Truck has not been ran for maybe 4 years, ran when it was parked. Cranks, no start, fires if fuel is poured into the the tbi. In attempting to troubleshoot this I have replaced the ICM, injectors, fuel pump. Gets fuel pressure at the tbi, the injectors are just not firing. Where do the injectors receive their actuation command from? checked and cleaned grounds at thermostat housing as well.
No fuel spray? Connect a noid light to the injector harness. Noid light should flash when engine is cranked.
Injectors are powered when key is in "Crank" or "Run". Injectors fire when they are grounded by the ECM. ECM gets the signal to fire the injectors from the ignition module via a wire harness.
Were the injectors you installed "new"? Or "used"? Could they be as stuck as the originals?
It runs if gas is poured into the throttle body. It's not ignition.
It has fuel pressure at the throttle body. It sat for four years and hasn't run without supplemental fuel since.
Possibilities:
The injectors aren't powered during "Crank" or "Run". Check the wire harness and fuses.
The injector aren't grounded. Check the wire harness and the ECM
^^^ Either way,
connect a 'noid light. If it flashes when cranking, there's power and ground to the injectors. That would verify the ECM, wire harnesses, ignition module signal to ECM, and the injector and ECM fuses
MOST LIKELY: Injectors are stuck, gummed-up with dried gasoline deposits. You do have fresh gasoline in the tank...right?
I had some issues with my '88 K1500. Thought I might have partially-plugged injectors. Swapped to a Treasure Yard throttle body assembly. Engine ran terribly. Shook like a dog ******** razor blades. One injector wouldn't spray. I swapped wire harnesses at the injectors, and the same one sprayed and the same one didn't spray. Obviously, I had power and ground on both sides of the injector harness. So I let the stupid thing run on four cylinders while I had a sit-down to think.
Right about the time I get settled with my Thinking Drink, "Poof", the engine RPM climbs, it smooths out, and both injectors are firing. It's run reliably on both injectors for years since then.
You could pull the injectors out of the housing, spray solvent into the injectors, or soak them in some solvent, and see if you can dissolve the deposits. Or you could be lazy, and just power the fuel pump with a battery charger to hold battery voltage for an hour. Consider dropping a big (20 oz) bottle of Techron in the tank before running the pump.
If it runs right after that...I'd drop a bottle of Techron in the gas tank for each of the next two tankfulls; and buy your gasoline at a "Top Tier" station.
