03 GMC 5.3 rebuild. Used cam from 05 LS2 Corvette 6.0. Shows cam sensor fault code. Erratic hard start, sometimes cranks just fine. New GM cam position sensor and old sensor behave the same. 350 miles so far and has been erratic hard start from first crank. Factory GM cam, I think it had the interrupter in front of the back cam bearing journal. I know that the LS2 had the sensor in the front cover. If there wasn't a provision on the cam for the rear sensor would it even crank at all?

 

I could be sending you down the wrong path here so I'd wait for someone else to chime in but I litterally just did the exact same thing BUT with a different cam. couldnt track it so I took the cam back out and wiped it out. The Cloyes timing set I had i guess was wrong (came in a kit with all my other engine gaskets) and the cam would walk in the block and the reluctor wheel on the back on the cm would fall out of range of the cam sensor.

 

Is there the lobe for the sensor on that cam? The LS2 is a gen 4 motor.

 

Did you swap it over to an LS2 timing cover with the cam sensor in it since you used the LS2 cam? The 03 engine used the rear cam sensor where as an LS2 engine had a cam sensor in the timing cover if im not mistaken?? Someone correct that if im wrong....

 

I cant say with absolute confidence it had the sensor lobe. I think it did though. If it didn't would it even crank at all.

 

Yes it would crank, but it's not going to find a good cam signal and actually run.

 

Did you happen to take a pic of the cam before you installed? If so you can post it up

 

The truck cranks perfect 75 % of the time. Idles at about 5-600 rpms and runs good. Driven just over 400 miles since installation. I didn't take photos of the parts before installation. Power is just fair, haven't just"got on it yet". Engine with 270k seemed more responsive. Now more details. Bored to 5.7, block tru-decked, 317 heads milled to 65.4 cc, LS2 cam installed at 113.5*, true roller double timing set, stock fuel pump and injectors. Electric fan conversion. No tune done yet.

 

This sounds accurate. He would need a cam sensor harness extension as well. Can probably get both from eBay for a modest price.

 

An LS2 cam does not have a built in reluctor on the back. As mentioned you would need the correct gear on the front, Use a front T chain cover with a sensor, and a relocation harness to plug into it.