So I'm back to trying to figure out the no-spark on my 2000 5.9 (gas).
Determined I'm not getting a switching signal from the PCM, but no crank sensor code shown with OBD (I was going to check it's voltage but the connector is really difficult to get to)
4 unrelated codes for high voltage at various sensors (battery temp, coolant temp, intake air temp, TPS)
All seems to tie back to the PCM. In looking at the PCM pinouts...
Black connector, A-4 is sensor ground, A-17 is 5-volt supply.
White connector, shows B-31 is 5-volt supply (guessing this is the secondary 5 volt).

I want to check the 5v supply outputs- is it a simple matter of grounding these individually to the sensor ground A-4?
I don't want to fry anything that isn't already toast...

 

I assume you mean putting the voltmeter between sensor ground and 5V, otherwise you're creating a dead short and that will not help. The high voltage codes are likely not unrelated but part of the problem. Do you get a tach bounce when you try to start it ?

 

Just the very slightest. Fuel gauge as well- does not read with key in "run" position- but CCD self-diagnostics show all is fine. I had read somewhere that some of the gauges get data from the PCM, so even though they "function" according to the CCD, I keep thinking this is a PCM issue.

 

All of the gauges on your truck get their cue from the CCD bus. Including the fuel gauge. One of the high-zoot scan tools should allow you to read what the PCM thinks fuel level is.....

 

If the tach moves a little during cranking that means the PCM sees a signal from the crank position sensor.

Questions:
What are the exact codes for the sensors ? Wondering if they are "circuit high" which are typically wiring problems.
How did you determine the PCM isn't controlling the coil ?

 

Doing Live Scan with the Blue Driver- while cranking- showed
Did not see tach bounce this time on the gauge (I could swear I saw it bounce yesterday), and no rpm's shown on scanner
Engine coolant temp showed lower limit, -40 degrees
Intake air temp same- lower limit, -40 degrees
Fuel system- "unknown".

Recap:
Voltage present from ASD to coil (checked w/volmeter). As I understand it, the PCM would need a signal from the crank sensor to activate the ASD (also, swapped the ASD relay with A/C clutch which I knew was fine). If so, the crank sensor would be functioning (and, no code present for faulty crank sensor). No switching signal to coil, checked with test light on the switching wire while cranking. Switching signal comes (or not in this case) from PCM.

Any reason to think this is the crank sensor, and not the PCM or something else (though, no clue what "something else" could be)?

 

That minus 40 degrees is going to be a problem. The PCM is going to be literally DUMPING in gas trying to get a mixture that will burn.

 

Would you replace the PCM if it were your truck?

 

Those -40 temps makes me think the truck thinks it is really cold out and dumping to much fuel and flooding the engine

 

No not yet