[supadups2k18]

Hi there I figured I would reach out to everybody to get some advice. I have a 2009 323i and at times usually in cold weather the car struggles for power on Startup and sometimes stalls all together. To date I have replaced the coils I have cleaned the mass airflow sensor and have replaced the spark plugs. I figured I would reach out first for suggestions on possibilities as to what other maintenance I could perform before moving to any other extreme maintenance. Any advice is appreciated!

[Anthony199]

Originally Posted by supadups2k18

Hi there I figured I would reach out to everybody to get some advice. I have a 2009 323i and at times usually in cold weather the car struggles for power on Startup and sometimes stalls all together. To date I have replaced the coils I have cleaned the mass airflow sensor and have replaced the spark plugs. I figured I would reach out first for suggestions on possibilities as to what other maintenance I could perform before moving to any other extreme maintenance. Any advice is appreciated!

I'd check battery voltage, test the starter (I think mechanics can check the starter performance), make sure you're using a thinner oil, 5w30 is better for the winter than 5w40, check spark plugs, check for vacum leaks (I have had many leaks when not returning the air box properly, so check that all the pipes and tight and properly installed from the throttle body all the way to the air duct behind the kidney grills), check injectors (maybe add Teflon injectors system cleaner to see if it improves), check fuel pump.

[Paliator]

Originally Posted by supadups2k18

Hi there I figured I would reach out to everybody to get some advice. I have a 2009 323i and at times usually in cold weather the car struggles for power on Startup and sometimes stalls all together. To date I have replaced the coils I have cleaned the mass airflow sensor and have replaced the spark plugs. I figured I would reach out first for suggestions on possibilities as to what other maintenance I could perform before moving to any other extreme maintenance. Any advice is appreciated!

Have you tried using a bmw scanner such as carly to check for codes? I would have thought the things you've already done would be the culprit. Maybe a code can give you more direction

[Fritzer]

I would look at your fuel system components from the symptoms you described. How long do you let it warm up, how cold?

[gbalthrop]

Originally Posted by supadups2k18

...2009 323i and at times usually in cold weather the car struggles for power on Startup and sometimes stalls all together.

Perhaps you should "reach out" to a Scan Tool, AND to the Forum, BEFORE throwing parts at it.

ANY P-code reader that can read P-codes (OBD II Fault Codes) AND basic Parameters, in this case ECTS (Engine Coolant Temp Sensor) signal as received by the DME (Engine Control Module). Engine Temperature, as measured by the ECTS, is the PRIMARY Input the DME uses to control ENRICHMENT or Air/Fuel Ratio.

If you ever used a small-engine device with a Manual Choke (lawn-mower, Chainsaw, Pressure Washer, etc, you know that you have to make the fueling "Richer" (HIGHER Fuel/Air Ratio) on cold start, and for first seconds after engine startup, or the engine will NOT keep running, even at idle, and certainly NOT when load is applied.

Early August is NOT exactly "dead of winter" in Toronto, and it probably hasn't gotten below 60F overnight for the last two months. IF you have a problem with engine starting or keeping running in the first 30 to 60 seconds after COLD Start (first start of day, ambient temp 60F or more) or it stumbles and hesitates until it has run 3 to 5 minutes (near fully-warm), but it has NORMAL POWER once warm, that is almost certainly an issue with enrichment when "cold", defined as less than ~ 150F engine coolant temp. If it starts and runs normally if restarted < 30 minutes after warm shutdown, that's one more confirmation.

As stated, ECTS signal is first suspect. How to test? Multiple choices, EACH with "cold" engine that has NOT been run for >6 hours:

1) If you have ANY scan tool that can read engine Parameters, simply connect it to OBD II Socket, turn Ignition ON, but do NOT Start engine; select Parameters or "Live Data" and look for ECTS or Engine Temp. If the Temp Value you see is significantly GREATER than actual ambient (outside) temp, then you have found the SOURCE of the probem, but see below BEFORE throwing parts.

2) NO Scan Tool you say -- sorry, you can't get off that easy -- YOU HAVE "Hidden Menu 7.00" Just follow the procedure found here, and you can read the ECTS signal (as received by DME) on your Instrument Cluster -- just do NOT turn off ignition or you will have to activate Hidden Menu 7.00 all over again. NOTE: you can use Hidden Menu 9.00 to monitor Alternator Output with engine running, so this is a handy tool to diagnose overheating or Alternator Under-charge or OVERVOLTAGE situations as well:
http://e90.wikifoundry.com/page/BC+hidden+menus

3) Measure Resistance (Ohms) across the spades of the ECTS after removing the connector. The resistance should measure something in the range of 2500 Ohms at 20C (68F) and 250 Ohms at 90C (194F). Since Resistance varies INVERSELY with Temperature (resistance Decreases as Temperature Increases), a short (decreased resistance would give a "False High" Temp signal and result in LEAN fueling, causing stall when engine cold.

Here is TIS diagram showing location of the ECTS, and also the TIS circuit diagram showing its wiring to the DME.
https://www.newtis.info/tisv2/a/en/e...engine/SFweFnV
https://www.newtis.info/tisv2/a/en/e...ooling/vFKjkjB

That is ONLY the "first suspect" so if the suggested tests do NOT show any issue with ECTS signal, Scan for Fault Codes and describe EXACTLY what symptoms occur and at WHAT engine Temp, similar to my description of classic symptoms of ECTS signal issues.

George