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GM 3.4L crank sensor glitch?

Wadmancpu
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8 years 1 month ago #14858 by Wadmancpu

GM 3.4L crank sensor glitch? was created by Wadmancpu

This is a wavef

orm from the 3x crank sensor on an 01 Grand AM with the 3.4. Appears every fourth spike is different. Look normal?

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juergen.scholl
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8 years 1 month ago #14871 by juergen.scholl

Replied by juergen.scholl on topic GM 3.4L crank sensor glitch?

This looks like anormal VRS signal, probbly not every 4th but every 7th spike is different. Your time base is at 100ms total screen, I suppose there is just one crank revolution to be seen. So this accounts for something less than 200 ms for a complete cycle (720 deg.) and then it would be taken while engine idling...

To be sure It will be necessary a picture where the supposed "glitch" is to be seen at least twice within one screen shot.

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Wadmancpu
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8 years 1 month ago #14875 by Wadmancpu

Replied by Wadmancpu on topic GM 3.4L crank sensor glitch?

Ok, what causes the 7th spike to be different? I have a hard starting issue with a misfire at idle.

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juergen.scholl
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8 years 1 month ago #14876 by juergen.scholl

Replied by juergen.scholl on topic GM 3.4L crank sensor glitch?

The seventh spike is caused by an additional notch in the reluctor. Its function is to identify crankshaft position.

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