[335i E92]

Afternoon

Had a couple of leaking injectors replaced recently, one of the symptoms was a puff of black smoke on start up.

However, now the injectors have been replaced I’m left with a puff of blue / white smoke on cold start up. This only happens after the cars been sat for 7-8 hours plus and clears instantly, seems the black smoke from un burnt fuel was masking something more sinister.

It's only been 7 months since the head was rebuilt and the valve seals we're replaced as part of the re-con, all done by Darren Wood so i'm 100% confident it’s not that.

What are the other possibilities, turbo seals? The car runs great and I’m only getting the smoke for a split second on start up. If it was turbo seals would I not have more smoke, like on idle etc? I’m 80k FBO’s on stock turbo’s so it’s feasible that they might be on their way out!!

Alternatively, could this be anything to do with a blocked PCV maybe?

[idnan]

Hi Howard

You were there when mine was smoking from a combination of bad turbos and bad o2 sensors and it was pouring smoke out the back.

I would look into the PCV system, do you run a catch can? I recently had a new valve cover fitted but you can buy upgraded PCV valves from the USA for $50 plus postage. They're made by the same guy who I got my turbos from.

[335i E92]

Hi mate

I remember your smoking issue being pretty bad, just thought mine might be the 1st small stage of the same issue.

Mike told me he replaced your crankcase cover and I was thinking of getting this done too now just hit 80k

Is it possible a blocked / faulty PCV system could cause my symptoms?

From what I've read you can't just replace the pcv valves as they're built into the crankcase cover so I thought you have to replace the whole thing including the 2 check valves?

What exactly is Rob Beck selling? Is it a complete replacement for the current PVC system or a bolt on to it? I was running an AR occ but took it off a few months ago.

[idnan]

You can't get the PCV valves on their own from BMW but the main one which is prone to failure can be replaced with the Rob Beck one. If you go on the other forum you will see a big topic on it with pictures and a how to guide.

I've not upgraded as my cover is pretty much new but I'm thinking that due to the high boost levels it might be wise. The check valve is available with the pipe which runs from the crank cover to the inlet tube.

What is your oil consumption like? Blue smoke is normally an indication of burning of oil so it could be valve stem seals, turbo bearings or PCV system.

[335i E92]

Is it the 'check valves' that can be replaced without the crankcase cover? Think I've seen these on another post, do they unscrew from the pcv system?

When I spoke to woods today Mike said the pcv system was one complete system that was all part of the crankcase cover but I was sure the 2 check valves are separate parts, confused!!

I'm using 1/4 litre evey 2k which is pretty normal I rekon. As I said I don't think it's valve seals as they were replaced recently, so its turbos or pcv system.

How is it possible for the pcv system to cause a puff of blue/white smoke on cold starts? Can anyone explain?

Will check out the RB pcv thread.

[335i E92]

Sorry Idnan, just re-read your last post properly. Understand the valves can't be purchased separately from BMW. Michael has kindly emailed me a detailed plan of the PVC system so I'll have a look and get aquatinted with it.

I don't think I'll need the RB version as I'm only pushing 14psi and don't plan to go beyond that.

If I was to just order a full new crankcase cover from woods will this contain the whole pcv system including all valves or is there a part if the pcv system not connected to the cc cover that also needs to replaced?

[idnan]

Theres a pipe with a one way valve in which you could change as well and it is under £30 so it's not too expensive. I damaged mine when I fitted my OCC so I ordered a new one not long ago.

It looks like this:



Part number 11157553949

Not 100% sure how the PCV valve can cause a puff on startup but I'm guessing a faulty valve could allow oil to drip back into the engine overnight.

[Mart1000]

Sounds like turbo seals to me. Oil seepage passing and going through on startup, clearing the excess.

[phil200tdi]

A small puff of white smoke is ok..

I wouldn't worry until you get a problem. Unless you are trying to justify RB turbos?!

Is your car running good now after the injector replacement?

[335i E92]

Funnily enough I had that valve replaced last week when I was getting the injectors replaced!!

Just been reading the up on the n54 pcv system and it had a note at the bottom of the diagram in bold saying that a faulty check valve can cause oil consumption & blue smoke and that the pcv system should be investigated 1st before changing turbos when these symptoms occur.

So, given I've already replaced the above breather valve is it literally just the cc cover that I need to replace?

Does the cc cover come with both check valves built in? If you look at the below link to RB's pcv thread you'll see a pic 1/2 way down page 1 of the 2 check valves I'm talking about. Given that they screw in I'm thinking they might not come as part of the cover?

http://www.n54tech.com/forums/showthread.php?t=15382

[335i E92]

Originally Posted by phil200tdi

A small puff of white smoke is ok..

I wouldn't worry until you get a problem. Unless you are trying to justify RB turbos?!

Is your car running good now after the injector replacement?

The smoke is white with a blue tint, not considering RB turbos n very much hoping this isn't the stockers on their way out!!

The new injectors have had a massive impact on the car, smoother, better mpg and power is a lot stronger too. Cars running great tbh it's just the smoke I'm concerned about.

[phil200tdi]

I suspect a catch can will sort it. I need to get one too..

