How to Test a GM 3.6L Timing Chain

Set up your labscope to scope 3 channels at a time. Attach a back probe to each lead and make sure your scope is grounded properly

Locate the two bank 1 camshaft position sensors and crankshaft position sensor, back probe the middle wire of each sensor to acquire a signal ↗ 2:16

Unplug VVT solenoid connectors to ensure engine is in base timing

Adjust your labscope software to get a useable pattern, recommended settings (0-10V scale, 20m/dv time base). ↗ 3:20

Label channels with their corresponding sensors to aid in waveform analysis ↗ 4:15

Pause the waveform and zoom in on one full engine cycle or two crankshaft revolutions. This will make it easier read waveform and to check the cam/crank timing ↗ 5:18

Check pattern of bank 1 intake camshaft position sensor signal, compare with known good pattern ↗ 5:49

Check pattern of bank 1 exhaust camshaft position sensor signal, compare with known good pattern ↗ 6:08

Locate the two bank 2 camshaft position sensors. Back probe the middle wire of each sensor connector to acquire a signal ↗ 7:15

Acquire waveform using same voltage and time scale and zoom in on one full engine cycle or two crankshaft revolutions. ↗ 8:53

Check pattern of bank 2 intake camshaft position sensor signal, compare with known good pattern ↗ 9:16

Check pattern of bank 2 exhaust camshaft position sensor signal, compare with known good pattern ↗ 9:24

If your waveform analysis shows your cam/crank timing is off, mechanical engine timing will need to be checked and repaired.