR valve there should be a little "heat sensor". If the ECM commands EGR and this sensor doesn't pick-up any heat - then it thinks that the EGR valve isn't working... Accel makes a block-off plate for their intake manifolds that could be used to block off the EGR valve if you want to remove it. Then just drill and tap a hole for this heat switch into the block off plate on the hot(exhaust side) and plug the vaccuum line from the EGR solenoid. Of course, this isn't emissions legal at all... I don't know if Accel offers this block-off plate for sell separately. good luck, T. - -- Terry Hartman voice:(972) 519-2920 txhartma@xxx.com "Question authority, but raise your hand first." ------------------------------ From: agunnesc@xxx.com (Andrew Gunnesch) Date: Wed, 16 Oct 1996 15:52:11 GMT Subject: carbon buildup in intake plenum? I had the throttle body off of my GM TPI engine the other day and what did I see, but the plenum was coated in a sooty substance. What would cause this gunk to get all over in my intake tract? Would the EGR be the cause of this? andrew gunnesch ------------------------------ From: William Boulton Date: Thu, 17 Oct 1996 06:58:16 +1000 (EST) Subject: Re: Bosch Technical Info Folks, I can only give you the address in Australia. Some others may like to add the addresses for other countries. Bosch have a "Technical Service" division in most branches. In Australia contact Robert Bosch (Australia) Pty Ltd Ph (03) 9541 5555 {main switch} Fax (03)9543 4293 {Technical Service} Good luck all, Bill Boulton. On Tue, 15 Oct 1996, George M. Dailey wrote: > At 07:46 AM 10/16/96 +1000, you wrote: > >For anyone interested in a good read, > > > >Bosch do a series of small booklets on various automotive topics in a > >series they call "Technical Instruction Booklets". Very well presented and > >CHEAP (A$6.50). Titles include "Mono-Jetronic", "Engine Electronics", > >"Motronic", "L-Jetronic", etc. A BIG list and all good. > > > >Bill Boulton > > > Who sells the "Technical Instruction Booklets". > > GMD > > ------------------------------ From: William Boulton Date: Thu, 17 Oct 1996 10:15:49 +1000 (EST) Subject: Re: Injector Fuel Flow Hey! Does anyone want to know how to estimate fuel flow requirements? Please note; I said ESTIMATE. What follows is a formulae for making an initial injector selection. BHP * BSFC FlowRate = ----------------------- Inj.Count x DutyCycle where: BSFC = Brake Specific Fuel Consumption = 0.5 lbs/hp.hour (US) = 227 gms/hp.hour (SI) You'll notice that the formulae uses MASS and not volume. Gasoline (on average) has an sg of 0.73gms/cc. I'll leave it to someone else to do the conversion for US units. If anyone has access to the Bosch micro-fische on injector specs, the flow rates are in GRAMs/MINUTE and not CCs/MINUTE. As you can see, there is a big difference. In the one example of injector specs I was able to obtain (in German), the continuous (static) flow rate was quoted in gms/min and the dynamic in gms/1000. Nominal fuel pressure is 2.5 bar in all (?) cases. The specs also nominate the pulse width used in dynamic sizing (2.0 or 2.5ms). Just to clarify, heres a couple of examples of EV2 injectors (Ford CFI). They are the little stubby flow through type. Bosch PN Static Dynamic ti.ms Used in -------------------------------------------------- 0 280 150 601 513.5 21.5 2.5 (Ford USA & Holley?) 0 280 150 608 441.3 12.82 2.0 (Ford Australia) In the past, I've tried to get fuel flow specs from people who have had the micro-fische and was told "they don't mean anything". Well they won't if you don't do the conversion, will they? If there are any engineers out there who would like to confirm, deny, or otherwise massacre the above, please feel free. I'll listen to anyone who has knowledge based on a solid foundation. The formulae came from an engineer at AC Delco and was confirmed by empirical evidence, so I have no reason to doubt its validity. If anyone wants to select injectors by working back from a BHP figure of a vehicle, heres a little trap to be avoided. I estimated the flow rates of 2 Porsche 911s, 1 