Sandovalmeister

Hello Fellows!

First of all, I'm new to the forum here, so I would like to say hi to everyone!

I have been going through search for the last couple of days and haven't found something that really helps with my issue in particular.

I have an 2008 3.0Tdi Q7. My car has always have the cold start problem where if it has been sitting parked for around 10 hours or more, it needed a really long crank to get the engine going (around 15 seconds). A couple of moths ago I went on a trip and left the car sitting in the garage for around 20 days. When I came back, the car simply would no longer crank for the 10-15 seconds, instead it would go for 4 to 6 seconds and die, and almost every time start right off on the second try.

A few days ago, I felt like starter was loosing strength, I would try to start it and the first crank would be weak and wouldn't start the engine and died in a few seconds, turn the ignition off and crank again and it would be much stronger, sometimes it did start the car, sometimes it required a third try.

Yesterday morning it did start on the third try, but in the afternoon, it would not even crank and haven't been able to start it since. I thought it was a bad battery, tried jumping the battery to the jump point beneath the hood and nothing. Had battery checked and it is ok.

All the lights on the dash come on, all other electric systems (lights, windows, back gate, etc. do work).

What could be the issue?

What I've done so far:
- Check Battery, turned out to be OK
- Checked main fuses in the box beneath the hood next to the ECU
- Did a capacitance discharge

Thanks a lot for your help!

D3Audi

Sounds like a batery problem. at 8 years it's time to replace the battery if you haven't already done. But it could be the starter itself wearing out. Good luck. Keep us posted on your findings.

Greystoke

Agree with D3...although you may think the battery is good it has been 8 years and probably has a couple of weak cells.

Grey

Clues

I vote replacing the battery too. Battery tests are very iffy based on a whole host of variables (my seven year old battery was professionally checked out as okay several weeks before dying).

One thing is crystal clear... a seven year old battery is living on borrowed time and is most likely not producing factory spec CCAs.

Greystoke

Don't forget to get a proper OEM spec or OEM battery and have the vehicle coded to it.

Grey

Sandovalmeister

Thanks a lot guys

But battery was replaced 6 moths ago.

Yesterday I tested the battery in my Q7, then I removed it and tested it starting my other car, and then took it to the battery shop where I bought it to have it tested.

I really don't think is a battery issue.

The only thing I didn't do was have the battery coded to the car when new.

the_duke

Sounds like you need to do a VCDS scan. Everything else is just guessing.

Sandovalmeister

You are totally right, the problem is that I live in Costa Rica and I don't know anyone with a scanner but the Stealer.

Will try every single thing that is in my reach before giving up and taking my car to the dealer.

D3Audi

You could always buy an OBD2 Bluetooth scanner on Amazon and the app Carista, it won't give the most in depth scan, but will still tell you what's wrong.

Edd W

You can do the battery coding change - it resets the battery management so the charging and loading rates are correct.

Is your car keyless?