[Hommamyy]

Hi everyone! My first post on this forum starts now!

So the thing is following:

I went today at the used cars dealership for a e93 335i manual (200 000km) after getting a decent offer for my f30 320d.

Took it for a spin, cranked well with cold engine, didn't feel any significant loss of power and everything worked well in the beginning. After a while (~10-15min) i stopped on a parking lot and revved it on neutral and found out that the valve case gasket seems to leak (smoke under hood and came through the air vents inside to cabin).

Didn't take a huge stress about it, and again after while of driving i managed to slip the clutch a little when changing from 1st to 2nd gear. But thought that was quite normal for n54 with that kind of mileage and thats what i'm thinking of it still. Completely normal I think.

But then comes the part when things got abnormal. On a not even that tough revving the car started having some serious misfiring and put on a yellow engine light but nothing was displayed on idrive screen. After that you could feel the misfiring and shaking well also in the cabin, also the car couldn't rev over like 4000rpm (not sure about the rpm but I think it was something like that) after that it felt like car hit a rev limiter, kinda like limb mode but still nothing shows on idrive.

Went back to the dealership and read fault codes with ista, faults stated in current km reading was 002AAF DME: Fuel pump, plausibility and 0029CD DME: Vombustion misfires, cylinder 1. After reading the codes I cranked the car again and engine was making pretty loud knockin noise that wasn't present before, didn't rev it anymore, just turned ignition off.

Dealer was horrified and promised to fix all the faults I stated. But I started to wonder what could make that kind of knocking noise and bad misfiring through the rpm range?

Would that kind of problems make you back off the deal? In Finland manual 335i e93 is pretty rare so not many cars to choose from and otherwise the car was pretty much as wanted.

Hoping for answers, thank you in advance

[nicky dj]

If you're getting actually rod knock. I would get out of that deal ASAP. I wouldn't even bother having them try and fix it.

[Hommamyy]

Originally Posted by nicky dj

If you're getting actually rod knock. I would get out of that deal ASAP. I wouldn't even bother having them try and fix it.

Of course that was one of the things that came to my mind, just sounds little off that the rod knocking would begin just like that after a crank and also at the same time with the misfiring problem. What would make it even more off is that it wasn't even the first crank after the beginning of the missfiring problem.

The only thing that sounds reasonable for me is the injector knocking.

And as mentioned the dealer promised to take care of the problems so as long as the car gets repaired, i don't think it matters what the problem is. Optimal situation for me would be that the dealer would change all the "mainstream" n54 weak spots from cheaper to expensive (plugs, coils, injectors, HPFP) because then I wouldn't need to empty my wallet on those.

Of course I can be wrong with it being the injectors, but based on what I have heard I think the rod knocking is pretty rare on n54 and even more rare on stock ones🤔

[david in germany]

On my 335i I was having a misfire on warm starts, when it did it, it does sound like rod knock. After chasing the misfire with plugs, coils and injector it turned out to be the bank 2 o2 sensor. After replacement, no more misfire.

Bottom line, misfires can sound really bad on these cars and as long as compression is good, it can only be fuel or spark. ( normally)

[nicky dj]

Put a little gas on it like the end of this video. You can literally "feel" it.

Is it a BMW dealership? If not stay away. All the other issues you mentioned are easily fixable for hundreds of dollars. If it's rod knock that's a $3K+ job or a new engine swap.

[Hommamyy]

Originally Posted by david in germany

On my 335i I was having a misfire on warm starts, when it did it, it does sound like rod knock. After chasing the misfire with plugs, coils and injector it turned out to be the bank 2 o2 sensor. After replacement, no more misfire.

Bottom line, misfires can sound really bad on these cars and as long as compression is good, it can only be fuel or spark. ( normally)

That's more like what I was thinking and sounds reasonable for me!

[Hommamyy]

Originally Posted by nicky dj

Put a little gas on it like the end of this video. You can literally "feel" it.

Is it a BMW dealership? If not stay away. All the other issues you mentioned are easily fixable for hundreds of dollars. If it's rod knock that's a $3K+ job or a new engine swap.

I'm not able to get to the dealership anymore because of the distance, so I can't anymore do the diagnostics by myself.

And it also is not a BMW dealership, in Finland it's very rare for anyone to buy a car from official BMW dealership for few reasons

1. Prices, the prices in BMW dealerships are way higher than in any other dealerships (for no actual reason)
2. Availability, I have never seen a car that i'm looking for being on sale at the BMW dealership
3. In Finland the smaller dealerships have high chance of being just as reliable or even more reliable than the BMW dealerships

So shortly, BMW dealerships and services done in BMW services are not that big of a deal, actually more like money waste!😄

Got a little out of the point... But for me the repairs are not a problem, I can do them mostly by myself, so the minor n54 problems that exist are not that big moneypit for me. If the engine really would have the rods that is knocking, they would still have to get the car running. In here the 335i is not that much of a "first car", here you have to pay +20 000€ for a e93 335i with some nice equipment. If one gets engine toasted at dealership, they couldn't just toss it behind the dealership and forget it.😄

Oh, and thanks all for answers!!!

[Emilime75]

From what you've told us about the car, this would be considered a neglected and poorly maintained vehicle. If so many problems popped up during just a test drive, there's no telling what all else will shortly after you decide to buy the car.

I get that this might be rare and difficult to find in Finland, but don't let your emotions get the best of you and make a poor, compulsive decision.

[Saif2018]

Originally Posted by Hommamyy

I'm not able to get to the dealership anymore because of the distance, so I can't anymore do the diagnostics by myself.

And it also is not a BMW dealership, in Finland it's very rare for anyone to buy a car from official BMW dealership for few reasons

1. Prices, the prices in BMW dealerships are way higher than in any other dealerships (for no actual reason)
2. Availability, I have never seen a car that i'm looking for being on sale at the BMW dealership
3. In Finland the smaller dealerships have high chance of being just as reliable or even more reliable than the BMW dealerships

So shortly, BMW dealerships and services done in BMW services are not that big of a deal, actually more like money waste!😄

Got a little out of the point... But for me the repairs are not a problem, I can do them mostly by myself, so the minor n54 problems that exist are not that big moneypit for me. If the engine really would have the rods that is knocking, they would still have to get the car running. In here the 335i is not that much of a "first car", here you have to pay +20 000€ for a e93 335i with some nice equipment. If one gets engine toasted at dealership, they couldn't just toss it behind the dealership and forget it.😄

Oh, and thanks all for answers!!!

If it's Rod noise then you are better off avoiding buying it. Unless this garage is gonna drop a new engine for you before sale, highly unlikely.