Go Back   Club Lexus Forums > Lexus Model Forums > IS Models > IS - First Generation
Sign in using an external account
Register Forgot Password?

Did I install a bad alternator in my neice's car?

Reply
 
 
 
 
Thread Tools Search this Thread Display Modes
Old 06-17-14, 07:40 PM   #1
RSpi
Rookie
Trader Score: (0)
 
RSpi's Avatar
 
Join Date: Mar 2012
Location: NM
Posts: 60
Thumbs down Did I install a bad alternator in my neice's car?

My niece has a 2001 IS 300 which has been having issues with the battery/alternator. I went to the car yesterday and it was DEAD. So I pulled the battery, took it to AutoZone, they charged it and said the battery is good. So I clean the battery post and the cable connectors, install the battery and fire it up. I have a www.ScanGauge.com (an OBD2 tool) so I plug that in and watch the volts.

When started the volts read 14.1. I take the car for a drive and the first stop or 2 the volts drop to 13.6 - 13.8, no big deal. About a mile away, 3 minutes into the drive, I stop at a light and the volts drop to 12.3 - 12.4. I drive a few miles and at stops the volts drop as low as 11.7. I figure the alternator is dropping off line and at low idles, I may just be reading battery voltage. It goes a little higher when I turn off the AC and head lights.

So I figure the alternator has an issue. I tell my brother and suggest a Toyota or Lexus part, he calls his son that works at a Lexus dealer, they call me back and tell me to go to a local auto parts store and get a new alternator for $125 with a lifetime warranty. I don't put up a fight and go forward and install the store box alternator.

I crank the car, 14.4 volts, I drive the car and a mile down the road I stop at a traffic light and the darn volts drop to 12.2 - 12.4. Another mile down the road and it drops to 11.9 volts. While driving it is between 13.8 - 14.2 volts.

Did I get a bad alternator from the store or does this car have another issue?
This ad is not displayed to registered members.
Register your free account today and become a member on Club Lexus!
__________________
'95 850 T-5R Wagon - Panther - Daily Driver 22 / 28 mpg, 260,000 miles.
---------------------------------
'01 IS 300, 115,000, Niece's car.

Last edited by RSpi; 06-18-14 at 05:37 PM.. Reason: typo
RSpi is offline   Reply With Quote
Old 06-20-14, 08:36 AM   #2
is3t
Driver School Candidate
Trader Score: (1)
 
Join Date: Jan 2013
Location: PA
Posts: 17
Default

This to me seems absolutely normal. My bike does the same thing as well as most of the cars I have purchased/ Tested.

Generally speaking at idle it is just making enough power to keep the car on, you have to really hit over 2k-3k to start making power. Generally i would see around 14 around 2500-3000rpms and it would level around either around there or 15 depending on the car.
is3t is offline   Reply With Quote
Old 06-21-14, 07:47 AM   #3
RSpi
Rookie
Trader Score: (0)
 
RSpi's Avatar
 
Join Date: Mar 2012
Location: NM
Posts: 60
Default

I will keep an eye on it. Every other car I hook my ScanGauge up to reads 13.4+ volts at idle. This one reads 14.2+ when I initially start the car. It doesn't start dropping down until the car gets warmed up.
__________________
'95 850 T-5R Wagon - Panther - Daily Driver 22 / 28 mpg, 260,000 miles.
---------------------------------
'01 IS 300, 115,000, Niece's car.
RSpi is offline   Reply With Quote
Old 06-21-14, 07:49 PM   #4
onepointon
Pole Position
Trader Score: (0)
 
Join Date: Sep 2007
Location: East Coast
Posts: 351
Default

Does the battery light on the gauge cluster ever come on? I would say that is not normal and would try another alternator. I have seen a few cars come into my dealership with issues very similar to this. I always recommend an OEM one have never had one come back. I see this mostly on ES and GX, but that could happen on any car really.
__________________
- ASE Master/Lexus Master Certified Technician -
onepointon is offline   Reply With Quote
Old 06-22-14, 04:24 PM   #5
DatSRBoi
Driver School Candidate
Trader Score: (0)
 
Join Date: Mar 2013
Location: Texas
Posts: 19
Default

Autozone and Oriella changed manufacture on reman alternator with bad regulators. I changed my alternator on my dads minivan 4 times in one year before going back to OEM.

What you are posting is somewhat normal if the battery is near fully charge and at idle for the most part. If thats the voltage while driving 11.7 is ok but normally it will be low 12s for me and on very warm days it dips into high 11s for a few seconds then jumps back up when the fans kick on.
DatSRBoi is offline   Reply With Quote
Old 06-22-14, 05:32 PM   #6
RSpi
Rookie
Trader Score: (0)
 
RSpi's Avatar
 
Join Date: Mar 2012
Location: NM
Posts: 60
Default

Thanks OnePointOn, I recommended a OEM alternator but hey.

DatSRBoi: The only time I have ever seen under 12v on my ScanGauge was right before a alternator or regulator change.

I'm going to recommend they change it again this week under warranty and see what happens. It starts out over 14v and while driving it is over 13.4, it drops under 12v when the car is warmed up and at stop lights.
__________________
'95 850 T-5R Wagon - Panther - Daily Driver 22 / 28 mpg, 260,000 miles.
---------------------------------
'01 IS 300, 115,000, Niece's car.
RSpi is offline   Reply With Quote
Old 07-01-14, 08:52 AM   #7
MY2J
Pole Position
Trader Score: (2)
 
MY2J's Avatar
 
Join Date: Apr 2007
Location: Miami, FL
Posts: 382
Default

I would recommend taking the batt. to charge again. It's always best to have a fully charged batt. when installing a new alternator. I've gone the auto parts store route before and because they are rebuilt (the one I bought was) you don't really know what you're getting yourself into. Long story short... I had to buy a OEM Denso Alternator from the dealer which was rebuilt as well but it worked out flawless! Good luck!
__________________
http://my.is/forums/
-Mike-
MY2J is offline   Reply With Quote
Old 07-02-14, 03:14 AM   #8
PIONEER
Driver
Trader Score: (2)
 
Join Date: Sep 2005
Location: Nc
Posts: 143
Default

You can start the car and then disconnect the battery and take voltage. Technically the car should stay running as the battery is only needed to crank the car. You can take your voltage then eliminating the battery. If the car dies, there's your answer.
__________________
08 E63 AMG Wagon
12 Frontier Pro-4x
14 Pathfinder Platinum
PIONEER is offline   Reply With Quote
Old 07-02-14, 03:14 AM
 
 
 
 
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
Alternator Issues eknine9 Performance & Maintenance 6 10-26-13 07:27 PM
Alternator Issues eknine9 Lexus Audio, Video, Security & Electronics 0 10-23-13 05:01 PM
Charging Voltage Mod for $.50 hotshot27 Performance & Maintenance 4 06-15-13 07:37 PM
General Charging Problem - Alt? Regulator? Deuce_B LS400 15 04-10-13 10:03 AM
Alternator not charging? visi0n Performance & Maintenance 8 07-27-09 07:08 AM


Thread Tools Search this Thread
Search this Thread:

Advanced Search
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

Forum Jump

All times are GMT -7. The time now is 11:36 PM.

Join ClubLexus
Advertising


Copyright © 2000-2008 Internet Brands, Inc. All Rights Reserved
Privacy Policy | Disclaimer | Terms of Use | JOBS


Get all contact info