Home Forums Articles How To's FAQ Register
Go Back   Xoutpost.com > BMW SAV Forums > X5 (E53) Forum
Fluid Motor Union
User Name
Password
Member List Premier Membership Search Today's Posts Mark Forums Read

Xoutpost server transfer and maintenance is occurring....
Xoutpost is currently undergoing a planned server migration.... stay tuned for new developments.... sincerely, the management


Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 02-01-2019, 05:30 PM
Member
 
Join Date: Mar 2011
Location: USA
Posts: 25
ala2000 is on a distinguished road
What is acceptable ripple voltage for E53 4.4i V8 water cool alternator?

I am trouble shooting for Trans. Failsafe Prog. Alternator ripple testing from autozone read 56mV and technician told me it was too high. Does anyone for sure knowing what is acceptable range?

May be someone with watercool alternator can go to the autozone to establish a baseline and share the result here.

Thanks.
Reply With Quote

Sponsored Links

  #2  
Old 02-01-2019, 08:16 PM
Member
 
Join Date: Jun 2013
Location: Virigina, USA
Posts: 1,953
StephenVA is on a distinguished road
I will look what that number means as there are standards for all the out puts
What was the highest amp out put measured?
Voltage?
Diodes failed, is that what they are claiming?
__________________

2005 X5 4.8IS
The Blue ones are always FASTER....

Current Garage:
2005 X5 4.8is
2002 M5 TiSilver
2003 525iT
1998 528i
Former Garage Stable Highlights
2004 325XiT Sport
1973 De Tomaso Pantera, L Model
1970 Dodge Challenger T/A 4 sp Alpine White
1970 Dodge Challenger T/A 4 sp GoManGo Green
1971 Dart Sport, “Dart Light” package
1969 Road Runner 383
1968 Ply Barracuda 340S FB Sea-foam Green

Last edited by StephenVA; 02-02-2019 at 04:28 PM.
Reply With Quote
  #3  
Old 02-01-2019, 08:19 PM
Member
 
Join Date: Jun 2013
Location: Virigina, USA
Posts: 1,953
StephenVA is on a distinguished road
Test
Bad diodes are a common cause of alternator failure. The diodes are part of the rectifier assembly that converts the alternator's AC output to DC. The alternator's charging output flows through six diodes in the rectifier assembly before it goes to the battery and electrical system.* To check for a possible bad alternator diode, switch your voltmeter to a low setting on the AC (alternating current) voltage scale. * With the engine running, touch the meter probes to the battery terminals. Any amount of AC voltage would indicate a bad diode, so you'll need to replace the alternator.
More details
Best Answer: One or more diodes in the alternator have failed. You can measure this yourself if you have a digital voltmeter - place the voltmeter across the battery with the engine running. The AC volts should be well under 0.1 volt, and I bet yours reads more than 0.5 volts AC. An oscilloscope gives and even better picture, but the meter tells the story. When I worked in aviation I saw dozens of those, and I have seen maybe half a dozen in cars. Recharging batteries by running the engine is a common cause.

Bad diodes reduce alternator output 33%, 67%, or 100%, depending on how many go bad, and the ripple can drive electronics crazy. If you have a bad diode and remove the battery lead for an old-fashioned alternator test the ripple can reach most of a hundred volts and ruin thousands of dollars worth of computers, controllers, sound system and security system components.
__________________

2005 X5 4.8IS
The Blue ones are always FASTER....

Current Garage:
2005 X5 4.8is
2002 M5 TiSilver
2003 525iT
1998 528i
Former Garage Stable Highlights
2004 325XiT Sport
1973 De Tomaso Pantera, L Model
1970 Dodge Challenger T/A 4 sp Alpine White
1970 Dodge Challenger T/A 4 sp GoManGo Green
1971 Dart Sport, “Dart Light” package
1969 Road Runner 383
1968 Ply Barracuda 340S FB Sea-foam Green

Last edited by StephenVA; 02-01-2019 at 08:25 PM.
Reply With Quote
  #4  
Old 02-01-2019, 10:17 PM
andrewwynn's Avatar
Premier Member
 
Join Date: Jun 2015
Location: Racine, WI
Posts: 3,154
andrewwynn is on a distinguished road
What is acceptable ripple voltage for E53 4.4i V8 water cool alternator?

+1. Yikes that's a big ripple. The diodes are part of the vReg. I would replace the VR and bet that would fix the issue. If you can get a slip ring kit to replace them at the same time better yet.


Update: 53 mv is only 0.053 v I misread as 0.53 at first. 1/20th of a volt shouldn't be causing problems but that is certainly an average. If it's 0.02 most of the time with a spike of 0.3v occasionally the machine will spit out "too high ripple" even if the average is reasonable.

