Sumbling/Hesitation Upon Acceleration due to loose Camshaft, new engine? - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

'74CamaroZ28 · 08-30-2021, 11:18 AM

I have a 2011 Camaro 2SS Automatic with an L99 110,000 miles on the odometer,
that for months has been stumbling/hesitating upon acceleration when engine fully warmed up. I took it to my mechanic and then to a Riverside Chevrolet dealer with no engine codes or engine check light, they could not figure out the problem. I researched the problem and found others with my problem, saying their Dealerships telling them that this is how the car normally ends up and just live with driving the car slowly.

Finally I took it to Tom Bell Chevrolet in Redlands California where they flew in a GM expert that was able to diagnose the problem, being that my Camshaft tends to move backwards just enough to disconnect from the camshaft sensor upon acceleration. They are saying that over time the camshaft carved out a small indentation inside the engine causing it to move backwards slightly.

The dealership is saying I need a new engine, which would add up to $10,000 parts and labor? This is incredibly frustrating as I have taken care of this car and done all scheduled maintenance.

I don't want to hear that "if you want to play you have to pay", because that is not true: I have a 2008 Stage 3 Roush with 200,000 on the odometer still racing. Is GM just a terrible brand nowadays, and "they don't make them like they used to?" Should I have bought a reliable Toyota (Lexus RC V8 with 467 HP) instead? Scotty Gilmore was right about American Cars. I now regret being part of the Chevy family.

Anybody out there with a similar problem and cheaper solution? How common is this problem?

gtstorey · 08-30-2021, 12:49 PM

To start with, have a non-dealer shop check it out. I'm not sure what indentation they might be talking about but it doesn't sound legit to me.

You can get a new LS3 short block for $4190 from Thompson Motorsports or fully forged for $6100 and I wouldn't think that installation would be much more than $3,000.

The LS motors tend to be reliable, but there will always be a chance of a problem.

'74CamaroZ28 · 08-30-2021, 03:46 PM

After talking to some engine shops, the culprit behind my camshaft problem is the Displacement on Demand. It causes parts to wear out unevenly and this is a known problem. LS3 motors are not affected by this, so even if I got a new L99 motor, it would be a matter of time before the new L99 wears out.

gtstorey · 08-30-2021, 03:52 PM

Quote:

Originally Posted by '74CamaroZ28

After talking to some engine shops, the culprit behind my camshaft problem is the Displacement on Demand. It causes parts to wear out unevenly and this is a known problem. LS3 motors are not affected by this, so even if I got a new L99 motor, it would be a matter of time before the new L99 wears out.

You could install an LS3 instead of the L99 although if it last another 100k how much car will you have left at that point.

1JEWLDSSRS · 08-30-2021, 07:10 PM

Sounds like it's time to do an aftermarket cam swap, and an AFM/DOD delete. Did mine at 98k on the clock. And yes it is a very well known fact that those "AFM" lifters are a bad idea and the weakest link in our L99 engines. Some folks never have problems, and some do, without any reason. They just SUCK!!

2013ZL1FUN · 08-31-2021, 03:40 PM

Yes Scotty Kilmer is right. After my current Camaro, I will not buy another. Just as well, as they probably not be making them anyway!

PaulsSS · 09-01-2021, 12:21 AM

Pull it apart and install a spacer.

morepowerjoe · 09-01-2021, 03:09 AM

My car lived to 151k miles with the afm. I then cammed it and got rid of the afm junk and now it's like a brand new engine all over again. I wouldn't think that the afm did that to the block and don't buy it. If it was me I would change out the cam sensor and find a way to recess the sensor a little but to test their theory. That would at least be a quick and cheap way to tell you if you do indeed need a new block. Also if the afm caused uneven wear on the camshaft lobes it would not have caused the rear of the camshaft to wear on the block. And who's to say it's not the camshaft itself that has the wear on the back side of it and not the block at all? And if that is the case then you could do a afm delete with a small camshaft upgrade and be good for another 100k miles.

'74CamaroZ28 · 09-01-2021, 03:29 AM

Tom Bell Chevrolet changed the Camshaft Sensor and Camshaft Sensor Harness and still the Camshaft loses connection with the sensor upon acceleration, causing the engine to stall. They were scratching their heads trying to figure out why, that's when the GM tech came in and said that the camshaft is loose due to part of the engine getting wore. I contacted some engine shops and they say that this is a problem that affects only the AFM engines; LS3 engines are safe from this, and if I install the same L99, I may have the same problem later on.

