Will diesel cause the AOS/MAF to fail?
 

Found out that the local station swapped diesel and premium this past weekend

I got the gas Sunday morning and when I started the car Sunday afternoon it puffed big blue smoke clouds. Shop is cleaning the fuel system. I find it hard to believe my one year old AOS failed exactly after getting diesel in the tank. I'm in discussions with the station insurance and want to make sure I submit a complete and fair claim.

Could the diesel have cause the AOS and MAF to fail?

I can see the possibility of diesel contamination effecting the AOS, but can't quite connect it to a MAF failure.
Outside air comes in the intake and past the MAF and throttle body before any fuel is introduced. I wouldn't count the MAF as bad anyway until the other issues have been cleared up and DTCs reset

note: The author has very little actual knowledge of how these things interact and is much better at taking things apart than putting them back together.

Agreed. Can't see how the MAF would have any clue.

Not really seeing how the AOS does either, but not ruling it out totally.

Seeing as it was their gaffe, you can't say definitively that diesel contamination would not compromise the AOS, so I'd have that replaced as part of the claim. My $.02

??? I thought diesel pumps were the same size as the old regular leaded pumps, which are too large to fit into an unleaded fuel tank. Thought this was a federal regulation.

OP didn't put the diesel nozzle into the filler, the gas station put Diesel Fuel into the Premium tank.

If it were me, I'd suspect that it ruined my cylinder walls, IMS, and crank bearings requiring a full replacement with at least a new 3.4L engine. :dance:

Agreed. :cool:

I have seen a few cars where that happened. The blue smoke is from the diesel in the gas. Once the fuel system is thoroughly flushed, and probably a change of plugs you should be fine. It likely will smoke a lot until all the diesel is burned out of the system. That can damage the O2 sensors and cats, but you are probably OK. I doubt that there is anything wrong with the AOS or MAF.

FWIW, a few years ago a local Audi dealer had a girl bring in an '02 S4 that started missing badly, then blew large clouds of blue smoke and stopped shortly after filling up with "gas". The dealer techs diagnosed it as a blown engine and quoted some outrageous sum for a new engine. She ended up taking it to another slightly shady independent shop that replaced the engine with a used one for half the price, which was still a huge profit. Once it was started, it too blew blue smoke and stopped. That is when they figured out that the tank was full of diesel fuel. They flushed the system and all was well, after a LOT of smoke. They didn't tell the owner the real problem, and kept the original engine that had no real problem...

Which is why no one touches my car with a wrench but me.

They "check is in the mail" from the insurance company, 3-5 days they say.

Fuel screw up
 

A family members Smart Car ( please guy`s no remarks ) diesel , fueled up with diesel that had water mixed in the gas station`s tank. There was a lot more than cleaning the glow plugs. Fuel system, pump and tank complete flush. New filter and gaskets . I think they had to do a reprogram ? And a charge to dispose the contaminated fuel. Gas station came clean and paid around $1400. I hated that little car .