B9 S4 - New Long Block Recommended - Misfire at Idle

[bpdef29]

Surprising "diagnosis" from Audi dealer today--curious if anyone has input.

Car has 59k miles and last weekend developed a constant Cylinder 2 misfire at idle ONLY. Runs perfect under any and all load. No other symptoms. Very well maintained.

Took the car to Audi after swapping plugs, etc. to no avail, and they recommended a new long block after finding metal flakes in oil. Didn't get any specifics on the flakes.

Compression test and leak down tests were fine. Borescope revealed nothing; no scoring or damage to piston, but it was allegedly "too dark in there" for them to confirm this for certain.

The alternative they presented for additional diagnosis was $12k to have "everything" taken apart to identify the issue.

I'm not a mechanic, but this doesn't seem consistent with a catastrophic bottom end problem, nor does it seem reasonable to fork over $12k just to determine whether it could be a fixable valvetrain issue.

I'm hesitant to write the car off at this point given the limited information I have.

What would you guys do? Bring to an indy to see if I can get a cheaper diagnosis?

[oesman]

Yea bring it to an independent shop in your area. Dealers are already struggling to staff technicians, most don't want to or can't rebuild engines or transmissions. Their game is swapping parts, not figuring out what sub-component went wrong. i.e. S4 owners having whole exhaust systems swapped because of actuator issues in the active exhaust. The $12k quote is a "fuck off" price, they don't expect you to pay $12k for a diagnostic.

[AldermanToffee]

Idle only leak would make me think it's vacuum related. These cars can be quite sensitive to vacuum.

Realistically though when you start entering the "new engine" territory I would heavily consider trading the vehicle in.

[bpdef29]

Thanks gents--going to take to an indy and trade it in once repaired (if fixable).

Will post the diagnosis when received to hopefully help someone out in the future.

[oesman]

Thanks gents--going to take to an indy and trade it in once repaired (if fixable).

Will post the diagnosis when received to hopefully help someone out in the future.

I think what AldermanToffee is suggesting is trading it instead of fixing or replacing the engine, if the engine is in fact bad. It's probably less cost than replacing the engine and possibly less cost than fixing the engine depending on what's wrong with it. Doesn't make much sense to trade it in once you fix it unless it's a small fix and you're tired of the car.

Idle only leak would make me think it's vacuum related. These cars can be quite sensitive to vacuum.

Was thinking that too, but weird it's just one cylinder. Though who the hell knows with dealer service centers, could be something really dumb.

[S4James]

swap coilpacks, observe, replace plugs, observe, swap injectors observe.

are there vacuum ports on or near that cylinder on the intake manifolds? I suppose it could be vaccuum. but do the classics first.

I know a few people have needed to change out their injectors.

[bpdef29]

Took the car to CarMax and disclosed the issue and Audi's recommendation. Appraisal came in just a couple grand short of KBB value, so in all likelihood I am going to ditch it as-is.

[oesman]

Usually the best bet unless you really like the car. Like I'd probably engine swap just because I'm so far into this project and I do genuinely enjoy this platform.

[njspeedfreak]

Definitely the smart approach as it limits your downside risks. But I do feel bad for the poor guy/gal who Carmax ends up selling that car to after they take it off your hands. My guess is they are not going to get the same disclosure that you gave Carmax.

[oesman]

My guess is they are not going to get the same disclosure that you gave Carmax.

They'll either wholesale it or fix it. Carmax has a pretty decent return policy (10 days) and a warranty (90 days or 4k mile) and they are trying to make like around $2k per car. There's not a lot of room for returns you know are gonna happen. Carmax is actually pretty great in my experience.

[bpdef29]

Usually the best bet unless you really like the car. Like I'd probably engine swap just because I'm so far into this project and I do genuinely enjoy this platform.

Project looks awesome--I actually used your grille DIY video last year when I swapped from base silver to BO.

Definitely the smart approach as it limits your downside risks. But I do feel bad for the poor guy/gal who Carmax ends up selling that car to after they take it off your hands. My guess is they are not going to get the same disclosure that you gave Carmax.

They'll either wholesale it or fix it. Carmax has a pretty decent return policy (10 days) and a warranty (90 days or 4k mile) and they are trying to make like around $2k per car. There's not a lot of room for returns you know are gonna happen. Carmax is actually pretty great in my experience.

Yeah, they will really take just about anything. Brought them my 100k 335i as-is and disclosed every leak, blown turbo seal, etc.; they gave an offer and said it was just going to go to auction.

Definitely an interesting experience with the S4, though. The appraiser pretty much insisted there was nothing wrong with the car despite me being extremely clear.

Going to pull the oil this weekend just as a courtesy.

[oesman]

Project looks awesome--I actually used your grille DIY video last year when I swapped from base silver to BO.

Thanks, I'm glad you found it helpful =).

[A4Qwattro]

Definitely the smart approach as it limits your downside risks. But I do feel bad for the poor guy/gal who Carmax ends up selling that car to after they take it off your hands. My guess is they are not going to get the same disclosure that you gave Carmax.

The might not, but Carmax has their warranty program which is why people buy from Carmax in the first place.

[njspeedfreak]

Unless they send it to auction. If the engine really is as bad as the dealer claims, neither CarMax or the Auction house is going to fix it - it's too expensive. Maybe they are willing to gamble it's not that bad and take a big loss if they are wrong, but my guess is it goes to Auction and is sold to some new buyer 'as-is' with no warranty.

[ILLITE]

Like stated above find an indy shop. Luckily I have one 15 minutes from me for what I’m unable or too lazy to do myself.

The dealer on any manufacturer not just Audi is a joke anymore.

It could be something extremely minor.

[Helladrew]

Just had a cylinder 1 dead miss on my brothers 80k mile 19 s4. Swapped coils and plugs and misfire stayed on cylinder 1. Compression was 210. All that’s left is injector. New OE injector fixed the issue.


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