LS no start = help please

[lutronjim]

I have a LC9 (ls3) with 65E tranny in my 70 C10 (connect and cruise package).

I have a no start condition (cranks but will not run) with no codes nor cel.

On key on I can hear fuel pump run briefly which is normal. This tells me computer has power and it sees enough fuel pressure to turn off pump.
I have a tank in back, in tank pump, pressure regulator near tank, filter near tank, and fuel line to engine - all new at conversion 3+ years ago.

Turning key to start cranks the engine but no start.

I'm guessing its either missing spark by not firing coils or missing fuel by not firing injectors.

This has happened 3 times in the last 3 years usually on first thing in the morning. By wiggling connectors and trying again got it going to get home. Don't have a clue if wiggling did anything or it just decided to start.

But if it will start, how do you find trouble. Complaints to GM got them to replace the entire wiring harness on their dime during year 1.

This morning I drove it to church for a meeting and 75 minutes later - no start.

Got wrecker to bring it home. This thing has been running great for the last couple of years sans my problem with the brake booster.

Wouldn't start at home. I swapped fuel pump relay with ignition relay - no start. Swapped fuel pump relay with power relay (I assume this is for computer) - no start. Fuel pump relay is good because I can hear it run

I was thinking of putting meter on coils and injectors to see if they are getting firing voltage. Problem is I don't know colors and don't know if my Fluke dvom will show up a short pulse.

Truck is on street and I will try in morning to see if it will start.

Any help would greatly be appreciated.