Hot start - slow crank - fixed! Updated 12/30/20
 

Like many I have dealt with a slow crank on a hot start pretty much since one year of ownership until now. So that is for about 3.5 years. 1.5 years ago the dealership replaced the battery under warranty for this issue. That kicked the can down the street for about a year. So, for the last 6 months I've been dealing once again with slow cranking on a hot engine.

I saw four paths to follow to attack this problem:
- add a new ground cable
- replace the starter
- replace the battery again
- sell the car

I decided last week to take the path of least resistance and add a new ground cable. So, I spent $40.00 to get one from Lethal Garage. I didn't have high hopes but miracles of miracles - it worked. I have driven the car about 8 times since adding the cable and I have not had anything even close to a slow crank on a hot engine. I have tried to make it happen by adding in short stops with each drive. Today I had four short stops and restarts in one trip. It cranked fine every time. Prior to adding the new ground cable I wouldn't have dared try that! Its the best $40.00 I have ever spent on this car.

If you too are dealing with this - I highly recommend you try adding a new ground cable.

Here is a cold start:
[https://youtu.be/n8Honktafms]
https://www.youtube.com/watch?v=n8Honktafms

Here is the first hot start:
[https://youtu.be/Z_cqf_TfAm4]
https://www.youtube.com/watch?v=Z_cqf_TfAm4

Here is the second hot start:
[https://youtu.be/nyA-AfeJCmk]
https://www.youtube.com/watch?v=nyA-AfeJCmk

I didn't add videos for the 3rd and 4th hot start as they were the same as the first two.

This video shows where I added the new ground cable:
[https://youtu.be/x1Q0s1vw9a8]
https://www.youtube.com/watch?v=x1Q0s1vw9a8

Edit: I just went back and listened this video and realized I failed to mention that the engine bolt I used is part of the serpentine belt system. I didn't take the bolt all the way out. I just loosened it and then cut a small piece out of the ear of the lug and slid the lug under the bolt and tightened it down. If you take the bolt out all the way you will lose tension on the belt.

Update 12/30/20: With the saying in mind that if one is good then two would be better - I added another ground. This time I took on the other end of the car and added another ground from the battery's negative post to the floor of the trunk. This cable is a little smaller (2.0 guage) and I bought it off of Amazon for $14.00. I placed the body end of the ground on a unused threaded stud sticking up out of the trunk floor (look to the lower far left in the photo). I have no idea if another ground is helpful and needed . I just added it for peace of mind - plus it was easy and cheap.

Please pay attention to the edit I added with the last video on cable location for the engine ground. Do not remove the belt tensioner bolt I used. If you do you will lose tension on the serpentine belt. Instead cut a small piece out of the cable's terminal lug making it look like a U and then slide it under the bolt. You can back that bolt out enough to slide the lug under it and tighten.

I continue to have normal starts whether the engine is cold or hot.

Attachment 1054234

Can't see the videos. They are listed as "Private".

Opps! I just went into youtube and made them all public. Thanks for letting me know.

So, just got a 2016 2SS, what happens when they get hot and you try to start?


Thanks,
Jim

The starter will crank so slowly that it may scare you that it will not start. Mine always did start but a couple of times it almost failed to start. It does not inspire confidence that is for sure. And for some people the start will fail totally. Believe me you will know if you get the problem. Its very distinctive!

The usual culprit of this is heat soak from the exhaust manifold, more pronounced with headers but it can happen stock. Get yourself one of these also.https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Is there a write up somewhere on where this ground cable goes?

The real test may be in july/august...

Curious about a write up as well. Can you provide a link to the cable you ordered?

No doubt a starter blanket may help. I’m just sharing what I’ve found. Poor grounding plus excess heat equals added resistance to electron flow. If the battery can’t overcome that resistance then insufficient voltage is available to crank the starter. A new ground cable attacks one end of the problem equation by reducing resistance. The starter blanket might help with the other end of the equation which is heat soak. BTW I bought a starter blanket a while back but was unsuccessful getting it to fit around the starter. It’s a very small and tight space to work with.

I showed where I installed the cable in the last video. It’s pretty straightforward. No doubt the summer heat can make this even worse but my car suffered from slow cranking in any weather whenever the engine was fully warmed up and I made multiple short stops.

Can you share a link to the item? That's a cheap item to install and couldn't hurt. I've never had the problem but why not?

So GM has a class action Lawsuit out for this instead of them just adding a proper ground cable?:facepalm:
Anyone call them and tell them how to fix it?:twitch::bonk::crazy:

Anyone call GM and tell them this is whats needed? Or do they want to try and fight the class action lawsuit out against them.:twitch::noidea:

Here's one for $14
https://www.autozone.com/batteries-s..._0_0?rrec=true

I can't say I have the issue. But I have over 42k miles on it now. My concern was how difficult to add that heat shield as a precaution. How difficult would it be to install if the car was on a lift?