05 Silverado 1500 5.3 L33 Intermittent crank, no start, on first try, exhaust pops

[colin7761]

I have been trying to figure out what is causing this issue. It seems to be acting like it doesn't know the camshaft position. Sometimes it will startup the first try, but often it will not start and pop out the exhaust after the engine stops spinning. Then the second attempt will start it up normally. It has had a new Crank Position Sensor before. The wires have been tested and are normal. Resistances have been checked in the wiring harness and they are good. Swapped in an extra PCM we had and that also had the same issue.
Now, with the issues it is having, it pointed me towards something wrong with the CMP (Camshaft position sensor). The CMP has been pulled. The tone Wheel on the cam seems to be fine and free of debris. The CMP Mounting surface has been cleaned and the sensor is fully seated. The current sensor installed is a spectra aftermarket one. There is absolutely no codes at all to indicate any issue.
The wiring to the CMP has been checked and is 100% good. Here is where it gets odd. I decided to replace the CMP with an OEM one from delphi, It made the issue worst and it didn't want to even start, it threw the code P0342. The wiring was checked again and still no debris on camshaft. The sensor was then switched to an acdelco CMP and it also didn't want to start and threw two codes P0342, and P0343. The wiring has been triple checked, and everything seems visually ok from the outside. The Spectra CMP was installed again and it starts most times, but will have the intermittent no start condition a few times a day, yet it throws no DTCS.
The engine has a tick noise, it will have to be torn down soon to see exactly what's happening there, possible cam/lifter tick. there was a few big chunks of metal in the oil pan, It's definitely not bearing material, but something broke somewhere. When its running it has no loss of power, just a distinct tick. What i really need help finding out is. Why is this starting issue happening? why do the different sensors not work, They are OEM.
If you read through the entire paragraph thanks for your help! I appreciate it. does anyone know why its doing this, has anyone had the same issue?

[Alvin]

It's definately related to camshaft position sensor.

Some won't throw a code but have a problem.

Stock cam C5 Z06's were bad about cam sprocket bolts backing out (seriously) and that would cause this too. Perhaps this is your noise

[colin7761]

Alvin, I appreciate your response. I would just like to add for everyone else, that this is not a fuel pump related issue. The pressure is good during this condition. Also, the spark plugs are firing and the injectors are injecting. This is what led me to believe a CMP related issue. Of course the engine will have to get torn down to see what is broken, I just wanted to see what you guys have to say as well. In case the issue continued after the engine was rebuilt. Thank you!

[edcmat-l1]

Need vehicle details. Is this a stock GM vehicle? Swap of some sort?

[colin7761]

Its a stock 5.3 L33 silverado 1500

[edcmat-l1]

If it has the correct cam gear in it, and a GM sensor, and nothing is wrong mechanically it has to be in the wiring. First culprit is going to be the connector and pins.

[2xLS1]

If it has the correct cam gear in it, and a GM sensor, and nothing is wrong mechanically it has to be in the wiring. First culprit is going to be the connector and pins.

Cam gear? Its a 05 Silverado 1500 5.3 L33. Don't confuse the OP.

[2xLS1]

Gen 3s don't need a cam sensor signal to run. Without the CMP signal the PCM will attempt to start the engine guessing if a cylinder is TDC compression or exhaust. If it doesn't start then it will wait 180 crank shaft degrees and then try again. When it starts it will continue to run off that sync until the next key cycle. In order for it to do that it must see a DTC for the CMP sensor. If it doesn't see any CMP codes will not attempt to do that. That is why without a CMP signal you can experience an extended crank when starting.

[colin7761]

there is never a dtc set with this spectra sensor installed

[2xLS1]

Throw any non GM AC Delco sensor in the trash.

[edcmat-l1]

Cam gear? Its a 05 Silverado 1500 5.3 L33. Don't confuse the OP.

Derp. You're correct.