NA and 1 turbo. The nominal flow rate of the turbo units was actually less because it ran at 3.5 bar fuel pressure and the NA used 2.5 bar. Tricky. One other thing, the injectors I listed above normally don't run at the 2.5 bar used for flow rate testing. I think it is usually 1.5 bar or there abouts. BTW. The BSFC figure is a sort of average. Newer engine types may give a little better and older ones a little worse. It's a starting point with the final configuration set by adjusting the fuel pressure. That's it for now Bill Boulton ------------------------------ From: Jennifer Rose Date: Wed, 16 Oct 1996 18:24:53 -0700 Subject: More GM EGR Hi Peter, George, Andrew The exhuast gas are route to just behind the throttle body in the plenum. The soot builds up over time, had soak mine in carb cleaner for two days to get it clean. My fuel pressure is already at 50 psi static(no vacuum at reg). Would prefer dittling with the EGR valve itself. Any ideas? California for me unfortunately. A friend came by intake, plenum, runnner, throttle body, fuel rail with injectors - no wiring,eletronics. Suggestions on which sysytem to use MAF/MAP. Any good sources for parts-now use local Upullit and GM Dealer. Am think about buying a pocket pro to read/burn eproms. Will this be ok for these eproms Need to keep cost low. Vance ------------------------------ From: john spears Date: Wed, 16 Oct 96 22:43 EST Subject: GM Controllers Changing the 86-88 TPI to the 89 MEM-CAL and unplugging the cold start injector is a nice improvement on these engines. Not only in cold starting, but also idle quality and all around running seems improved. The change I recommend to customers though is to "go all the way" to the 90-92 730 ecm. This really improves the running of these engines as well as freeing up the intake for better looking air cleaners, etc. By using the old MAF and EGR temp sensor wires for the newly added MAP sensor you don't have to string any new wires either. You must also change the knock sensor, as the early high impedance sensor that used the mid-function module, will not work with the ESC circuitry located on the new MEM-CAL. The wiring changes at the ECM to switch from the 165 to the 730 takes a little concentration, but it pays well!! (ha) I have never had a disappointed customer after making this conversion. John Speartech Fuel Injection Systems p.s. If anyone wants to send me their EPROM with return postage, I'll take care of that pesky code 32 problem!! ------------------------------ From: Darrell Norquay Date: Thu, 17 Oct 1996 03:53:23 GMT Subject: Excellent Gasoline FAQ Yo all: The other day, whilst surfing about, I chanced across one of the most informative FAQ's I have ever seen. It was on the F-body homepage, and it is a FAQ all about gasoline. Now before ya throw up yer hands in disgust, it has sections on detonation, water injection, octane improvers, how octane is measured, combustion chamber properties, alternative fuels, and even how to build a 1000Hp Honda Civic engine. It's a little technical chemistry-wise, but once ya get through all that it is an excellent read. It puts to bed a whole lot of the arguments previously bantered on the list about detonation, the why's and wherefores. Also has a bibliography as long as your arm which is alone worth the price. Should be required reading for all on this list. I downloaded it, but it's a pretty big .HTML file, I can only read it with Netscape. If someone (Johnny? JSG?) could give me instructions on how and where to upload it, it would be an excellent addition to the DIY_EFI and EFI332 websites. I don't know about the legality of this, but it does have a big header giving credit to the F-body homepage and the author, so I imagine it's PD. If ya can't wait, do a Webcrawler search for F-body Homepage, it'll take you right to it. regards dn note change of address: dnorquay@xxx.com ------------------------------ From: peter paul fenske Date: Wed, 16 Oct 1996 20:33:36 -0700 Subject: Re: More GM EGR Hello all Well you can go higher, up to 70 PSI before the injectors start to act