Crank, no start, no rpm signal, help

Alright guys, this has been driving me up the wall here and I thought I?d bring in a little help.
Quick back story?I?m a 21 year veteran in the automotive repair industry, owned a repair shop early in my career for 6 years then switched to restorations and customization/swaps, that sort of thing, closed my shop during the pandemic and have been building personal cars from my home shop full time since then and i do EVERYTHING myself, metal shaping, rust repair, interior, glass, engine buildin, machining (manual only), body, paint, chassis, and electronics.
So I know my way around a swap, and can build pretty much anything. BUTTTTTTT this thing has me completely stumped and it?s driving me absolutely crazy.
Okay, so vehicle is a 1993 GMC s15 Jimmy 4x4, has a 5.3 swap w/ heads, cam, custom stainless single exit exhaust, built 4l60e 2wd conversion (2wd?s are hard to come by in my area and this one was OUTSTANDING condition so I caved and went the route I did. OG PAINT is immaculate interior is like no one had ever even sat on it, etc. ),

Anyways, the story?.
Get the truck running, start doing my tuning thing, getting some miles on it, runs great, no issues, and the other night, pulling up to a pizza joint, sputter sputter sputter dies. Won?t restart. Have my laptop w/vcm scanner so I take a look see what is going on, and I have a p0335 (crank sensor circuit malfunction) run home, grab one out of another 5.3 I have laying around, pop it in, and fired up, drive home great. No issues. I?m thinking cool, I?m going to hit the cars and coffee in the morning in Lake Tahoe. Go to fire it up. Crank crank crank no fire. No rpm signal, check for signal with an oscilloscope, i have pulse, but no 12v signal coming from the pcm, double checked all my grounds, connections, fuses, even popped in another pcm I had for another project (gm 0411 dbc return fuel rails). Nada, nuthin, just cranks. I put power to the 12v ignition wire #2 on blue connector with a power probe, fuel pump lights off, and injectors fire (checked with noid light) but no coil fire. I have checked depth on the sensor, deeper, shallower, doesn?t matter, even ran temp hot leads to the stand alone harness relays and fuse panel, nuthin.

So I?m stumped. Any help would be astronomically appreciated and grateful.

Jeezus can we get a summary? And where's the data log and any other pertinent real technical info to go along with the way too long story?

Okay, no start but cranks, no 12v signal out of the pcm @ pin 2 blue, checked and remounted all grounds, have all power connections to pcm full battery voltage and ignition switched pins (can?t remember off top of my head exactly which ones) 1993 gmc s15 jimmy with stand alone 0411 dbc built-ish 5.3, 243 heads, comp cams xr series cam. Truck ran, then quit, put in new crank position due to the p0335 in a parking lot, got it home, and cranks but now no start since. Injector and coil grounds good, no positive at coils as well.

No rpm signal from crank position, 12v reference, good ground at sensor.

I can try and get log but there everything but rpm is up to snuff. Just dead flat at zero.

Do you pro's remember all of the pinouts for all of the ECM connectors? Does pin 2 Blue mean anything to you without the wiring diagram? For myself I would need a wiring diagram for that to mean anything.

Have you tried to start it with flammable spray? But it won't start without an rpm signal. Not sure what "rpm is up to snuff. Just dead flat at zero." means if the rpm is zero when the rpm isn't actually zero.

Quote:

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Originally Posted by gtstorey

Do you pro's remember all of the pinouts for all of the ECM connectors? Does pin 2 Blue mean anything to you without the wiring diagram? For myself I would need a wiring diagram for that to mean anything.

Have you tried to start it with flammable spray? But it won't start without an rpm signal. Not sure what "rpm is up to snuff. Just dead flat at zero." means if the rpm is zero when the rpm isn't actually zero.

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Okay, sorry if that was a little hard to understand.

Channels key on engine off, and when cranking.
Map is at 80ish (I?m at 4500ft elevation),
tps 0-100% when throttle is depressed.
Maf frequency 0hz cranking
zero commanded afr.
Module voltage is equivalent to battery voltage near exact same or just a 0.1-0.2 under.
Iac has a step count but seems high in the 200 count range?
ect is accurate
iat is close to ambient.

No rpm, no spark advance.

Pin 2 blue connector is 12 volt + reference voltage to the crank sensor @ position A on the sensor connector.
Both Denso and Delphi wiring schematics as per all-data

Have you checked it with an oscilloscope? Signal wire to ground, should see the pulses of the crank reluctor wheel while cranking.

Quote:

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Originally Posted by We-R-138

Okay, sorry if that was a little hard to understand.

Channels key on engine off, and when cranking.
Map is at 80ish (I?m at 4500ft elevation),
tps 0-100% when throttle is depressed.
Maf frequency 0hz cranking
zero commanded afr.
Module voltage is equivalent to battery voltage near exact same or just a 0.1-0.2 under.
Iac has a step count but seems high in the 200 count range?
ect is accurate
iat is close to ambient.

No rpm, no spark advance.

Pin 2 blue connector is 12 volt + reference voltage to the crank sensor @ position A on the sensor connector.
Both Denso and Delphi wiring schematics as per all-data

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Pretty much everything the ECM does is based upon rpm. Forget everything else until you get an rpm reading.

Absolutely. The only thing is..why? Why no voltage at crank sensor reference voltage. I?ve swapped pcms with a buddy and it works flawlessly on his car. So what am I missing? I?ll try and attach the diagram I?m using.

If that PCM works in another vehicle then it is capable of supplying B+ on blue pin 2. That leaves the wiring in your vehicle. Remove the wire from the connector and put a short test wire in it's place and check for B+ on the test wire. Have you checked your +12 battery and +12 ignition inputs to the PCM are there when cranking too? I've seen swaps where they are there with KOEO but lose one or both when cranking.