SN-L005V07518D 4.3 vortec Working on a unit that's not starting when up to temperature cranks all day. cold start, unit starts perfectly fine. idles smooth. has good spark. new spectrum regulator. new throttle body diaphragm. starts right up with a small amount of ether and runs until shut off manually. new plugs, wires, cap rotor. does this sound like a relay is overheating? possibly an injector issue at the throttle body? thank you for your time.
If you give it a shot of the juice it starts and you have to do it every time ? Or just to get it going for its first start of the day ? Did it start all the sudden or has it been this way. ? Usually iyou can attribute it to two things.. Low compression, the cylinders don't have the necessary suction to pull the charge into the cylinder or enough to compress the charge to initiate combustion. A compression test would give to above piston condition and a leak down test would give you valve and cylinder leakage. Other would be fuel pressure. You could have injectors leaking down or inadequate rail pressure to crack off. There should be a schrader valve on the rail that will allow you to put a gauge on it to see what the pressure is at the rail. Those are the two most likely causes if the unit runs once a starting fluid is used. I would start there. Of course you could have a vapor lock issue but thats not common on fuel injected engines since the lift pump supplies more than ample psi. Usually to much and the extra fuel returns to tank. A quick test with a few simple cheap tools on the above mentioned will give a place to start