alexf91

Hello everyone, I've recently started having problems with my car and I seek advice. My dad helped me buy a 2003 ES 300 5 years ago from a Lexus Dealer. We found the car in a used cars website. The car had around 110,000 miles and according to the CARFAX, the previous owner took it to the dealer frequently and all that was ever done to the car was an oil change. I don't use the car a lot since I use public transportation to get to work everyday and only has a little over 130,000 miles. Overall the car has worked great and only had two minor issues. First the AC was not blowing cold air and I fixed that by changing the relay for the magnetic clutch (I read that on this website). Later on I installed an aftermarket Pioneer radio, new JBL speakers wired to a 4-channel JBL amp and an alpine sub-woofer with an Alpine amp and eventually had problems with the car not starting and I fixed that by replacing the battery (November 2017) which I bought at Sams Club and is a Platinum Duracell. For the last 2 years I've had no issues.

Just a couple weeks ago after a long drive I noticed the check engine light went on and started getting worried and felt like something was going to happen soon. I didn't turn the car on for a week or two because of a knee injury. Two weeks ago when my knee got better, I got in my car and it struggled to start. I didn't think much of it as I thought that it was due to not having it on for a while. I drove it to a car wash and then parked it to dry the car and use the free vacuums. After I was done, my car wouldn't start. I always keep a Stanley jump starter in the trunk and got the car started and drove it back home. I checked the battery with a multi-meter and was getting around 11.8 volts. I took the battery to Sam's Club to get it tested. They charged it, tested it and everything was good and they showed me the voltage and cold cracking amps. I checked the battery myself and was reading 12.58 volts. I started the car and checked the voltage and noticed the voltage dropping. Eventually it went back down to 11.8 volts after I turned on the AC, radio and lights and the car turned off. I then thought that maybe it's the alternator so I removed it and took it and O'Reillys to get it tested and they told me that it failed and is shot. So eventually I got the Ultima re-manufactured alternator from O'Reillys and installed it (maybe I should have had it tested). Before I put the battery back on, I took it to Sams Club again and this time they said that it wouldn't charge so they replaced it for free. I installed the battery and the car stared fine but guess what? the battery started to drain again and eventually it shut off and won't start unless I jump start it.

A few days later (today), I checked the battery with my multi-meter and it read 12.24 volts. The car started fine but when I check the voltage at idle, it stays the same and dropped to 12.11 volts. Once I start messing with the lights or windows, the car shuts off and then won't start again unless I jump start it. I checked all the fuses and none of them are blown. I removed and visually inspected the relays and none of them look damaged. I'm guessing my next move is parasitic draw test? or a proper relay test? I'd like to check everything I can first before I go to a mechanic. What could the problem be? Has anyone had a similar experience? Any advice would be greatly appreciated. Thanks.

LeX2K

Sound like the replacement alternator is bad I highly recommend you buy a Denso 210-0816 remanufactured unit. You can keep getting alternators at your local shop but many over the counter brands are known to be bad right out of the box.

aufenscuht

Hey brother. Ultima is JUUUUUNK. I run a shop and tried them twice in a pinch. Within a month both went bad. Lexus 2000 is right. Get a Denso and be worry free. Even if it is reman (which it most likely will be). Put the vehicle on a parasitic draw test and have someone with an infrared lens/camera look for a hot spot with fluctuations if this does not resolve your issue

alexf91

You guys might be right. I did a parasitic draw test and was only getting an insignificant amount. I think that either the alternator is bad or the voltage regulator plug is bad because it looks damaged but I don't know how to test it. Im thinking of taking he alternator to get tested at multiple locations. I went with Oreillys because I read that the Denso remanufacturing is outsourced and could be bad as well and they only offer 1 year warranty. I also read that the Autozone and Advance Autoparts alternators are junk. At least I have the lifetime warranty so if its bad then I will ask for anothere one otherwise I will have to spend money on a Denso. None of the fuses are bad but I’m yet to test the relays.

aufenscuht

I have zero problems from Denso and purchase them almost daily. Voltage regulator issues in the mainstream junk is well known about. Yes they have a lifetime warranty, but the better question is how often are you willing to change them upon failure. The cheap Mexican outsourcing will answer that question for you. Go OE.

alexf91

Well honestly It doesn't take me long to replace and Denso is 1 year warranty. What if it goes bad after a year? If i can get my money back then I’ll try the Denso. I’ll report back.

shortstop

With the car running the volts should be between 13. 7 to 14. 7 volts to recharge the battery. Make sure your negative connections are good. Anything under is no good.

alexf91

When I first installed the Ultima Alternator I was getting around 14 volts but I kept checking and it was slowly going down to eventually 12.2 volts. And I did let it run on idle for a while and it never got better.

Oro

If you have verified the grounds are good, then another thing is to look for AC voltage "leaking" from the alternator. Put the meter in AC Voltage mode and the hot lead to the alternator output, and the ground to earth. If you see AC voltage you know the VR is bad in the alternator.

You can also take the car to an O'reillys or other and they will have a Bosch or other diagnostic tool they can clamp on and also test.

In general, if your factory alternator goes bad from worn brushes or a bad bearing, it's always just best to replace those and keep using the good windings and voltage regulator, and it costs only ~$15 to replace those parts.

alexf91

I owe you guys an update. So my cousin (who is a mechanic) showed up to my house to take a look at my car. He said that on Japanese cars, when you replace the battery and alternator you have to keep reving up the engine until it maintains some RPM at idle. The car turned off on him a couple times but after a while of reving up the engine, it did not shut off and maintained a decent voltage reading. He also added a little more tensions to the drive belt. It has been around 4-5 months and I have had no problems with my car since then. I hope this helps anyone out there having new alternator problems.

Richardsr

Can’t say as I’ve ever heard of “revving the engine” to cure a new alternator of low voltage output, but “belt tension”... yes.

In my experiences, the diodes are working in the VR or they’re not. I dunno’.

Maybe someone here who’s an expert on “Japanese cars” can elaborate?

alexf91

He said an older mechanic that used to teach him showed him this trick. Just need to give it some gas for a while. It seemed really odd when he told me but it worked.