does anyone else notice that when they turn on their lights, or bright lights, the fuel pump makes less noise and the idle changes? is the only fix for this the higher-amp alternator mod? my voltage reads about 13, but still, even my 4-ways make the damn pump rise and fall. same thing with the window motors.
under powered alternator?
- Thread starter andrw
- Start date
glowstang93
20+ Year Stangneter 
I used to have to replace alternators about every 2 yrs when i replaced it with the factory stock unit. Then I got tired of it and talked to a Alternator Shop. They told me that the stock 75 amp alternator is a poor design, small diodes and too much heat cause them to go downhill fast. He suggested I put in a 3G alternator. I used one from a 93 econoline van (v8) 95 amp. I wish I had went bigger, but anyways... I still have problems with the engine idle coming down when I have every power accessory on ( especially defrost/fan/rear defroster/headlight), but its not as bad anymore. There are plenty of tech articles on the 3G replacement. It is not hard at all, I didn't even have to grind anything. The 3G is what 94 and up have in them. Another cruel joke from Ford, lets get rid of these crappy alternators 
Good Luck
Good Luck
Get a 3G alternator. I put one on not too long ago and WOW.
You will have to modify your power steering bracket. Basically take a grinder and grind away at it so that the alternator fits... make sure you dont grind away the hole where the peg from the tensioner pulley sits... that would be bad.
as far as wiring theres 2 plugs. one is D shaped... that one stays the same except for the white wite with black stripe. On the other harness you cut the two thick black wires with the orange stripe, splice them together with a ring terminal, and attach them to the charging post on the new 3G alternator. Take the white and black wire and put a spade terminal onto it, and attach it to the single plug (also known as the stator terminal plug)... and thats it. If you want, you can transfer over your old pulley to the new alternator... I just got a gatorback belt that was 1/2" bigger than stock from autozone for $20... at idle my voltage never drops before 16V and never goes over. With EVERYTHING ON I never get below 14... and with my optima yellow top battery, when the car gets turned off it has a nice 12.8 charge in it.
One of the best mods done yet!
You will have to modify your power steering bracket. Basically take a grinder and grind away at it so that the alternator fits... make sure you dont grind away the hole where the peg from the tensioner pulley sits... that would be bad.
as far as wiring theres 2 plugs. one is D shaped... that one stays the same except for the white wite with black stripe. On the other harness you cut the two thick black wires with the orange stripe, splice them together with a ring terminal, and attach them to the charging post on the new 3G alternator. Take the white and black wire and put a spade terminal onto it, and attach it to the single plug (also known as the stator terminal plug)... and thats it. If you want, you can transfer over your old pulley to the new alternator... I just got a gatorback belt that was 1/2" bigger than stock from autozone for $20... at idle my voltage never drops before 16V and never goes over. With EVERYTHING ON I never get below 14... and with my optima yellow top battery, when the car gets turned off it has a nice 12.8 charge in it.
One of the best mods done yet!
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