BMW e46 Strange Issues

[Gabriel]

This is a long story, but please bear with me. I will start from the beginning.

A couple of weeks ago I was making a long road trip to Hamburg, which is roughly around 500km from where I live (the Netherlands). Everything was fine, I had the front Xenons on all of the time since I was driving on the highway. All of a sudden about 150km away from my destination the light on the dashboard comes on suggesting that there is something wrong with the right headlight. Since I was driving pretty fast and wasn’t in the mood to pull over and check it I continued driving. The lights stayed on for some time and then all of the lights on the cluster went away and wouldn’t come back on, pretty scary stuff. I immediately pulled over and shut off the car. After I started it, everything was back to normal, the Xenon headlights were working, the lights on the dash were back on, but I noticed the front right indicator was blinking faster than usual for a couple of seconds before normalizing. I thought it was what caused the issue, since I modified the bulb inserts to accommodate new amber bulbs.

I continued driving on, no problems. On the way back, which was the next day everything was fine, I was making great progress, when I decided to stop for some gas and a smoke. I put the car in neutral (yes I have a manual) and started decelerating. I immediately noticed that there was something wrong. The more I stopped, the more the car started to jerk around, it was horrible. However, when I put my foot on the gas, the problem magically went away and showed again when in neutral and not giving gas. Nevertheless, I decided to still put some fuel in my car and stopped at the gas station. Put some gas in, but then I couldn’t start the car. I could hear the engine trying to, but it seemed that there was just not enough electrical current to do so. I waited for a couple of minutes and then after attempting one more time I finally got a start. The jerking around however was til present. After driving some more like that I stopped for a smoke again and opened the hood. Since I always have my tools handy I disconnected the battery and reconnected it again. Voila, the jerking around problem went away.

Can someone explain what was causing the problem, because I have no adequate explanation. I don’t even know if the dashboard going out is connected to the second issue… Could it have been the battery? How come it can produce such a problem?

PS: My car is a BMW e46 328i (2000) with around 85000 miles on it. I had no engine check lights, battery lights or anything out of the ordinary on the dashboard. I have had no problem since then.

Topic

[college man]

Seeing the car did recognize a electrical problem with the right head lamp.
The lights you modified to put in may be drawing to much power for the stock
system or your charging system is starting to have a problem. Have your battery
and alternator load checked. Also check your cables are clean and tight.
see if these links help.

http://www.ericthecarguy.com/electrical-videos

http://www.ericthecarguy.com/faq/solving-automotive-electrical-problems

[Andrew Phillips]

I have seen problems like this occur with bad batteries and when the alternator is going bad. First, make sure the battery terminals and cable clamps are clean and tight, make sure main grounds (engine block, body ground, and engine-to-body ground) are clean and tight. Check battery voltage with a voltmeter across the battery terminals with the key off and also with engine running. You should have 12.5-13.8 volts with the engine off, and 13.6-15.0 with the engine running. If you do not see similar voltages, especially if the voltage with the engine running is higher than 15.0, your alternator is suspect. If the voltages are good, then, like college man said, have the alternator and battery tested. The alternator could still have troubles even if it is still charging the battery. The battery could also have troubles even if it is holding a charge. Modern electrical systems are much more complex than in older cars.

[Gabriel]

I found that the problem of jerking around is caused by a clogged ICV that did not always close properly causing poor idle and cylinder misfires. Although it is usually considered a part not subject to maintenance I managed to break of the metal pin holding the both parts together and opened it up. After a thorough cleaning of the ICV, the car is as good as new.

The battery on the other hand is completely f*cked and I will be buying a new by one the end of the week.

[Mike]

I’ve seen several times before, situations where a ‘bad’ battery can still get a car started even though it’s causing strange electrical behavior or preventing the system from operating at a normal voltage. You’re probably still on the right track.

[Author]

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