Intermittent low RPM shaking and flickering lights

Hi,

Shorly after my alternator rebuild I have been experiencing the following:

Symptoms

• Intermittent low RPM shaking
• Using power windows will lower the idle RPM slightly
• Headlights are flickering

Facts

• Capacitor reads 14.3V+ at idle
• The ECU does not have any stored errors
• Pushing the throttle will alleviate the symptoms

The shaking part is intermittent. The ECU is not throwing any errors and I have been unable to find any leaks (e.g. intake boot).

I believe the flickering of the lights etc. must be related to the non-OEM volt regulator I put in the alternator when I rebuild it; however, it does provide ample power (14.3V+ @ idle) - a lot more than the old one.

If the issues are unrelated, could it be the CPS? MAF?

It's really annoying since it drives great most of the time.

"Capacitor reads 14.3V+ at idle". What do you mean by "capacitor?"

"a lot more than the old one" What is the voltage at 1500 RPM? If more than 14.2-14.4, it's too high. The electronic systems are sensitive to battery voltage.

Could it be the battery?

Sent from my GT-I9300 using Bimmer App

Ok, so I just cleaned the ICV. Let's see if that helps anything at all.

edjack,

I have a capacitor connected directly to the battery it has a voltage readout. When everything is on (lights, amps etc.) it runs up to 14.8V.

I'll check what it reads at 1500 RPM tomorrow! Thanks.

mjalloul11

The battery is less than a year old, so I'm hoping it's not it. It read 12.5-12.6V last time I checked, with everything turned off.

Update.

Edjack you were right. It was reading up to 15V during idle. I swapped it with my old non-refurbished alternator and it now drives like it should without flicking lights and intermittent shaking during low RPMs.

I'll have to get a replacement volt regulator though. It was brand new!