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Category: Chevy
Satisfied Customers: 24125
Experience:  ASE certified tech ADVANCED LEVEL SPECIALIST. Wisconsin certified emissions state inspector
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What does the cam sensor do in a 98 5.7 vortec..Faulty

Customer Question

What does the cam sensor do in a 98 5.7 vortec? Will engine not start with Faulty cam sensor?
Submitted: 6 years ago.
Category: Chevy
Expert:  AMEDEE replied 6 years ago.



I do not believe the engine will start without this input to the computer. If it does, I cannot imagine it will run very good.


The Camshaft Position (CMP) sensor is located within the distributor. The operation of the CMP sensor is very similar to the Crankshaft Position (CKP) sensor. The CMP sensor will provide one pulse per camshaft revolution (1x signal). This signal will not affect the drive ability of the vehicle. The VCM utilizes this signal in conjunction with the crankshaft position in order to determine which cylinder(s) are misfiring.



Customer: replied 6 years ago.

The crank tells the plugs to spark. I have no fuel. What tells the injectors to pulse?

Expert:  AMEDEE replied 6 years ago.
The pcm tells the injectors to fire based off of various inputs.
Customer: replied 6 years ago.
35 lbs. fuel pressure. Good spark. Hold starting fluid about two and one half feet from throttel body and push about once a second and it will idle fine. stop starting fluid and it dies. can buzz test injectors with snap solos scanner. All work. Tried used good spyder not expecting it to work and it did not work. Does cam sensor have any thing to do with injectors or pulse width?
Expert:  AMEDEE replied 6 years ago.

YUP! you bet it does!


The cam sensor is in the distributor. It rides off of the camshaft. THe engineers have programed the injectors to fire at a certain time in relation to the valves... so having it ride off the camshaft would make the most sense.

Expert:  AMEDEE replied 6 years ago.
But I believe the fuel pressure specs should be about 60 psi on your engine.
Customer: replied 6 years ago.
Sorry, I think I can pull up the factory info and read, and get better information. Thanks. Gregg
Expert:  AMEDEE replied 6 years ago.
If you give me your vin I can double check for you in a few references. But if you are sure... then we cna just stick with the cam sensor.
Customer: replied 6 years ago.
if i was sure I would not need to ask a question. Fuel pressure, 35 to 45, You can drive down the road with a gauge in your hand and run 70 with 10 to 15 pounds. You get down to about 8 and engine will die. 35 is plenty to start a engine. Thanks, Gregg
Expert:  AMEDEE replied 6 years ago.

Ok.. just wanted to be thorough.


I hope this helps! Please don't forget to hit the "accept" button if you have found my answer helpful. You can always accept my answer now, and repost back again later on if you have any more questions. If you want to discuss it some more just hit "reply", it's free to do so otherwise don't forget to hit "accept" and leave positive feedback if you found my answer helpful.


Customer: replied 6 years ago.
Not Helpful. Thanks, Gregg
Expert:  AMEDEE replied 6 years ago.
Well I answered your question about the cam sensor didn't I?

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