Please tell me this is an alternator problem!

[MustangMatt1966]

Ok, so yeah, i have been looking for an excuse to get a new alternator, but my dad for some odd reason thinks mine is fine. I have one of those controlling dads that doesnt want their 18 year old son to have a well equiped stang. So anyways, my idle has been acting weird for some time now, and just tonight when i got home, i decided to experiment in the garage. The car has the original alternator i think. I have a tach, seperate shift light, electric fan and a couple other things. So i was idling in the garage and turned on the headlights, wich also promts the tach light to turn on, and my idle drops, to the point where the car is barely idling, then i turn on the electric fan, and the idle drops even lower, and then the car stalls. From what i think, the alternator just doesnt have enough juice to run all the crap and is drawing from the firiing power or something. Can someone please explain this to me..........
thanks,
Matt

 

[mxmattd]

Unfortunately I don't have any answers for you, but my name is matt, i'm 18, i have a 66 V8 coupe, and i'm having alternator problems as well. Its like looking in a mirror.

except that my car won't run 13's.

 

[2nd Mustang]

Amperage draw is more than the alternator is putting out? Or maybe a bad battery that is shunting down the charge, or maybe a shorted (grounded) electrical circuit draining the charge, or maybe a full moon? Electrical gremlins suck. But seriously, if it charges okay with the other accessories off, it sounds like the alternator can't keep up with the demands of your electrical mods.

 

[DukeGnarley]

let the car idle without any accessories running, get a multi meter and check the battery voltage at the terminals and see what she reads. then turn on all the power stuff and check again. theoretically, the two voltages should be in the same ballpark, if not, i would think alternator or maybe voltage regulator?. if it's one paticular accessory that's screwing things up, then you could have a short.

 

[12sec67]

let the car idle without any accessories running, get a multi meter and check the battery voltage at the terminals and see what she reads. then turn on all the power stuff and check again. theoretically, the two voltages should be in the same ballpark, if not, i would think alternator or maybe voltage regulator?. if it's one paticular accessory that's screwing things up, then you could have a short.

i'm going with the voltage regulator.

you could take it off and have it tested along with the alternator and battery if all else fails.

good luck
Rich

 

[D.Hearne]

One easy way to tell if the alternator isn't putting out is to start the engine , then remove the positive terminal from the battery. If the engine dies, the alternator isn't working. But It also sounds to me like your alternator is also not keeping up with electrical demands, time for one with a higher output.I have the same problem with a V8 Ranger, But I'm thinking on dual alternators.

 

[mustangman70]

Time for a 160 amp powermaster alternater

 

[ratio411]

I think your alt is putting out. It may be overloaded, but I think that is another issue.
You have a problem, but I would look elsewhere...
Dave

 

[Gummi Bear]

It definitely sounds like you have way more accesory power draw than the stock 35A alternator can keep up with. Since the alternator can't keep up with everything else, it also can't keep up with the items critical to keeping your car running.

First - build a proper auxilliary power system, with everything fused on it's own circuit, and triggered by relays. Learn to do it right, if you half-ass it, you will burn your car down.


For an alternator look into a 3G Ford alternator. Available at any parts store for around $100 with a lifetime warranty. 3G stands for 3rd generation. What is on your car presently is a 1G small case. An alternator for a 1994 Mustang with a 5.0 is a direct bolt in. The wiring will need some upgrades, and for that, PM me and I'll give you complete instructions on what to do.

The 3G alternator is rated for 130A, but can put out as much as 160A at full throttle. It is internally regulated, so you can eliminate your present regulator, and a rat's nest of wire associated with it. It also charges at idle, where the 1G doesn't charge until it hits between 1000 and 1200 RPM.

I'd suggest to you that you upgrade all of your charging and battery cables at this time. Look for the largest that you can find, and something with brass or aluminum terminals will charge much better than the lead ones that come stock. Make sure that all of your cable connections are clean and conducting to their fullest potential, dirty and corroded contact surfaces will not conduct.

Having your battery and alternator tested is not a bad idea, but make sure that the nincompoop doing the testing knows what he's doing. I've seen them botch it more than once.

 

[WORTH]

Do you know the engine is dying from low voltage, or is it dying because your putting a load on the alternator and slowing the engine down? It's normal for the engine to slow down when you put a load on it. You better get a meter and find out what it is doeing before you wastemoney on parts you don't need.

 

[MustangMatt1966]

k, so i am definately starting to lean toward overloading the alternator. I am wanting to get this fixed because i also have heat starter schock, so on a hoty day, when i am running my accessories, the idle goes down and the car dies, then i freaking have trouble getting to starter to turn due to the long tube headers...so i want to get this problem fixed as soon as possible, thanks everyone for your help and suggestions U GUYS ROCK
Matt