If saturation injector PW specs are 2 ms - 12 ms, might it be normal for the PW to briefly drop to less than 0.25 ms (or even go to 0) when letting off throttle? A fuel saving feature of the ECU? or should it not shorten to anything less than idle PW of 2 ms?
Thank you, Lance
Depends on the car, probably, but yes, that's normal on at least some cars - when the throttle is released, or on a long closed-throttle deceleration, the fuel delivery will be greatly decreased or even cut off.
I must say, you sure are persistant! =) If it's not ignition coils, it's injectors....
If you hook up an A/F ratio gauge (LM3914 + LEDs) you can watch the engine hover around stoich. I know with Toyota, during decel., the fuel injectors are cut off; can see it with the gauge as the O2 level goes so lean that the O2 sensor loses "grip" of it. Now, if I can rig up my scope to watch the injector waveforms while I'm driving and capture them shutting off during decel, I should be OK. Almost as bad as a cell phone....hehe.
-Tim
Thanks guys. This car has been to a couple of master techs, w/o luck. I'm not giving up on it, until I've exhausted all possibilities. Has been mostly a good learning experience - learning basic auto tech and theory, learning to use a scope, etc., but with of course a few frustrations through in. I'm have found some testing irregularities - now the trick is whether they're real or artifact - discerning normal vs abnormal.
Lance
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alancemor....AT..yahoo.....DOT...com
Indian Summer wrote
I even compiled his data.
Same thing with Hondas above 1200 rpm. However, based on certain events there are no cut off, even on a long closed-throttle deceleration.
If successful, please share your method. I need to stabilize the erratic injector waveform on a scope.
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