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Crankshaft Position Sensor – Jeep Cherokee

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Vehicle:Jeep Cherokee 4.0

Crankshaft Position Sensor – Jeep Cherokee Waveform Notes

These waveforms are from a 1991 Jeep Cherokee 4.0 with an intermittent stall, hesitation and no start. Naturally the Jeep would not act up in the bay once the scope was hooked up, however, a short road test flushed out a single bump symptom.

A PicoScope 3223 two channel automotive oscilloscope was used to capture the waveforms. The timebase was set to display 5 seconds on each screen. Each channel was set to take a sample every 5 microseconds – a total of 980,393 samples per screen. In total 18 screens were recorded. (The PicoScope Automotive software is capable of storing up to 32 screens so even after capturing 90 seconds of waveform there was still plenty of room in the waveform buffer.)

Several pre and post symptom CKP failures were captured during the short road test, including the actual failure that caused the symptom.

Watch the video and see how much information was actually captured in a very short time. No other automotive scope has these capabilities.

Thanks to Nick Brownrigg and Autonerdz.com for supplying this waveform.