is this natural?
09-08-2011, 08:40 PM
#1
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is this natural? 98 v6 firebird 5 speed. when i push in the clutch to shift, the tach goes down, but slows down as it gets to 1500 and sticks there for a second, then goes on down to 1k. this isnt a symptom of a problem is it? i dont think it is but im just curious of why it does that, i think its pretty cool
09-08-2011, 11:40 PM
#2
A manual trans. car will have a tendency to stall if the idle is not sufficient to keep the engine running with the clutch pushed in. Automatic trans. cars don't have this issue as they're not completely disconnected from the driveline like a clutch does.
Carb'd cars accomplished this with different mechanisms, sometimes idle stepper motors, vaccuum pots etc. to keep the idle up. In the case of an EFI car with IAC like yours, the PCM usually controls that to accomplish this anti-stall.
The 1500 part isn't necessary from a drivability perspective, but may help a less-skilled driver more smoothly shift gears or it may be emissions related. In short, your car sounds fine.
Carb'd cars accomplished this with different mechanisms, sometimes idle stepper motors, vaccuum pots etc. to keep the idle up. In the case of an EFI car with IAC like yours, the PCM usually controls that to accomplish this anti-stall.
The 1500 part isn't necessary from a drivability perspective, but may help a less-skilled driver more smoothly shift gears or it may be emissions related. In short, your car sounds fine.
