Has anybody ever had their knock sensor go bad, if so how did your car run? What r the symptoms?

 

I would think it would either register false knock or not register any at all. I've never heard of them going bad though.

 

Yes... they can go "bad". When the PCM does not see the correct resistance/voltage on the knock sensor circuit, it sets a code and defaults to a calculated knock retard of as much as 15degrees. You will definitely lose power. The symptom would be an SES light.

I have also heard of cases where sediment has plugged the opening in the KS, causing it to continue to operate within parameters, but produce a huge knock signal. That would net you the same power loss, but wouldn't set a code or light the SES.

Put a scanner on it, and check for knock retard, and codes.

 

Just scanned car with Auto-Xray and there reads no knock retard, but knock signal is 246, this sounds to me like some sediment got into the hole in the knock sensor and is causing a ruckus. Thanks for the helpful hints!

 

Knock signal? Perhaps you were looking at knock count. It is a cumulative register that records instances of knock. Every engine is going to record some and does not indicate something is wrong. The register will reset to zero after a set value (probably 255) and begin counting upward again.

 

Yes Rob, that si what i meant, knock Count, thanx for the heads up!

 

The knock sensor could only cause timing to be pulled. You said it doesn't have any spark retard though. Therefore if you're having a performance problem, it must be from another cause. Maybe a thorough explanantion of your problem, including the "Arcing problem" you alluded to in another post would help. Also a list of the sensor readings may show someone here where to start looking.

 

Well I can tell you that the O2 sensor readings are all over the place even though I replaced them about 4 months ago. Everything else seems within parameters, it is hard to start on initial startup, the coil is arcing. Odd thing is if I shut the car off and let it set for about 10 minutes it will start right up on the first try, but anything longer than 10 minutes, and it is hard to start! Maybe this new info can help someone diagnose my problem! Thanks

 

Your starting problem is either fuel leaking into the intake manifold and puddling or the fuel is draining back into the tank and causing longer cranking to get started.

You need to check fuel pressure after the engine is shut down. Chances are high that it will drop like a rock in the first hour. Then we need to find out why. The first thing that is easy to check is the FPR. Pull the vac hose off the fuel pressure regulator and see if its wet. If so the FPR needs replacing. If not you will need to lift the fuel rail along with all the injectors out of the intake and have someone cycle power several times without cranking the engine to see if any injectors are leaking.

If they are ok, you won't see any fuel coming out of the injectors. But if any are leaking, you will see a spray or dripping. This would then be the cause of the hard starting among other problems.

The last problem left if the others are ok is the fuel pump check ball is stuck. This requires replacement of the pump. If this were the problem you could do a simple test where you cycle the power on for 2 seconds without starting and then turn off and cycle power on again. Do this about 3 times and see if the car starts easier after the 3rd cycle. If it does not, chances are the injector(s) are sticking or the FPR is defective. If you have checked the vac hose and it is dry and this test doesn't help then the injectors must be leaking.

Good luck

 

Well the last time I checked, my fuel pressure was fine, and the fuel pressure regulator is also good, so i think we can rule them out! Thanks

 

If the fuel injectors are leaking, would this cause a roughh idle and hesitation? Also, could this cause the car to load up on fuel, which is then causing the coil to arc? Slopoke, please let me know if I'm on th right track!

 

The reading are supposed to be "all over the place". They constantly change, but hold pretty steady at WOT.

 

The reading are supposed to be "all over the place". The constantly change, but hold pretty steady at WOT.