Cam Sensor Help

[1BADDAM]

Car has 74k, developed a dead miss at 1/2 to 3/4 throttle. Narrowed it down to the cam sensor, as when disconnected (batch mode) car ran like a raped ape, no miss. Pulled the cap, it looks like new, interrupter ring is ok noticed it rotates a few degrees side to side, tab is on interrupter ring, although was slightly bent in toward the center of the ring (could be an issue ..???, going to order RJC repair kit regardless.) Shaft has roughly .045" -.050" end play.

Is this end play excessive enough to cause the missing ? I notice when you pull up on the interrupter ring the shaft rotates, causing the ring to move, thus changing the degree of rotation on the window. Would tweaking the sensor CW or CCW a few degrees cure this or does it need to be shimmed at this point ? TIA

 

[1BADDAM]

Bueller............Bueller

 

[jpwalt1987]

I know this is an old thread but I basically have the same question. Can anyone answer this?

 

[TurboBuRick]

Tweaking the sensor can correct drive ability issues. Does that answer your question?

RL

 

[trbojo]

Tweaking the sensor can correct drive ability issues. Does that answer your question?

RL

dealing with a similiar issue....is rotating the cap clockwise advance?? i think that's what i remember...

 

[EVIL]

The cam sensor only goes in one way. It is not adjustable.

 

[trbojo]

The cam sensor only goes in one way. It is not adjustable.

if you rotate the body one way or the other, you are changing the point at which it starts the sequence......advance or retard.....just like a distributor....

 

[bison]

dealing with a similiar issue....is rotating the cap clockwise advance?? i think that's what i remember...

The rotation is clockwise so to advance you would turn counterclockwise. There is no advantage to playing with position. As long as its not too far off it will work. The only danger with it is if it were to somehow rotate enough while under power to be in the next cylinders firing while under power. The timing would be way off and catastrophic engine damage would be the result. I've never seen this happen though.

 

[trbojo]

The rotation is clockwise so to advance you would turn counterclockwise. There is no advantage to playing with position. As long as its not too far off it will work. The only danger with it is if it were to somehow rotate enough while under power to be in the next cylinders firing while under power. The timing would be way off and catastrophic engine damage would be the result. I've never seen this happen though.

I've talked to Eric Marshall about this...his experience, especially with aftermarket cams is that the cars seem to run best with the cam sensor advanced as much as you can....i've also seen plenty of guys with drivebility issues clear them up this way....i just couldn't remeber which way to rotate....i'll be trying it out today...

 

[TurboBuRick]

The rotation is clockwise so to advance you would turn counterclockwise. There is no advantage to playing with position. As long as its not too far off it will work. The only danger with it is if it were to somehow rotate enough while under power to be in the next cylinders firing while under power. The timing would be way off and catastrophic engine damage would be the result. I've never seen this happen though.

I have fixed several cars and saved people a ton of time and money with a simple tweak of the cam sensor. Sometimes these problems have plagued for years and no one else could figure it out. Every part been replaced but the condition still exists. In some cases a module swap will require the cam sensor to be tweaked. I'm sure you have experienced the same. No?

RL

 

[jpwalt1987]

The reason I bring this up is in the "explosion in intake pipe" thread.

 

[bison]

I've talked to Eric Marshall about this...his experience, especially with aftermarket cams is that the cars seem to run best with the cam sensor advanced as much as you can....i've also seen plenty of guys with drivebility issues clear them up this way....i just couldn't remeber which way to rotate....i'll be trying it out today...

I've played with this on the dyno and saw nothing but it's definitely possible that at low rpm low pulse width there is some advantage in drivability. There are so many variables that it's hard to say what is doing what. The cam sensor is relying on the timing set to rotate it and they are usually sloppy. Also as already mentioned the cam sensor has some end play when installed and the gear is a helix so it's advancing/retarding slightly as the sensor moves. Also the cam could be installed advanced or retarded. If you stack all these clearances you can see where there is a lot of room for the cam sensor to be "off". If I have a car that acts weird I loosen it and turn a few degrees at a time till it runs better. The factory setting usually is gtg.

 

[jpwalt1987]

http://www.turbobuick.com/forums/threads/explosion-in-intake-pipe.383009/

 

[bison]

I have fixed several cars and saved people a ton of time and money with a simple tweak of the cam sensor. Sometimes these problems have plagued for years and no one else could figure it out. Every part been replaced but the condition still exists. In some cases a module swap will require the cam sensor to be tweaked. I'm sure you have experienced the same. No?

RL

Yup. Typically shows up as a low rpm drivability problem. I just turn the cam sensor a dew degrees and it's gone. When cars run screwy I check the sensors use the flow chart. 99 times out of 100 it's an ignition problem. I've fixed at least 5 cars in my life where the owner changed plugs but must have dropped one and closed the gap. Often I go back to the last area that was altered. Even if the owner doesn't believe it's a potential problem area

 

[trbojo]

Yup. Typically shows up as a low rpm drivability problem. I just turn the cam sensor a dew degrees and it's gone. When cars run screwy I check the sensors use the flow chart. 99 times out of 100 it's an ignition problem. I've fixed at least 5 cars in my life where the owner changed plugs but must have dropped one and closed the gap. Often I go back to the last area that was altered. Even if the owner doesn't believe it's a potential problem area

the problem i was having was just about the same as when i had a cracked plug.....a quick blip of the throttle in park would cause a backfire through the intake....i advanced the cam sensor this afternoon and problem is gone......

 

[bison]

the problem i was having was just about the same as when i had a cracked plug.....a quick blip of the throttle in park would cause a backfire through the intake....i advanced the cam sensor this afternoon and problem is gone......

A cracked plug would be worse with increased cylinder pressure. The cam sensor out of adjustment wouldn't bennies dependent at all and probably would do nothing at high rpm/pulse width

 

[turbofabricator]

The cam sensor is being pulled DOWN into to timing cover when the engine is running. It is stopped by the oil pump drive shaft. It will not vary with rpm. I personally have never seen any gain with a cam sensor adjustment. It either runs or it doesn't. But then again I've only been tweaking these cars since 1988. I surely don't know everything.

 

[jpwalt1987]

The cam sensor is being pulled DOWN into to timing cover when the engine is running. It is stopped by the oil pump drive shaft. It will not vary with rpm. .

Ken, this is what I was wondering as I was checking the play in the sensor and noticing how it interacted with the helical cut can gear. Thanks.

 

[BEATAV8]

I was messing with my TR6 ignition today and tried the base timing feature and cam sensor phasing feature. Found out my base timing was good, right on the money, but my cam sensor was way retarded. Car has/had a few weird gremlins I wonder if they were related... gotta drive it some more and take some data.

 

[TurboBuRick]

Could be.

I like to advance them (counterclockwise) as far as I can. I turn the sensor then start the car. Rinse and repeat till the motor does not want to start. At that point turn the sensor back clockwise a tad and lock it down.

That's the way to do it without the tr6 cool guy phasing feature.

RL