Camshaft Position Sensor Alignment
 

What exactly does the camshaft position sensor do or indicate to the PCM? I know it tells the PCM when to fire the injectors but based on what? I haven't read anything specific to these 2Vs, but some generic articles say it indicates when #1 is at TDC. The sensor is on the driver's side, so by default if the above this is true, it would have to also indicates when #6 is at TDC (since they have the same TDC. And, would this be following the opening of the exhaust valve? So in the end, when the "bump" on the gear is in direct alignment with the sensor pickup in the front cover, #1/#6 would be at TDC after the exhaust open event of #1?

I have the ModCamPonents cam gears where the I can move the gear independently of the cam, so I want to check and make sure I have everything aligned properly to ensure my fueling is timed properly.

Scott

the crank and cam work together to tell it when and for how long to fire the injectors and the plugs. They're magnetic pickups so they're only going to tell when there's magnetic metal within a certain proximity.

The injectors will fire based on a number of things sensor inputs, same with the plugs.

The cam is turning at half the speed of the crank so the ECU can determine at least 3 specific time/status conditions with the 2 sensors.

Ok, but let's say that I installed the main gear without regard to the cam position, so that in relation to say the key way, it is not in the same position as it would have been with a stock cam gear on there, what will be the effects? It will fire the injectors at incorrect times relative to valve opening/closing correct? And if so, would the sensor pickup on the gear crossing the sensor indicate to the PCM that #1 cylinder is at TDC following the exhaust event?

I am having issues with unbalanced fuel trims, as much as 12%, and am nearly 100% positive that the cams are installed to the proper centerline (I just had the motor out again and checked, checked, rechecked, and checked again to ensure that it was right, but I didn't even think about the position of that pickup on the gear. I installed the gear and then dialed the cam is as necessary.

So the overall question is, does the pickup indicate #1 TDC (in other words could I put #1 at TDC and make sure the pickup on the gear is in alignment with the sensor) or is it offset, which the computer takes into account with its calculations and such? And if it is offset, how would I get it aligned properly? I can make sure the cam doesn't move from its degreed centerline (I have the holding fixture) and can then rotate gear whereever I need it.

Scott

It's possible for you to get 2 results but I think you've got it... you should be able to do that though I'm not sure if the sensor picks up ON #1 or at some point before or after it.

After getting home and putting a stock driver's side gear on a driver's side PI cam I have laying around and just eyeballing things, it appears that the sensor pickup would cross the sensor after intake close, before exhaust open on #6, which makes sense.

If we assume no offset, it could signal TDC since neither valve is open, but the exhaust of #6 is about to open. When this is happening, #1 intake is about to open, which the fueling cycle would then be starting relative to this, accounting for injector delay and such.

I would feel comfortable for my purposes concluding that the pickup indicates TDC, but would definitely like to have some reassurance from someone else out there. But I think I am going to pull the cam cover tomorrow just to see how close/far off it really is from this point.

Scott