The Top Mitsubishi Galant VR-4 Resource

Join the best E39A 1991-1992 Mitsubishi Galant VR-4 community and document your GVR4 journey.

  • Software Upgraded - Reset Your Password to Login
    In order to log in after the forum software change, you need to reset your password. If you don't have access to the email address you used to register your GVR4.org account, you won't be able to reset your password. In that case, follow the instructions here to regain access to the forum.

Alternator Rewire

Hertz

Staff member
Joined
Jul 29, 2002
Messages
13,501
Location
Chicago, IL
I've been observing a consistent decrease in charging system voltage over the past couple weeks. It definitely loses voltage over time (giving about 13.5 at startup, but 12.5 or less after 30 minutes).

I found that I have a leak at the downpipe gasket that is blasting the alternator with hot air. Luckily I made a heat shield when I installed this alternator, but it has suffered, and I'm sure the radiant heat was enough to start cooking the alt.

There is some definite corrosion/heat damage at the alternator and I'd like to do some rewiring, but even after reviewing the schematics, I'm still unsure of which terminals are what.

The schematic indicates three wires, B, S and L. B is apparently the post connector, S and L are the plug. If I understand correctly, of the S and L, one goes through the ingnition, the other straight to the fusible link.

Okay, so what is B?

Better yet, which of these terminals B or S&L can I add some wire to in an attempt to possibly get better voltage?

Thanks in advance,
-Ryan
 

Rausch

Well-known member
Joined
Dec 21, 2004
Messages
12,049
Location
Cleveland, OH
post the schematic. i'll see if i can dig it up on mitchell's, but you should be able to beef up/re-run the bigger (10ga?) wires with no issues. for that matter, any of them, but the big guys being the most important to the battery. you sure the regulator is not freaking out when it gets hot?

B would be where you'd want to beef things up.
 

Rausch

Well-known member
Joined
Dec 21, 2004
Messages
12,049
Location
Cleveland, OH
The diagram in Mitchell's sux, but it appears that the two 10 ga wires are the white ones? you can replace those either with the same size, or larger to see if you get better voltage.
 

Hertz

Staff member
Joined
Jul 29, 2002
Messages
13,501
Location
Chicago, IL
Is it okay if I don't have larger gauge wire? Can I add additional runs of the same gauge?
 
Last edited:

atc250r

Staff member
Joined
Sep 11, 2003
Messages
13,235
Location
Orange County, NY
I can't make out the small letters in the pic (even after I magnify it) but the post is the terminal marked B-16 in your diagram. Like Aaron said, that's the one that carries the current and that's the one that you want to replace with a nice, heavy gauge wire.

John
 
Last edited:

i cut both of the 10ga wires and just ran a piece of 2 ga i had laying around the shop (the ground lead of off a warn winch is the perfect length) right from the big terminal on the alt to the batt. seems to work quite well. and it seems to have mellowed out my voltage fluctuation
 

GVR-4

Well-known member
Joined
Apr 22, 2002
Messages
2,610
Location
Asheville, NC USA
I just did this upgrade, Hertz. The recommendation is 4 gauge, but anything bigger can be used. I used some 1 gauge or 0 gauge (not sure which) I had laying around for the positive lead and the ground. I soldered some copper lugs from Lowes to the wire with my 550 Watt /ubbthreads/images//graemlins/jawdrop.gif soldering iron. I also soldered a copper washer with the same size hole in it as the posts on the alternator over the hole in the lug. The 0-1 gauge lug has about a 3/8 hole in it for the post and the alternator posts are like < 1/4". I bought a nice 145 amp fuse from Autozone that was made in the US (not some Chinese junk) and used that between the positive lead on the box that bolts to the battery and the positive wire going to the alternator. The Galant alternator does not have a grounding wire from the factory, but relies on the connection to the chasis for grounding.

I have only noticed a slight difference in voltage readings on the logger.

I'll snap some photos. Describing it in words is not an effective way to communicate what I did.

BTW, on the alternator there are only 1)the positive post (recognizable by the red plastic insulator), 2)the negative post (alternator chasis ground) and 3)the place where the harness plugs in. These are the only specific connections.
 
Last edited:

Hertz

Staff member
Joined
Jul 29, 2002
Messages
13,501
Location
Chicago, IL
So you bypassed the original 100amp fuse in favor of a new 145?

Did you follow the stock routing of the harness?
 

GVR-4

Well-known member
Joined
Apr 22, 2002
Messages
2,610
Location
Asheville, NC USA
No, I left the stock wiring alone and added everything. The 145 amp fuse is stricly for the 1 gauge positive wire. Routing was custom. /ubbthreads/images//graemlins/wink.gif

Sit tight and I'll see if I can get some photos to show up at night.
 

GVR-4

Well-known member
Joined
Apr 22, 2002
Messages
2,610
Location
Asheville, NC USA
Amazing these came out so well when it's pitch black outside.

I routed the wiring under the radiator. I'll try and take more photos tomorrow of the alternator and the routing.







 

spooling92vr4

Well-known member
Joined
Jun 7, 2005
Messages
2,511
Location
long island, NY
ive seen people do this before.. they just run a bigger gauge wire from the positive on the battery to the alt seems to work out.. maybe you should try one of those grounding strap kits?
 

GVR-4

Well-known member
Joined
Apr 22, 2002
Messages
2,610
Location
Asheville, NC USA
Here are some more pics. Hertz, I was wrong. The two cables do follow the stock routing for the harness under the radiator. I zip tied the two cables to the harness in some places. Also the fuse is a 175 amp fuse, not 145. It's more visible in these pics. I couldn't get any of the alternator to turn out without crawling under the car- maybe another time. The red wire is positive and the brown one is the negative. I just anchored the alternator ground to the chasis under the same bolt that grounds the negative lead from the battery.







 

Hertz

Staff member
Joined
Jul 29, 2002
Messages
13,501
Location
Chicago, IL
Quote:
ive seen people do this before.. they just run a bigger gauge wire from the positive on the battery to the alt seems to work out.. maybe you should try one of those grounding strap kits?



You guys are the best.

I just picked up a cable from Autozone, looks just like GVR-4's. I'm confused why you elected to put another fuse in there, the stock 100A will blow first?

Also purchased a replacement nut for my downpipe, and will put in another gasket (thanks spooling for sending me those last year!) I'm thinking I should try a split or wave washer under it to help keep it from backing out again... or maybe grow some muscles and torque it down tighter when hot. /ubbthreads/images//graemlins/wink.gif
 

iceman69510

Turn Right Racing
Staff member
Joined
Mar 5, 2001
Messages
10,964
Location
Michigan
The stock exhaust pipe nuts should be crimped and thus self locking. Shouldn't back off. Do you have that type?
 

Hertz

Staff member
Joined
Jul 29, 2002
Messages
13,501
Location
Chicago, IL
Nope. Lost the first set after AMS installed my turbo. Don't know if they were crimped. Lost a single one in the last couple weeks, re-installed by me after having exhaust manifold off and torqued cold.
 
Support Vendors who Support the GVR-4 Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications RixRacing RockAuto RTM Racing STM Tuned

Recent Forum Posts

Top