Engine Rpm's Stay High - Chevy Cobalt Forum / Cobalt Reviews / Cobalt SS / Cobalt Parts
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post #1 of 16 (permalink) Old 03-06-2010, 05:38 AM Thread Starter
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Engine Rpm's Stay High

People,

My 2010 manual transmission LT1 is nice, but noticed maybe a quirk with the engine. When I shift to the next higher gear and let off on the gas pedal , the rpm's do not drop right away as with other cars I have owned. Is this normal? It is kind of annoying and done see the logic in why this could have been engineered this way.

Thanks
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post #2 of 16 (permalink) Old 03-06-2010, 07:58 AM
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did you let off the clutch pedal? Not trying to sound like an arse, but if you shift to a higher rpm and let off the gas pedal and the clutch, the rpms should stay where they are supposed to be for that gear.

If you are in gear and the clutch is let out, then what ever speed and gear you are in determines engine speed, but if you are talking about you are in N and let off the clutch and gas and the rpms don't drop to idle then there might be a computer issue needed to be resolved by the service department...
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post #3 of 16 (permalink) Old 03-06-2010, 12:26 PM Thread Starter
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did you let off the clutch pedal? Not trying to sound like an arse, but if you shift to a higher rpm and let off the gas pedal and the clutch, the rpms should stay where they are supposed to be for that gear.

If you are in gear and the clutch is let out, then what ever speed and gear you are in determines engine speed, but if you are talking about you are in N and let off the clutch and gas and the rpms don't drop to idle then there might be a computer issue needed to be resolved by the service department...
Thanks, Steven. Well, I thought I explained it right, but when one goes up to the next gear, hey, you let off on the pedal AND you push in the clutch to disengage, right?

I mean, how else do you shift? My other cars wotk OK, but this cobalt's rpm's linger at whatever rpm you leave it at when shifting, say, 3000, instead of dropping from having let off on the gas pedal......
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post #4 of 16 (permalink) Old 03-06-2010, 12:30 PM
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How fast are you trying to shift? Your RPM's are going to stay up as long as the clutch is engaged. As soon as you depress the clutch pedal the RPM's should drop to your idle.

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post #5 of 16 (permalink) Old 03-06-2010, 12:36 PM
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I know what you are talking about, you are talking about when you push in the clutch before you shift the rpm's take a second before they start to drop, and drop rather slowly, I have a feeling this has to do with the electronic throttle that these cars have.
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post #6 of 16 (permalink) Old 03-06-2010, 12:37 PM
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How fast are you trying to shift? Your RPM's are going to stay up as long as the clutch is engaged. As soon as you depress the clutch pedal the RPM's should drop to your idle.
This. The engine speed may pick up a little or flare if you take it out of gear too fast with your foot still lightly on the gas. While in the middle of a shift, the engine is freewheeling because it is not connected to the rest of the drivetrain. If you release the clutch (which means apply the pedal) while still applying the gas pedal your engine RPM will pick up much faster without the weight of the transmission on it, and will linger there until you shift into the next higher gear.

As long as your RPM's are dropping once the clutch engages (foot off the pedal) then you don't have a problem.

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post #7 of 16 (permalink) Old 03-06-2010, 12:52 PM
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These engines are slow to de rev... so that might be what you are seeing is because of how long it takes these engines to get back to idle you think there might be a problem... but there isn't. just as long as you don't have an engine light on, you are fine.
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post #8 of 16 (permalink) Old 03-07-2010, 12:34 AM
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This is normal, it helps you shift to the next gear.
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post #9 of 16 (permalink) Old 03-07-2010, 12:39 AM
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These engines are slow to de rev... so that might be what you are seeing is because of how long it takes these engines to get back to idle you think there might be a problem... but there isn't. just as long as you don't have an engine light on, you are fine.
this!

I took me some getting used to but theres nothing wrong with it
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post #10 of 16 (permalink) Old 03-07-2010, 05:52 AM Thread Starter
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Wow, a treasure chest of information....thanks guys! Yeah, and no, I do NOT keep the gas pedal depressed when I disengage the clutch, and yeah, I understand now why the rpm's stay up there for maybe 1-2 seconds.......one poster here explaimned it helps shift smoothly to next gear.

I guess this "engineering" was done to help the ever growing population that is becoming more and more MT shy, and assist them to shift easier. Less than 5% of cars sold today are MT.......

Thaks!

---------- Post added at 05:52 AM ---------- Previous post was at 05:48 AM ----------

Quote:
Originally Posted by G5Steven View Post
These engines are slow to de rev... so that might be what you are seeing is because of how long it takes these engines to get back to idle you think there might be a problem... but there isn't. just as long as you don't have an engine light on, you are fine.
Man, I get it, but gees, it sure takes getting used to. I have another new car that does the exact opposite!! The rpm's react so fast, they drop instantly. And that forces one to let the clutch out faster and not dink around. Because of that, the car will shift smoother if you shift at the 3000-3200 range vs the 2000-2400 range........

Still, its a neat car.
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