Incompetent tech or am I missing something here?

[imzjustplayin]

Does anyone have or know the spec/test procedure for the 2007 Toyota Tundra V6 charging system? The only specs I know are that the voltage range at idle is 13.2v to 14.8v with no load. My issue at the moment with my Tundra is that when I turn on the fans, high beams and radio, the voltage sags into the 12.5V range or less and I find this to problematic. I also found that on cold start, the air pumps can cause the battery voltage to sag to 11.6V with the voltage returning to a bit higher 13.2v with no electrical devices running. The tech also mentioned that they tested the alternator back in January at 83 amps 10v and that supposedly 'it was fine'.

How can I convince the technicians that there is something clearly wrong with the charging system on this vehicle? I mean the service adviser has no issue with agreeing with me but that they're going by what the technician is saying. I even got the service adviser to come with me and look at another vehicle on their lot (2011 Tacoma V6), monitored the charging voltage and saw that it was significantly higher like 13.7v+ at idle whether there were electrical devices not running or everything running at the same time.

[sonofa]

Originally Posted by imzjustplayin

Does anyone have or know the spec/test procedure for the 2007 Toyota Tundra V6 charging system? The only specs I know are that the voltage range at idle is 13.2v to 14.8v with no load. My issue at the moment with my Tundra is that when I turn on the fans, high beams and radio, the voltage sags into the 12.5V range or less and I find this to problematic. I also found that on cold start, the air pumps can cause the battery voltage to sag to 11.6V with the voltage returning to a bit higher 13.2v with no electrical devices running. The tech also mentioned that they tested the alternator back in January at 83 amps 10v and that supposedly 'it was fine'.

How can I convince the technicians that there is something clearly wrong with the charging system on this vehicle? I mean the service adviser has no issue with agreeing with me but that they're going by what the technician is saying. I even got the service adviser to come with me and look at another vehicle on their lot (2011 Tacoma V6), monitored the charging voltage and saw that it was significantly higher like 13.7v+ at idle whether there were electrical devices not running or everything running at the same time.

You sure it isn't your battery?

[imzjustplayin]

Battery was brand new at the time of the test, I mean like 1 day old. Also put the battery on a float charger prior to testing again this past month, and still noticed the issue. Finally got them to do a more close look at the vehicle, they put in another, brand new battery, conducted their tests which were minimal, said it was fine, I said otherwise. Finally consulted with a technician and spoke with him directly (opposed to service advisor), showed him my readings via the OBD-II scanner and how the voltages were sagging when I turned on the electrical devices, also pointed out a whining noise coming from the engine bay which I thought could be the diodes in the alternator which would explain the poor voltage control, he took in the vehicle again. Finally I get a call on Friday saying they did more tests and found the alternator to be bad and the source of the whining noise coming from the engine bay. Now they say they can't fix it because it's not under warranty even though this has been an on going issue. Damn piece of crap!

[ToyoGuard]

Anytime you start a car the battery will drop to around 10v - 10.5v, that's normal. On toyota high speed alternator's as long as it doesn't drop below 12v with a load then it's considered good. As long as your getting 13.5v - 14.5v during idle with no loads your fine.

If you're still worried, On a lot of newer toyota's anytime the battery is disconnected or the computer is reset your idle get's screwed up. A low idle can screw up your charging voltage. Try cleaning the throttle plate to help the computer re learn the parameters. I believe your fine though. Also, you cant go by the 2011 tacoma alternator cause it can have a different/higher amperage on the alternator

[Tercel GTS]

I build alternators for a living. Your V6 unit should make 100 amps with a voltage setting of 14.1 and the whining you hear are bad diodes. The rectifier is welded in place so rebuilding is not a real option. I'll update tomorrow with a site you can buy one from very inexpensive.

[imzjustplayin]

Well I got the truck back and they replaced the alternator at no charge except for the labor which was $160. Voltage does not sag like it did anymore and there is no more whining noise coming from the engine bay. For the most part, I'm very satisfied though I'm slightly suspicious this alternator could go again because currently, the charging voltage is about 13.2/13.1v which is just barely failing spec (13.2v-14.8v).

If the engine is fully warmed up and the engine bay is warm (so alternator above 80f), ambient air temperature is 90F, with the highbeams, and interior blower fan at max speed, with the gear shift in "D" (drive) while at a complete stop (like waiting at a red light), the engine will idle at about 700rpm and the charging voltage will sag down to 12.7V. I'm going to call the dealership tomorrow and ask them how long the warranty is on this part and to note what I'm observing.