I think it may have jumped timing, so I took an oscilloscope reading from both camshaft position sensors. My scope does not have isolated grounds between each channel so I cannot do a cam/crank relationship test, so I'm forced to read both camshaft sensors simultaneously and try to interpret timing from that by comparing to known good waveforms from Picoscope's Waveform Library...
If I'm reading this waveform from my truck properly, it appears the timing relation between banks is off by almost 90 degrees!
Known good waveform from library (Bank 1 in blue, Bank 2 in red):
Higher resolution photo: https://ibb.co/vJnvwJ1
Waveform from my truck (Bank 1 in blue, Bank 2 in red):
Higher resolution photo: https://ibb.co/4grjxWq
I thought this engine is an interference engine, so wouldn't timing being out that badly have caused valves to slam into the pistons and cause catastrophic damage? There is no valve ticking, no lower end knocking, no smoking out the tailpipe.
Here is a YouTube clip I took of the truck during a cold startup (relatively speaking, it was 75 degrees outside), engine idling, and throttle was never touched during this clip (it has an exhaust leak due to the passenger side manifold being cracked, but that's an old problem that's been there for at least a year so ignore that): https://youtu.be/_AKQ7HI33kQ
I can measure the crank or camshaft independently, and they are both inductive, but when I try to measure both simultaneously it shorts the crank sensor and the truck won't start at all. My understanding is that the crank sensor and cam sensors use different grounding paths or something, and if your scope does not have isolated grounds between channels then you just can't do it. You gotta have a scope with isolated channel grounds. I tried it anyway, but like I said it won't start at all until I disconnected either one of the signals (cam or crank), then it would fire up.
A channel blue wire where black wire where.
B channel red wire where black wire where.
See the following forum post with a reply by Steve Smith for how to connect your scope inputs and grounds