Cam Sensor Information and C3I Module Pinouts
Paul Frericks and Tom Chou and Ken Mosher
Cam Sensor Adjustment Procedure
1. Measure on a piece of masking tape and mark it at 1.45" and tape it to the Balancer at 0 degrees.
2. Bring #1 to TDC and then grab the intercooler fan and rotate the motor to your mark (25 degrees ATDC). This takes a little patience and muscle. You can try bumping it with the starter, but I'm never very successful at that.
3. Back probe the middle wire of the cam sensor (marked B and normally blue) with a voltmeter. Turn the key ON, but leave the engine OFF.
4. Loosen the sensor with a distributor wrench or a wobble socket and extension.
5. Rotate the sensor full CLOCKWISE. The voltmeter should read 7.5+ volts.
6. Slowly rotate the sensor COUNTER clockwise until the voltage drops.
7. Secure the sensor at the instant the voltage drops.

The sensor is a hall effect device with a rotating metal ring that is driven from the front of the cam gear via a shaft (like a distributor). This ring passes thru a grooved sensor molded into the sensor cap. The metal ring has a notch or window cut out of it. When the window goes by the sensor, the voltage drops, which tells the ECM where #1 TDC is.

Cam Sensor Adjustment Procedure with an Oscilloscope
1. Somehow, tap into the ignition module connector. Pick your cam & crank sensor signal & GND from there.
2. Put 1 channel of the scope on the cam and another channel on the crank signal.
3. Rising edge to falling edge (and vice versa) on the crank signal is 60 crank degrees.
4. Falling edge of cam signal occurs 25 deg ATDC of #1 cylinder on compression stroke. Make SURE this is occurring on the compression stroke and not the exhaust stroke of #1. If you do set the cam sensor to the exhaust stroke, it will be 180 cam degrees (360 crank degrees) out of sync - the engine will still run but not as well as fuel will be puddling for 1 crank rev.
5. Rising edge of crank signal for #1 cyl occurs 10 deg BTDC.
6. This means that the falling edge of the cam signal should occur 35 degrees after the rising edge of the crank signal. Remember that half a period (rising to falling edge or vice versa) of the crank signal is 60 crank degrees, so use it as a ref to measure the 35 degrees.
7. Spec is +- 5 degrees so you don't have to be exact. Also, obviously the engine has to be running to do this. Setting the CPS with a scope like this is the most accurate method, although the static method of setting the crank 25 degrees ATDC and twisting the CPS till you're on the borderline where it switches is probably within the 5 degree spec.
8. The hold down bolt is either a 14mm or 9/16. I always use a 14mm 1/4 inch drive. I've done it with a 3/8 drive and u-joint, but the CPS itself is kinda in the way as the bolt is kinda tucked under it. In some cars (mine for instance), the CPS distributor shaft is put in in such a way that once the CPS is correctly set, the "ears" that bolt the plastic cover to the unit are directly in the way of the hold down bolt so you can't get a socket wrench on it. In those cases you have to pull the shaft out and reposition it.
C3I Module Pinouts
Description Color
A 423 ECM B4 EST White
B 424 ECM D5 Bypass Tan/Black
C 430 ECM B5 Ref. High Purple/White
D 121 Tach Lead White
E 951 ECM A11 Cam White
F 453 ECM B3 Ref. Low Black/Red
G 918 Crank Sensor B Signal Green
H 952 Crank Sensor C GND Black
J 916 Crank Sensor A 12v White/Red
K 952 Cam Sensor C GND Black
L 917 Cam Sensor B Signal Blue LT
M 916 Cam Sensor A 12v White/Red
N 439 Ignition Power Pink/Black
P 839 Ignition Power Pink/Black

Description Color
A 423 ECM B4 EST White
B 424 ECM D5 Bypass Tan/Black
C 430 ECM B5 Ref. High Purple/White
D 453 ECM B3 Ref. Low Black/Red
E 121 Tach Lead White
F 643 Crank Sensor B Signal Blue/White
G 642 Crank Sensor C GND Black/Yellow
H 641 Crank Sensor A 10V+ Black/Light Green
J 630 ECM A11 CAM Black
K 633 Cam Sensor B Sync Brown/White
L 632 Cam Sensor C GND Black/Pink
M 639 Ignition Power Pink/Black
N 631 Cam Sensor A 10V+ Yellow
P 439 Ignition Power Pink/Black


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