Killing Alternators

[Nebusoku]

I have an interesting problem that has me stumped.

I replaced my alternator about 2 years ago when I got my Q. It was running just fine. About 1 Month the alternator went out, I replaced it and the new one just died last night in the same fashion.

**** Problems Seen ****1st alternator - 2 years ago the coils went bad and were crossing.

-- Replaced Battery at this time.

2nd alternator - 1 month ago - was over charging and causing acid to push out of the vents on the battery. So had acid boil out all the way down to the frame rail and had also gotten into the alternator. So the alternator stopped charging and the lights went dim and it stalled out the engine.

-- Replaced Battery at this time.

3rd alternator - 1 day ago - was over charging and causing acid to push out of the vents on the battery. So had acid boil out all the way down to the frame rail and had also gotten into the alternator. So the alternator stopped charging and the lights went dim and it stalled out the engine. Also within a week before it died the radio would turn off the speakers when the car was over 2000RPM and the Trac and ABS system kept turning on and off at random. 2 days before it died I had to replace the right side low beam head light and had the auto store check the alternator while running in the car. then yesterday the left head light died so I replaced it as well. While I was out driving the lights started going dim on the dash the system reported that one of the tail light was out. I decided to pull the car off, before it died the transmission was bucking and having issues shifting, the engine was stalling out and the power steering went out. I had the car towed home.

during the time line I would run Nissan Data Scan against the car and everything was showing fine and the voltage was reporting in the 13-15 range when the car was running.

Also checked all the lights when I got it home and they work just fine.

Was able to start the car today off of the little power left in the battery I stayed running but the Battery/Alternator checker at home showed no charging and when the Load was applied from the checker the car died since no power to keep the car running.

****************************************Car Info

1994 Infinti Q45Trac SystemNo Mods to the Electrical System

[Q45denver]

The question always asked is whether the alternator was from Infiniti or rebuilt?

[Skibane]

The fact that your 2 latest alternators were both overcharging is kind of suspicious - almost sounds like a problem outside the alternator.

The voltage regulator (inside the alternator) measures the battery voltage through a low-current connection (made at the alternator's "S" terminal) that is separate from it's high-current output connection to the battery (made at the alternator's "B") terminal. On the Y33 vehicles, this low-current wire is a Yellow/Red color where it connects to the alternator, and becomes a White wire as it leads to the battery.

If the low-current wire develops a bad connection at any point between the alternator and the battery, the alternator's voltage regulator won't "see" the battery's true voltage - and may attempt to charge a battery that is already charged. This can cause electrolyte boiling (and a ruined battery, too).

So, it might not hurt to check this low-current wire, over its entire run between the alternator and battery, making sure to look for dirty contacts at the alternator connector itself, the intermediate connector where this wire changes colors, and at the 7.5 amp fuse that protects this wire.

[Nebusoku]

mine is a G50 series Q45 yes it a rebuilt the original was the original in the car which had the winding coils go bad.

I am replacing the ground wire and checking the positive wire for any corrosion

the harness from the back of the alternator is fine and clean and I run Di-electric grease on the connections.

from the battery on the G50 it has the main cable down to the starter and the 2 main lines to the fuse/relay center in the engine compartment.

[Skibane]

There is a HUGE difference in the quality of Nissan's "rebuilt" alternator, versus just about every other "rebuilt" brand. Even the very best of the other brands seems to last only half as long as the Nissan. It's EXPEN$IVE (around $315 with shipping from Infiniti Parts USA), but worth it.

[dsagers]

Take a look at http://www.rushps.com

He is a good guy to work with, and really knows his stuff.

I started burning up alts about every 4 months after a new stereo was installed.

Finally found Rushps, and he built me a killer set up that provides enough power to my stereo to ruin my hearing...

[dsagers]

Nebusoku

I called Rush Power Systems last night and pointed him to your post, he isn't a member, but sent me a message to cut and paste. Hope it provides you some help.

Hello Dave,

always good to see you have another challenge for me. I checked out the link and have some ideas if you would like to cut and past this.

