LQ4 swap into 77 c10 no start issue got me stumped

[Tbrendal]

1st post here so please bear with me, I swapped in a 2006 LQ4 with a 4L80e into a 77 c10 2wd truck. Been working on it for a few years now and went to try and start it for the first time. Sadly, there is a no start condition. I have verified all the normal stuff and am at my wits end as to why, I am not getting any spark as verified with both the plug removed and grounded and my inline spark tester. I have verified that my ignition relay is hooked to a 12v in run and start power source(was the HEI power wire). I have checked power to my coils in both run and crank with good results. I have verified all my grounds from the PCM connectors out. I have completed an initial start "tune" based on what others have said as far as deleting VATS and making the recommended changes for my engine configuration which is as follows. Stock LQ4 with the exception of a Elgin sloppy stage 2 cam. The engine/trans/wire harness/pcm all came from the same donor truck a 2006 Silverado 2500 4wd. I also converted the trans from 4 to 2wd.

I am new to HPtuners as well as tuning this platform, I have experience tuning the old style TBI system, I had a 90 chevy with a 350 and vortec heads, cam, high rise intake, that I managed to tune so I think I should be able to pull this new stuff off! It is so much nicer not having to burn chips!!!

Anyhow, If there are any masters out there that are up for a challenge please take a look at my tune and scan log and see if you can tell what the heck I am doing wrong or missing.

I look forward to making some new friends here on the forum!2024-3-27- Safe spot for 1st start.hpt4th no spark.hpl5th.hpl

[edcmat-l1]

If you don't have any spark, and you have power to the coil packs, the most likely cause is bad or no grounds for the coil packs. There should be a ground wire for each bank that normally would be bolted to the back of the heads. Need to check to see if they're there.

[Tbrendal]

I have verified those grounds multiple times. verified power as well.

[Tbrendal]

look at my scan log, i added all the coil test and they indicate passed.

[edcmat-l1]

If you have power, ground and RPM you should have spark. Where did the harness come from?

The control circuit test doesn't mean you have power and ground.

[blindsquirrel]

May be a red herring but there are a couple spots in the log where the engine is cranking but control module voltage drops to 0.00V.

[Tbrendal]

I just double checked again and I have power in on and start/crank. I took the grounds off the heads again and cleaned again and verified good continuity between the black coil wire and battery ground/chassis/engine ground.

[Tbrendal]

I think I prolly turned the key off.

[Tbrendal]

Could the PCM be bad? It looks like it is working with the exception of the spark not being there. It is my understanding that the PCM provides the ground when it wants the plug to fire. Is that a correct assumption?

[blindsquirrel]

Ignition Coils

Each ignition coil has an ignition 1 feed and a ground. The PCM supplies a low reference and an ignition control (IC) circuit. Each ignition coil contains a solid state driver module. The PCM will command the IC circuit ON, this allows the current to flow through the primary coil windings for the appropriate time or dwell. When the PCM commands the IC circuit OFF, this will interrupt current flow through the primary coil windings. The magnetic field created by the primary coil windings will collapse across the secondary coil windings, which induces a high voltage across the spark plug electrodes. The coils are current limited to prevent overloading if the IC current is held high too long. The spark plugs are connected to their respective coils by a short secondary wire. The spark plugs are tipped with iridium for long life and efficiency.