DIY_EFI Digest Monday, 14 July 1997 Volume 02 : Number 237 In this issue: le jetronic fault codes? Re: EGO and the Smog Pump fuel-cut Re: EGO and the Smog Pump Re: fuel-cut Re:Source for LH-Jetronic info? Re: fuel-cut See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: "nico badenhorst" Date: Sun, 13 Jul 1997 14:46:44 +0300 Subject: le jetronic fault codes? Hi Richard, i know the motronic ml4.1 system, as fitted to (in my case) the 2L gsi opel kadett ( 8v) i think its called a vauxhall astra ? in the uk ? ,anyway i know this system returns the error codes via the engine warning light on the dashboard if certain pins in the diagnostic plug are shorted out.. so my other car is a opel monza 1.6L gsi ( again i think its called a belmont in uk?) the efi seems to be very similar to the L jetronic sytem ? ,but it does seem to have a micro proccesor since it returns error codes in the same way as the ml4.1 system its been my understanding that this system on the 1.6l is the le or maybe l3 jetronic, have i maybe got the wrong name acociated with this aplication? any more info? thanx a lot , nico ------------------------------ From: "Steve Meade" Date: Sun, 13 Jul 1997 10:24:03 -0700 Subject: Re: EGO and the Smog Pump - ---------- > From: Johnny > To: diy_efi@xxx.edu > Subject: Re: EGO and the Smog Pump > Date: Sunday, July 13, 1997 12:55 AM > > Robert Harris wrote: > > > > Dah, correct me if I am wrong ( aw go ahead and do it anyway) > > but doesn't the EGO sense total oxygen in the exhaust stream > > and get "happy" around stoic? If true, then when we shove > > extra oxygen via the smog pump into the exhaust, do we not have > > to shove unburned fuel from a too too rich mixture into the exhaust > > to make shore that the result is stoic at the sensor? Am I missing > > something here or is the total extra oxygen so low that it doesn't > > make much difference in the fuel consumed?? > > There are a couple factors involving the smog pump. Firstly, by > injecting air (has O2 in it) into the exhaust manifold right at the > port, it enables any unburnt hydrocarbons to get burned, or reburned > even. Besides cleaning up the exhaust, this post combustion also > increases the temp going into the cat, which helps the reaction that > takes place there. Secondly, at least in the old days, exhaust sniffers > measured hydrocarbons in ppm, so if you add air, you are reducing the > ppm, even though the actual total emissions would stay the same (except > for the reburning effect). This was especially true in the few years of They still do measure in PPM in the US judging by my last smog test. How much smog is actually reduced by the smog pump action? > smog pumps with no cats. Because the O2 part of the injected air gets > used up in the post combustion process, it shouldn't change the output. > I'm not even sure if air pumps are still the rage or not though. > I was looking through my Porsche parts catalog and there are smog pump listings for 911's up through '94, all 928's (V8), early 924's (2.0L VW I4), and 914 2.0 (2.0 VW w/Porsche heads). So, apparently smog pumps have been pretty popular at Porsche until recently. I don't know how adding O2 before the lambda sensor could preserve its output though. Does all of the O2 injected air get used up in post combustion burn? If it does, than wouldn't some of the leftover O2 from original (cylinder) combustion get used too and alter the O2 sensor reading? Or, does it work out that the reading is preserved since injected O2 won't get used up if there's not enough fuel which would still read a lean condition? > Even the cleanest of piston engine combustions are still pretty dirty > right at the exhaust port. Burning gasoline, even with the best of > combustion chamber designs, and "perfect" injector and spark management, > you still have to massage the exhaust to get it to meet the current > spec. Don't all new US gasoline vehicals have cats? I am no expert on I don't know if it's written in legislature anywhere but I don't believe there are any mass production passenger vehicles with gasoline internal combustion engines that don't have cats. Out here in CA you can fail a smog test "visually" meaning that your car can pass the sniffer test (OK emissions) and still fail because it has an "unauthorized part or modification." You may see a lot of parts which say they have "CARB" exemption numbers. That means their product is registered and allowed by the California Air Resources Board. Though, I know there are some engines out there that probably could pass without cats when new. One problem though is that in the US car manufacturers must warrant the emissions system for 5 years and lots of miles. If the car ever fails within five years the manufacturer must fix it. For that reason the cats are a good insurance policy for clean cars which are clean when new but after 30,000 miles of owner-neglect they might not be. An