Changes by last author:
Added:
| * PlugAndPlayHonda |
| * plug-and-play (eg. PlugAndPlayJetronic): an ECM applied to a specific connector and set of sensors to provide plug-and-play install (or rather plug-and-tune, since tuning still often needed unless someone has done it already and published results) |
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* plug-and-play (eg. PlugAndPlayJetronic): an ECM applied to a specific connector and set of sensors to provide plug-and-play install for a given unmodified harness (or rather plug-and-tune, since tuning still often needed unless someone has done it already and published results). One can use existing tables (no need to retune). Usually some extra wires are used for WBO2 (the dumped ECM rarely features WBO2). |
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** intercepting ignition and injection signals: this is very problematic and complex
** MAP or MAF substitute (fooling) * tunetime piggyback: watching inputs and intercepting or just watching outputs of an alien ECU for diagnostics (detect faults) and logging the control tables (maps). This makes a lot of sense, when used as a tuning aid (vs. runtime piggyback). The tuned maps are executed with a normal ECM ( native or plug-and-play style install) during production-runtime. |
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** intercepting ignition and injection signals: this is very problematic and complex: the piggyback ECM has all the signals that is enough to control the engine, and it has some extra signals that are not really needed (injection/ignition outputs from the original ECM). These just add to the weight/uncertainty/problem sources/costs/wire jungle. NOTE that this works, but is an awkward way for this task. See MAP/MAF substitute below, or see plug-and-play above for better options.
** MAP or MAF substitute (fooling). If one want's to keep the original ECM (instead of going plug-and-play, see above), this is the best option. By fooling the ECM (makes original ECM think it is running at lower MAP/MAF, except where the extra fuel is needed, of course) it allows swapping in significantly larger injectors (+30..100% vs. +10..20% that is upper limit with original ECM if MAP/MAF fooling is not applied), also nice closed-loop lambda control (using WBO2). * tunetime piggyback: watching inputs and intercepting or just watching outputs of an alien ECU for diagnostics (detect faults) and logging the control tables (maps). This makes a lot of sense, when used as a tuning aid (vs. runtime piggyback that is used all the time, for driving). The tuned maps are executed with a normal ECM ( native or plug-and-play style install) during production-runtime (without interception). |
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---- Ok. So I still don't understand why this won't work. The main thing I really want to do is use a wideband O2 to adjust AFR at WOT. At WOT I believe the stock PCM runs completely open-loop. It has no feedback and just dumps a ton of fuel. I want to lean out the mixture at WOT only, using water injection, wideband o2 and EGT readings as inputs. If the ECM is running in open-loop mode, what would be wrong with intercepting the injection signals? The ECM should have no idea what's going on. When the ECM goes back into closed-loop I would run the injection pulses exactly as they are recieved from the ECM. Another possible use someone might have is to run larger injectors with the stock ECM. Couldn't you come up with some fairly simple pulse-width transformation that would shorten the pulse-widths of the injectors at all times (within range) so that larger injectors appear to the stock ECM to perform exactly like stock injectors? Even in closed-loop mode this would seem to work, because the ECM would still be able to obtain 14.7 pretty easily... The reason we can't just plug in bigger injectors is that the stock ECM has a limited range it is allowed to adjust the pulse widths to obtain its AFR target... So, it wouldn't be able to sufficiently trim fuel to idle the car. But, I believe the main idea here is to use a seperate computer to close the loop around WOT (open-loop) operation using a wideband O2 and EGT. What would be the problem with this? Thanks! |