Good point, but by the time the cars goes into closed loop the noise has
dissipated.
"Steve" > wrote in message
...
> JazzMan wrote:
>
>> Steve wrote:
>>
wrote:
>>>
>>>
>>>>I noticed this weekend that my 1999 Buick Century is developing the
>>>>classic symptons of Piston Slapping (ticking noise when cold ... goes
>>>>away as engine warms up).
>>>>
>>>
>>><snip>
>>>
>>>>Is the Piston Slap likely to be the cause of the cyclinder miss? Or, do
>>>>I have two problems?
>>>>
>>>>Any suggestions on how I should proceed would be greatly appreciated.
>>>>Thanks,
>>>>
>>>>Steve
>>>>
>>>
>>>Piston slap doesn't cause a misfire, but a stuck valve or collapsed
>>>hydraulic lifter certainly does. And it also makes a ticking sound that
>>>goes away when the engine warms up.
>>>
>>>Piston slap isn't a "tick", its a deeper sound- more of a muted "clank".
>>>A single piston slapping can sound a little like a tick, but if all the
>>>pistons have some slap what it really sounds like is a diesel engine
>>>idling.
>>
>>
>> Will the knock sensor pick up piston slap and cause the ECM
>> to go into KR?
>>
>> JazzMan
>
> Knock sensors pick up all SORTS of engine noises and trigger KR. Wrist-pin
> noise is notorious for a false KR trigger on a lot of engines. Both piston
> slap and wrist pin noise happen at the right time window in the combustion
> cycle to trick the computer into thinking its knock. Some other noises
> fall at the wrong time (valve or lifter noise, for example).
>
>




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