E36 Electrical Issue

[Rompsku]

Hi Guys

First post in a long time, but really need your help.
I'm having a weird electrical issue and can't seem to properly diagnose the it.

It probably started more than a year ago when my son ran done the battery a few times, ever since then the battery couldn't hold a charge for more than day or 2.

It got worse last month, to the point where all electronics eventually died while driving and couldn't even jump start. Car would die as soon as the second battery was disconnected. Lights where flashing on and off, cluster needles were moving very erratically, car was running extremely rough, etc.

Finally decided to get a new battery 2 weeks ago, however as soon as I installed it and started the car, I noticed the battery light on the dash was not fully lit up when the key was turned to ignition 2. Usually all the instrument lights lit up, but no battery light this time. This continued on for 4 days, eventually the battery ran totally flat with the same symptoms as before.

I suspected the alternator, had it tested on and off the car and it passed with flying colors. Checked the battery cables and all grounding points in the engine bay and boot, behind alternator and they all look good. Charged the battery overnight, and got the car started, but battery ran dry again after a few hours.

So, after taking the car to 3 mechanics and an auto electriction, the issue still isn't solved. Here's the really weird bit. Last night, in a bid to get the car working, so I could get to work, I tried replacing the fuses and relays. For some reason, after removing the radio fuse, the car started right up and the battery light disappeared, drove well and even charged the battery properly. Then this morning, I noticed the battery light flickering again. Revved it a few times and it went away for a while, but eventually resurfaced after driving for about 30 minutes.

Any idea what could be causing this?

Gonna try the pulleys and belts this afternoon, suspect there might be some slippage after the alternator removals. But why would a 20 amp blade fuse cause all sorts of problems? I don't think it was the fuse, but it seems to have fixed the problem, temporarily at least. It really seems like a bad ground to me, any ground points in the cabin I should check?

Thanks for the advice guys.

 

[Gizmo]

Pull the radio out and check the wiring, I have seen some seriously dodgy installs in my time!

 

[Rompsku]

Pull the radio out and check the wiring, I have seen some seriously dodgy installs in my time!

That was the first thing I checked as the radio was a recent installation. I did the install myself and had an experienced friend double check the wiring, nothing dodgy that we could find. Even tried it with the radio out of the car, but still the same symptoms.

 

[Zound]

Might be worthwhile investigating the voltage regulator

 

[danieljames]

Might be worthwhile investigating the voltage regulator

+1. very plausible.

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With the car idling what is the voltage across the battery. Should be around 14v

 

[Rompsku]

Might be worthwhile investigating the voltage regulator

+1. very plausible.

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With the car idling what is the voltage across the battery. Should be around 14v

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Will check this out and confirm. Car was at an auto-electrician on saturday and they confirmed the alternator is working correctly. Did tests with the alt in and out of the car. I assume this would check the voltage regulator as well? Alternator passed, was charging at 14.2 volts.

Drove the car home now, about 50 km, battery light was barely noticable 90% of the time, could only really see it when accelerating. Waiting for the car to cool down so I can check the belts.

Will try to get a multimeter tomorrow to check voltages myself.

All electronics are working fine as far as I can see, except for the instrument cluster which tends to die randomly for a few seconds, but a tap on the dash usually fixes that. Pretty sure it's a separate issue though.

 

[danieljames]

If the light comes on during acceleration it could be a belt issue. Although maybe not the belt itself, but perhaps the tensioner is shot. I had my tensioner out a few weeks ago while diagnosing a noise. The bushes on the tensioner were very badly worn bit luckily the little shock absorber was in good condition.

 

[JayDrft]

Hi Romp,

I am no electrical expert - however, a sure fire way to have peace of mind that the alternator is not the culprit. Simple test really...may have been performed already, but in its absence, something could have slipped by.

Once you get the car running, disconnect the positive terminal of you battery, if the car dies out - its the alternator thats not charging(and from your symptoms you explained, it seems its not charging).

If it continues to run after pulling the terminal off positive, then it can be ruled out that the alternator is operating as it should.

Another thing to check for - interior lights and door trigger switches....you may have some form of light pulling power out of the battery...look for any suspect components on or running when they not supposed to.

Hope it helps.

 

[danieljames]

^^agreed this is a sure fire way to test he alternator....but im go in to ask a noob question here....

I've fone this test before on previous vehicles...(older), but when disconnecting the battery, isn't there a possibility of it sending s spike through the circuit that could damage the dme?

