Cam trigger moves position

Have been trying to tune a VW 2.0 ABA engine for about a week now and have been having trouble setting the base ignition timing. I’m using a link G4x fury ECU. The Crank trigger is a 60-2 three wire reluctor and the Camshaft position sensor is on the original distributor of the engine. I’m running direct spark now because of this will be a turbo engine so I need both triggers. The problem I’m having is that on the lab scope in the ECU the camshaft trigger moves position so it isn’t always in the same place making it impossible to set the ignition timing. I can also see this on the timing light as the timing mark moves clockwise around the pulley as I crank it. Trying to narrow down if this is a setting I have in the ECU or something mechanical possibly. Thanks!

OK, I'm NOT an "expert", by any means, but if I understand it correctly, you're setting the engine up with full, sequantial ignition and fuel, and using the distributor ONLY to provide a reference for camshaft position?

It seems like the distributor is set with the sensor signal point too close to the 'start" point of the crankshaft, the missing tooth the sensor uses to index the crank position. If the camshaft is also variable timing, it's possible the cam'and crank signals are too close together at times, maybe even crossing over, which will really confuse the ECU.

Have you tried rotating the distributor body - or removing it and replacing it with the drive a tooth or two, or three, if it's fixed in place - advanced or retarded, so the distributor/cam' sensor is further from the crankshaft's? You may need to adjust the cam sensor position in the software, but as I said, I'm no expert and will leave that for someone else.

The cam sensor has no influence on ignition timing, it is only used to determine phase (ie so the ecu know if the next TDC is compression stroke or exhaust stroke).

When the "set base timing" screen is open the spark will occur at the exact same point on the crank wheel in reference to the missing tooth gap.

The fact you have observed the spark moving and the scope has captured the cam tooth in different locations compared to the crank suggests to me possibly the trigger wheel is not secure. Is it a factory trigger wheel or something aftermarket/DIY? I have seen some nissan and BMW trigger wheels that are fitted to pulleys with a vibration dampers built in slip around due to a failed bond, so I would look for possibilities like that.

Another trick that may help confirm it is the trigger wheel moving, you can remove all spark plugs except #1, in the trigger scope you will then see the amplitude of the teeth dip when it slows down at #1TDC compression once every 2 revs. The dip should be the same number of teeth from the gap everytime if the wheel isnt moving.

Thank you guys, I went through all of this for about 2 days going back and forth trying things, I even went back and did the timing belt job over thinking I was missing things. Last resort I pulled the oil pan down to see if their was a missing tooth or something odd on the tone ring and found the tone ring was completely sheared off from the crankshaft, I actually am surprised I was getting any reading at all. So now it’s time to take the engine back apart.