I wish I would have known this was an issue, that way i would have done an AFM delete.

I live in California, unfortunately, do you guys think that I wont pass smog with an LS3? You know, due to it being a "different engine" from the L99 and the computer ratting me out? We all know that it will pass the sniff test, but California doesn't care about the environment really, just cares about making the little guy pay for beaurocratic red tape.

morepowerjoe · 09-01-2021, 03:49 AM

Unfortunately the ls3 would require a different tune making it not pass. I didn't even realize that you were in Cali and even with a afm delete you would not pass because the l99 would need a new tune as well. It's either time to get a new l99 engine, a new car, or best of all move.

gtstorey · 09-01-2021, 06:45 AM

Is there anything to wear beyond the cam and cam bearings?

08-30-2021, 11:18 AM	#1
'74CamaroZ28 Drives: 2011 2SS CAMARO RS Join Date: Oct 2015 Location: Riverside, Ca Posts: 8	Sumbling/Hesitation Upon Acceleration due to loose Camshaft, new engine? I have a 2011 Camaro 2SS Automatic with an L99 110,000 miles on the odometer, that for months has been stumbling/hesitating upon acceleration when engine fully warmed up. I took it to my mechanic and then to a Riverside Chevrolet dealer with no engine codes or engine check light, they could not figure out the problem. I researched the problem and found others with my problem, saying their Dealerships telling them that this is how the car normally ends up and just live with driving the car slowly. Finally I took it to Tom Bell Chevrolet in Redlands California where they flew in a GM expert that was able to diagnose the problem, being that my Camshaft tends to move backwards just enough to disconnect from the camshaft sensor upon acceleration. They are saying that over time the camshaft carved out a small indentation inside the engine causing it to move backwards slightly. The dealership is saying I need a new engine, which would add up to $10,000 parts and labor? This is incredibly frustrating as I have taken care of this car and done all scheduled maintenance. I don't want to hear that "if you want to play you have to pay", because that is not true: I have a 2008 Stage 3 Roush with 200,000 on the odometer still racing. Is GM just a terrible brand nowadays, and "they don't make them like they used to?" Should I have bought a reliable Toyota (Lexus RC V8 with 467 HP) instead? Scotty Gilmore was right about American Cars. I now regret being part of the Chevy family. Anybody out there with a similar problem and cheaper solution? How common is this problem?

08-30-2021, 07:10 PM	#5
1JEWLDSSRS Drives: 2011 SS-RS Join Date: May 2011 Location: FLORIDA Posts: 11,426	Sounds like it's time to do an aftermarket cam swap, and an AFM/DOD delete. Did mine at 98k on the clock. And yes it is a very well known fact that those "AFM" lifters are a bad idea and the weakest link in our L99 engines. Some folks never have problems, and some do, without any reason. They just SUCK!! __________________ TSP STAGE 3 CAM,231/246 @112 LSA 614/641 LIFT, CIRCLE D 5C-4200-4500 CONVERTER,LOD INTAKE.CORSA EXHAUST. DSS 1 PC DS. PEGASUS SOLID CRADLE MOUNTS. 486RWHP/475RWTQ.LOTS MORE. Last edited by 1JEWLDSSRS; 09-01-2021 at 05:20 PM.

08-31-2021, 03:40 PM	#6
2013ZL1FUN Drives: 2013 ZL1 Convertible A6 BRM Join Date: Feb 2015 Location: Dayton Ohio Area Posts: 499	Yes Scotty Kilmer is right. After my current Camaro, I will not buy another. Just as well, as they probably not be making them anyway! __________________ 2013 ZL1 CONVERTIBLE BRM A6 OHIO

