Steve Neu wrote:
>> Your car and every other FOUR cylinder automatic ever made does
>> the same thing to a greater or lesser degree at low engine RPMs
>> especially under load (in gear). Mounting the engine transversely
>> makes low RPM shuddering more noticeable than a longitudinal
>> mounting. The closer you can get the crank pin throws, the
>> smoother the engine will perform at idle under load. In this
>> respect, the only engine configuration that would produce more
>> vibration would be a single cylinder engine.
>> "Never let school interfere
>> with your education - Mark Twain"
> I know what you are talking about but this is worse than normal.
> When its in gear with the AC on the RPMs are low enough the engine
> actually knocks at idle when hot. More throttle or setting the
> idle up does not seem to stop the knocking and rough running. It
> acts like the stall speed of the torque converter is too low or
> the AC compressor is too much load for the engine.
Ok, you have an understanding of the "normal" level of vibration that
all four cylider engines exhibit under low rpm loading. If this is a
new phenomenon, then get the car to a diagnostics station and find
out what's wrong.
An "in-gear" idle RPM with the A/C ON should be about 700-800 rpm
with the compressor running. There will be the normal engine
vibration in this condition but not knocking sounds. Might check for
other mechanical sources than engine spark knocking.
"Never let school interfere
with your education - Mark Twain" >> Stay informed about: 89 Camry--rough idle