Rough start up

[Thomas6702]

Hello everyone

Thomas, 26 years old from France

I own an E92 DCT M3 and I am trying to deal with an pain in the a*** issue

Got the car in december 2015 and since the begining the start up has seemeed weird to me. Fluctuating rpm's only on morning starts.
At first this would only occur when i left the car a few days.. Actually this happens every day ONLY at the first start...

I have already replaced the ICV, the glow plugs and the low fuel pressure sensor

I have no error codes and car runs just fine but i hate the way the car acts at startup...

What I have noticed is that on a few starts the car did give a pop like a misfire but still no codes.. (Oem exhaust with only modified rear muffler)

Can anyone help out here ? :-(

I love this car so much and have done rod bearings and DCT oil change + joints
I am an mechanic and love working on this car but it can realy a pita some days...

Thanks a lot :-)

[Helmsman]

Thomas, read about this, seems a quite common behavour. Give it some searching and Im sure you will come up with a few suggestions.

Good luck

[Thomas6702]

Originally Posted by Helmsman

Thomas, read about this, seems a quite common behavour. Give it some searching and Im sure you will come up with a few suggestions.

Good luck

I replaced the ICV and fuel pressor sensor reading suggestions here...

I don't mind repairing the car i just don't want to replace half the engine

[Thomas6702]

Just been doing some more reading... Really don't know what to think anymore every single guy with this issue seems to have replaced a different piece

o2 sensors
Secondary air valves
Fuel vent valves
Some sensor on the servo brake hoses

I'm going to go nuts...

[Thomas6702]

Up..

[Todd0131]

Mine does it as well. I just let it go through the cold start junk and it runs fine. I don't even think about it anymore.

[Amirsm3]

That's the normal cold start cycle. You can have this coded out.

[Thomas6702]

I have geard about coding out the cycle but what do the cats say about that ?

It's more the misfire sensation that I don't like
Fluctuating I can accept but the impression of a missing cylinder i can't deal with

I just deleted the DME adaptation and went for a drive i will see in the morning if it is better...

[Thomas6702]

One point i did not mention is that sometimes when the car is warm it sounds at idle as if it where in cold start cycle.. Is that normal ?

[rcracin]

Originally Posted by Thomas6702

One point i did not mention is that sometimes when the car is warm it sounds at idle as if it where in cold start cycle.. Is that normal ?

if i let my car idle for too long, it sort of goes into the cold start cycle for a minute and then goes back to normal. probably too much unburnt fuel while idling so the cold start kicks in to push more air maybe?

[Thomas6702]

I don't know... These cars are so complex lol

[Helmsman]

Originally Posted by rcracin

if i let my car idle for too long, it sort of goes into the cold start cycle for a minute and then goes back to normal. probably too much unburnt fuel while idling so the cold start kicks in to push more air maybe?

Noticed the same, sign we shouldn't idle for too long...

[Rob-Shanghai]

Thomas6702 hello, I know this discussion is now many years old and you have probably moved on to a different car but I am having the exact same problem. Actually mine does misfire sometimes during and only during the cold start. I don’t get a CEL but if I scan I see multiple misfires. Sometimes all cylinders. But after the first start of the day it runs perfect. Complete steady idle and pulls smoothly. I wonder if you ever found the cause of this problem. Thanks Rob