Jolide21

First time on a forum asking about a car so don't know how this really works but I have a 2009 Audi s5 coupe and I am getting two things the elf light and error codes about all of my ignition coils all 8 And was wondering if anybody had this problem mechanic couldn't figure it out put new spark plugs still did the same car starts a little slow takes a while the problem just started. Anybody know what I should do just bought the car at 95k and it's at 105k

Thanks in advance

plat27265

Do you know if it former owner had the intake valves cleaned of carbon deposits? Carbon deposits on the intake valves is a major cause of error codes especially on a car with 105k miles.

SloopJohnB@mac.com

Also, if car starts a little slowly, i.e., the engine turns over noticeably slower than you're used to, load test the battery. If it still has the OEM battery, chances are it needs to be replaced. You're not as bad off as BMW owners that have an Intelligent Battery System (IBS) that varies the charging voltage based on battery life...a new battery has to be synced to the IBS electronic control unit or else it thinks the battery is old and overcharges them.

Replacing a battery on your car is as easy as using a portable starter battery that plugs into your cigarette or 12V lighter/source socket. Make sure the socket is live, i.e., some cars shut the socket(s) off with the ignition off, so you might have to leave the ignition on or on accessory. Then you can disconnect the pos cable, wrap it with a plastic glove so it doesn't ground (because your portable battery is energizing it!), remove the neg cable and battery hold down bolt and then the battery. Replace the battery and reverse the steps.

Frogfoot

A question - apparently later cars also have that battery sync - when was it introduced in S5's?

lmariorod

Just changed my battery today. 4 1/2 years of short drives with radar detector,
front and rear dash cams have taken a toll on my OEM battery.

Car still starts fine but battery mgmt was shutting down alarm and interior lights.

Car runs much better with new, group 49 battery/ 1085 CA/900 CCA, Reserve Cap. 185

VCDS under>>>> 19-CAN Gateway->Long adaptation->Channel 4->Battery Identification. Change last serial number digit and save.
Battery mgmt now adjust for changed new battery.

Jolide21

So better is fine just had bought a new one when I bought the car the EPC light doesn't go away and while I drive it like stutters a lot of loss of power but the light turns on when I turn off and on the car it's fine till I pass 4,000 rpm then the light comes on

SloopJohnB@mac.com

The car has a diagnostic code system. You should get and post the codes.

Jolide21

Alright so the codes thatnits giving me are "ignition coil (A-H) primary/secondary circuit" today it shut off and didn't wanna turn on and it started flashing the check engine light then it turned off and drove fine but then the check engine came on again and then I ran the codes again and the ignition coils were the same codes thrown again.

jschrauwen

What sort of scanning system tool are you using?
Use VCDS or similar (like Carista, OBDeleven, etc etc) to get the codes and code numbers and post those code numbers.
First thing that came to mind was also carbon build-up on intake valve area.

Lets get some history on this car.
Did you get the servicing records from the previous owner(s)?
If no history, was the car's previous owners city dwellers? Did they live and work within a city?
Does or did the car get routine trips on the highway for at least 30 minutes in duration at sustained highway speeds?
Do you regularly give it an Italian tune-up? If not, you should start now.
If you have any records of oil changes, which brand and viscosity was used and how frequently was it changed? There seems to be a correlation that using a good brand/quality oil like Motul 300V 10W60 and similar does minimally reduce the amount/degree of oil vapour passing through the PCV's back into the intake plenum which is the root cause of carbon build-up on the intake track.

This video might help explain things.

(Walnut or soda blasting would be the best option)

jschrauwen

Audi FSI Engine Carbon Build-up Megathread
https://www.audiworld.com/forums/a6-.../#post24920979
https://www.audiworld.com/forums/a6-.../#post23927685
https://www.audiworld.com/forums/a6-...2777180/page3/