Anyone have experience with Mitsubishi Reman Alternators?

[talon77]

I just replaced my dead alternator (stock) with a remanufactured alternator I bought from the dealership. The replacement unit is actually the upgraded 90amp galant version, which bolted right in. The problem is that at idle (850 rpm) I'm only getting 13.55 volts across the battery with no load from lights, ac, or any accessories. I used to get about 14.3 volts at the battery with the old alt under the same loading conditions. I believe that the new alt has a bad voltage regulator in it. My question is, has anyone here ever had a bad reman alternator purchased from mitsubishi?

For reference:

-The new alt is charging because I can see the voltage cycling back from 13.55v to 13.53v back to 13.55v and so on.
-At 2,500 rpm I'm only getting 13.8v at most.
-I've replaced all of the grounding straps on my car with new 8-gauge and I've even added a new 4-gauge ground from the alt body to the chassis.
-I've upgraded the alt output wire to a single 4-gauge from alt to fuse box.
-Alt relay seems to be working fine, alt fuse appears fine.
-With AC and lowbeam lights on, I'm only getting 12.85v.
-Car off, battery voltage = 12.7 volts.

I can only conclude that the new reman mitsu alternator is no good, any input before I go back to the dealer to request an exchange?

Thanks

 

[DGajre777]

I've had my rebuilt Mitsubishi alternator (that I got from the dealership) for almost a year now. Heat is a factor that you have to add in and also the fact that as heat is generated in the engine bay the efficiency of the alternator goes down. I see 13.8v with all my accessories off and my engine running. With A/C and headlights the volts go down to 12.5v for about 4-5 seconds when I first turn it on and then climb up to 13.8v.

 

[talon77]

Yep, I've noticed the output drop with temperature increases as well. My problem is that fully warmed up w/AC on and lights on, the voltage hangs out at 12.85v and does not climb back up. I can see that the alternator is charging since it'll cycle between 12.85 down to 12.83v back up to 12.85, etc... just not charging as much as I'd like it to.

What I'm thinking is that if the alternator functioned properly and my starting output cold at idle, no AC no lights was 14.5v (instead of 13.55v, which is what I'm getting), then my final output fully warmed up with lights and AC would be higher. (i.e.: 13.8v instead of 12.8v, for example).

I guess at this point I'm just trying to find out if others had problems with reman units from Mitsubishi. I know that by reputation they are supposed to be far more reliable than autozone type reman unit.

 

[DGajre777]

You should have a 1 year warranty on it on parts and labor, take it back and get it replaced. If you have a volt meter in your car, show the service guy the voltage drop and they'll get you another one.

 

[talon77]

DeGajre, you might get a kick out of this... I explained my problem to the parts mgr at the dealership today about the 13.55v; he looks into it; gets back to me and asks me if I have a Sears DieHard battery...yes, I do. Evidently (according to the dealership) Sears Diehard batteries are an anomaly which causes voltmeters to read lower, when connected to mitsubishi alternators. Thus, my warranty claim for replacement has been denied at this time.

Unless you guys know something I don't, I don't believe there is any truth to that whatsoever. Anyways, just to say I did it, I will swap my battery with another to see what it does. I have clearly conveyed to the mgr that if I swap batteries and the condition does not improve, then I will pursue the exchange under warranty.

 

[DGajre777]

Hmm, interesting. Yeah, just swap in a different battery or go to Walmart pick up a battery and see what voltage readings you get. You can always return the Walmart battery if it doesn't make a difference. IF there is any truth to what he is saying, even a new alternator will give you the same voltage readings.

 

[talon77]

Yep, that was news to me too... I'll try it and let you guys know. I'm not holding my breath on this one though.

 

[Defiant]

DeGajre, you might get a kick out of this... I explained my problem to the parts mgr at the dealership today about the 13.55v; he looks into it; gets back to me and asks me if I have a Sears DieHard battery...yes, I do. Evidently (according to the dealership) Sears Diehard batteries are an anomaly which causes voltmeters to read lower, when connected to mitsubishi alternators. Thus, my warranty claim for replacement has been denied at this time.

