Charging system problem light came on - Fuelly Forums

Android Users - Coming Soon! - Migrating from aCar 4.8 to 5.0

Reply
 
Thread Tools Display Modes
 
Old 10-10-2007, 01:34 PM   #1
Registered Member
 
Join Date: Jun 2007
Posts: 71
Country: United States
Charging system problem light came on

The battery shaped indicator light came on last night. I was able to complete my errand and return home safely. Now I retested the electrical system using a DVM. With the engine off, the battery was reading 12.34 V. With the engine on, the battery was reading 11.xx V.

Questions:
  1. What would cause an electrical system to be at a lower voltage when the car engine's on?
  2. Would the OBD-II computer code help to diagnose the problem?
  3. Are there any other tests I can do to diagnose the problem?

I would prefer to leave the option of taking my car to the mechanic/dealership as the last option. Thanks in advance for replying.
__________________

__________________
GasSavers_rGS is offline   Reply With Quote
Old 10-10-2007, 02:47 PM   #2
Registered Member
 
MetroMPG's Avatar
 
Join Date: Dec 2005
Posts: 4,223
Country: United States
Yup, what he said.

Also, from your DMM reading of the 12v battery at rest, you need to fix the problem soon, or you'll also damage your batt. I'd get it on a charger ASAP if you haven't fixed the problem yet. Starting batts aren't designed to be deeply discharged.
__________________

MetroMPG is offline   Reply With Quote
Old 10-10-2007, 02:51 PM   #3
Registered Member
 
Join Date: Oct 2005
Posts: 1,978
Country: United States
Quote:
Originally Posted by theclencher View Post
alt not charging
That's what I was thinking...

The large chains like AutoZone will do a load test free of charge (no pun intended).

Take this situation:

I've heard of cases where the battery goes bad.
The alternator makes an extra effort to charge it.
Meanwhile, the battery fails and is replaced.
But the alternator was weakened by the bad batt.
Then the alternator fails.

LSS, test both to prevent damage to either.

RH77
__________________
rh77 is offline   Reply With Quote
Old 10-12-2007, 06:09 PM   #4
Registered Member
 
Join Date: Jun 2007
Posts: 71
Country: United States
Quote:
Originally Posted by theclencher View Post
alt not charging
Based on my Haynes Repair Manual for my car, the alternator is connected to the EVR. The EVR is supposed to control the field coils of the alternator. Is it possible that the EVR is failing to provide enough current to create a high enough voltage? How could I tell?

Also, what's the going mileage that alternators might start failing?
__________________
GasSavers_rGS is offline   Reply With Quote
Old 10-12-2007, 06:12 PM   #5
Registered Member
 
Join Date: Jun 2007
Posts: 71
Country: United States
Quote:
Originally Posted by MetroMPG View Post
Yup, what he said.

Also, from your DMM reading of the 12v battery at rest, you need to fix the problem soon, or you'll also damage your batt. I'd get it on a charger ASAP if you haven't fixed the problem yet. Starting batts aren't designed to be deeply discharged.
MetroMPG,

Thanks. I haven't moved my car since I posted so the problem shouldn't be getting worse.
__________________
GasSavers_rGS is offline   Reply With Quote
Old 10-12-2007, 06:15 PM   #6
Registered Member
 
Join Date: Jun 2007
Posts: 71
Country: United States
rh77,

Quote:
Originally Posted by rh77 View Post
That's what I was thinking...

The large chains like AutoZone will do a load test free of charge (no pun intended).
A load test of:
  1. The battery? (already tested to be a "good battery")
  2. The alternator? I do not feel confident to removing my alternator.
  3. The whole electrical system?

Quote:
Originally Posted by rh77 View Post
Take this situation:

I've heard of cases where the battery goes bad.
The alternator makes an extra effort to charge it.
Meanwhile, the battery fails and is replaced.
But the alternator was weakened by the bad batt.
Then the alternator fails.

LSS, test both to prevent damage to either.

RH77
How does an alternator "become weakened" by a bad battery?
__________________
GasSavers_rGS is offline   Reply With Quote
Old 10-12-2007, 06:32 PM   #7
Registered Member
 
Join Date: Mar 2006
Posts: 675
Country: United States
It is most.......likely that it is the alternator. It isn't to difficult, typically to change. However, on that car you have a couple of things against you. First, the serpentine belt has to have the tension released, to pull the alternator and then tensioned to reinstall it. Second, it is a bit tough to get at the bolts that hold it in, because even though their are only two bolts, they are on the back side of the engine, under the cowel.

The alternator is good for 70,000-150,000 miles. Anything over that and it is on highly borrowed time. I'd pull it and replace it, or take it to a garage you trust and have them do it.

I would charge the battery, as well, although if the car will still start on it's own, without a jump, I would just replace the alternator and then use it.
Gary Palmer is offline   Reply With Quote
Old 10-12-2007, 06:36 PM   #8
Registered Member
 
Join Date: Jun 2007
Posts: 71
Country: United States
Quote:
Originally Posted by Gary Palmer View Post
The alternator is good for 70,000-150,000 miles. Anything over that and it is on highly borrowed time. I'd pull it and replace it, or take it to a garage you trust and have them do it.
Gary Palmer,

Maybe this may be a factor.
__________________
GasSavers_rGS is offline   Reply With Quote
Old 10-12-2007, 06:55 PM   #9
Registered Member
 
Join Date: Mar 2006
Posts: 675
Country: United States
Well, I don't know if tip toeing works, but it's worth a try. Maybe the Ford alternator is built better? I just know on my 94 Chrysler it died at a little over 150,000 and when I put new brushes in a Honda, at 150,000, they were on the far edge of short.
__________________

Gary Palmer is offline   Reply With Quote
Reply

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 Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Congrats to COZX2 on the 100+ MPG fill! MetroMPG General Fuel Topics 58 12-23-2007 08:34 PM
Things To Look For When Buying A Civic Hx panamacolin General Fuel Topics 9 06-06-2007 09:43 AM
Loremo Sludgy General Fuel Topics 7 10-29-2006 10:16 PM
Any ideas how to install this? Compaq888 General Maintenance and Repair 0 12-21-2005 01:46 PM

Powered by vBadvanced CMPS v3.2.3


All times are GMT -8. The time now is 12:57 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.