There should be no pulses on any ground wires. I'm not sure how you're getting that result, but you should find 0.2 volts on the ground wires for the sensors because those go to ground through the Engine Computer first. In it, the monitoring circuitry is responsible for "dropping" that 0.2 volts. Most people don't notice that 0.2 volts and see it as 0.0 volts, which is okay.
I never measured the voltages on the ground, or "return" wires for the injectors and ignition coils, but those also go to ground through the computer and its switching transistors. That would suggest there will be more than 0.0 volts on them, but that's hard to measure because there's current pulsing on and off through them. A break in one of those ground wires would stop one injector or one ignition coil from working, but that would result in different symptoms. The engine would try to run, but very poorly.
I'm more interested in your observation, " im baffled by having no hot wire voltage to the fuel injectors.", And earlier you were on the right track when you found 0 volts on the dark green / orange wire. That voltage comes from the automatic shutdown, (ASD) relay two times. First, you will find 12 volts on that wire at any injector, any ignition coil, and on the two smaller terminals on the back of the alternator, for one second when the ignition switch is turned to "run". That's best observed with a test light because most digital voltmeters don't respond fast enough. If you see the light turn on for that one second, it proves that entire circuit and relay are okay, and the computer has control of it.
Next, the ASD relay turns on again when the computer sees engine rotation, (cranking or running). That's when it sends 12 volts to the ignition coils, injectors, alternator field, oxygen sensor heaters, and fuel pump or pump relay. The computer knows the engine is rotating by the signal pulses it receives from the crankshaft position sensor and the camshaft position sensor.
I'm sorry if I'm repeating myself. I'd rather do that as long as it means I haven't overlooked an important comment.
The crank / no-start I was involved with was caused by the sheared-off dowel pin I described earlier, but one ignition coil did turn on and off intermittently during cranking, which added to the confusion. I had that fault code for "cam and crank sync". You don't have that code. Instead, you have the more common code 340. Joe is more than qualified to continue on with your diagnosis. I just wanted to add these comments of value so no possible elusive cause got overlooked. I'll pop back if I feel the need to add another wondrous comment.
Saturday, July 30th, 2022 AT 6:22 PM
