engine misfire and cold start problem

[318technoviolet]

the car is still in the garage they are working on it will get back to you all when it is done

[CirrusSR22]

What did you find out?

I''m trying to figure out a cold start problem myself. Last year my car fired-up and ran perfectly after a cold start; cold being -10F to -20F range. This year I had a morning where it cranked for about 30 seconds total (over numerous attempts @ -14F) and had random "pops" in there. When it did start, it ran poorly for about 30 seconds.

The battery is good, since it cranked like crazy for the entire time. I also bought a new one just in case. There is no CEL. Even on cold starts now (0F-15F) it'll start pretty quickly, then run rough for about 30 seconds. RPM stays even, but there's a noticeable lumpyness.

Air filter is brand new. Plugs are stock NGK with 6,000 miles/6 months on them.

I think I can rule out air leaks, since the idle does clean up after a short time, and when the car warms. Also, I think intake temp or coolant temp sensors can be ruled out, since the idle will clean up far before the engine is making any heat. Idling just 30 seconds at -5F doesn't produce much heat.

I just removed/cleaned out the throttle body including the idle control valve (ICV), which I suspect might be an issue, but there was no change. Maybe it's lazy when cold? The ICV is now clean, and the "valve" also seems to move freely when poked at.

Any ideas?

EDIT: Just cleaned the MAF with CRC brand MAF cleaner. We'll see what happens.
EDIT #2: I think I narrowed it down to bad/water contaminated fuel. After my ICV and MAF cleaning, the car still ran a little rough. Shortly after, I pu a can of Seafoam in the gas tank (has isopropyl alcohol) and filled with premium B.P. gas. I let my car sit outside for a number of hours in -3F to -7F air temps. It fired up perfectly, and ran smoothly!

[318technoviolet]

Hello all sorry for the delay i changed the crank position sensor and this did not cure the problem the car has been in the garage (bmw specialist ) for 4 weeks now and they still have not found the cause of the problem or fixed it they have tried a new lambda and cat as mine was bad new ecu, mass air flow meter, IAT sensor, engine coolant temp sensor after trying all these parts the garage called me and said that they still could not find the problem so i took the car to a real independant bmw specialist and within one day they said that the engine compression was low and are doing a few more tests before they let me know what is causing it i just hope its not the piston rings or valves will keep you all informed

[geodesy]

hey whats up im a tech...if it only happens in cold weather and goes away while car warms up or as u drive then i would check your crankcase valve(its known as a pcv valve) follow the hose from your valve cover..make sure hose is not cracked...also sometimes a bad crankcase valve causes a whistling strange sound while u drive...u will need hex keys to remove the screws that are placed underneath the crank case valve..if your motor is shaking most likely the valve is bad..it can be a tricky problem to diagnose...part costs 70 to 80$...take care n goodluck

[geodesy]

dont forget to check crankcase valve...common problem

[geodesy]

check your crankcase valve and hose goin from your valvecover to the crankcase valve...check hose and valve...very common problem with the ti.

[318technoviolet]

no it did not work car has been with abmw specialist and they say that the car needs an engine rebuild as they cant find any thing wrong so i decided to get a second hand engine and got a friend to change it for me. but before i did this i added a one litre of lucas oil stabilizer and it helped the car start first time when its cold so if you dont want to do a engine replacement you can add the oil stabilizer every time you change oil

[318technoviolet]

the problem is due to engine wear worn valves or seals and or pistons rings and can be cause by overheating. all the missfire codes were related to the same cold start problem

[b.u.ti-ful]

How many miles do you have on the car?

[318technoviolet]

The has 120,000 miles on it