73 F100 240 I6...

OK, I have a dead alternator, but I want to know why??

Just in case it isn't coincedental.

OK I have driven the truck more than I have since I got it and rebuilt the engine. It has sat for days, and even a couple weeks at the tme and never had the first trouble starting up, always peppy.

Everything in the engine compartment (including most wiring) is new since the rebuild in the August time frame; with the exception of the alternator, battery and voltage regulator. Meaning new Starter and remote selenoid close to the battery as well.

I have also recently wired up a very simple stereo system which is one reason I am concerned that there is a problem becuase it has acted funny the past couple of days. The system consists of a 100 watt rockford fosgate amp behind my seat connected to door speakers. There is a fused link directly to the battery terminal and the ground is about a foot long bolted directly to the cab of the truck with the starlike washers that have dug into the metal (and I did remmeber to scrape some paint off the contacting surface for the ground). The remote-on lead was well spliced and even soldered into hot radio wire. The amp is only hooked into a portable CD player I am using since I wanted to keep the original AM radio in place.

I noticed the other day that if the lights were not on the sound sould cut out intermittently and if I turnied the lights on, the sound would never give me a problem.

Then today I noticed the truck didn't turn over wuite as peppily as it usually does, but I thought it may have also ben because of the colder weather ofter the rain last night.

Well I am about a 2 miles from work this morning and the sound quit working altogether with the lights on, and with the CD player still playing of course.

Then about a mile later the truck dies and no more juice. I just put a new battery in it, becasue I wasn't in much of a position to do much else. With the truck running I removed the negative cable and sure it enough it dies.

In adition to the stero problems, my blower motor whnes and makes some noise until it gets warmed up.

My question is, did the stereo or maybe even extra drain on the blower motor ruin my alternator? Or was this coincidental???

I'm not sure what the amperage is on my alternator is, but I would think that a 100 watt amp wouldn't hurt anything. it appears that 61 amp is the standard new, but I know the alternator in my tbird is 110 amps.... Seems that 61 amp is kinda whimpy...

Am I overpowering it???

Thank guys

 

Moved to Electrical forum.

 

Take the alternator and get it checked at the store, or just buy a new one. Try not to do the "pull the cable off while running" thing, because if there is a problem with the charging system, you could burn out your new amp, electronic ignition, and who knows what else. Get a multimeter, and check the voltage with the truck off at the battery. Then check the voltage at the battery with the truck running. If the voltage is higher with the truck running, you know the charging system is working. Look for around 14.5 volts when running.

I am not sure you have the trigger wire for the amp wired in the right place, since it's cutting on and off with the lights. Find a better place, or rig a switch hooked to a hot wire to turn it on and off till you get all this figured out.

 

An easy test is to measure the voltage at the field terminal of the alternator. If you have around 11 volts and the battery is 12.6 or lower, the alternator is bad. No field voltage is a bad regulator or a wiring problem.

 

Ok, it seems as though the regulator was bad...

I replaced it befoer the alternator, and now the alternator charges, but now my interior lights won't come on, nor will my afermarket tach.....

This is getting on my nerves!

 

"pull the cable off while running" thing, because if there is a problem with the charging system"

yes never pull a battery cable off with engine running to test an alternator Ever, this can send a voltage spike of over 100 volts through your system. Always use a volt / amp meter to check it properly.

 

Check your fuses. Maybe you had the door open when you where testing and popped the light fuse. Cross your fingers when checking the tach. Maybe you tapped it into the same fuse that popped.