E90Post
 


 
BMW 3-Series (E90 E92) Forum > BMW E90/E92/E93 3-series General Forums > General E90 Sedan / E91 Wagon / E92 Coupe / E93 Cabrio > Alternator Woes



Reply
 
Thread Tools Search this Thread
      04-13-2021, 11:20 AM   #23
RayLivingston
Lieutenant
140
Rep
445
Posts

Drives: '07 335i Sedan
Join Date: Aug 2018
Location: California

iTrader: (0)

And, one final bit of helpful information about the cars power wiring:

https://www.e92n55.com/wp-content/up...us-systems.pdf
Appreciate 1
e90yyc2424.00
      04-15-2021, 05:25 PM   #24
RayLivingston
Lieutenant
140
Rep
445
Posts

Drives: '07 335i Sedan
Join Date: Aug 2018
Location: California

iTrader: (0)

OK, brand new Bosch alternator is in, along with a new radiator. All seems OK-ish, so far. Battery was fully charged (overnight), and showed 13.1V with no load 24 hours later, after cooling down. Alternator output seems to be mostly 14.5-14.7V, which is a bit higher than I expected. OBDFusion reports occasional single samples up to about 15.1V, but I believe that is noise in the Bluetooth adaptor, as I also saw at least one down around 11V. Driving around (just a few miles), it was mostly between 14.3 and 14.7V. When I checked the steady state value, with engine idling, OBDFusion shows 14.7, and I measure 14.7 directly on the battery terminals with a Fluke DVM, and 14.9V between the engine block and the "jumpstart" block on the RH side of the engine bay.

My battery is an AGM. Does that voltage seem right? I suspect with a bit more driving, it will likely come down a bit, but don't know yet how much. I'll take it for more of a drive tomorrow and watch what it does.

Tomorrow I'll try to rig up long leads for the DVM, and directly measure voltage drop across the two main cables from the battery to the engine bay, and also try to get a reading of voltage in the engine bay when cranking, to ensure no bad connections in the big cables. I did check the engine ground strap, and it is clean and solid.

Is there anything in INPA that would be worth looking at?
Appreciate 0
      04-18-2021, 09:36 AM   #25
RayLivingston
Lieutenant
140
Rep
445
Posts

Drives: '07 335i Sedan
Join Date: Aug 2018
Location: California

iTrader: (0)

After several days, and several hundred miles, new alternator is still working perfectly. So, the failure of the first replacement was just a fluke - infant mortality. Monitored battery voltage over a >200 mile drive yesterday, and saw nothing unusual. Highest voltage seen right after cold start, was 14.7V, that quickly came down to ~14.2V, then gradually reduced to a pretty steady 13.7V for the remainder of the drive. Still not sure the car is properly coded for the AGM battery, but have a friend who works at a BMW dealer who can take care of that for me. So, that'll get done sometime in the next couple of weeks.
Appreciate 0
      04-18-2021, 02:48 PM   #26
mweisdorfer
Major General
mweisdorfer's Avatar
United_States
1900
Rep
6,968
Posts

Drives: 2007 Black/Black 335i e90
Join Date: Apr 2011
Location: Holly, MI

iTrader: (0)

Garage List
2007 BMW E90 335i  [0.00]
2008 bmw x5  [0.00]
Quote:
Originally Posted by RayLivingston View Post
OK, brand new Bosch alternator is in, along with a new radiator. All seems OK-ish, so far. Battery was fully charged (overnight), and showed 13.1V with no load 24 hours later, after cooling down. Alternator output seems to be mostly 14.5-14.7V, which is a bit higher than I expected. OBDFusion reports occasional single samples up to about 15.1V, but I believe that is noise in the Bluetooth adaptor, as I also saw at least one down around 11V. Driving around (just a few miles), it was mostly between 14.3 and 14.7V. When I checked the steady state value, with engine idling, OBDFusion shows 14.7, and I measure 14.7 directly on the battery terminals with a Fluke DVM, and 14.9V between the engine block and the "jumpstart" block on the RH side of the engine bay.

My battery is an AGM. Does that voltage seem right? I suspect with a bit more driving, it will likely come down a bit, but don't know yet how much. I'll take it for more of a drive tomorrow and watch what it does.

Tomorrow I'll try to rig up long leads for the DVM, and directly measure voltage drop across the two main cables from the battery to the engine bay, and also try to get a reading of voltage in the engine bay when cranking, to ensure no bad connections in the big cables. I did check the engine ground strap, and it is clean and solid.

Is there anything in INPA that would be worth looking at?
The voltage on the new alternator seems on par with what it should be. Remember, you have a 180amp alternator.
Appreciate 0
Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 03:05 AM.




e90post
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST