Cold start issue
Thread Starter
Intermediate
Joined: Aug 2017
Posts: 26
Likes: 4
From: North Wales PA
Cold start issue
I'm having a cold start issue with my 2017 Z06 m7. My car would always start at approx. 1200 rpm .. stay there for 20 seconds or more and then drop down to 1000 rpm and stay there for a good 45 seconds or more .. and then drop to around 800 rpm for a while and then a final drop to around 650 rpm(normal idle).
The first couple times taking it out this season it is starting at 1000 rpm and dropping within 10 seconds down to 800 rpm and then pretty quickly down to 650 rpm. This happened on Sunday when it was only 50 degrees in my garage. You can hear that the motor is not really happy at such a low rpm while still being cold.
Otherwise the car runs great and I'm having no other issues.
Has anyone else experienced anything similar and if so what was the remedy to the issue? I have an appointment next week at my local dealer.
Thanks for any feed back!!
The first couple times taking it out this season it is starting at 1000 rpm and dropping within 10 seconds down to 800 rpm and then pretty quickly down to 650 rpm. This happened on Sunday when it was only 50 degrees in my garage. You can hear that the motor is not really happy at such a low rpm while still being cold.
Otherwise the car runs great and I'm having no other issues.
Has anyone else experienced anything similar and if so what was the remedy to the issue? I have an appointment next week at my local dealer.
Thanks for any feed back!!
Safety Car
Joined: Aug 2012
Posts: 3,960
Likes: 1,106
Very normal, the advanced "idle" speed along with a rich fuel mixture and retarded timing is about getting the cats hot in a hurry in order to meet EPA cold start emissions standards and not about having the engine running smoothly. The maximum cold start idle speed and the time it spends in each step is dependent upon engine and air temperature.
And as others noted, the LT4 isn't noted for a smooth idle. Surprisingly, my 2018 GMC Denali with its 6.6L turbo diesel has a smoother idle than either my 2016 Z06 or 2014 Cadillac ATS (3.6L).
And as others noted, the LT4 isn't noted for a smooth idle. Surprisingly, my 2018 GMC Denali with its 6.6L turbo diesel has a smoother idle than either my 2016 Z06 or 2014 Cadillac ATS (3.6L).
1st Gear
Joined: Dec 2025
Posts: 1
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I'm having a cold start issue with my 2017 Z06 m7. My car would always start at approx. 1200 rpm .. stay there for 20 seconds or more and then drop down to 1000 rpm and stay there for a good 45 seconds or more .. and then drop to around 800 rpm for a while and then a final drop to around 650 rpm(normal idle).
The first couple times taking it out this season it is starting at 1000 rpm and dropping within 10 seconds down to 800 rpm and then pretty quickly down to 650 rpm. This happened on Sunday when it was only 50 degrees in my garage. You can hear that the motor is not really happy at such a low rpm while still being cold.
Otherwise the car runs great and I'm having no other issues.
Has anyone else experienced anything similar and if so what was the remedy to the issue? I have an appointment next week at my local dealer.
Thanks for any feed back!!
The first couple times taking it out this season it is starting at 1000 rpm and dropping within 10 seconds down to 800 rpm and then pretty quickly down to 650 rpm. This happened on Sunday when it was only 50 degrees in my garage. You can hear that the motor is not really happy at such a low rpm while still being cold.
Otherwise the car runs great and I'm having no other issues.
Has anyone else experienced anything similar and if so what was the remedy to the issue? I have an appointment next week at my local dealer.
Thanks for any feed back!!
