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-   -   Blue Smoke Issue at Idle/Decel (https://www.n54tech.com/forums/showthread.php?t=58302)

kleiner 06-03-2019 05:46 PM

Blue Smoke Issue at Idle/Decel
Having an interesting issue regarding blue smoke from the exhaust. Recently put on cldp’s which exposed the fact that my car is burning oil. The rate of oil loss is negligible, with me not having to add any over the past 5000 miles (1/2 on the gauge right now). When I come to a stop, blue smoke comes out from the exhaust. This only occurs at low speed and while I’m idling. Once I start going again, the car blows the smoke out then stops smoking.

Now, I thought it was turbo seals. However, I saw no evidence of this while installing the **’s. Furthermore, if I keep the car in drive and throw the JB4 on map 4, the problem stops. Therefore, this seems vacuum related. Any ideas on what to replace first, as what little information I was able to find seemed to just be people taking blind shots with various things solving the issue.

gunda 06-03-2019 07:44 PM

1 Attachment(s)
Might want to start with your PCV system as this issue has been discussed numerous times. Below is a link to a good discussion, but in summary you should use have a low & high side OCC setup, retain factory flapper on high side, and recirculate the high side to a vaccum source (single turbo filter or turbo inlets for twin turbo setups)

Dual Catch Can - Why you want to do it | BMW - SpoolStreet

Also here is a diagram of my setup currently, hope this helps.

Attachment 87050

BIMMIN 06-05-2019 07:13 AM

I have the same issue. Never tried the map 4. But switching from regular automatic mode to sport shift mode, it never smokes accept if I got into moderate boost and come to a stop really quick. Even then its negligible.

I've always been baffled as to why it wont smoke 98% of the time in sport mode. Assuming has something to do with the heavy engine braking that is introduced in sport mode.

I've converted to external pcv system from RBTURBO.COM and have the bms high side catch can as well. Valve cover and gasket had been replaced right before I purchased the car. Rebuilt head as well

naoaki 06-11-2019 09:19 AM

I have the same problem. I strongly smoke when I stop driving. I am trying out various setups. Remove the high and low side flappers and use OCC to recirculate (very idling failure and do not stop smoking) Remove only the high side flapper and the low side is the external system of RB (no idling failure etc. There is some deterioration in response in extremely low speed area and smoking does not disappear) Leaving the flapper on the high speed side On the low side is the outside of RB (no bad idling and there is no problem at all but some smoking remains) I have two cats You are deleting As soon as I delete it and smoking starts, I try various setups to solve it, but I can not solve it completely. What I noticed is that there is less smoking when idling when using A / C. Using A / C will increase the idling rpm. About 800rpm. I think that the blue smoke problem has a close relationship with the negative pressure of the engine. How is it?

K.Jameel 06-12-2019 06:33 AM


BIMMIN 06-13-2019 11:29 AM

I get no smoke 98% of the time in sport shift mode. There is heavy engine braking in sport mode, so I think your on to something with negative pressure

dawhiz 06-13-2019 12:30 PM

If it's the turbo seals then it will progressively get a lot worse one day. Remove the inlets from turbos and check for shaft play forward and backwards to eliminate that.

naoaki 06-16-2019 11:04 AM

I recently succeeded in significantly reducing blue smoke during idling and normal driving under light engine brakes. The setup is a high side recirculating system using BMS OCC, which is normally used, and the low side is an external system using 8AN lines using VTT's PCV deletion adapter. I am using a check valve on the way. The OCC uses an adapter so that 8AN lines can be connected using a small type of BMS. I used to use the RB external system before, but the setup is similar, but the blue smoke is clearly reduced. Speaking of the difference the line is from 6AN to 8AN and the check valve is to some extent on the way, but the amount of blue smoke has decreased surprisingly. In my opinion, it is probably because the line is thick and ventilation is good. I was delighted that I was bothered with blue smoke by removing two cats.:happy

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