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Type: Posts; User: daleulan

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  1. Replies
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    19620 Functional sketch, I may have a couple...

    19620

    Functional sketch, I may have a couple of errors but basically there is a filter, precision rectifier, fast filter, buffer with gain and offset adjustment, slow filter, and comparator.
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    This is a bit late but I always use a...

    This is a bit late but I always use a post-catalyst heated O2 sensor (Bosch LSF4.2 works well) and look for wiggles there. I try to get the front o2 thresholds set to get the rear O2 (with catalyst)...
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    I write OEM software, that's why I don't post on...

    I write OEM software, that's why I don't post on here very much. But we compensate for a lot of things - current buildup time (vs battery voltage), fuel pressure (we have a fuel rail pressure...
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    Those calibrations are pretty much only done for...

    Those calibrations are pretty much only done for only emissions, it's interesting to play with the O2 gains and watch an analyzer. I used to play with a mechanic's 5-gas (NOx/HC/CO/CO2/O2) and if you...
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    The Nailhead was on there. I was thinking of the...

    The Nailhead was on there. I was thinking of the 350 X engine or the 455.
  6. If you have a monolithic catalyst it can be a bit...

    If you have a monolithic catalyst it can be a bit rough on it - normally under DFCO conditions there's not much mass flow so the cat doesn't temperature cycle so much but with essentially atmospheric...
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    Depends on the engine cylinder count, mask type,...

    Depends on the engine cylinder count, mask type, and especially if you are needing misfire detection to work. Especially on a 58x wheel (60-2) with VRS sensor, the misfire detection window can't be...
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    I am not 100% sure whether GM uses their adaptive...

    I am not 100% sure whether GM uses their adaptive CKP learn to correct ignition timing but I don't use it for that in my software. The timing variations learned from what I have seen are so small...
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    I think this might be what you are looking for....

    I think this might be what you are looking for. It's a rough disassembly I did about 20 years ago.
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    BLM is only giving you the difference between the...

    BLM is only giving you the difference between the airflow the ECM thinks is there (after subtracting out the EGR that it thinks is there) compared with what is actually happening on the engine, not...
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    I use one of the smaller HP laptops. For an...

    I use one of the smaller HP laptops. For an burner I have a Conitec GALEP5 - it programs not only EPROMs but also all of the GALs and single-chip micros that I use for my other projects.
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    One thing to be cautious of when swapping O2...

    One thing to be cautious of when swapping O2 sensors around - planar 4-wire sensors. They are very nice in that they can light off quickly, they are faster, more accurate, and that's what most OE's...
  13. Thread: O2 + NOx!

    by daleulan
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    Oh yes, if really good emissions were your final...

    Oh yes, if really good emissions were your final goal of closed-loop control and you wanted to stick with a GM P4, one could probably hack in postcatalyst O2 sensor software into any of the P4-based...
  14. Thread: O2 + NOx!

    by daleulan
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    4,164

    The NOx sensor's lambda cell is indeed a wideband...

    The NOx sensor's lambda cell is indeed a wideband cell. In most configurations the NOx sensor and its electronics come as a calibrated pair and a CAN bus of some kind is used to communicate the...
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    On that ECM the internal signal ground is...

    On that ECM the internal signal ground is connected to the case. So you should not ground the case otherwise you will get ground loops and sometimes that can cause the ECM to burn up - if the...
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    Measure the voltage between terminals A9 and A12....

    Measure the voltage between terminals A9 and A12. If it's somewhere lower than 4 volts then maybe something (the scan tool or the wiring harness) is putting the ECM into a test mode. The self-test...
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    What you see out of the postcatalyst sensor can...

    What you see out of the postcatalyst sensor can depend on the design OSC (cerium dioxide) loading of the catalyst. Early OBD-II catalysts used lighter OSC loading and so you would see an attenutated...
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    The rear sensors are indeed used for fuel trims....

    The rear sensors are indeed used for fuel trims. There are three functions of those sensors in 'typical' software. I don't have a disassembly of GM's code in front of me but the most obvious is for...
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    I'm thinking that the injector asymmetry on the...

    I'm thinking that the injector asymmetry on the injectors and/or the async fuelling mode were both used to cover up (or otherwise compensate for) some air/fuel distribution issue much as the Buick V6...
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    If I remember right, some of the 4.3L TBI engines...

    If I remember right, some of the 4.3L TBI engines had different injectors installed in each bore and you had to make sure you put the right one in each spot. To me that implies that there is a fuel...
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    We all make mistakes. Half of us probably...

    We all make mistakes. Half of us probably wouldn't be around if it weren't for mistakes....

    Seriously, though, my new engine management software is so superior to the stuff I wrote a decade ago,...
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    Going back a couple pages.... TBI engines...

    Going back a couple pages.... TBI engines generally had a thermostatic air filter installed for fuel evaporation reasons (emissions, throttle body icing) and so in the stock air system configuration...
  23. Yes, relocation to Calgary where we have hardware...

    Yes, relocation to Calgary where we have hardware and software development and dyno cells.
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    You got 82% (14 right out of 17). But I have to...

    You got 82% (14 right out of 17). But I have to admit that I used the shape of the alternator to choose between the major manufacturers if I didn't know the engine. Some seemed pretty obvious (409...
  25. Wanted - ECM Software Test/Calibration Engineer

    I work for a medium-sized global company with a small-sized (16 employees) division up in Calgary, Alberta, Canada. Our division of the company designs and manufactures electronic fuel injection...
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