[Jebuzz]

Hi everyone.

This is my first post, so forgive me if I mess up anything.

I recently bought a 2012 f30 with a N47 engine.

This car has been reprogrammed to around 150hp, I don't know, but that might be relevant.

Oil consumption is ok, oil level has been steady.

After driving around 10k Km, I've noticed the following. Under hard acceleration (flooring it) the engine smokes white smoke from the engine bay area, not the exhaust. It doesn't matter if it's hot or not. If I floor it it will smoke, if I don't it won't (or I can't tell it's doing it).

At first I thought it was the VGC, did a full engine clean and there's no oil coming from the passenger side near the exhaust.

I've checked the return hose from the injectors and it is dry. There was also this hose coming from the fuel pump and that one is also ok.

Did notice when there was smoke, there was also some fluid (which I assume is diesel) pool (you can tell there's like a small puddle) near the injectors.

Driving normally, no hard accelerations there's usually no smoke. But once I drove for a long time pretty fast at high revs and when I got to the destination I noticed I was trailing white smoke and it was also coming from the engine bay and some of it was entering the cabin.

The smoke smells like diesel.

One time I did clean the splash guard below the engine and while washing it noticed it was drenched with diesel.

Also in the oil pan, near the screw there's usually a diesel drop dripping at the bolt, which I assume is dripping from the top of the engine down ( I think it's diesel because it's a clear liquid and not black)

I have 2 hypothesis regarding this.

The first one is that the injector's copper seals need replacement or the gaskets on the VCG for the injectors, and with hard acceleration, there's more pressure so they're just letting the fuel leak from that seal to the top of the valve cover and it pools there. However, I don't understand how it drips from that point to the exhaust manifold or near hot engine parts to make it smoke. But the fact that there's diesel near the oil pan, proves it is dripping somewhere.

The second is I have either a cracked valve cover, or the gasket is worn and I just don't know what diesel smells like.


I'm kind at a loss on this one. I'm waiting on UV ink that I'll be putting in the fuel tank, and that way I hope I can tell where it is dripping.

Do you think the repo might be the problem? I don't know if there's an increase in fuel pressure when the engine gets reprogramed.

I'm tempted to order a new Valve cover with gaskets and the copper seals and just replace the entire thing.

Any help would be deeply appreciated.

Feel free to ask any questions. I'll try to post pictures/ a video from below the engine as soon as I can.

Pedro

[Eddamoo]

Firstly want to say its a great amount of detail you've gone into here!

When you say a fluid is pooling somewhere, can you check if its diesel by smell?

My first guess was the return pipes as the o-rings can fail, but you ruled that out. My next thought would be to check the injector hard-pipes - a leak from a loosened pipe will be far worse at wide-open throttle. You need to check their torque with a spanner-ended socket with a torque wrench.

I wouldn't have thought Copper Seals as you can often hear when they leak with a distinct 'tsst' sound.

[Jebuzz]

Hi again.

Thank you, I assume that my drive is proportional to how much this is driving me crazy.

After further inspection I can also now see some fluid next to where the VCG is 🙃

I've taken a few videos and I assume this will help visualizing what I'm trying to explain in a second language.

Regarding the high pressure lines I've already had a mechanic friend of mine checking them all for tightness, he said they were good. But maybe I should try it as well.

Also this is the first time I tried it, but smoke also comes out of the oil filler cap. Which makes it harder for me to understand.

I'll be replacing the the valve cover most likely now. But I'm pretty sure that won't solve the problem.

Here are the links to the videos I've taken. I hope they help.

Video 1

Video 2

Video 3



Thanks for helping 👌

[Eddamoo]

Your English is perfect - better than most English speakers! You cant beat a few photos or videos though!

The vapor coming from the oil cap is normal - it will be mostly water. Check it when the engine is running and make sure there's no excessive 'blowing' pressure coming from the oil cap or dipstick tube.

To me, on Video 2, the front of the engine rocker cover looks wetter than the back. I suspect that the issue with you seeing smoke when 'flooring it' is that the rearward G-Force is taking the pooled diesel and forcing it to the back of the engine, dumping it on the DPF at the back - hence the sudden white smoke.

I try wrapping every pipe and union in some blue tissue paper and then run the engine to see which part gets wet.

[Dongeryon]

Hi Jebuzz

Any update about the findings?

I have a 320d f30 and facing very similar issues.

One thing to mention tough
When I drive in sport mode the smoke doesn’t show up only in comfort mode.

[Jebuzz]

Originally Posted by Dongeryon

Hi Jebuzz

Any update about the findings?

I have a 320d f30 and facing very similar issues.

One thing to mention tough
When I drive in sport mode the smoke doesn’t show up only in comfort mode.

Hey, no update on it. Since it only happens when I push the car I've postponed the repair. However I'm thinking on tackling this now and I'm gonna start with the lowest cost to replace. I'll do the injector seals, then the gasket and then the valve cover. I'll stop once it's fixed.

I've noticed it drips all the way to the oil pan, but other than that no news sadly.

[frodmyster]

Hi, did you get to the bottom of this?