Simulated Problem Waveform's
Here are some examples that show how certain conditions will affect the sensor waveform. All of these were captured from a 94 Toyota pickup 4cyl 60k miles at 2500 rpm engine at operating temp. The first image shows the normal waveform with good switching and rise time. All of the conditions were simulated to create the waveforms captured.
The waveform above is the normal sensor pattern. Biased slightly high, but switching nicely.
The first image is one injector not firing.
This is one spark plug shorted.
Intermittent spark plug firing.
Slightly rich engine. Here's a bit of propane added to the engine.
Very rich engine. Even more propane.
Dead rich engine. Enough propane to go full rich.
Slightly lean engine. Here's a bit of a vacuum leak.
Very lean engine. Even bigger air leak.
Dead lean engine. Major air leak.
EGR valve slightly open at 2500rpm.
EGR wide open at 2500rpm.