[raptor5244]

I notice a slower turnover when it is warm. I think it is starter heat soak.

[Camaroky]

Well I don't know if it's good or not that there seems to be a few of us that have the same thing going on. Could be normal or could be something worse

[Raven87]

Either the starter is bad - and I do not think this is the case - or there is something limiting sufficient voltage/amperage reaching the starter to turn the engine over.

OP - if you have a good battery charger that has a boost/jump capability, hook it up and give it a few minutes. With the charger connected, if the car starts normally you know the battery is bad. If it still does the slow crank, it's downstream of the battery.

Just a suggestion that has helped me trouble shoot this sort of problem many times in my 62 years.

Regardless what the dealer says, my first suspect is the battery. But it may be between the battery and the starter or the starter itself which is probably the least likely problem.

[Raven87]

I've had two C7s with the LT1 and neither of them did what the OP is seeing, even on cold days.

[JAZ]

The starter is probably not getting sufficient cranking amps to turn over the motor when hot. Assuming it is not heat soak in the engine (needing more cranking amps), then it is likely a resistance in the electrical system to the starter.

I would start by looking at the ground return path from the starter to the battery which is probably through the engine block to the large black (negative) cable to the battery.

If you have an ohm meter, check for zero resistance between the engine block and the negative post of the battery. Check while cold and while hot. If you find the resistance varies with heat, or if you don't have a meter, then check all of the ground connections that you can find. There are three in my car. Battery to Engine, Battery to Fender, Engine Block to Firewall.

Remove the ground cables where they attach to the engine block or chassis, check for any issues (eg. rust on an old car, signs of heat damage on the cable, loose connections), clean then replace and tighten the cables. You should be able to measure zero resistance from the engine block to the chassis and to the negative battery post when cold or hot.

I had the same problem with my car of slow/not starting when hot. After I cleaned up all of the grounds, it started far better hot or cold, idled better when hot, and generally ran better.

[ocautomotive]

Guys this problem was fixed a while ago. It turned out to be two bad negative cables causing too much voltage drop. They replaced the battery, starter, and both negative cables and the car starts up better than ever.

[Daves1SS]

Originally Posted by ocautomotive

Guys this problem was fixed a while ago. It turned out to be two bad negative cables causing too much voltage drop. They replaced the battery, starter, and both negative cables and the car starts up better than ever.

Thanks for the update. Mine did it again today. Guess I'll start looking into getting it fixed....

[Whis]

Am I the only one that cant hear anything other than the actual car start up?

[ocautomotive]

Originally Posted by Whis

Am I the only one that cant hear anything other than the actual car start up?

turn up the volume, you will hear very slow cranking.

[franksredhot]

I've had this same problem but it is so intermittent that it's going to be tough for the dealer to replicate. If I drive the car for a long period, turn off the engine, and then quickly try to re-start, it barely cranks. But it always ends up starting. I'll see if the dealer does anything about this. Anyone know if there is a TSB for this?

[exxit]

This happens to me and does seem to correlate with the temps outside (maybe).

Car will always start, but sometimes its just slow (super slow) like as if the battery is low. However it's never not started.

Maybe it is those negative wires themselves? Any idea where they were located?

[ocautomotive]

Originally Posted by exxit

This happens to me and does seem to correlate with the temps outside (maybe).

Car will always start, but sometimes its just slow (super slow) like as if the battery is low. However it's never not started.

Maybe it is those negative wires themselves? Any idea where they were located?

Yes it was two bad negative wires for me. My car got so bad that it didnt start all. Negative wires (I believe there are two) were replaced and all is good. My starter also went bad because it burned itself out trying to crank so much and start.

[Lampslife]

It’s the starter, they go out because it’s so close to the hot exhaust. I’m about to be on my 3rd starter. Wrap it in heat repellant wrap

[ctrlz]

Originally Posted by JAZ

The starter is probably not getting sufficient cranking amps to turn over the motor when hot. Assuming it is not heat soak in the engine (needing more cranking amps), then it is likely a resistance in the electrical system to the starter.

There is a lot of subjective info in this thread. Jaz has the right idea. Time to get some objective measurements and compare the readings for slow crank vs. normal crank cars.
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