When testing the CMP sensor on my 97 C1500 I ran across a strang reading and would like some opinions before spending any money. There are 3 tests that I ran....the first two passed no problem....but the third test has me stumped. says to hook some jumper wires between the CMP sensor and its connector creating a connection. I had tp hook a DC volt meter to terminal B to check for a voltage reading between 5-7. What I got was it would jump upto a bit over 5 volts speratically....it jumps up and down . Any idea's? Replace?

 

My explination of my problem is a bit lacking so let me run down it a bit...


I'm having a timing problem....done EVERYTHING....and am now down to testing sensors. The CMP sensor being the main suspect. The chiltons repair manual describes a test to check the sensor. Here's what It says to do and what I did....

Disconnect the cmp sesor wiring harness and connect an LED test light between CMP harness terminal C and battery ground.
With the ignition on and engine off, verify tat the test light illuminates.
If not as specified, repair or replacethe fuse and/or wiring....PASSED

Next, carefully connect the test light between CMP harness terminal A and C and verify that the test light illuminates.
If not as specified, repair the CMP harness ground curcuit (terminal A)....PASSED

Last, turn the ignition off and disconnect test light. Connect suitable jumper wires between the cmp sensor and cmp sensor harness. Connect a DC volt meter to the jumper wire corresponding to cmp terminal B and battery ground.
Start the engine and verify that the voltage signal is 5-7 volts.
If not as specified, the cmp sensor may be faulty....

that last test is the one in question. The voltage is jumping everywhere hitting up to 5 volts speratically.e run it down a bit....

 

Went ahead and bought a new cmp sensor....fixed nothing!....Just throwing money at it....

Gonna have to start a new thread.