AudiWorld Forums - Help: 13 A8L jerking when auto start

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Help: 13 A8L jerking when auto start

Hey guys so my 13 A8L 4.0T has this weird jerkiness when the engine auto starts (the start/stop system). It is so bad that feels like someone just kicks in the back. I know the start/stop system adds some vibrations to the car but this issue is way worse than normal. However It only happens randomly, I’d say 1 out of 10 times. Other times it works just fine.

Anyone ever experienced similar issue before? Does it sound to you like an engine issue (eg. Battery, starter, spark plug, etc), or drive train problem (like the connection between engine and transmission)?

Any thoughts and info would be helpful, thank you guys very much!

I have experienced a similar issue; it is worse when the A/C is on high. There are times where it is almost imperceptible and others where the car lurches. I also had an A7 with the same issue. I think it is just a poor design. The dealer has never diagnosed it as being 'abnormal'. I recently drove a Q8 and, while greatly improved, you were still able to feel it re-start.

I have the same issue and find that being a bit more deliberate/controlled in how I release pressure on the brake pedal can make the transition from stop to start a bit more graceful. I also confirmed in the manual that the amount of pressure applied to the brake pedal at a stop can determine if the stop/start function kicks in.

I’ve also driven a new Q5 with this feature turned on and find it just as “jerkey” as my ‘15 A8.

Unless your trying to hypermile your A8 it may be better to turn it off.

Stop/Start is a mixed bag on virtually every car I have driven. There are either jerky starts or hesitation/lag when engaging.

On my '15 NWB 4.0T I leave it off, and thanks to SmartKey it stays off.

In addition to my wife hating the jerky starts, the whopping 10% potential fuel savings is just not worth the aggravation of the intermittent jerkiness OR the increased wear and tear on parts. The difference over 20,000 miles per year is negligible. If I get 30 mpg using stop/start, I'll pay $2000 for fuel @ $3.00/gallon. A 10% savings = $200. Even if I am way off and the savings are 20% that's still only $400/year. How much would it cost to replace the starter and other parts associated with the system? And if they have made the system more robust, then by keeping start/stop off I shouldn't have to worry about it failing for a long, long time.

When purchasing a car tipping the scales just under $100,000 I do not see fuel economy as an overriding factor. It's too bad VW Diesel-gated as those who treasure fuel economy still had a viable option in this league until VW mucked it all up.

Quote:

Originally Posted by Lonewolf95 (Post 25276658)

Had this problem too. Did an engine flush a week ago and haven't experienced it since. That starts are now almost imperceptible. But it's only been a week...

Edit: changed out spark plugs and coil packs a few months earlier too

Thanks for all the input guys. I read from Audi SSPs that Auto start/stop also requires the transmission to pump extra fluid when the engine turns on so this may also cause the jerkiness. Recently I have done a transmission flush and it seemed to help with the issue.