Strange cold weather behavior
 

Hey guys, hope Christmas was good for you guys. I was up in the mountains over the holiday and had a strange issue. The car would start just fine in the morning. Temperature was around 28-30degF. Drove the car roughly 20 minutes to the slopes and shut it off for about 3 hours. I came back and attempted to start it and it would continue cranking for about 8-10 seconds and then slowly sputter to life. After it started it ran just fine. This happened to me twice. No warning lights no nothing. Any ideas?

Not enough battery maybe?

Battery loses some power when temp drops.

Crank Position sensor going bad?

For the next few weeks...I'd take 20 seconds each morning (or right before each start-up) and do TEST 9 to see what the battery voltage is (with the ignition in position 1...that way fewer items are running and making a draw on the battery's power reserves).

If your battery's voltage, right before each cold start, is below 11.89 volts...and this is your X5's original battery (which very well could be since its an 06)...like others suggested...your battery may have been giving you the first signs that it doesn't have long for this world.

Or it could have been that the lower temps & higher elevation took a toll on the battery's CCA (cold cranking amps) and RC (reserve capacity). :)


http://www.bimmerboard.com/members/q...f%20Charge.jpg

Thanks for the input. I have been getting the battery light intermittently over the last few months. The battery is less than year old but I'm sure that I have either an alternator or voltage regulator on its way out.

Checked my voltage with key in position 2. Readout was 11.89 volts. Could my alternator be only charging so much and then cutting out?

Just monitor the voltage in OBC. Link in my sig for your assistance. QSilver with the facts. Nice stuff dude.

Thanks Q and Slick. I've been using the OBC to monitor the voltage and will continue to.

If your battery light has been coming on...do keep an eye on the charging system by running TEST 9 while driving around (or when the engine is running). You want to see voltage levels "consistently" above 12.5 volts.

It may dip lower than 12.5 volts (briefly) while idling at a light if you have lights, radio, heater, etc running...but should jump back up when RPM rises etc...and again, should stay between 12.8-14 volts while the engine is running.

If the alternator/charging system is not putting out enough voltage to keep the battery topped off...it will slowly kill the battery and eventually leave you stranded. The battery warning light illuminates when this condition occurs...it is a warning that the battery is the VICTIM...not the culprit. :)