2011 Chevy Silverado with a fussy cam sensor

Hello!

We recently purchased a 2011 Chevy Silverado 1500 with the 5.3 engine.  The engine was swapped out for one out of a 2009 before we purchased it.  It runs fine, does have an extended crank and a CEL that we have been fighting with.

Primary code:  P0341-00  Camshaft Position Sensor Preformance.

It has other codes for P0010-00  Camshaft Position actuator solenoid circuit  (it was never installed on a 2009 for VVT)  and the P0315-00 for the crank/cam variation relearn

At this time we're concerned with P0341-00 for the cam position.  When we removed the sensor from the timing cover we noted it had a slight 'ding' in it.  Small chip of plastic broken off.

We have replaced it with a 'house brand' one, and then with a OEM GM sensor as we've been told the 5.3 engines are a bit fussy.  The harness has also been replaced with a new one and new wires run up the split tubing where I can reach things for testing.

We still have the error codes.  Oddly enough the new sensor(s) also got a very small impact 'ding' that we can't really explain.  We used an endoscope camera and examined the reluctor ring.  There looks to be a very small defect, but when staring into a hole it's hard to tell.  I had the wife (small hands) reach into the sensor hole for any raised or sharp edges.  Smooth and nothing notable.  

On the scan tool under the cam actuator test (which of course, ours does not have-) It does record the crank RPM and cam RPM.  The crank RPM is constant.  The cam RPM drops out every few seconds and then returns.  Very odd.  

I will attach a photo of the installed (verified by GM part # that was on the part) timing cam gear.  Also I'll attach a photo of the waveform that I was able to photograph.  Picked up one of those mini oscilloscopes.  Took a while to get used to it, as if it's left in AC mode the waveform looks totally trashed.  Flipped it to DC mode and it looked like decent square wave forms.

To me the wave form doesn't match the raised sections of the reluctor ring.  The ring is present as far as we can tell, but that scope pattern doesn't look uniform enough.



It should be  "Long Tall...short down.  Long Tall..short down...short Tall pulse up....long short break..small Tall pulse up.  Long short break...Long  Tall pulse"... repeat.

The wave form looks like it's showing most of that, but I think it's missing one of the "Tall Pulse Ups".  I want to say it's the first long tall pulse isn't showing up correctly, as I do see a short tall pulse up, followed with 'down pulse' and then directly up to a wider tall pulse.

It's like that first long tall pulse isn't showing up, but it picks up after that small blurp up.  (I'm starting this cheesy description at about the 9:00 position.)


 I hope that makes sense.  At this point I'm thinking we might have to pull the front of the engine apart and inspect the Cam timing gear for damage.  It just looks like it's missing part of the waveform.

Any assistance would be fantastic.  I've run this past a few GM forums, they've asked for the wave pattern, but never replied.

Thanks!  I'm glad to answer any questions I can to resolve this.

Steve B-

 

Did you change the cam gear to one without VVT?
The VVT cam gear may have a different reluctor, hence the codes and contact with the sensor.

I thought about that at first.  As the place we purchased the truck from is a salvage yard that also swapped the engine out.  We know the owner a bit, he does a lot of buying/trading/etc..  This truck happened to be extremely clean for NYS, and just needed an engine replacement which he had in the 'yard'

It was a complete swap out, so the 2009 engine came with the original cam, gear with reluctor wheel and timing cover.  Everything is the same, except the 2009 only had the 1 3 pin connector for the cam sensor..and didn't use a 5 pin connector (3 pin for sensor, 2 pin for the solenoid for VVT)  I've triple checked the wiring to the sensor-  It's 100%.  Both setups used the same cam sensor.

The timing cover with the VVT has provisions for the cam phaser and used the same sensor.  I'll attach a photo of what that reluctor looks like.  It's the same for where the signal should go 'high' and 'low'. 

The notches cut out in the metal on the VVT style, are a perfect match for the non-VVT cam gear.

I'm still puzzled when I look at the waveform.  I think it's not seeing one of the segments on the reluctor and that's why it's getting confused.

Steve B-