[idnan]

Originally Posted by 335i E92

Funnily enough I had that valve replaced last week when I was getting the injectors replaced!!

Just been reading the up on the n54 pcv system and it had a note at the bottom of the diagram in bold saying that a faulty check valve can cause oil consumption & blue smoke and that the pcv system should be investigated 1st before changing turbos when these symptoms occur.

So, given I've already replaced the above breather valve is it literally just the cc cover that I need to replace?

Does the cc cover come with both check valves built in? If you look at the below link to RB's pcv thread you'll see a pic 1/2 way down page 1 of the 2 check valves I'm talking about. Given that they screw in I'm thinking they might not come as part of the cover?

http://www.n54tech.com/forums/showthread.php?t=15382

The cc comes with all the valves built in pal so that's all you need to replace as far as the pcv is concerned.

[335i E92]

Ok cool!!

As I said I'm booked in AGAIN at Woods on Friday to investigate. Hoping its a straight forward cc cover replacement n not the feckin turbos!!

[335i E92]

Update:

Had an oil change a month or so ago, it took 1900 miles to move from 4 full bars to 3. I check my oil level on every trip and today its gone down from 3 bars to 2 meaning it’s ¼ litre in just 420 miles!!

I’m thinking this is too extreme for it to be a PCV issue, booked in to Woods tomorrow to inspect. Seriously hoping it’s not the turbos.

Oil sensor was changed recently so the readings are true. Bad times!!

[Nigelo]

Mine uses a fair bit of oil - I'd been thinking it was due to a constant diet of 5-10mins journeys. It's actually scaring me now that I think of it. I've put 2L in in around 4000 miles.

But no or very little smoke has appeared and I'm curious as to were it's going. Fitting my catch can this weekend in case it's all going through the Pcv valve.

[335i E92]

Your consumption is similar to mine based on my latest reading, ¼ litre over 400 / 500 miles which = Issue somewhere!!

Much like yours my car isn’t smoking at idle or on acceleration from what I can see, I don’t have any obviously leaks and don’t get any burning oils smells so it puzzling as to where it’s all going, on top of that my cars running strong. Certainly doesn’t feel like my turbos are shot and I’m sure that if they were leaking ¼ litre within 400 miles I’d be smoking pretty badly, currently I have a tiny puff of blue / white smoke on cold start that clears instantly.

Hopefully Darren Woods will have a better idea tomorrow when they inspect my intercooler & intake for oil etc.

Anyone concerned about this issue should take a look at the below thread, it seems a blocked PCV can cause all of my symptoms, here’s to hoping!!

http://www.n54tech.com/forums/showthread.php?t=15382

H

[creepy coupe]

If on cold start-up.I wouldn't have thought it a turbo issue, as the turbo won't be hot enough. How many miles has the engine covered?

[335i E92]

The more I think about it the less I think it’s the turbos, as you say I’d be seeing smoke when at temp rather on cold start.

My head was fully rebuilt when I had the head gasket replaced only 6 months ago so I also no its not valve seals etc, cars now 79k. All work was done at Darren Woods so I have no reason to suspect poor workmanship.

Thinking about it, there must have been something that caused the head gasket to go first place and the obvious is excessive crankcase pressure possibly caused a blocked faulty PCV system?

Only thing that puzzles me is where the feck does ¼ litre of oil go in 400 miles without any smells / leaks? Does this fit in with a PCV issue?

[idnan]

My oil consumption at its worst was 1 litre every 1500 miles and I had a big oil leak from the front turbo which was actually dripping down and covering the subframe. So if you're using that much oil it must be going somewhere.

As an interesting aside, there have been a fair few reports across the pond of people experiencing high oil consumption using other grades of oil which is resolved by using BMW spec 5w30 or 0w30. I have no experience of this but it might be an option for you guys to try.

[335i E92]

I’ve always used the same oil, Castrol Edge 5w 30w so I donÂ’t think it’s that.

Thinking about it logically:

What is causing white / blue smoke on start up only? Can’t be turbos as Creepy pointed out as they would smoke constantly and wouldn’t be hot enough to cause smoke on cold start up anyway.

This is has definitely got to be something that collects in the combustion chambers over night that’s ignited and instantly burned off once the engine is started. All of my injectors have been inspected and replaced so it’s not that and in any case the injectors wouldn’t cause the loss of ¼ litre oil in 400 miles.

The question is, is it possible that a faulty PCV system can cause smoke on start up only? I don’t fully understand how the system works tbh, is it possible if a PCV system is faulty that its dumping oil or blowby back in to the cylinder chambers over night, leaking down the intake maybe?

Trying to quantify where ¼ litre of oil goes in just 430 miles with no trace other than a little smoke at start up. If you break it down the has car probably seen 35 – 40 cold starts over 430 miles so it’s more than possible that its burned ¼ litre of oil on start ups alone.

[zltm089]

my oil consumption is quite bad as well...about 1 litre for every 1000 miles...

not sure if its the "nature" of the journeys...as I did a few long trips up north ( 4/5 hours of driving with no stops and flooring it on the motorway within the limit of course...) i always had to bring at least 2 litres of oil in the boot....

when doing short journeys in town, its not that bad...its only when i get on the motorways....

very