funny, have trouble opening, flow pattern all that. Remember 20% increase in fuel pressure only gives you 10% more fuel. >My fuel pressure is already at 50 psi static(no vacuum at reg). Would prefer >dittling with the EGR valve itself. Any ideas? California for me unfortunately. The EGR have been wondering. If a small delay relay is connected to the egr valve solenoid and used to gnd the thermal switch this might fake out the ecm. Or a hobbs switch. Other than that time to get into the code and disable the bit error for egr. I only have a faint idea how to do this. > >A friend came by intake, plenum, runnner, throttle body, fuel rail with >injectors - no wiring,eletronics. Suggestions on which sysytem to use MAF/MAP. >Any good sources for parts-now use local Upullit and GM Dealer. I suggest you rob a J car or so of its harness, sensors, and 730 ecm. Gm stocks a lot of the connectors you might need. GEt the 90-92 5.7 F body calpak and build the VATS defeat as me and others have posted on this net. A 280zx fuel pump will get you on your way. > >Am think about buying a pocket pro to read/burn eproms. Will this be ok for >these eproms Need to keep cost low. If you tinker with gm make certain you can burn 2732, 27C128, 27C256, and 27C512. > >Vance > > > GL: peter ------------------------------ From: peter paul fenske Date: Wed, 16 Oct 1996 20:40:01 -0700 Subject: Re: GM Controllers Chomp!!!!! >the ESC circuitry located on the new MEM-CAL. The wiring changes at the ECM >to switch from the 165 to the 730 takes a little concentration, but it pays >well!! (ha) I have never had a disappointed customer after making this >conversion. > > John >Speartech Fuel Injection Systems > >p.s. If anyone wants to send me their EPROM with return postage, I'll take >care of that pesky code 32 problem!! > Yep John is right so rob the J Car of its knock sensor. If you use a ohmmeter the new style knock sensor will read about 3K. The old piezo type reads about 100K. Someone who can get rid of code 32 HMMMM Later: peter ------------------------------ From: "Johnny" Date: Thu, 17 Oct 1996 01:30:55 -0700 Subject: Re: Excellent Gasoline FAQ The way to do it is to put a link to it on our websites. Unfortunatly, I am only the list slave and have no access to the guts of the web site, the other john will have to do that. But until then, here is the link in this mail (suprised you didn't include the link darrell). http://www.vtr.org/maintain/gasoline-faq.html - -j- - ---------- > From: Darrell Norquay > To: DIY_EFI@xxx.edu > Subject: Excellent Gasoline FAQ > Date: Wednesday, October 16, 1996 8:53 PM > > Yo all: > > The other day, whilst surfing about, I chanced across one of the most > informative FAQ's > I have ever seen. It was on the F-body homepage, and it is a FAQ all about > gasoline. Now before ya throw up yer hands in disgust, it has sections on > detonation, water injection, octane improvers, how octane is measured, > combustion chamber properties, alternative fuels, and even how to build a > 1000Hp Honda Civic engine. It's a little technical chemistry-wise, but once > ya get through all that it is an excellent read. It puts to bed a whole lot > of the arguments previously bantered on the list about detonation, the why's > and wherefores. Also has a bibliography as long as your arm which is alone > worth the price. Should be required reading for all on this list. > > I downloaded it, but it's a pretty big .HTML file, I can only read it with > Netscape. If someone (Johnny? JSG?) could give me instructions on how and > where to upload it, it would be an excellent addition to the DIY_EFI and > EFI332 websites. I don't know about the legality of this, but it does have > a big header giving credit to the F-body homepage and the author, so I > imagine it's PD. If ya can't wait, do a Webcrawler search for F-body > Homepage, it'll take you right to it. > > > > > regards > dn > > note change of address: > dnorquay@xxx.com ------------------------------ End of DIY_EFI Digest V1 #316 ***************************** 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".