09 TACO VOLTAGE VOLTAGE QUESTIONS..

My charging system is acting suspect.. if you have a 2nd gen taco auto trans & digital volt meter let me know what your idle, cruising 50-65 mph and stoped in gear hvac off voltage is. As this would help determine if mine is cooked. I know I may have to bench test it just cant at the present Thanks.

 

A/c voltage would come from an inverter, your truck should only have about 13 bolts of d/c

 

Think he is talking about his air conditioning being on or off not AC "bolts". you don't need to drive it to check voltage it will vary depending on load and state of battery charge 13.2 to 14.2 just rev the engine a bit. Guess I should ask why you think some thing is up.

 

After cleaning off crud on the pos terminal I noticed my cheap Wallyworlds batery terminal was being eaten away by corosion also half my cable terminal was eaten away thus in theory at least it could over work/ruin my alternator depending on how long its been runing like that. Add to that while driving back to Wally world to exchange the battery the truck would stall out low or stoping speed. NEVER did this before just riteafter I cleaned the battery. I can only guess the EFI requires a min amount of voltage to operate corectly wich it wasnt getting causing it to die out acording to my UltraGauge 11.8 -13.2 V. So after replacing the batt & terminals it continiued the same symptoms so while at Wallys garage I asked them to do a a/c check and all 3 batt, starter and alternator showed ok. From there went to Autozone where I was told the voltage was to low to register on their meter ,

drove straight to Oreilys where their meter said ( good diodes low output ) heres where it gets weird on my way
home from Oreilys the truck seemed to drive back to normal no stalling and voltage never droped below 13.4 V
drove it 50 miles today to and fro work never stalled once . Weird ; my nex move when time allows is to bench testthe alt. BTW : does anyone know this models alternator amperage specs 80-120 amps ??

 

If the voltage was low enough to effect the electronics chances are it would not crank in the first place so if it started when you went from store to store it sounds more like they did not know how to read their own meter. I'm going to guess a bench test will produce the same results.

 

subd, for more info. also wondering if having a voltage at 13.1 when crusing, or in idle is ok, and normal for these trucks.
not to hijack the thread but my scanguage II is also reading 13.1-13.6. wondering if the 13.1 is a problem. I just upgraded door speakers and a 10in sub, with 2 amps.

 

A weak battery has high resistance it takes more voltage to charge it. As the battery reaches 12.7 volts the resistance starts to fall and the charge voltage drops. In order to charge a battery the alt must have a higher voltage than the battery when you alt voltage is in the 13.1-13.5 or so that is all that is necessary to keep the battery charged. When you turn on the AC or lights and run the heater fan that will make the alt. work harder but the voltage still may only be it the 13.5 to maybe as high as 14.2 depending on the load. The alt does not have a fixed amp output in other words if it's rated 130 amps and the battery is fully charger and nothing is on it may only be making a few amps when you start add loads the current rises towards it's max output. When an alternator is tested with a machine and they want to know if it will do max output the field windings are fed at full voltage with a jumper by passing the regulator this forces the alt to reach full current. Current follows voltage so if the voltage is there the alternator most likely is fine. If you think you may have a bad diode a simple voltage check is usually all that is necessary if there is any doubt a voltage check in the AC range will let you know pretty quick if a diode is bad there should be very little AC voltage present in the system.

 

Dude, that answered all my questions and makes a lot of sense! Thank you very much!

 

Day 3 aft battery change still at 13.4 in gear stoped 13.6 crusing 14.2 Volts at cold start appears to be normal to me no more stallin out . 40* F and windy rain plus superbowl so will bench test as needed and pray I dont get stranded most likely gona wait for some good weather and bench test. I will say just from my personal experience I really think if the alt was gonna burn out I beleive it wood have by now at least thats my experiece with American cars. The battery icon comes on everytime at ignition like all warning lights then turns off like it always has vs stayin on like theres a problem good ole dummy lights.

 

This is good detailed info thanks.