Chevrolet Repair: fuel in oil, coolant temp, rear cylinders

Question
Hello I have a 1998 5.7L C1500 Suburban. Immediately after starting fuel pours in engine filling  rear cylinders with fuel and it also goes in oil. Of course you get a what I call hydraulic lock, the starter will not turn over until fuel is expelled. Installed new spider with the engine. It is a rebuilt GM long block less than 700 miles. It does have some original sensors some have been replaced. Any suggestions what could cause this.I really need help.
Thanks,
Jimmy

Answer
HI JIMMY, SO YOU HAVE INSTALLED NEW FUEL INJ,S. NEXT STEP WILL BE TO REMOVE THE HARNESS TO THE INJ AND CRANK THE ENG OVER LIKE THIS. FUEL SHOULD STOP SPRAYING IN. IF NOT THE INJS ARE FAULTY.  WHICH IS A LONG SHOT..THE NEXT STEP IS TO CK THE WIRING HARNESS TO THE INJS AND MAKE SURE THE HARNESS ALL LOOKS GOOD, NO PINCHED WIRES [NEW ENGINE THIS IS POSSIBLE. THIS COULD BE SHORTING THE HARNESS OUT CAUSING FUEL TO SPRAY IN..THE NEXT COULD BE A FAULTY COOLANT TEMP SENSOR .THINKS THE ENG IS REAL COLD SENDING ALL KINDS OF FUEL TO THE INJ..LAST IS A FAULLTY PCM [COMPUTER] SENDING A SOLID SIGNAL TO THE INJ WITH NO PULSE,[THIS MEANS ON OFF ON OFF]SIGNAL TO THE INJS.. THE INJS SHOULD HAVE A PULSE..IF YOU CAN NOT SEE ANYTHING OBVIOUS I WOULD GET THIS TO A SHOP THAT HAS A SCAN TOOL AND HAVE THEM CK DATA. THIS WILL MAKE THINGS FASTER FOR YOU AND LESS GUESS WORK AS WELL...LET ME KNOW IF YOU NEED MORE INFO AND HOW YOU MAKE OUT..,,TOM..