LT4 cold engine temp hesitation issues
Thread Starter
Instructor
Joined: Feb 2005
Posts: 200
Likes: 3
From: NY
LT4 cold engine temp hesitation issues
Hope it's okay to ask this question here since it's LT4 related....I have a CT5-V Blackwing 6 speed manual and I am experiencing engine hesitation/porpoising as the engine is coming up to temperature. It happens in 2nd, 3rd and 4th gears in the 2k to 2.5k rpm range and it's quite obvious. Dealer had the car for a week and claimed they could not feel it. I am hearing this might be normal for the LT4 but it does not feel normal to me. Have any of you experienced this with the C7 Z06? There is no info yet on the BW forums on this issue hence I am checking here. Thanks in advance!
Last edited by cnair; Sep 9, 2022 at 03:11 PM.
Tech Contributor
Joined: Oct 1999
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From: Charlotte, NC (formerly Endicott, NY)
I have owned my C7Z since Dec 1st 2015 and have never noticed what you describe. The car has 21K miles on it with about 6K of them being track miles. It isn't normal for them to act like yours is doing.
Bill
Bill
Thread Starter
Instructor
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From: NY
Thanks for the feedback.....yeah I figured this wouldn't be normal.
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I have 20K miles on my 2017 and nothing like you have described. Mine is street driven and auto trans.
Drifting
Joined: Jul 2017
Posts: 1,369
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From: Kingston, Ontario
When you say hesitating, do you mean reduced throttle input? Like you give it 40% throttle when cold and it feels like you're doing 20%? Or do you mean there's some lag from when you push the throttle to anything happening?
I own a C7 Z06, owned a ZL1 1LE and have driven a Blackwing on track so I have some experience with the LT4 but I've never experienced the above other then the terrible throttle calibration from a stop with the manual using a stock throttle body which has nothing to do with what you're describing.
For such an odd issue you're best bet may be to take the dealer tech for a ride when cold and show them what you're referring to rather then dropping off and saying it does X or Y. Hopefully you find a solution.
I own a C7 Z06, owned a ZL1 1LE and have driven a Blackwing on track so I have some experience with the LT4 but I've never experienced the above other then the terrible throttle calibration from a stop with the manual using a stock throttle body which has nothing to do with what you're describing.
For such an odd issue you're best bet may be to take the dealer tech for a ride when cold and show them what you're referring to rather then dropping off and saying it does X or Y. Hopefully you find a solution.
Thread Starter
Instructor
Joined: Feb 2005
Posts: 200
Likes: 3
From: NY
When you say hesitating, do you mean reduced throttle input? Like you give it 40% throttle when cold and it feels like you're doing 20%? Or do you mean there's some lag from when you push the throttle to anything happening?
I own a C7 Z06, owned a ZL1 1LE and have driven a Blackwing on track so I have some experience with the LT4 but I've never experienced the above other then the terrible throttle calibration from a stop with the manual using a stock throttle body which has nothing to do with what you're describing.
For such an odd issue you're best bet may be to take the dealer tech for a ride when cold and show them what you're referring to rather then dropping off and saying it does X or Y. Hopefully you find a solution.
I own a C7 Z06, owned a ZL1 1LE and have driven a Blackwing on track so I have some experience with the LT4 but I've never experienced the above other then the terrible throttle calibration from a stop with the manual using a stock throttle body which has nothing to do with what you're describing.
For such an odd issue you're best bet may be to take the dealer tech for a ride when cold and show them what you're referring to rather then dropping off and saying it does X or Y. Hopefully you find a solution.
Drifting
Joined: Jul 2017
Posts: 1,369
Likes: 1,341
From: Kingston, Ontario
If the dealer felt it, could you leave it with them for an extended period of time so they can replicate it for GM? The fact they felt it is good but this sounds like something that will take a little longer.
Or you drive the crap out of it and hope something blows up under warranty that would then be easily rectified.
Or you drive the crap out of it and hope something blows up under warranty that would then be easily rectified.
Thread Starter
Instructor
Joined: Feb 2005
Posts: 200
Likes: 3
From: NY
If the dealer felt it, could you leave it with them for an extended period of time so they can replicate it for GM? The fact they felt it is good but this sounds like something that will take a little longer.
Or you drive the crap out of it and hope something blows up under warranty that would then be easily rectified.
Or you drive the crap out of it and hope something blows up under warranty that would then be easily rectified.
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From: South Florida
Hope it's okay to ask this question here since it's LT4 related....I have a CT5-V Blackwing 6 speed manual and I am experiencing engine hesitation/porpoising as the engine is coming up to temperature. It happens in 2nd, 3rd and 4th gears in the 2k to 2.5k rpm range and it's quite obvious. Dealer had the car for a week and claimed they could not feel it. I am hearing this might be normal for the LT4 but it does not feel normal to me. Have any of you experienced this with the C7 Z06? There is no info yet on the BW forums on this issue hence I am checking here. Thanks in advance!
Thread Starter
Instructor
Joined: Feb 2005
Posts: 200
Likes: 3
From: NY
If you're not clutching out properly, the ECU will actually engage traction control for clutch slip. Manual C7 Z06's do this as well if you are lazy on clutch out. It can feel exactly like misfires. Also, when the car is cold the ECU ads a bit of timing while it comes up to temp. If you're using poor gas quality or octane, this would certainly cause the knock sensors to pull a lot of timing on throttle transitions.