| 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. |