showcattleguy

Hello
My wife and i purchased a new 2015 Q7 3.0T in November. From the onset we had a sporadic shudder under acceleration from about 20-60 mph. We too it to the dealership on 3 separate occasions but nothing ever came of it because no codes were stored and they couldn't replicate the shudder driving around the block. So last week my wife was picking up our 9 month old daughter from the sitters and the car just shut down. She called Audi and they said limp it to the dealership. They immediately claimed the issue was fuel and made it known that i would be responsible for the cost. When i asked the service mgr what he meant by poor fuel he said it was my responsibility to have an independent lab test it for quality, contamination, etc. So they drained the fuel system and replaced the fuel filters and put " good " gas in it. Same problem. The car has 4500 miles on it! When we purchased the car the salesman said he likes to use an octane booster in every tank and specifically named Gumout. So that is what we used 93 plus the octane booster. When the service mgr heard me say that he latched onto that being the problem. He is saying i need to have the injectors cleaned and possibly replaced and replace the spark plugs because they have a yellowish orange tinge to them. I have called another dealership who informed me that an octane booster should be safe for the vehicle. The service mgr is sticking to his guns though. So a really long story to ask a simple question... Could an octane booster cause this many problems?

B490MTL

Take it to another dealer, you are clearly being told lies. Octane booster shouldn't be needed and fuel filter replaced at that millage sounds more like a way for them to test the problem instead of finding it.

Bklyn_Quattro

complete BS. bring the car to another dealer and make the call to AOA to report their slimy actions. My friends wife's Q7 TDI had similar problems and as soon as the adviser heard that it was 'the wife's car', he immediately assumed that she has mistakenly put good ol' petrol in it instead of diesel. He said they would have the fuel tested but that she would NOT have to pay for that...

smith2010Q7

Queastion on your problem?
You stated a 3.0 tdi. and then you also say you used 93 octane. With a booster.
From what I have read you used 93 unleaded and not diesel for your diesel engine. If what I have read it looks like you are using the wrong gas for your TDI 3.0.
Plus dealer said spark plug which your engine is a 3.6 and not a 3.0 and then a 3.6 is a gas engine for 93 octane is the correct fuel.
Please correct me if I mis understood.

showcattleguy

The engine is a 3.0 liter supercharged gasoline. I have involved AOA and they are currently investigating the situation to see if there is a reason to "introduce good will". After draining the fuel system and replacing the fuel filters did not solve the problem, the dealer did a fuel injector flush at a cost of $500. It "sadly didn't work" but they want to try it again and use a different chemical and charge $800. Then if that doesn't work they want to replace the injectors. The service mgr said Audi technical support told them there was magnesium deposits in the injectors. When i asked if they pulled an injector the guy got flustered and said no. When i asked to drive the car he became even more upset and said i couldn't because it was on a lift. This dealership is just swapping out parts at my expense and blaming it on fuel instead of diagnosing the problem. I love the Audi product, I really do but this dealership is really really making me wish i purchased an X5.

imjustdave

wow... sounds like they are guessing here... Sorry they are doing this to you. I think a Frank conversation with them is in order, guessing at the issue is different then knowing what the issue is and fixing it. At this point I think it is ovious that it isn't a fuel issue but they are hard nose stuck on the fact that it is fuel related. Changing a filter isn't a bad thing but how about actually testing the fuel... it will either come back good, or bad.... If its good then how did the fuel system become bad.
OR maybe its something else I know shocking...

VAG-Fan1

I've had my Audi dealer use this "bad fuel" excuse once before, but it was a long time ago on a different vehicle. Stick to your guns, but try to keep the "honey" attitude as long as you can before going "vinegar", you're more likely to get good will treatment, though for the life of me, I can't figure out why Audi of America isn't putting the issue to rest with the dealer, given the newness of your Q. You are still clearly under warranty and your dealer is speculating at what you might have done wrong, which they should not do.

I'd make sure you have everything documented so if you need to go lemon law, you are in a good position to do so, and if the time comes you can gently remind your dealer and AofA of your right to exercise the lemon law.

And your salesman is full of BS on the octane booster. From what I've read, the modern Bosch Motronic ECU programming routinely and frequently querries the knock sensors in your (forced induction) engine to adjust fuel delivery and timing. Bottle added Octane booster never really reaches a truly homogeneous solution state with your gas, so it's possible that it's fooling your ECU into correcting/adjusting for fuel quality that isn't really there- it doesn't surprise me it went to limp mode.

Using a fuel system cleaner on a full tank of gas occasionally is fine, but you really don't need to use it on a new vehicle. Also, if you look up what the process is for cracking gasoline from crude, you will find that refiners have a pretty wide range of variables they are allowed to play with and still call the product gasoline, so you can actually get "bad gas" on occasion, but it really isn't in the refiner or station brand's best interest to develop a bad reputation for selling poor or inconsistent quality gas.