taken19

Can a cam position sensor failure error cause the car to lose ignition and turn off? I was driving with HOD at Homestead today and the 5th session going into turn 8 I went off track due to this. I was threshold braking and downshifting into 2nd and all of a sudden the brakes went hard. Started pumping but lost 85-90% of the braking force. When I went off , I relaized that I had no power steering and dash was dead.

Never had the car shut off on me, but it would make sense due to the loss of a cam position sensor.

Can somebody back me up or prove me wrong?

Current engine codes are as follows:

Pending P0341 cam position sensor
Pending P0016 cam crankshaft position correlation sensor
P0341 cam position sensor

I'm guessing an easy fix, just replace cam position sensor? Or could it be more than that?

Any ideas / suggestions welcomed.

Sean

wallyman424

No, the cam position sensor has nothing to do with the car running, it just makes it slightly hard to start. I ran with a disconnected cam position sensor for about 2 years with no ill effects.

Crank position sensor on the other hand will cause problems. I personally haven't heard of one failing at speed and causing issues like yours. Usually the symptom is a no-start.

Does the car start and run now?

taken19

Car will turn over but not start now. Needed a flatbed to get it home. What does it take to swap crank position sensor?

redtopz

Like Wally said, only the crank position sensor will prevent the car from starting. If the sensors don't solve the problem you might have some serious problems. I had a cam position warning that turned out to be from loose cam bolts and the cam sliding out of position. Broken timing chain could cause your problems.

wallyman424

Yes, thats the diagnosis I was going to hint at. I think you've got something broke in there.

When it cranks, does it sound ok, or do you hear valves slapping?

sspeed30043

I agree with the broken chain theory...
Pull a valve cover to see if you have any valve motion...
I think you will have to pull the intake anyway to get at the sensor.

I wouldnt crank it anymore...until you van verify the chain is good..but the damage is already done if it is...

wallyman424

And just to answer your question about where the sensors are located. The camshaft sensor is behind the intake manifold, next to the oil pressure sensor. The Crank position sensor is under the engine, by the starter.

I would put the car on jackstands, pull a valve cover, put it in gear, turn the rear tires to rotate the engine and look to see that your valves are moving up and down. If so, this will not be an expensive fix.

travisnd

Yep... could be a broken timing chain for sure.

taken19

Thanks for all the info guys. To answer some of the questions above:

When I attempted to start the car it sounded normal except it wouldn't get spark. No nunusual noise like valve parts slapping around.

I have the Katech C5R timing chain. I really can't imagine that breaking with only 485 rwhp. I know for sure I did not mechanically over rev the motor as I was at about 60 mph when downshifting into 2nd. I have a 2005 S51 C6 so second tops out at over 70 mph.

I guess I will put it up on stands and inspect. Otherwise, I like the idea about pulling valve covers and manually turning rear tires.

NOSLO6

These were exactly the symptoms when my LS3's timing chain broke.

Pull the valve cover and see if the rockers move when you crank it. If not, the timing chain is broken.

96CollectorSport

Just curious but do you have an aftermarket balancer on the engine? If so what kind?

taken19

Yes but I can't remember which brand. Why do you ask? Someone in the C6 tech section asked the same question.

Took off the valve covers today and 6 springs are compressed with the rocker arm moving freely. About 0.125" gap. Tried to turn over motor and no vavletrain components move - not a good sign. Looks like it may be a broken timing chain for sure. The question is what caused it???

I will post pics in a few with the gap between valve stem and rocker arm.

taken19

Here is what they are supposed to look like... no gap between valve stem and rocker.




I have 6 that look like this:




I bought the Katech C5R timing chain. I thought these were indestructible. Does the vendor have any warrantee if it broke due to material defect? I will start pulling the motor apart in the next week or so to confirm this was the problem.

wallyman424

Unfortunately aftermarket dampers (all except ATI superdamper) have been implicated in a LOT of blown motors. I'd wager that your damper isnt an ATI and that might be why this happened.

Sucks man, but looks like the worst case scenario right there.

taken19

How does the aftermarket UD pulley cause a blown motor?

wallyman424

I'm not completely sure, but I think it has something to do with the dampner function not working appropriately, allowing harmonic vibration in the timing chain. Maybe someone else will know better.

travisnd

The smaller aftermarket balaners don't dampen the crank harmonics very well. As such, the crank can develop a harmonic vibration which breaks the timing chian with sustained higher RPM use. I'm not an engineer so maybe one on here can give a more technical explanation. I only use ATI 10% underdrive dampers on my LS track/race cars. They have a prooven track record (pun intended).

96CollectorSport

The harmonics on these engines at peak torque are very violent and need a good dampener to cancel out these harmful harmonics, the only ones that seem to work for road racing are the stock GM units and ATI (which are 2 dampeners in 1)-they are expensive but if you want an underdrive pulley they are your only option.
To find out if you were a victim of bad harmonics look at the timing chain when the motor is taken apart, if it has stiff links then that points to a dampener that didn't dampen well enough. Each link in the chain should move freely if any of them seem to have resistance then it wasn't the chains fault.
The harmonics of the engine are trying to break the chain apart and if they are not dampened enough that's just what it will do.

taken19

Wish I would have known this a year ago. Built the motor for the drag strip but fell in love with the road course. I guess now is my chance to build correctly this time.

Can you seasoned vets give advice for a good build? LS6, LS2, LS3? I'm considering a dry sump at this point as well, but can't let the budget get too big. I can sell my existing FAST and headers to offset some cost.

taken19

Good info, I will definitely look into it. The UD pulley I have does not have dampening material in it - I think its an SLP or similar. It's a shame I didn't look into this more before I did my build last year, but I sure won't make the same mistake again if it was the cause.