I'll take a reading on my car and report what I find.
__________________
E53 / M54 2001 3.0i gas LHD (pair of them: his & her)

Last edited by andrewwynn; 02-01-2019 at 10:31 PM.
Reply With Quote
  #5  
Old 02-01-2019, 10:45 PM
andrewwynn's Avatar
Premier Member
 
Join Date: Jun 2015
Location: Racine, WI
Posts: 3,154
andrewwynn is on a distinguished road
Ok I just measured my vBat at the cig lighter.

250msec average was about 70mV but 1mSec spikes were -350 and +400 mV. So on an oscope there will be a tiny sliver of voltage spike of about 1/3v probably each time the current switches which diode is allowing forward bias.

Now I really want to figure out which oscope app/hardware to get for my iPhone.
__________________
E53 / M54 2001 3.0i gas LHD (pair of them: his & her)
Reply With Quote
  #6  
Old 02-04-2019, 09:55 AM
Member
 
Join Date: Mar 2011
Location: USA
Posts: 25
ala2000 is on a distinguished road
Thank you all for the responses.

When car is running idle with no other accessory is on, the alternator measured 14.5v which is good. My one year old battery reading is good at terminals under the trunk but reading is not good (failed) under the front hood at auxiliary battery posts. May be this is normal or may be battery voltage drops too much from battery to the front. I have no starting problem at all.

Most online reading said that ripple voltage should under 50mv but can go high up to 100mv depend on the car. So I do not know the ripple that I got 55mv is too high or is acceptable. The car throw "Trans Failsafe Prog" from time to time and seems to be slipping between 2nd to 3rd gear. But it will disappear if you restart the car. My 01 X5 V8 only has 120K. I love the car but it will be disappointed say the least that tranny failed at 120K.

Thanks,
ala2000
Reply With Quote
  #7  
Old 02-04-2019, 10:55 AM
Member
 
Join Date: Jun 2013
Location: Virigina, USA
Posts: 1,953
StephenVA is on a distinguished road
Disassemble, Clean and re-tighten the jump + post under the hood. Also check and clean the grounds and positive wiring connections to the starter and the alt. Then retest. The jump point gets most of the failed issues. Also, check the grounds points near the battery for poor connections.

Look up Volt drop testing for a quick measurement of how to test these points.

Examples
https://www.aa1car.com/library/voltage_drop_testing.htm
https://www.youtube.com/watch?v=qPpHRuddhh4
__________________

2005 X5 4.8IS
The Blue ones are always FASTER....

Current Garage:
2005 X5 4.8is
2002 M5 TiSilver
2003 525iT
1998 528i
Former Garage Stable Highlights
2004 325XiT Sport
1973 De Tomaso Pantera, L Model
1970 Dodge Challenger T/A 4 sp Alpine White
1970 Dodge Challenger T/A 4 sp GoManGo Green
1971 Dart Sport, “Dart Light” package
1969 Road Runner 383
1968 Ply Barracuda 340S FB Sea-foam Green
Reply With Quote
  #8  
Old 02-05-2019, 01:29 AM
andrewwynn's Avatar
Premier Member
 
Join Date: Jun 2015
Location: Racine, WI
Posts: 3,154
andrewwynn is on a distinguished road
I highly doubt a ripple is yours problem but an actual drop in voltage eg dips to 12v when coming to a stop, that's the kind of thing that will give you failsafe mode. Use something to monitor voltage real-time and see if you get drops below 13v.
__________________
E53 / M54 2001 3.0i gas LHD (pair of them: his & her)
Reply With Quote
  #9  
Old 02-06-2019, 02:04 PM
Member
 
Join Date: Mar 2011
Location: USA
Posts: 25
ala2000 is on a distinguished road
I turn on the cluster testing mode with test 9, I will be able to see voltage while I am driving. idle time=13.5v driving without headlights on=13.8-13.9v.

Here is how to for turn on the cluster test mode
https://www.ifixit.com/Guide/How+to+...k+feature/7617

Thanks,
ala2000
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

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
Trackbacks are On
Pingbacks are On
Refbacks are On





All times are GMT -4. The time now is 01:06 AM.
vBulletin, Copyright 2019, Jelsoft Enterprises Ltd. SEO by vBSEO 3.6.0
© 2017 Xoutpost.com. All rights reserved. Xoutpost.com is a private enthusiast site not associated with BMW AG.
The BMW name, marks, M stripe logo, and Roundel logo as well as X3, X5 and X6 designations used in the pages of this Web Site are the property of BMW AG.
This web site is not sponsored or affiliated in any way with BMW AG or any of its subsidiaries.