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2001 chevy pick up 2500 8.1 engine

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5 years 1 month ago - 5 years 1 month ago #27005 by autojoe
Does anyone know if both cam and crank needed for starting and if crank sensor is pull up or pull down design. It has three wire signal 12 volt feed and ground. I am assuming because it has 12 volt feed that it is a pull up design. What's confusing is that I know it is a hall effect sensor but in alldata is says The Crankshaft Position (CKP) sensor is a magneto resistive type sensor which I have seen on newer vehicles for abs wheel speed sensors which are only two wires. I can't believe that alldata info system says this for 2001. I don't know if newer vehicles are using magneto resistive type sensors for cam and crank sensors.
Last edit: 5 years 1 month ago by autojoe. Reason: New information added

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5 years 1 month ago #27010 by Tyler

autojoe wrote: What's confusing is that I know it is a hall effect sensor but in alldata is says The Crankshaft Position (CKP) sensor is a magneto resistive type sensor which I have seen on newer vehicles for abs wheel speed sensors which are only two wires. I can't believe that alldata info system says this for 2001. I don't know if newer vehicles are using magneto resistive type sensors for cam and crank sensors.


Sounds like a misprint, IMO. No one that I know of is using magneto resistive sensors for cam or crank signals. You're absolutely right to call BS. ;)

Does anyone know if both cam and crank needed for starting and if crank sensor is pull up or pull down design. It has three wire signal 12 volt feed and ground. I am assuming because it has 12 volt feed that it is a pull up design.


I don't know to a certainty - just don't see many 8.1s around any more. :lol: But if it's anything like the 5.3s and 6.0s, they'll start without the cam sensor. The CKP signal is detailed enough that the PCM can figure it out with a long enough crank time.

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5 years 1 month ago #27014 by autojoe
Thanks Tyler. Do you know if pull up or pull down circuitry?

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5 years 1 month ago #27016 by juergen.scholl

autojoe wrote: Do you know if pull up or pull down circuitry?


Disconnect the sensor and measure voltage on the signal wire coming from the pcm with koeo. Voltage present = pull down. No voltage present = pull up.

An expert is someone who knows each time more on each time less, until he finally knows absolutely everything about absolutely nothing.

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5 years 1 month ago #27017 by autojoe
Thanks I know how to determine pull up pull down but there may be a signal wire issue.

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