ouzoman

I have a 2012 auto with the centennial pkg. I bought it used from Wisconsin a year ago with 6K on it; it now has 10k. The acceleration has never been as responsive as my 2003 auto was and both cars are stock; I chalked this up to the electronic type controls and although I don't like it I guess I will live with it if that is part of the C6 technology. Now for the real problem: after driving aggressively for a bit if you stab the throttle sometimes it goes nowhere; a total loss of power to the point where I look down to see if the engine is still running. This can happen off a dead stop, at low speed or even on the freeway at higher speeds; anytime you are off the accelerator for a moment and then romp on it. When driving like an old lady it does not do it; it just has an annoying lack of responsiveness but then it gets going. I think my power is OK once it opens up. The total loss of power lasts about 3 seconds where you are only coasting; during this time I instinctively feather the throttle (not sure if it helps though) and then it's back to running normal. No error codes and the dealer can not find anything wrong. Having some mechanical and electrical knowledge I might guess that I am tricking the computer by pushing it then off and on again; maybe a function of a safety system not working properly? Any advice would be greatly appreciated!

Russell Boulding

If it is truly 3 secs. That is an issue. The programmed coast to open throttle delay is supposed to only be about .7 seconds. The zero-torque command to protect the drivetrain on downshift is only supposed to last as long as .5 secs. Which means if you go coast to rapid acceleration you might get .7 seconds of slow throttle then if you decide to accelerate hard enough to force a downshift another .5 seconds of zero torque then potentially another .7 secs of slow throttle opening. This perfect storm would would only get you to about 1.9 seconds of aggravation. Unfortunately, this aggravation is programmed in and is considered "normal".

I have found with these cars that first easing into the throttle and waiting for it to "catch" and then getting into the throttle more avoids situations where you go to pass and are hung out to dry by the electronics. The trigger to starting the programmed slow throttle opening is the throttle being fully closed prior to an attempt at hard acceleration. So try not to start from a closed throttle. Unfortunately, nothing can really be down to prevent to zero torque delay for some downshifts.

Some of this may be solvable with tuning. But, that is not my area of expertise.

torquetube

Check that you don't have a loose hydrocarbon pad inside the air filter housing.

Kenny94945

Are you saying this delay only happens after the car is hot/ warmed up in other words no issue when the car is cold or just started?

My first thought was a traction control delay.

Just guessing here: You might have a buddy watch the thottle body blades. Excessive carbon buildup between the blade and the TB perhaps. Loose connectors. Check the wire voltage at the TB. It sounds like your writing the throttle body doesn't open for 3 seconds when you stab the throttle when hot.

Good hunting.

ouzoman

Thanks for that explanation. My first guess was 3-4 seconds but as we all know it seems like an eternity when you press "go" and it doesn't so I was being conservative at 3; I suppose 1.9 seconds is in the realm of possibility. Now that I know the design of the operation it seems like it's a built in problem under those driving conditions. Unfortunately there are times when you are off the throttle and then want to accelerate quickly, at least for those of us who have Corvettes because we like to drive aggressive at times. If anyone out there has tips on getting around this with tuning or any other means any advice would be greatly appreciated.
Thanks again!

ouzoman

Thanks for all the additional suggestions. I checked the hydrocarbon pad in the air cleaner and it is snug in place. The throttle body throat looks squeaky clean so no problem there. As for voltage, I have no idea where to measure or what voltage I am looking for. The car has warmed up when this has occurred because I am not likely to romp on it like that when it is cold; I can try to duplicate the problem when the car is cold if there is a value in it.

AORoads

Altho most would/might recommend against this idea, your car is still w/in 3/36 B2B warranty and a trip to a good dealer w. a good Corvette tech might explain if the problem is normal or not. Other than that, going to an indie shop that specializes in Corvettes is also an idea, but tuning the trans or car computer will potentially affect the powertrain warranty. That doesn't mean they can't at least tell you if it's normal or not. Without geo info on where you're located it's not possible to recommend anyone/shop in particular.

ouzoman

I'm happy to get an expert opinion and I took it to a dealer but they didn't seem to even understand the problem existed (an indication that it may be "normal"). In all fairness it is hard to duplicate in a crowded area and with a car that is not your own. I am in the SF bay area near the airport and have not had the best of luck with the Chevy dealers in the area. I am willing to travel for a reputable shop with good mechanics so any referrals would be appreciated. A bit off topic but I am also thinking of extending the factory warranty; if anyone has a referral for a fair deal on this please post it.
Thanks!

v26278

Just a thought, but maybe its just the nannies. As tires get older and worn they start to lose grip, maybe yours have and when the trans kicks down under full throttle the TC nannies are cutting power. Have you tried it in Competitive Mode, does it still lose power? On hard shifts, with tires past their prime and cool weather, a healthy LS3 can break traction in all three of the lower gears. My LS2 could do that until I got new tires.

torquetube

Does it behave any differently if you first depress the fishtailing-Corvette button for 10 seconds to switch off TC and AH?

Peter_Reinhard

Agree with previous post. Turn the traction control off and see if that is it. It happened to me too with my old tires. They looked good but must have lost their grip. Spun all the time, and with TC, the car would just stop like the throttle was cut.

ouzoman

Thanks for that suggestion I will try it in the next couple days as we just had a drizzle and the roads are wet (plus I'm a bit of a chicken to go wide open with the TC off anyway!). I did just put on a new set of Michelin tires and we have relatively warm weather here (SF bay area). I really don't think I'm spinning because when the problem occurs I never get the revs up, it literally does nothing when you stab it to the point where the first couple times it did it I looked down to see if the engine was running. So far this seems to be the most relative explanation to what I am experiencing:

"If it is truly 3 secs. That is an issue. The programmed coast to open throttle delay is supposed to only be about .7 seconds. The zero-torque command to protect the drivetrain on downshift is only supposed to last as long as .5 secs. Which means if you go coast to rapid acceleration you might get .7 seconds of slow throttle then if you decide to accelerate hard enough to force a downshift another .5 seconds of zero torque then potentially another .7 secs of slow throttle opening. This perfect storm would would only get you to about 1.9 seconds of aggravation. Unfortunately, this aggravation is programmed in and is considered "normal". "

I'm just not sure if I am actually going far enough down to initiate a downshift response; in thinking about it could you have downshift protocol from a dead stop? This has occurred from a dead stop as well.