Truck wont run
I have a 1997 Chevy K1500 ext cab short bed Z71 with a 5.7L 350 Vortec I snapped a rod so I bought a new short block from a 1999 C1500 Suburban I got the it rebuilt and in my truck I replaced everything on the motor but now it wont run it will start and stay running as long as you hold the key in the start postion. I have replaced the Timing Chain, Crank Sensor, Ignition Coil, Distributor, Spark Plugs, Spark Plug Wires. I check all the fuses and they are all good.
The ignition switch should provide 12 volts in 2 positions - hot in crank, - hot in run.
The "hot in crank" 12 volts is only provided for the ignition circuit.
The "hot in run" provides 12 volts for the ignition circuit and all vehicle accessories.
We know the ignition circuit is ok, the engine runs if key is held in crank.
So, is the problem with the ignition switch, or somewhere down-stream?
When key is in the run position, will radio, heater, etc work?
If no, problem is probably ignition switch; if they will work, the problem is in the circuit providing 12 volts to the coil when key is in run.
On some vehicles, there is a resistor to reduce the voltage at the coil; if you have one, check the condition and the wires. The engine computer might do this on your vehicle (I don't have a wiring diagram).
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when the key is in the run position everything works just not the motor
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I figured out the issue I think since the truck is a 1997 and the engine is 1999 the Ignition switch is different and that is what is causing the issue Duralast/Ignition Switch
For your 1997 Chevrolet Truck K1500 1/2ton P/U 4WD 5.7L SFI 8cyl
Part Number: LS931
For your 1999 Chevrolet Truck C1500 1/2ton Sub 2WD 5.7L SFI 8cyl
Price: $93.99 Part Number: LS947