will not start without priming throttlebody

Car: Chevrolet, Blazer S10, 2010, 2.8 - Back to Fix-It

Q.have 1986 s-10 blazer, after changing oil, and filter, airfilter, fuel filter, sparkplugs, and wires, and draining radiator, will not start without priming throttlebody, after starting will idle, and rev, but dies when throttle opened completely.
I have replaced fuelpump, injectors, intake gasket, throttlebody base gasket, throttle position sensor, temp control sensor, accelerator pump, relays, ecm, replaced entire distributor, coil, timing gears, and chain, battery cables, altenator, starter, vacuum lines,3 relays on d/s fender, idle/air controll sensor, I have replaced evrything I can think of that has anything to do with starting, and running. what can problem be?

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Answer We need to take a few steps back, and look at a basic on your vehicle.
It runs when primed, but only at idle.
You need to run the engine with a fuel pressure gage on there.
These things will run if the pressure is low, but they will not stay running and usually just trying to bring the RPM up will cause the engine to die if the pressure is low.
You must have a minimum of 9 to 13 lbs of fuel pressure for your year make and engine size.
Back then, GM gave us a Fuel Flow Test and a Pressure Test.
Here's the flow test.

FUEL FLOW TEST
- Disconnect the fuel feed line.
- Apply battery voltage to the fuel pump test terminal (terminal "G " of ALCL connector).
- Fuel Pump should supply 1/2 pint or more in 15 seconds.
- If flow is below minimum, check for fuel restriction. If there is no restriction, check pump pressure.
Do these two tests (Flow test..pressure test) and you'll most likely isolate your problem.

Addition THAT'S NOT THE PROBLEM, ALREADY CHECKED FUEL PRESURE, GOT PLENTY.

Answer Since we know then that the fuel system is maintaining fuel pressure, you need to check for a restriction in the exhaust system.
The best way is to simply disconnect the exhaust in front of the CAT Converter and see how the throttle responds with the exhaust system opened.

Addition seems to be plenty of exhaust flow coming out of tailpipe.

Answer As you attempt to raise the rpms on the engine, the exhaust flow should push large amount of air out the tailpipe. Another test is to remove the oxygen sensors to allow the exhaust to escape pre catylist just to verify there isn't a partial restriction.
As I review the steps you have taken to this point, I'm running into a road block here as well, not having the truck here with me.
There were some problems over the years with the aluminum wires that are connected to the injector.
Can you visually see by looking down the throttle body, if the fuel shuts off abruptly when it dies, or is it more like it is losing the spark and the fuel seems to continue to flow.
I would buy a can of carb spray and introduce additional fuel in the form of carb spray at the point when it seems to cut off. If when you spray the addional fuel it continues to run, then we can be relatively certain, that we have a fuel delivery problem.
If when adding the carb spray things remain the same, we should look more at the ignition system shutting down.

Addition the fuel seems to shut down when throttle is open completely, but carb does fine at idle, and when you flutter throttle to rev engine. It's getting fuel at start up, but engine still wont start without priming throttlebody, and then when throttle is open wide seems to lose fuel flow. I've checked voltage at injector connections, and had plenty of voltage. But that was with engine off. I'll try the carb spray, and see what happens, if nothing else it may atleast help me eliminate one more thing.

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will not start without priming throttlebody