I am working on a 2000 blazer with a 4.3L engnine. It was running well but was giving me a code P0340 which indicates a cam sensor cuircit problem. I replace the sensor and found w broken wire to it that was preventig it from getting any voltage. I now gets 12 volts to the sensor and has a good ground. I also replaaced the rotor. Tried starting the truck and it will sputter/diesel for a few seconds and than die. With the key in the on posistion the SES light is on but has no codes. The battery light stay on as well. I have a fully charged battery. I have also checked for spark from the coil and it is good.

I have also checked the crank position sensor and have 12v and ground to it.
What could be the problem.

 

Check the pressure of the fuel system. Sounds like a weak fuel pump or fouled injectors.

 

Cam sensor won't prevent the engine from running. You can disconnect it completely and engine will still run.

If you have spark from the coil then the crank sensor is not the problem.

But did you pull the distributor out when doing repairs? If so, I bet you have put it back in the wrong position.

 

I did no pull the distributor, but I did replace the rotor. Tried using starter fluid and it still will not start, so I do not think it is the fuel pump.

 

do not have a fuel pressure gage handy will try to do it Monday. Did try using starter fluid and it would not start.

 

Try unplugging the cam sensor. Shouldn't matter, but who knows! Otherwise go back and take a good hard look at the rotor - compare with the old one.

 

Put a fuel gage on it. Pressure is 58psi in ON position 64psi while cranking. Replaced crankshaft position sensor. Did not help. Replaced distributor cap. No help.
not sure if it matter, but when cranking the engine the tachometer jumps all over the place.

 

You might want to try putting the old rotor back on and check your results. Did you triple check that your spark plugs wires are in the correct order?

 

Tried old rotor and checked plug order still no just diesels
tested to verify that it is getting signal from ignition control module and it is good.