The ECM has to 'guess,' before you actually complete the gear change, what gear you're changing to. If, when shifting into neutral, you move the shifter even slightly towards another gate, it thinks you're going to shift to that gear and blips the throttle. If you leave it in neutral instead, it will blip again when you do actually shift. I see this every now and then.

Correction: I realized it's probably the TCM (transmission control module) that's doing the "guessing," and telling the ECM (engine control module) what's going on, so the ECM can control the revs.

 

The ECU has to 'guess,' before you actually complete the gear change, what gear you're changing to. If, when shifting into neutral, you move the shifter even slightly towards another gate, it thinks you're going to shift to that gear and blips the throttle. If you leave it in neutral instead, it will blip again when you do actually shift. I see this every now nd then.

Exactly!
If you’re driving aggressively, it will blip when you put it in neutral, and blip again when engaging the lower gear at times.


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Mine only does a single blip, works perfectly. Perhaps your “Hall rail sensor” needs adjustment. That is the part that measures the shift lever movement and starts the throttle revenge process.

 

Are you dropping more then one gear when down shifting? Mine double “blips” if I drop 2 gears.Eg 4th-2nd gear. It only “blips” once if I downshift just the one gear.

 

Hall rail sensor...haven’t heard of it, but I asked the local Corvette mechanic if there was some adjustment that is off, and he said there is no adjustments! Hmmm...I’ll mention that to the dealer. Makes sense by the way it acts.

 

Quite often when i downshift just one gear, no hesitation and not lingering in neutral, it still double blips. It does it a lot from 4th to 3rd at lower rpm, say 2000. Higher rpm around 4000 it seems to be okay. There is no problem with over revving or under-revving. A few times when I come to a stop, I push the clutch in and leave it in the gear, not touching the shifter, and it blips once. Other Z’s I drove at Ron Fellows school have not mis- blipped at all, so I know it’s not my imagination or driving habits. Thanks for the help!

 

Certainly possible it's an issue with the car. One other thing to check, be sure your foot is fully of the throttle when you are shifting.

 

Z-nut, you might get a friend to ride along and then film you doing these shifts to show the tech.

 

I've had to relearn how I drive a manual with the rev match. I have a long time habit of dropping into neutral coming off the freeway and jiggling the shifter to be sure I'm in neutral before I let the clutch out. Rev match does not like this.

 

Yep rev match would go with that first jiggle to the left and assume the highest lower gear (if that makes sense) is where you are trying to go and match those revs.

Might try my method as I even use it for passing 18 wheelers on the Interstate. Just pull back on the shift lever with no side pressure. The shifter springs will bring you to direct drive 4th. Rev match makes it perfectly smooth. One very unique feature in the C7 is I usually am in cruise control on the Interstate set 7 mph over the limit. Hate to ride next to an 18 wheeler (one through a rock and put a small crack in my windshield a month after I got my Z51) so I pass quickly. Then I shift back directly to 7th and even though the clutch was depressed cruise control resumes without hitting the “Resume Button.” Great feather but if not expecting could be an unwanted surprise!

 

Rev match over reving on mine so I quit using it.I do ole school instead.Works well for me.

 

hello! did you ever figure this out? My c7z is also doing this. Definitely didn’t used to either.