Engine swap cranks but doesn't start
 

I have a 2002 blazer 4.3l 4x4 that was my son's. He drove it hot and blew a head gasket. I purchased a 4.3l out of a 2000 s10 2wd. Everything went as expected until it was time to fire it up. It cranks but doesn't start. No engine codes. Will run if you pour gas in the throttle body. Has fuel to the valve stem at the throttle body. Any ideas?

Is there any chance that the gas is bad or old?

These engines are particular about fuel pressure. You should test pressure and leak down per the sticky.

Since it fires up with gas down the throttle body lets assume for now that spark is good. That leaves fuel injectors. We can test for injector pulses at the harness if we get this far.


George

Thanks for the reply. I had to rent a pressure tester.

I drove the blazer into the shop to do the swap. So I think the gas is good. Pressure tester showed 42#.

42 pounds at initial key on or 42 pounds after the 10 min leakdown and if so what was the key on pressure?

George

Initial

That why your truck wont start. Now you have to find out if its the injectors/regulator or the fuel pump so move down to the fuel filter fitting and test there. If that fails then its either the fuel pump or its wiring/power. If it passes then its the injectors or regulator.

Fittings in post #43:

https://blazerforum.com/forum/2nd-ge...eakdown-88305/

George

Same at the tank side of the filter

OK then its the fuel pump, or its power/ground/wiring. First thing to check is the voltage at the fuel pump priming tab at key on.


George

11.91 volts

That's a little low, what's your resting battery voltage and your battery voltage at key on when its 11.9V at the priming tab?


George