Hello all-

Strange occurrences about a week ago to run by you.

I turned the key to start my car in the morning, as usual.
It cranked normally, and started within just a second or so.
However, as I let go of the key, it suddenly stopped.
I thought maybe I had let go just before it fully cranked (even though I had seen the rpm gauge go and clearly heard the engine firing).
So I turned the key again. This time, the starter was barely turning over, with the classic 'dead battery sound' of a slow 'rrr, rrr, rrr'.
It was so weak I was sure it wasn't going to start, but then it did.

I scratched my head, and went to work.

Either two or three more times in the next two days, the very same thing occurred.


Strong crank, engine starts, then dies.
Then weak crank, but engine starts, and is normal.

Now it's been about a week or two, and it hasn't happened since.

My best guesses from me (completely clueless) and my Dad (big brain) and my neighbor (ex mechanic big brain) went like this:

Me
-the first time it happened, I thought 'maybe' I let go of the key too fast
-but having started this car thousands of times, it's unlikely that I suddenly was too quick on the draw for a couple days, and then not
-so no good explanation for why the car stopped
-loose connection somewhere could explain the slow crank, as the battery itself seemed fine 3 seconds earlier (the first crank), and was fine again later.

My Dad/neighbor
-tested the battery, it's properly charged / charging
-electrical problem could be shorting out the battery after the first crank and nearly draining it
-but that doesn't explain the engine stop
-starter motor solenoid may be getting stuck after the engine starts, and the engine decides to shut down or ??
-intermittent nature could be due to an intermittent electrical failure
-starter motor could have a dead spot

So-
we don't seem to have a good explanation, nor a good way to diagnose at this point.

I've not taken it anywhere to look for trouble codes, but I will be at the dealer next week for unrelated cosmetic issue so I may have them run the codes.

The three of us were pretty befuddled by the sudden appearance, and now disappearance (so far) of the problem.

We all agreed it seems unlikely that the two issues (engine stop, and sudden weak crank) were just coincidentally happening at the same time, but a good causal relationship was not clear.

I believe this may qualify for what the CarTalk Brothers call a 'stump the chump' challenge.

Feedback welcome.

Thanks all

 

The first place I would check is the battery cables. Not only at the battery but also at the other end of the cables.

Check to see if cables are loose or if there is corrosion at the connection.

When starting you draw the most current. A high resistant connection will get hot and get worse, which would explain the slow starter motor the second start attempt.

JR

 

I've experienced the same symptoms when the battery was very weak. After you check all connections, you also might consider getting the battery load-tested.

 

Could be the switch in steering column

 

All the battery and ignition switch threads make sense for the 2nd piece (weak cranking), but what about the first engine stop itself?

As an update, it's now not happened since I posted...

I did have the battery looked at, it was charging properly, and there was no corrosion or local wiring issue, but I haven't checked the wiring all the way downstream.