[S1lentHarbinger]

Hey guys, first post here. I should have checked this out years ago. My 2016 SS had hot start problems to the point where I've now had multiple starter replacements and GM always applied the band-aid fix and never scratched below the surface. That said, super happy I found this, read through it all and wanted to say thanks to SSDan for getting this great thread started, to TP2SS for the detailed writeup on the cable lengths to the sound tube and KLG for your battery setup.

That said, waiting on my custom cable from BestBoatCables and (just sadly had my supplemental battery cable order cancelled, but on that soon). I'm hoping this fix at least alleviates the problem, and it sounds like it will! Thank you everyone!!! This has been the bane of owning this car, and excited that there may be light at the end of the tunnel!!!

If anybody is familiar with the terminal/eyelet sizes and length for the trunk cable install, can you please share? I'll provide a detailed summary of my two cable installs for future readers of this thread

[SSDan]

Originally Posted by S1lentHarbinger

This has been the bane of owning this car, and excited that there may be light at the end of the tunnel!!!

If anybody is familiar with the terminal/eyelet sizes and length for the trunk cable install, can you please share? I'll provide a detailed summary of my two cable installs for future readers of this thread

I don't know the exact details for the cable I used for the battery. I bought it locally from an Advanced Auto parts store off the rack. It was 4G and the eyelets were the right size.

This solution has helped many and I hope the same for you. Good luck and keep us posted.

[S1lentHarbinger]

Apologies @SSDan, I completely forgot you had posted the link to the AutoZone cable. There are quite a number of pages on this thread haha.

Part is ordered, should have both by Saturday. Admittedly, my starter was just replaced (again), so *right now my hot start issue is all but eliminated, but I'm sure it would otherwise return with time. After bringing the car home from the stealership I let it idle for 20 minutes in an effort to simulate typical heatsoak circumstances and (edit: each time I went to start it) it cranked a few times in short succession with authority. That said, I will try to write up a detailed log of the install (photos/battery terminal measurements cold/hot/running pre&post install). I'm not the most mechanically inclined but these mods are simple enough, however if anybody wants me to test/take measurements during the install in any particular order (trunk/block ground first/together) let me know and I can try to accommodate.

Thanks again to all who contributed to this thread!

[S1lentHarbinger]

@SSDan -- forgive me for the delay in getting back to this as well as my lack of photos. I can go back and take some if you think it will benefit the community but all in all, I added the following:

1/0 AWG 27" - 3/8 terminal cable from the negative peg in the bay to the sound tube mounting bolt
4 AWG 18" +/- - 3/8 terminal cable from negative battery terminal to the bolt the fuse box connects to. I didn't see an unused bolt with an available nut, so cleaned off the paint on the rear/left-most bolt on the passenger side trunk fuse(?) box. In all cases used dialectric grease at all connection points.

Background to my situation
Prior to installing the above cables, my starter was replaced 2 times, and what I was told upon my 3rd replacement, that the nut connecting the battery to the starter was not fully seated, began arcing over time (have a pic of the nut if anybody cares to see), which was replaced when 3rd starter was installed. Previously, when I would begin getting weak starts I would jump the car and it would start with authority, until eventually that nut melted away from the arcing to the point it no longer had sufficient contact and the car refused to start. Now that that's been replaced, the car seems to start without issue. After returning from the dealer, I let the car idle for +/- 20 minutes on a ~65* day and it would start again no issues. Nevertheless still didn't have confidence my issues wouldn't return.

Now (post-wire-install) while I haven't had any 'hot' days per se, temps did get above 73*F on two occasions at which point I made sure to run some errands to test startup with a hot bay and have had ZERO issues whatsoever. I've also been monitoring voltage and everything seems to have hit a proper equilibrium. Immediately after the starter replacement, my (new) battery wouldn't hold a voltage over 12.25V at rest, regardless if having driven it. Now that I've added the battery cables, I see my dash cluster showing voltage frequently in the high 13's, low 14's (it would never hang there previously). Further, my battery now sits at a pretty 12.6-12.7V overnight without any of my previous parasitic drain. As far as my Camaro is concerned, all seems right with the world.

Extending a genuine thanks to everyone on here who's contributed to this thread. I was anticipating trading it in while it still had some extended warranty left. Not committing just yet, need to see how it handles warm temps, but I've begun scouting headers/cai's which I never bothered with previously amidst my issues.

Thank you all!!!! If anyone wants pics / voltage readings / etc. let me know and I'll update accordingly.

[SSDan]

Originally Posted by S1lentHarbinger

@SSDan -- forgive me for the delay in getting back to this as well as my lack of photos. I can go back and take some if you think it will benefit the community but all in all, I added the following:

No problem - I appreciate you replying and keeping this thread alive so others can benefit. I'm glad all is good with your car now. I believe you should be good to go.

Prior to me adding the ground cables I would get the slow crank on a fully warmed engine regardless of outside air temps (not just hot days). Since December 2020 when I added the cables I have had no starting concerns regardless of the weather. This fix saved me from selling a car that I love.

No need to add more pictures or write-ups beyond what you have already done unless you want to. There is plenty of detail in this thread for anyone else needing help.

Cheers!

[BlackBumblebee]

Hello again. Thanks to @SSDan for adding so much to this thread. I've done the 1/0 gauge wire to water pump fix, however it wasn't working 100%.

