Code P0336: Crankshaft Position Sensor Performance

[97LT1Z28]

Well guys, the saga continues..... motor still idles rough and misses randomly. I've replaced everything in the ignition system with new parts - everything from the complete optispark, wires, plugs, icm and coil!

I got a code P0336 Crankshaft Position Sensor Performance. I replaced the sensor and cleared the code but it comes back.

I've read in other forums that the crank can become bent if the harmonic balancer separates from it's outer ring. The bent crank can contact the sensor and trip the P0336 code. I'm on my third harmonic balancer due to the outer ring separating.

Now the dumb questions ... would a bent crank cause the poor idle and random miss that comes and goes several times each time I accelerate? Can you check the crank without pulling the motor out? Any other suggestions?

[TraceZ]

what would cause the balancer to seperate 3 times? Dont you find that odd?

I bet that points you directly to the problem.

[Rob B (shoebox)]

Seems real odd to me. Maybe a bent crank is causing the damper failures. No way to accurately check a crank while in the engine. I would imagine you would feel some vibration come and go at sympathetic frequencies/RPMs.

[97LT1Z28]

Other than the balancers failing, it ran great! But now, I'm getting the code, the rough idle and the engine miss throughout the RPM range (comes and goes several times while I accelerate). How about a loose timing-chain? Is there a way to check for that?

[94 formula]

Other than the balancers failing, it ran great! But now, I'm getting the code, the rough idle and the engine miss throughout the RPM range (comes and goes several times while I accelerate). How about a loose timing-chain? Is there a way to check for that?

To check the timing chain you have to remove the wp, opti, crank pulley, and timing chain cover. Once the covers off you can measure the slack of the timing chain and see if its within tollerance.

[TraceZ]

There may be play in the timing chain, but I dont think that would cause the motor to eat harmonic balancers.

It's gotta be an issue with the crank, IMO.

What else could possible cause habitual balancer failure? Maybe if the balancer was constantly exposed to a chemical that could disolve it, or if the belt is not lined up and pulling the balancer in a odd direction?

[Rob B (shoebox)]

Excessive slack in the timing chain can cause some crank sensor performance trouble codes.

[97LT1Z28]

Excessive slack in the timing chain can cause some crank sensor performance trouble codes.

and . . . . .possibly the rough idle and random misfire . . . . I think we're onto something here!

[TraceZ]

and . . . . .possibly the rough idle and random misfire . . . . I think we're onto something here!

But it does not explain why you went through three harmonic balancers.

That is not just bad luck, you have a problem that is causing the balancers to fail. The crank position sensor sits directly behind the balancer and would be easily impacted by that same problem.

You cannot just ignore the fact that the motor is eating balancers because you dont want to admit you need to tear it apart and fix it.

Replacing the timing chain is not going to fix the balancer problem and even if it does stop the error code for the time being the problem will eventually resurface because you never fixed the root cause. If the motor has already gone through three balancers, it is only a matter of time before it is needing a fourth one and so on. I just cannot believe that car has had 3 "defective" balancers and there is nothing wrong with the motor. There has to be something wrong with the motor.

[97LT1Z28]

I had some small oil leaks that got on the balancer - they're fixed now. I think the oil caused the seal to break down and throw the outer ring on the balancers -

Man . . . Hopefully it's not the crank . . . I hope I'm not gonna have to swap an engine here!

[fastTa]

Sounds to me like maybe you have a crankshaft hub that has possibly wiggled itself loose on the snout. Check to make sure that the bolt is tight. This could cause enough harmonics to throw the CPS code and could also be the cause of your 3 trashed crank dampners.

[97LT1Z28]

I never thought of that - I'll check that tonight. . . .