Hello...I hope someone can shed some light on a problem I'm having with my beloved 2001 325ci. Several years ago, I replaced a battery, then another, and now another in response to a intermittent no-start/no crank problem. Certainly seemed like something was draining my battery. I've also replaced the alternator and the ignition switch. (When the issue occurs and I turn the key, I get lights and hear various items whirring, but it never cranks...however...I can roll or push start the car.)
I've read and thought quite a bit about this, and I'm wondering...could this be a bad starter?
Thanks in advance for any help anyone can provide!
Muddywolf
"The blues had a baby and they named it rock and roll." McKinley Morganfield
Since you have replaced the alternator and ignition switch, along with multiple batteries,
I would certainly suspect a faulty starter solenoid.
You can try to confirm the next time the issue occurs,
by attempting to start - while someone knocks on the solenoid with a wrench.
The battery draining issue needs to be addressed. Also, a lead acid battery's lead plates can be physically damaged by repeated deep discharging. The result is the battery has a lower capacity.
The battery drain can be caused by the final stage resistor (FSR). The FSR is used by the climate control (IHKA) to vary the speed of the cabin climate fan. Does your fan act irrationally? So, pull fuses 28, 62 & 63 to see what happens. If that doesn’t stop the battery draining you’ll have to use a digital volt/ohm/ampere meter to determine the source. Basically, the meter, set up to read amps, is connected to the ground cable and the battery’s ground lug. The car goes to sleep and you check the reading. It needs to be less than 70ma. If it’s appreciably higher, start pulling fuses one at a time.
Does the car go to sleep? The only real option you have is a amp draw test either a meter or oscilloscope which for me works better... asking for quick help online only lead tto more gray hairs and an empty wallet. On a 46 the first thing I start with on a draw is the final state
Last edited by Driiven; 01-22-2018 at 04:05 AM.
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I think Driiven means the final stage resistor (FSR). It’s part of the hvac system for the passenger cabin. Basically, the automatic climate control (IHKA) uses the FSR to provide a wide variety of fan speeds. The symptoms of a bad FSR include erratic fan speeds. However, the FSR is known to fail and drain the battery.
The best way (imho) to find a power drain is to connect a digital volt/ohm/ampere gauge in series with the battery. That is, remove the ground cable and connect the meter’s lead to the cable and the battery post. Set the meter up to read amps. DO NOT ATTEMPT TO START THR ENGINE. Allow the car to go to sleep and check the meter. The current draw should be less than 70milliamps (0.070 amps). Start pulling fuses one at a time if it’s higher than that. Happy hunting.
o
yeah final stage, stupid ios autocorrect
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Parasitic battery drain diagnostics:https://www.youtube.com/watch?v=QRso1A0VScw
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