Took the car to the reputable RPM motorsports in NC and they SOLVED it. Loose battery terminals. Aka when I installed the replacement battery I hadn't tightened it enough apparently! Felt so stupid!! Anyways, its been done and after 2 days, startups have been FLAWLESS. Even my steering wheel audio skip controls are working better which was always a problem. So when I got my car from the dealer, they hadn't tightened nuts enough either

Lastly, i talked to them about possibly wrapping the starter. However, they mentioned it may cause damage due to the wrap retaining water from driving through the rain. May sometimes rust wires and such. Woulda never though of this! So fair warning to be careful.

[wal-dog]

Mine is doing it again. Worked for a couple months but now the slow crank is back on hot start. Anybody have it come back?

[arpad_m]

Originally Posted by wal-dog

Mine is doing it again. Worked for a couple months but now the slow crank is back on hot start. Anybody have it come back?

Nope. How about genuine battery weakness? If you're still on the original, it is on its way out.

I replaced my original battery made in Feb 2018 about a month ago, and the car's even peppier to start now, cold, warm, and hot (it hadn't been unreliable before that, just noticeably slower, which the battery tester proved out).

[SSDan]

Originally Posted by arpad_m

Nope. How about genuine battery weakness? If you're still on the original, it is on its way out.

I replaced my original battery made in Feb 2018 about a month ago, and the car's even peppier to start now, cold, warm, and hot (it hadn't been unreliable before that, just noticeably slower, which the battery tester proved out).

Agreed. Check the battery. To overcome the heat soaked starter you have to have both a strong battery and the least circuit resistance possible (the extra ground cable provides that).

Good luck and please report back.

[S1lentHarbinger]

Originally Posted by wal-dog

Mine is doing it again. Worked for a couple months but now the slow crank is back on hot start. Anybody have it come back?

wal-dog, have you taken any voltage measurements? At the point of when I added the additional cables to mine, I had already replaced the battery maybe 6 months or so prior, so it was still relatively new. Take everything i list below with a grain of salt, as I was using a cheapo Home Depot voltmeter from GenElectric, and my results aren't necessarily indicative of minimum #'s you'd need or want to see:

Pre-Wiring
engine off, after sitting overnight ~12.22V
engine start, would spike to ~13.65V and then settle back around 12.25V
running ~13.2V (measured at battery terminal, not at starter terminal)
post-drive, engine off ~12.24V

Post-Wiring
engine off, after sitting overnight ~12.5-12.6V
engine start, spikes -- did not measure
running ~13.6-13.8V
post-drive, engine off -- will teeter between 12.5 and 12.6V

If you don't already own, a cheap voltmeter at HomeCheapo can be had for I believe ~$30 or so, but I would recommend getting something a little better. I picked up the cheapest one available and wish I had gotten something a little more robust since they last forever. In either case, hopefully the above helps.

[Sephx1]

On my son’s 2016 SS we have replaced the starter with new OEM, removed the larger aftermarket primary cat on the starter side that someone installed on it and replaced it with OEM, checked the heat shield, installed a new Optima battery and checked all of the factory grounds. I already added a cable underneath from the body at the trans tunnel to the transmission. Still an intermittent issue with hot starts after sitting. Bought the 27” cable from battery cables USA to run to the sound tube bolt. 5/16” hole at the negative connection, 3/8” at the block. Cable shipped the same day, very pleased with the quality, service and price. Will report back as to whether the problem persists.

Oddly, my 2021 appears to use the same ground wiring and it’s not an issue.

[The Chief (tm)]

+1 on custom-ordering experience with BatteryCablesUSA. I think I also managed to order before the day's cutoff, and they're not too far from me, so even w/reg. ground shipping I got the stuff on the second day after ordering.

Nice idea on using the bolt at the sound tube; skips the step of cutting out the lug end of the cable (if otherwise using the tensioner bolt)!

[Msquared]

Originally Posted by Johnnyb2016

Added an extra ground to mine today.
Ran from sound tube mount to the negative post near the headlight
Used 1/0 cable and plated copper ends.

Johnny (or anyone here who knows), what specifically are the two cable clamps that you used to secure the cable to the water pump housing (e.g., metal with rubber padding, black plastic, what size, etc). Where did you get them? Home Depot has several kinds in stock, so I'm just curious what works best. Also, was this a 27" cable length, or was it shorter?

Update:
Answered my own questions and emulated Johnny's setup. I use a 27" cable to the exact same specs that sephx1 shows on his order slip in post #291. It was not a bit too long! 24" would not have worked. The clamps I used look identical to Johnny's. I got them at Home Depot, and they are Gardner Bender Insulated Cable Clamps showing as 5/8" size on the package, part # PPR-1558. Those were on the shelf in my local store, and they fit the outside diameter of the cable perfectly (which I measured at 5/8" also, using calipers). The come in a perfect pack of two, and their bolt holes are also the perfect size for the water pump bolts. For some reason they don't show up on the HD website. Odd. The installation is easy, and I like routing it over the thermostat because it keeps this cable a lot further away from the serpentine belt. My only caution would be to do one of the thermostat housing bolts at a time so as not to encourage any leaks that might occur if you take two off together. Probably not a big deal either way, though.

[chovaz]

Originally Posted by wal-dog

Mine is doing it again. Worked for a couple months but now the slow crank is back on hot start. Anybody have it come back?

Yep, fixed for me for a bit (over Florida winter, maybe a coincidence) but with hotter temps back, it's happened 3 times again already. Came back here to check new solutions...