Nissan Junker Electrical System
As usual... I was filling the mada up at the gas station. Left the engine running for ac to the family. After filling, got in and applied brakes to shift. Sounded like a coffee can full of springs being shaken with disney toon sound effects.
Engine temp 192, all other temps cool. Applied brakes a couple of times to trouble shoot. On third app, the brake fail light came on. Observed charging voltage at 13.1V. Shut off engine, restarted, all good to go. After all my previous voltage enhancements, normal charge rate at idle 90 degrees oat, was 13.8V. At 30 degrees oat, nominal charge rate is 14.3V. Battery is a 13.2V AGM battery.
So I stopped by my local starter/alternator shop. Anything closer than 15 miles to a Nissan dealer will contaminate results! Found out that in 2007, Nissan switched suppliers from Hitachi because Hitachi alternator internal voltage regulators won't tolerate heat. All Nissan dealership analyzing equipment will indicate falsely that the charging system is hunky dory. But the Nissan dealership equipment is not capable of analyzing the internal voltage regulators, or their carrier voltage, which is AC voltage.
Had my Hitachi alternator replaced under warranty in 2012. Factory instruction supercedes any and all Hitachi alternators since mid year 2007. But, since Nissan dealer sub sub sub contractor maintenance facilities have (still) an overstock of bad Hitachi alternators, they won't tell you about the all bad Hitachi alternators, and won't put in the correct, non Hitachi upgrade alternators unless you catch them, and call BS on their attempt.
The result is that if the alternator heak soaks (city or in town driving) the voltage will start jumping around. If the regulator temporarily fails, you will see a drop to reference voltage (12.1V), then a few seconds later the voltage will climb back up to maybe charge 13.3V, will charge 14.1V, no charge 12.1 V.
Per the man who builds alternators, you should never see any voltage below 13.8V steady state. And if you see the voltage drop to system reference voltage of 12.1V, your regulator, and thus your alternator is bad. With everything in the car turned on, and 1500rpm, you should see 14.5V on a fully charged battery, or higher if your electrical system integrity will support it. If my charge drops to 13.1V, and I get on the freeway, as the alternator cools, my voltage level will return to 13.8V.
So I am now looking at trying to locate an after market alternator that will put out 13.8V-130 amps at 575rpm with everything turned on. 14.5V-160 amps at 1500rpm or above. Factory norm for a Hitachi is a max of 65 amp output at 1500 rpm with everything turned on. Same as my itty bitty outboard fishing motor!!!
The brake fail light came on at 11.7V battery level. 13.4V charging output. A good indicator of how bad and wrong the factory Nissan computer programming is. They are aware of the problems at Nissan North Americam but choose to do nothing!
Will keep you posted.
Last edited by F4N4EVR; 05-18-2016 at 05:40 PM.
Reason: Nissan quality level spell check