Unless you guys know something I don't, I don't believe there is any truth to that whatsoever. Anyways, just to say I did it, I will swap my battery with another to see what it does. I have clearly conveyed to the mgr that if I swap batteries and the condition does not improve, then I will pursue the exchange under warranty.

Give me a fcking break. Batteries are batteries. They don't care whose alternator is connected to them. Defy him to find you another that's putting out thirteen-and-a-half when new. Mention small claims court.
What bunch of goddamned horseshit.

Mitsubishi isn't worth the powder it'd take to blow what's left of it to hell.

 

[Geezus_Aach]

....interested in see what the results are. good info, thanks talon77!

 

[Morphius]

14.3 sounds pretty high. You really shouldn't see anything more than 13.8 at any point. I would speculate that your old alt had a bad regulator and was overcharging your battery before the regulator went bad.

 

[DGajre777]

14.3 sounds pretty high. You really shouldn't see anything more than 13.8 at any point. I would speculate that your old alt had a bad regulator and was overcharging your battery before the regulator went bad.

Good point, and if that is the case, his current battery probably has a few dead cells in it. Time to get a new battery.

 

[pitbull419]

Beat me to it.
An over charging alternator will kill some cells in a battery.Thus making your battery weak.
Which intern will cause you charging system to be a little weak.
My bet is when you change the battery you will get normal readings and have a normal operating charging system.

 

[pitbull419]

DeGajre, you might get a kick out of this... I explained my problem to the parts mgr at the dealership today about the 13.55v; he looks into it; gets back to me and asks me if I have a Sears DieHard battery...yes, I do. Evidently (according to the dealership) Sears Diehard batteries are an anomaly which causes voltmeters to read lower, when connected to mitsubishi alternators. Thus, my warranty claim for replacement has been denied at this time.

That has to be the biggest load of $hit I have ever heard.
Did he tell you not to change the gear oil in your rear end because it had been in there to long and changing it would make it worse???????

 

[talon77]

UPDATE!!! Swapped in the big Optima Red Top yesterday and.... It fixed my voltage problems, SO I THOUGHT!!! My voltage readings across the battery w/new Optima:

Car off = 12.5v
Idle (around 850rpm, engine cold), No AC, no Lights on = 14.37v
Idle (engine warmed up 9 minutes), No AC, no Lights on = 14.13v
Idle w/lights on = 14.04v
Idle w/lights and AC (both fans on) = 13.62v

I thought those numbers were good until I drove the car around the block a few times (approx 20 minutes low speeds not exceeding 25 mph in residential neighborhood). During the drive, the car exhibited normal behavior no funky lights on the dash (I was driving w/lights and AC on). However when I returned back to my garage I noticed the dash lights were dim; voltage read = 12.5v!!!??

For now, I am concluding that the engine HEAT is completing degrading my alternator output. When car is cold, alternator works just fine; when the engine compartment gets hot, the alt output takes a dive.

For reference, the alternator has been relocated to the rear of the engine using Jays alt reloc kit. When I did this mod I thought it would help to COOL the alternator since the alt used to sit at the front of the engine, right next to my external WG off the O2, but I guess the back of the engine is still way hot.

Now, I am pondering the following:

1. Installing alt cooling tube (this sounds like a good idea, but in bumper-to-bumper traffic this won't do a thing.
2. Installing shims on my hood to hopefully vent some of the heat at the back of the engine (where the relocated alt resides).
3. Installing heat barriers. (wrapping downpipe?, heat barrier for alternator?, etc).
4. I have a carbontrix heat vent I will install on my hood, maybe that might lower the OVERALL engine compartment hood temps?

Any constructive input? Anyone with this same problem after relocating the alt to the back of the engine? I'm dying here guys...this electrical issue is seriously bumming me out.

 

[DGajre777]

Are you running a heat shield on your exhaust manifold? If you are, I vote for the hood vent.

 

[talon77]

Yep, running exhaust mani heat shield but still need to modify or fab up lower heat shield. I'm REALLY hoping the hood vent helps too.