09-01-2021, 03:09 AM	#8
morepowerjoe Drives: 2012 Chevrolet Camaro l99 Join Date: Aug 2020 Location: Austin, TX Posts: 2,100	My car lived to 151k miles with the afm. I then cammed it and got rid of the afm junk and now it's like a brand new engine all over again. I wouldn't think that the afm did that to the block and don't buy it. If it was me I would change out the cam sensor and find a way to recess the sensor a little but to test their theory. That would at least be a quick and cheap way to tell you if you do indeed need a new block. Also if the afm caused uneven wear on the camshaft lobes it would not have caused the rear of the camshaft to wear on the block. And who's to say it's not the camshaft itself that has the wear on the back side of it and not the block at all? And if that is the case then you could do a afm delete with a small camshaft upgrade and be good for another 100k miles. __________________ DSS FX Forged Pistons, Eagle ESP L19 Forged Rods, ARP Head and Main Studs, TSP PRC 260 CNC Ported Heads milled .030, Cometic .040 Head Gaskets, GPI SS3 VVT Camshaft, GM Performance Racing Lifters, CHE Trunnions , Molly Pushrods, Melling 10355HV Oil Pump, Cold Air Inductions CAI, Fast LSXR Intake Manifold, Nick Williams 103 TB, TSP 1 7/8" Longtubes with 3" TSP Exhaust, ZL1 Fuel Pump, Mishimoto Radiator, Mishimoto Oil Cooler, Tru Cool 40k Tranny Cooler, 3600 Circle D Converter, Fluid Dynamics Balancer Build Thread https://www.camaro5.com/forums/showthread.php?t=609817

09-01-2021, 03:49 AM	#10
morepowerjoe Drives: 2012 Chevrolet Camaro l99 Join Date: Aug 2020 Location: Austin, TX Posts: 2,100	Unfortunately the ls3 would require a different tune making it not pass. I didn't even realize that you were in Cali and even with a afm delete you would not pass because the l99 would need a new tune as well. It's either time to get a new l99 engine, a new car, or best of all move. __________________ DSS FX Forged Pistons, Eagle ESP L19 Forged Rods, ARP Head and Main Studs, TSP PRC 260 CNC Ported Heads milled .030, Cometic .040 Head Gaskets, GPI SS3 VVT Camshaft, GM Performance Racing Lifters, CHE Trunnions , Molly Pushrods, Melling 10355HV Oil Pump, Cold Air Inductions CAI, Fast LSXR Intake Manifold, Nick Williams 103 TB, TSP 1 7/8" Longtubes with 3" TSP Exhaust, ZL1 Fuel Pump, Mishimoto Radiator, Mishimoto Oil Cooler, Tru Cool 40k Tranny Cooler, 3600 Circle D Converter, Fluid Dynamics Balancer Build Thread https://www.camaro5.com/forums/showthread.php?t=609817

08-30-2021, 12:49 PM	#2
gtstorey Drives: 2010 Camaro SS2,L99, LSA SC Join Date: Aug 2017 Location: Huntsville, AL Posts: 2,147	To start with, have a non-dealer shop check it out. I'm not sure what indentation they might be talking about but it doesn't sound legit to me. You can get a new LS3 short block for $4190 from Thompson Motorsports or fully forged for $6100 and I wouldn't think that installation would be much more than $3,000. The LS motors tend to be reliable, but there will always be a chance of a problem.

08-30-2021, 03:46 PM	#3
'74CamaroZ28 Drives: 2011 2SS CAMARO RS Join Date: Oct 2015 Location: Riverside, Ca Posts: 8	After talking to some engine shops, the culprit behind my camshaft problem is the Displacement on Demand. It causes parts to wear out unevenly and this is a known problem. LS3 motors are not affected by this, so even if I got a new L99 motor, it would be a matter of time before the new L99 wears out.

09-01-2021, 12:21 AM	#7
PaulsSS Drives: 15SS Camaro Join Date: Dec 2020 Location: US Posts: 345	Pull it apart and install a spacer.

09-01-2021, 03:29 AM	#9
'74CamaroZ28 Drives: 2011 2SS CAMARO RS Join Date: Oct 2015 Location: Riverside, Ca Posts: 8	Tom Bell Chevrolet changed the Camshaft Sensor and Camshaft Sensor Harness and still the Camshaft loses connection with the sensor upon acceleration, causing the engine to stall. They were scratching their heads trying to figure out why, that's when the GM tech came in and said that the camshaft is loose due to part of the engine getting wore. I contacted some engine shops and they say that this is a problem that affects only the AFM engines; LS3 engines are safe from this, and if I install the same L99, I may have the same problem later on. I wish I would have known this was an issue, that way i would have done an AFM delete. I live in California, unfortunately, do you guys think that I wont pass smog with an LS3? You know, due to it being a "different engine" from the L99 and the computer ratting me out? We all know that it will pass the sniff test, but California doesn't care about the environment really, just cares about making the little guy pay for beaurocratic red tape.

09-01-2021, 06:45 AM	#11
gtstorey Drives: 2010 Camaro SS2,L99, LSA SC Join Date: Aug 2017 Location: Huntsville, AL Posts: 2,147	Is there anything to wear beyond the cam and cam bearings?