First of all I am not sure what the year of the vehicle is, however 90's versions up to early 2k's use a two wire plug. The first has constant and the second on has key on voltage. Both should be checked for voltage with key on.

Also check that the battery light comes on when the key is in the on position with the engine off. The light completes the regulator circuit, so if the bulb is burned out it can cause a problem.

The next thing to check is the charge wire and fuse. The best way to do this is with a voltage drop test and wiggle the harness and fuse during the test. I have seen loose connections at the fuse, damaging the regulator.

Finally I would do a voltage drop test on the ground side, check engine, body, and frame. From what I have read I would guess (without looking at it) this is the problem.

I know what is a voltage drop test? Rather than just spend an hour typing I will just say go to my blog, the instructions are there. Just click the link. http://www.rushpowersystems.net/?p=7 (Mid way down in the article) also read the ground section here http://www.rushpowersystems.net/?p=3 <http://www.rushpowersystems.net/?p=3>

Now let me say this, I am not a re-builder, I only build new. But I must defend my quasi brothers, if all else fails take the car with the alternator installed to a professional rebuild shop.

The reason I say that is because they have the equipment to test the entire system and determine what went wrong. I have no doubt that the regulator is damaged.

The question is: what damaged it. Once the problem is found and fixed then go with a factory unit if desired. And finally if all else fails go with a one-wire alternator. This way you will bypass the factory wiring completely. The only wire that is need is the cable to the battery.

Hopefully that helpsDarren FlintownerRush Power System

[Q45tech]

Over the last 12 years of working on 90-96 Q45 [multiple hundred different ones] we have never seen a Q45 that just replacing the alternator with an oem factory unit doesn't solve not just in short term but for years and years.

Now we have had to replace a few fuses that aftermarket alternators blew when the owners tried to cheap out but nothing else.

Many times battery clamps and terminals are also replaced but that is a precautionary measure to cranking problems not exactly alternator related.

I would say we have at least 20 customers with some type of external amplifiers and subwoofers with extra wiring from battery to trunk where most have at least a large capacitor or auxillary batteries or both.

[Jesda]

Nissan alternators will last 200k+ if you keep your batteries fresh. Only a bit of neglect is required (jump starting without later removing the battery to trickle charge, for example) to ruin them.

So, Nissan alternators are very reliable in normal situations, but not at all robust. Use a quality battery (charge before installing) and don't add a discotheque to your stock electrical system.

[Q45tech]

The failing alternator symptoms you describe sound just like those from Nonadvaced, Crapa, or FailureZone that we have seen many times in past.

Actually I changed my oem as built at 235k [12.5 years] because the bearings were noisey and I had a new [2 week old] Nissan rebuilt from a wrecked Q..........preventative mainteance = change things before they fail.

At 12.5 years I had collected a pile of good used parts froms wrecks and Byron spent a half day changing out alternator, wiring, compressor, hoses, condenser, cond fan, new dryer, all front headlight assemblies ..........none of which had failed per se.

That was 5.5 years ago [81 kmiles] and I've been collecting a pile of parts for the next rehab. Only the used compressor failed at 4.5 years.

[dsagers]

Problem is that, like a lot of other people, I want a high performance stereo system.

Nothing really extreme, but with the stock alt being right at the threshold, just adding a 400 watt amp and some good speakers, the stock alt burns up about every six months.

I can trace my alt problems right back to the stereo install, then just like clock work the alts burn up. I've tried factory replacements, expensive NAPA units, cheap units. I'm going to order up a custom unit, with better components, a bullet proof regulator and battery bigger cables.

The real work will be building the mounting brackets to put a slightly larger case in the stock location.

[Q45tech]

That's what everyone who mods the stereo should do, have a custom built alternator created.

You just cannot expect the oem to survive [ for very long] under abnormal conditions.

For me listening to NPR or rarely talk radio at low volume is enough. But then again cup holders are forbidden as are loud passengers [duct tape].

Every municipality should have a vigorously enforced noise/music ordinance..........see too many old rockers now with hearing aids and sound induced neural damage.