 

[Nikhil]

Check your earth cable as well it may have come loose at the point where it connects to the chassis.

 

[Rompsku]

^^agreed this is a sure fire way to test he alternator....but im go in to ask a noob question here....

I've fone this test before on previous vehicles...(older), but when disconnecting the battery, isn't there a possibility of it sending s spike through the circuit that could damage the dme?

Auto electrician got really pissed when I told him that the car died when I disconnected the battery while it was running (I was jumping the car with a second battery connected to the one in the boot, and boot battery wasn't holding any charge at all, so car died when removing jump cables from the second battery). Told me I could harm the DME by doing that, so definitely trying to avoid that at all costs.

Tested the belt, seems fine at first, but if I push down a bit hard, I'm able to move the tensioner pulley rather easily. In fact, I could probably remove the belt from the alternator pulley without having to loosen the tensioner if I pulled it hard enough. That isn't good, right?

 

[danieljames]

No that isn't good. I had a hard time fitting the belt even while pushing down the tensioner. I'd say pull that off aswell. It's not that hard. Remove the top alternator pulley and then there's just two bolts holding the tensioner

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Or was it 3???????

 

[Rompsku]

Thought as much. Anything I can do to confirm it's the belt / pulley that's the issue? Read about the soap on the belt trick. Should I try to see if that improves things before I rip everything off?

But definitely thinking it's the tensioner. Had great difficulty getting the alternator off the first time, needed a buddy to help. But got it off in 5 minutes the next day to clean the air intake, Might have harmed the tensioner first time I removed the belt. Doubt that tensioner has been touched in the last 5 years at least.

 

[danieljames]

I personally don't know of any tests. But it's not hard getting the tensioner assembly off seeing as you've removed most of the stuff before. You can remove the tensioner assembly without removing the alternator provided the viscous fan is already off. That's about as far as I can help

That's just a pic of how worn my bush was although it didn't cause any noises while in that state

 

[Rompsku]

Hi Guys, so this morning the car wouldn't start. Needed a push. Battery didn't have enough charge.

Ran fine for about 2 minutes before the abs light showed up. I knew this meant trouble so turned back home immediately. Car started running very very rough, sputtering and struggling to stay alive.

Barely made it home. Car is totally dead now, barely any life in the battery.

So confused now. Car ran fine yesterday despite the battery light flickering, nw its totally dead.

Any suggestions. Gonna try getting it to a different auto electricia . any good ones near Muizenberg?

 

[danieljames]

There's an ex bmw mechanic that lives in promenade road lakeside/zandvlei. Goes by the name ziggy. I can't give you any information on his work although he always has work in from of his place

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Another thing to check for - interior lights and door trigger switches....you may have some form of light pulling power out of the battery...look for any suspect components on or running when they not supposed to.

Hope it helps.

I would check this.....

 

[JayDrft]

Romp,

I personally think your alternator is Kaput!!! And thats just my assessment from the issues that you described.

If the battery light is on, only the alterntor will give you that signal. Do the test with the cable, if it cuts out, its the issue...you said you done that and it died.

if the Regulator was faulty, it would surely have popped some fuses by now. A faulty regulator is more ikely to cause issue with the DME as most components require 12volt power, which the regulator takes the 14 odd volts and stabilises the output to a consistent 12volt, give or take.

Your alternator could be operating well, but if belts arent tight, then pulleys arent driven properly. Another point, what you mentioned happened this morning where it showed signs of a poor running car, that indicates that there is not enough power in the system to even provide spark for the fuel injection and ignition, this usually indicates a dead battery, but you got a new one, so it simply says that the battery being new, is not being charged in order to keep enough charge to allow the car to run.

Again, I am no expert - however, I have enough hours of "Sukkeling" to succesfully say that I have some experience.

 

[Rompsku]

Unfortunately I have to agree with you Jay, doesn't make sense, but seems to be the case.

Waiting on a tow so I can get it to another auto-electrician and hopefully get some proper answers.

Anyone know where I can find a cheap alternator. Does any E36 alternator work on an 328i?

 

[Solo Man]

It is a known fact that the hedgehog (final stage resistor) in the aircon system will also drain the battery, if the hedgehog is faulty. I am not saying this is the case as the alternator sounds dodgy to me also. But cannot rule out the hedgehog. Google it for more info. Just my 2c

 

[ballisticz466]

I'm rather intrigued as to what the fault could be.

For some reason, after removing the radio fuse, the car started right up and the battery light disappeared, drove well and even charged the battery properly.

Possibly a connection issue around that area?