Skoda Laura: Diagnosing a very weird starting issue

I am wondering if I should get the alternator serviced at an electrical shop in my next planned car major service?

BHPian sunilch recently shared this with other enthusiasts:

I now have an odd problem to diagnose.

The car usually needs 2 cranks to start. All lights come up properly when I insert the key. The first twist of the key does nothing. The second twist starts it properly. Once the car is warm (after a short drive), this doesn't happen again. But this happens every-time I start the car after a few hours (say after overnight parking).

Battery is only 13 months old and all other functions are working properly.

This has had been the case for a couple of months now. My driving is not daily but this issues happens every-day now. This isn't dependent on the season or time of the day.

Now, today I did notice another issue. If I run the car with AC on (works perfectly), phone on charing and music playing (radio or via AUX), for a while (say about 20-30 Kms) the horn goes weak, indicating drained battery.

If I switch off the AC and phone charging, the horn gets back to normal after 5-10 mins.

So what could be the problem here? Battery? Alternator? Starter Motor?

Not yet shown to the FNG, but would visit them in few days. Car is now 14 years old, has run about 1.03L Kms. During last service (in June-July this year) I asked FNG and a couple of folks to check the Alternator for any service that it may need. Everyone advised to not to touch it since it is working as expected. Their idea is simple, replace it when it breaks. Otherwise let it be. I am wondering if I should get the alternator serviced at an electrical shop in my next planned car major service? Or is it just paranoia?

Here's what BHPian Bsilver had to say on the matter:

Check voltage after turning on all electricals, it should return 14.2V or greater than 14 at least. If not returning then the alternator is at fault, and you may have to inspect the alternator. If it is returning 14.2 V then nothing to worry about the alternator. Check if the terminals and leads are free of any debris, if they are clean them, and reinstall in the correct manner.

If you have done all of this, then looks like there is some other problem with the vehicle and needs further diagnosis. One of the concerns is that, when you are starting it after a long time, the pressure in the fuel lines is dropped due to the halt, when you are trying to crank, your fuel pump is not generating enough pressure at the first crank, to fuel the engine, and hence not starting. If you halt for lesser time, the pressure in the fuel lines has not dropped much, and the pump, even if compromised, still is generating sufficient + the delta of the pressure before stop to fuel the engine. This indicates a weak fuel pump. In order to check this, any competent FNG with a scanner needs to access the fuel system, and check whether the requested value is being delivered by the fuel pump, if not, then change out the fuel pump, as it has gone weak after years of usage. If not, then there are other ways, once you try this out, post the results here.

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