StayinStock

Morning guys, trying to diagnose my buddies 09 z06 he just picked up for him. Car is a sub 20k mile bone stock z06, 1 owner garage kept its whole life, super clean example. He's been having a problem where once the car is at operational temps and he goes to restart the car it hangs for a moment or two before starting. It reminds me of a bad cam sensor issue I had with my TBSS, however I'm not getting any codes when I plug HP Tuners into it, I can watch the crank and cam sensors on the scan tool and everything seems to be functioning so I don't think thats it. Battery is brand new, voltage is all where it should be, alternator is charging. I feel like im missing something just not sure what. It wont do it every time so it's been hard to track. Also one other oddity and it may honestly be a non issue. I let the car warm up to 215 the other day and the fan never kicked on. This seems abnormal to me but I run an aftermarket setup and my fans kick on at 190 so maybe im just overthinking that part. Can anyone maybe direct me on what I should be looking into. @C5 Diag any thoughts?

C5 Diag

I would check the battery ground cable at the block and the positive terminal connection at the starter looking for some corrosion or loose connection possibly…a scope would be better to check the cam and crank signals but not many owners have one…may even be the starter…hard to diagnose on the computer !!

StayinStock

I really need to invest in a scope for my own use anyway so this might be the one that finally makes me do it.Anything budget friendly you'd recommend? I'll check through those things and see what I can find.

C5 Diag

Hantek makes some budget friendly 2 channel scopes that you can get on Amazon…don’t know about their quality though…you have to look at its input voltage because if you want to scope an injector whose voltage exceeds 100 volts and your input voltage is 50 volts you may fry the scope…you would use an attenuator to knock that voltage down…you would buy a 10:1 attenuator.

Kszo6

I had a zo6 do that with a fresh ls7 for a few days… And then it dropped a valve.

1Hotrodz

You mentioned a new battery; check the battery connections for tightness. I know this sounds obvious, but the devil is in the details...

Mixedup

following - mine does that too -

soybeanrice

if battery is good, starter is most likely culprit.

LT1 Z/28

I'd take the starter and battery to a parts store to get them tested. Should help diagnose those too and it's usually free. Header car?

WasVette

Classic Z06 starter heat soak; it probably is only doing it on warmer days after a brief stop; if you let it sit longer, the starter will cool off, and it will start fine most likely.
I wrapped our starter with the Lingenfelter heat shield and added an extra zero gauge ground from the battery to the frame (around 24’). Also cleaned the front right frame grounding point where the ground comes from the engine.

if you do a search on this, you will find it is quite common

Mixedup

My C6 427 'Vert with HCI has had the hot start issue since I got it in Nove - 2 batterys later and still afraid it won't start after my first stop and the car is hot .....- Florida area today in the high 80's got caught in stop and go traffic - temp read over 220 - by the time I made it to my destination it was back to around 200 + - went inside, bought my stuff and 10 minutes later - started car like a champ! My first attempt to fix the issue resulted in I had the high torque starter already before my shop visit today - the difference is a "big 2" negative ground cable and a Anti Gravity Battery - 1500 CCA installed- car turns over like a champ now - hot or cold.

So happy to have this worry behind me. Thanks Joe at PowerTech - Great guy and great shop.

PS no relationship with antigravity or PowerTech - nothing to gain other than my attempt to help other members.

"Save the Wave"

C6_Prodigy

My GS had the same symptoms and it was the starter. Terminals were bad. It would start fine on a cold start anytime, but would have a hard time restarting until one day it just didn't. New OEM starter was wrapped in heat shielding and it's been good for 3 years, knock on wood.

Billy182

Did your buddy ever fix his start issue?

StayinStock

I've been out of town so haven't had a chance to follow up with him yet.