system over charging? to much !!!!

[lilwade]

hello, i am really sorry to post this if this has been covered alot, but i have looked and looked in your forum for this question , always finding low voltage problems, but we have to much. We want to know would the alternator be bad causing an over charge or would it be a voltage reg some where bad. how should we go about tracking this problem down,. this is a 91 525i battery was reading 15+ @ idle, lights pulsating, reverse lights would flash intermit...... and battery test good and car will cut off if it gets to high which i guess you know. please help

[shogun]

How much can you trust your multimeter?
Is it a good one and have you tested several times?
Is the battery inside the tester good? If it is bad, you will read more volt.

[Jon K]

How much can you trust your multimeter?
Is it a good one and have you tested several times?
Is the battery inside the tester good? If it is bad, you will read more volt.


Forget a multimeter - unlock your OBC and do TEST 9 and monitor the voltage that the OBC is seeing. It sounds exactly like a failed voltage regulator - this will kill your car. Fix it asap.

[lilwade]

Forget a multimeter - unlock your OBC and do TEST 9 and monitor the voltage that the OBC is seeing. It sounds exactly like a failed voltage regulator - this will kill your car. Fix it asap.




okay walk me through ulocking obc and doing test 9. also where is voltage reg located and is there a way to test that? i have a very expensive meter and yes new battery. we were first told this was overcharging by another shop, im getting the readings too, and also the surges with lights ect. afraid it will burn up something. want to do the work myself though........so didnt get shop to touch it any further.

[shogun]

Here we go
http://home.iae.nl/users/bts/obc.htm

And this will also help you
http://shrubbery.student.utwente.nl/sean750/VoltageRegulator/VoltageRegulator.htm

[lilwade]

Here we go
http://home.iae.nl/users/bts/obc.htm

And this will also help you
http://shrubbery.student.utwente.nl/sean750/VoltageRegulator/VoltageRegulator.htm


that regulator info is e32, is it all exactly the same for 5 series cars.
So its probebly isnt the altnator? yeh or neah? couldnt this over chargeing cause the trans program to initiate since voltage can trigger that fault? i have had that to pop up to...

[shogun]

The only difference is that you have much more space in the engine room of your 525 compared with the 750 V 12 E32 engine room.
Board computer has the same function. On E32 and E34 many parts are interchangeable.
But the basic info are the same.

[lilwade]

The only difference is that you have much more space in the engine room of your 525 compared with the 750 V 12 E32 engine room.
Board computer has the same function. On E32 and E34 many parts are interchangeable.
But the basic info are the same.


okay, so ill do the test 9 , but is there a way to test the regulator if i am getting high readout on obc. read one post said check it with meter? how much should regulator cost and best place to get it fast?

[shogun]

just change it
http://catalog.bmaparts.com/epcvsoapimc.epc?cookieID=1OV0KQRMC1PN0PV87O&drillid=8&subcatid=801078@@Charging+System&source=BIMMERINFO&clientid=bmaparts

[lilwade]

Okay, just got home from work and ws able to do the 9 test. Key on engine off was 11.9v-12.2 , @ starting 9.6v, and @ idle 15.6-16.15and @1500rpm 15.68- 16.84 and @ THAT HIGH CAUSE TRANS PROGRAM LIGHT TO COME ON.

[rob101]

drive with your lights on all the time and with the rear windshield heater on all the time this should help with reducing the amount of charge that makes it to the battery. and get a new regulator asap.