Car cranks but doesn't start
 

Hello Experts,

I have 2001 base 986.
For about a week, I have had intermittent starting problem. I can hear the car crank but it won't start.

Questions:

If you have your headlight turned on BEFORE starting the car, is it normal that the headlights go dark? (I think the lights going dark is the proof that I have a bad battery but both Pepboys and Autozone tell me that my battery, about 3~4 years old, is good as it holds 80% SOC.)

I have wonderful headlights I bought from Nine8Six.
Can anyone with setup like mine check if the headlights go out as you start?


What's done so far.
- I am ruling out the alternator as I can measure 14.30ish volts from the battery terminals.
- As long as the battery is hooked up to my NOCO G3500 charger, the car starts without problem. (I may have first 2001/986 EV Boxster, ever. :p)


Thank you in advance.

what is 80% SOC????
Percent of charge or voltage reading is meaningless.
You need Amps.
What you want is a load test done on the battery.
That tests cold cranking Amps
With that said if the car will only start with charger hooked to the battery then you need a new battery.
Also the light going dark is when you try to start the car is another sign that your battery is toast.

Thank you blue62.
Of course you are right. It's got to be the battery.

The battery is still under a partial warranty at Pepboys. I will push back this weekend.

Blue62, do you have experience with something like this?
https://www.amazon.com/gp/product/B07Z67MMGC/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
It say it can do load test. Should I trust it?

No experience with that one but some limited experience with other makes.
Yes it looks like it will load test. The range is 100-2000 Cold Cranking Amps.
Looks like you can do some other testing with it.

What I usually do is voltage drop tests when I am having issues with starting or charging systems.
A good quality Digital Voltage meter is a valuable diagnostic tool when it comes to anything electric on an automobile.
Understanding an electrical system, how to test it and access are the real issues.
With a good quality Digital Voltage Meter you can test O2 sensors, fuel injectors,
Maf sensors. Anything electrical on your car. Most of the time you can find info on how to do the test on the Web and or Youtube.
I think your much better off with a good Digital Voltage Meter.
Much more useful.
I just have to go back to youtube or the Web when I want to do things like a voltage drop test. So I know I am doing them correctly.

If you have a place like Battery Plus they will load test your battery free of charge.
Autozone Pepboys, places like that they can't even count your change.
Just buy things you need there, don't take advice from them.

When you buy a battery you want the on with the most Cold Cranking Amps that will fit in the car and you can afford.
It will cost you more but it will last longer.
At least that is my experience.
Keep a battery tender on is if it is not a daily driver.

"What I usually do is voltage drop tests when I am having issues with starting or charging systems."
Well, the headlights going dark means voltage is getting too low, right? (I just checked my bimmer. Its headlights stay on during the start up.

"Autozone Pepboys, places like that they can't even count your change."
LOL. I must maintain a working relationship with the local Autozone as they accept my used oil even though I buy the oil from Amazon. :D

I know AZ used to do the 'real' load test but not any more. They connect that 'reader/tester' to the battery and in 1 second, they tell me my battery is good. I just don't know how much I can trust the new 'testing' process and its results.

Thank you again for your help.
I really appreciated it.

:cheers:

Yes the headlights going dim or dark when you try to start the engine means the battery doesn't have enough power to do both.
It is sort of like a voltage drop test.
The lights going dim shows that the voltage is dropping out when you try to start the car.

Here is a Boxster EV if you want to watch: https://www.youtube.com/watch?v=4_SOP86n-PM