interesting side note, I bought an '86 Porsche 944 that was originally purchased in Missourri. It does not have the "California" smog package on it. I live in CA and had to have the smog done to register my car. Now this car is 11 years old with 74,000miles and doesn't have the CA smog stuff. Here's some test highlights at 2500RPM: Hydrocarbons: Allowable: 150PPM Tested: 003PPM CO%: Allowable: 1.20% Tested: 0.01% CO2 Tested: 15.4% O2 Tested: 0.0% > what's currently out there in production land. Are there any? Not sure > about post combustion enhancers (smog pumps). Seems like most of the > stuff I have worked on had 'em, but I try to stay away from that new > stuff as much as I can. > > -j- =-=-=-=-=-=-=-=-=-=-= Steve Meade smeade@xxx.com ------------------------------ From: "Stefan Olsson" Date: Sun, 13 Jul 1997 22:11:04 +0200 Subject: fuel-cut Hello all, Iam working with an Bosch Motronic system for Volvo 940 Turbo. Is there any one out there ho knows the address for the fuel-cut ? (Boxnr 0 280 000 962,954,937,939,984) (I have talked to Superchip but they dont know how to do it) Please help me iam desperate! Stefan ------------------------------ From: "Christopher G. Moog" Date: Sun, 13 Jul 1997 16:40:54 -0400 Subject: Re: EGO and the Smog Pump Steve Meade wrote: > > > > > Robert Harris wrote: > > > > > > Dah, correct me if I am wrong ( aw go ahead and do it anyway) > > > but doesn't the EGO sense total oxygen in the exhaust stream > > > and get "happy" around stoic? If true, then when we shove > > > extra oxygen via the smog pump into the exhaust, do we not have > > > to shove unburned fuel from a too too rich mixture into the exhaust > > > to make shore that the result is stoic at the sensor? Am I missing > > > something here or is the total extra oxygen so low that it doesn't > > > make much difference in the fuel consumed?? > > Many cars route the air pump outlet as follows: 1. To the exhaust port when first started. This allows unburnt HC to burn lowering emissions and heating the cat(s) and EGO sensor. The engine is operating in open loop and the EGO is not functioning. 2. To the cat once warmed up. The engine controls will keep the engine slightly rich producing CO. The CO scavenges the oxygen released when the three way cat reduces NOx to nitrogen and oxygen. This helps prevent the reverse reaction (oxygen and nitrogen recombining to form NOx compounds). The air pump outlet is sent to the cat (at the midpoint of the cat, where oxidation is occuring) this helps to burn any HCs and to oxidize any remaining CO to CO2 (and yes some of the nitrogen and oxygen are recombined to form NOx but the metals used don't encourage this reaction). Since the cat is down stream of the EGO the sensor is reading oxygen out of the engine. ------------------------------ From: "Steve Meade" Date: Sun, 13 Jul 1997 14:29:20 -0700 Subject: Re: fuel-cut - ---------- > From: Stefan Olsson > To: DIY_EFI > Subject: fuel-cut > Date: Sunday, July 13, 1997 1:11 PM > > Hello all, > > > Iam working with an Bosch Motronic system for Volvo 940 Turbo. > Is there any one out there ho knows the address for the fuel-cut ? > (Boxnr 0 280 000 962,954,937,939,984) > (I have talked to Superchip but they dont know how to do it) > I don't know the location for the fuel cutoff, but there's another problem involved. Depending on the version of Motronic (1.0, 1.1, 1.3, etc) there is at least one checksum and possibly more. My understanding is that the chips are worthless if you don't change the checksum when you change something inside of it. > Please help me iam desperate! > The only person who can really help you is Jim Conforti. But, he's really busy. > Stefan =-=-=-=-=-=-=-=-=-=-= Steve Meade smeade@xxx.com ------------------------------ From: "Stefan Olsson" Date: Mon, 14 Jul 1997 01:34:33 +0200 Subject: Re:Source for LH-Jetronic info? Hi Michael I have worked a lot with this engines (B230ET,FT) and i think its an fantastic engine ! You can tune it to over 350Hp without any bigger modifications (exept for the early mod there You must change the pushrods) If You whant more info send me the number on Your ECU and Your E-mail addr Best regards Stefan Sweden ------------------------------ From: Bernard Ward Date: Sun, 13 Jul 1997 20:44:14 -0400 Subject: Re: fuel-cut Stefan Olsson wrote: > > Hello all, > > Iam working with an Bosch Motronic system for Volvo 940 Turbo. > Is there any one out there ho knows the address for the fuel-cut ? > (Boxnr 0 280 000 962,954,937,939,984) > (I have talked to Superchip but they dont know how to do it) > > Please help me iam desperate! > > Stefan You might want to talk to Volvo Tuner ipd@xxx.com, as they are very knowledgeable on all things "Volvo" Barney ------------------------------ End of DIY_EFI Digest V2 #237 ***************************** 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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