Cam Sensor Setting

[pdzz]

I got my engine back in the car today. I set the cam sensor with the Casper's cam tool. Tried starting it and the timing was way advanced. Backed the sensor off 25 degrees and it started right up. First question, isn't the cam sensor used for starting purposes only?? Secondly what could I have screwed up?? Thanks in advance no pun intended. Phil

 

[VadersV6]

Did you have the motor past top dead center on the compression stroke when you set it? Or was it right at TDC? Maybe your timing chain is really wacked out.

 

[pdzz]

new roller timing chain, does have the three settings but I put it at zero, not the 2 degrees before or after.

 

[bruce]

I got my engine back in the car today. I set the cam sensor with the Casper's cam tool. Tried starting it and the timing was way advanced. Backed the sensor off 25 degrees and it started right up. First question, isn't the cam sensor used for starting purposes only?? Secondly what could I have screwed up?? Thanks in advance no pun intended. Phil

I'd venture to say, you had it off to begin with.

FWIW:
An engine won't start till the ecm sees a cam synch. Below ~400 RPM the motor runs in batch fire, and only uses the timing as set mechanically, and the dis module, the ecm doesn't do anything timing wise till 400 RPM.

The cam sensor has nothing to do with the actual ignition timing, other then synch'ing which coil to fire.

 

[pdzz]

Thanks for the quick responses, I am assuming once the engine is running the cam sensor is out of the picture??

 

[d0n_3d]

eeehhhh I wouldn't say that...I've had problems with my car starting and I've had to mess around with the cam sensor position a little bit...seems to be this way with bigger cams...but it seems like no matter where I set it, the car still has a hard time firing right up on cold starts...it takes a good 5 revs before it fires on cold starts...when it's warm it fires right up...can anybody shed some light on the cam sensor positioning exactly? does it really matter if you are off a little bit? do you HAVE to set it right when the light goes out on the tool?

 

[Blown&Injected]

GN T-Type Org has great the details about what's going on:
http://www.gnttype.org/techarea/ecmsensors/camsensor_FAQ.html
and how to set it:
http://www.gnttype.org/techarea/ecmsensors/camsensor.html
there are some other procedures for setting the sensor, but I have found this one to be simple and straight forward.

Standard Motors, part number PC16 I believe, is the entire sensor for about $50, if anybody needs the whole part.

 

[turbopaul]

This is a must read on how the cam sensor works....

http://www.turbobuicks.com/forums/showthread.php?t=17681

the cam sensor is used for sync only, and has no effect on fueling or timing. The myth about how the cam sensor affects fueling seems to be a tough one to stomp out.

Paul

 

[turbodave231]

CAMSHAFT SENSOR TIMING PROCEDURE

1. With the timing marks lined up (compression stroke #1 cylinder) rotate the crankshaft so the timing mark is 25 degree past top dead center.

2. Take a paperclip or safety pin and backprobe the cam sensor connecter pin B (middle wire). Hook up your volt meter to the clip and to ground. Put your voltmeter on the 12 volt DC scale.

3. Ignition on engine stopped.

4. Loosen camshaft sensor retainer bolt, rotate camshaft sensor counter clockwise until the sensor switch just closes. This will be indicated when the voltmeter reading goes from a high of (5 to 7) volts to a lower voltage. This voltage drop indicates that
the switch is closed. The camshaft sensor at this point should be rotated very slowly back clockwise until voltage on the volt ohm meter goes back to its high reading noted previously. This step insures the camshaft sensor is perfectly positioned in the
edge of the on/off window.

5. Tighten camshaft sensor retaining bolt.

6. Reinstall #1 plug and spark plug wires to coil.

7. Remove paperclip or safety pin.