Quote:
Originally Posted by dcb
...P.S. rmccomiskie, it might help if you record both simultaneously, at cd stereo sampling rate but 8 bit depth. the raw wave format is pretty easy to decypher, don't know about compressed, but having both signals captured at the same time could be something of a rosetta stone for that ECU signal if other VW/Audi groups don't have the answers.
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Well...maybe not quite a Rosetta Stone but it's an informative comparison. I frankensteined both the injector and ECU fuel flow signals into a stereo audio plug and captured them with my SoundCard Scope. The green signal is from the injector and the red signal is from the ECU.
This is about 30 mph steady on level ground:
You can that there are 6 ECU pulses for every injector pulse as expected.
...and this is about 30 mph uphill accelerating hard.
The ECU pulses appear to be scaled down from the injector pulse width but I expect them to be proportional.
Then I started coasting downhill at about 30 mph...
When coasting, the signals start out looking like the engine is at idle.
...after a couple of seconds, the signal looked like this...
The ECU signal goes completely flat while the injector signal shrinks to a very short pulse. The flat ECU signal may present a problem because the external interrupt routines will not execute.
More analysis needed. I'm working on it.