cam position sensor
12-19-2006, 11:20 AM
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cam position sensor First off sorry if this is the wrong forum or if this has been posted before elsewhere but the search isnt working atm.
Basically i would like to know if there is anyway i can test if my cam sensor is bad (car wont start just backfires occasionaly when i try starting it). I have the sensor out of the engine right now infront of me but that doesnt help too much being that i never took a look at a working / broken one before lol.
Thanks for your time
Basically i would like to know if there is anyway i can test if my cam sensor is bad (car wont start just backfires occasionaly when i try starting it). I have the sensor out of the engine right now infront of me but that doesnt help too much being that i never took a look at a working / broken one before lol.
Thanks for your time
12-19-2006, 12:03 PM
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Originally Posted by raven_450
First off sorry if this is the wrong forum or if this has been posted before elsewhere but the search isnt working atm.
Basically i would like to know if there is anyway i can test if my cam sensor is bad (car wont start just backfires occasionaly when i try starting it). I have the sensor out of the engine right now infront of me but that doesnt help too much being that i never took a look at a working / broken one before lol.
Thanks for your time
Basically i would like to know if there is anyway i can test if my cam sensor is bad (car wont start just backfires occasionaly when i try starting it). I have the sensor out of the engine right now infront of me but that doesnt help too much being that i never took a look at a working / broken one before lol.
Thanks for your time
12-19-2006, 12:19 PM
#3
All Hall-Effect sensors use three wires to do the job.
One wire carries the power voltage and a second wire supplies the sensor ground. Both are supplied by the ignition module or computer.
The third wire is the "signal". This wire is the sensor's output to the computer. The voltage rises to 5Volts and falls to near zero with the movement of the shutter.
Testing a Hall-Effect sensor is simple if you have a digital volt-ohm meter. The most difficult part of a test would be accessing the sensor's wires (usually...but you already are at the sensor so it's no problem).
Take pins/needles and clamp then in the alligator clips of your volt-ohm meter. These will become your probes.
Insert the "red pin" into the 12volt wire (I find it easy to slip it into the connector itself through the weather seal in the back). and the "black pin" into the ground. MAKE SURE THESE DO NOT TOUCH EACHOTHER!!!!!!!!!!!!!!
Key on the car and you should see 12Volts. If no 12Volt, you have a problem somewhere else.
Now, take the "red pin" out of the 12volt and insert it into the signal. Now turn the car over BY HAND (otherwise this event will happen to fast to really catch) and as you make your way around (remember to go AT LEAST 2 turns as the cam turns 1/2 crank), you SHOULD see a 5Volt "blip." If no 5Volt signal, the sensor is bad.
This same process happens with the Crank Sensor also.
Not to discurage you, but I had this EXACT "problem" a while back. The car would turn over, backfire/try to fire on the wrong stroke, etc. My reluctor wheel was welded when I built the engine (so it CAN NOT turn/move) so I felt it HAD to be the sensors. I replaced both the crank and cam sensors (which turned out to both be good), tested EVERYTHING, and always had a good signal. My final result was a dead computer (ie: I could still "connect" to it through a scanner but something inside burned out).
Now I have a FAST XFI.
One wire carries the power voltage and a second wire supplies the sensor ground. Both are supplied by the ignition module or computer.
The third wire is the "signal". This wire is the sensor's output to the computer. The voltage rises to 5Volts and falls to near zero with the movement of the shutter.
Testing a Hall-Effect sensor is simple if you have a digital volt-ohm meter. The most difficult part of a test would be accessing the sensor's wires (usually...but you already are at the sensor so it's no problem).
Take pins/needles and clamp then in the alligator clips of your volt-ohm meter. These will become your probes.
Insert the "red pin" into the 12volt wire (I find it easy to slip it into the connector itself through the weather seal in the back). and the "black pin" into the ground. MAKE SURE THESE DO NOT TOUCH EACHOTHER!!!!!!!!!!!!!!
Key on the car and you should see 12Volts. If no 12Volt, you have a problem somewhere else.
Now, take the "red pin" out of the 12volt and insert it into the signal. Now turn the car over BY HAND (otherwise this event will happen to fast to really catch) and as you make your way around (remember to go AT LEAST 2 turns as the cam turns 1/2 crank), you SHOULD see a 5Volt "blip." If no 5Volt signal, the sensor is bad.
This same process happens with the Crank Sensor also.
Not to discurage you, but I had this EXACT "problem" a while back. The car would turn over, backfire/try to fire on the wrong stroke, etc. My reluctor wheel was welded when I built the engine (so it CAN NOT turn/move) so I felt it HAD to be the sensors. I replaced both the crank and cam sensors (which turned out to both be good), tested EVERYTHING, and always had a good signal. My final result was a dead computer (ie: I could still "connect" to it through a scanner but something inside burned out).
Now I have a FAST XFI.
12-19-2006, 03:42 PM
#6
Originally Posted by 2001CamaroGuy
Insert the "red pin" into the 12volt wire (I find it easy to slip it into the connector itself through the weather seal in the back). and the "black pin" into the ground. MAKE SURE THESE DO NOT TOUCH EACHOTHER!!!!!!!!!!!!!!
Key on the car and you should see 12Volts. If no 12Volt, you have a problem somewhere else.
Key on the car and you should see 12Volts. If no 12Volt, you have a problem somewhere else.
uhh, if you're going to do this, i reccomend you tape off the pins/probes, first....because if they short you WILL fry the PCM. there is no load resistor or diode protection to save it....
12-28-2006, 07:17 PM
#7
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Best thing to do would to be to get a Tech II and watch the cam counts, or, better yet, just see what error is present. that will be the easiest rather than chasing your tail. If you take it to a garage, do it around 5 and try to watch what the guy does and how he figures out the problem. This will be the best learning session you could ask for, and, if you talk to him right, you probably won't even get charged.
