I find these kind of jobs very interesting! The sad thing.....This is a guy that has sent me work in the past (Owns a Vending Company), But always whines/complains because I use OE parts that are naturally more expensive.....So he deals with other shops that will gladly use cheap parts.
UNTIL they can't fix something! He calls me saying his 2002 Chevy Express 3500 box van has a wiring issue & that ALL the ignition components have been replaced but still has no spark.
Crank sensor, Cam sensor, Distributor cap, Rotor, Coil, & Ignition module are all new.
*Confirmed that it indeed has no spark out of the coil.
*Cam & Crank signals are present via Scan Data
*Has a good 5-Volt square wave signal from the PCM to the Ignition Control Module
*Has a Primary control signal output to the Ignition Coil from the Module, Along with having a 12-volt return from the Primary Windings (Meaning the coil has power)
There was NO positive Induction on the Primary Coil Control circuit, A good coil will spike the voltage on the Primary circuit past 100-volts when Secondary voltage is released/induced.
This coil was pulling the Primary Circuit all the way to ground....Meaning it's was probably shorted internally? I would have liked to put a Amp Clamp on the Primary to prove it out but this rig has a 300,000 miles on it & I'm not going to mess with the harness causing future issues!
Though I did go one step further that in all honesty I didn't have to.....
A Coil is a Coil, Standard 2 wire ones are anyway, I had some COP coils off a 2013 Ford 3.7L & adapted it to the GM coil connector.....Nice strong spark!!
In the moment, I was concerned about possible damage to the Ignition Control Module because the shorted Coil, But it had control so that's not likely an issue.
1st pic.....Good square wave from the PCM to ICM
2nd pic....Control signal on the Primary.....Negative Induction (Firing line going down)
3rd pic.....Ford COP adapted to the coil connector