Alternator Question

[djcrook73]

Hey all, I have an 03 that I do not drive often. Sometimes not for months. Went to Grab it yesterday and it started right up. Drove it to my Cousin's for dinner and went to go to the store and she would barely turn over. So I said okay the battery's probably had it since it's about 5 years old. Went to go jump it about an hour later and lo and behold it started up without having to jump it no problem. So upon watching the volt gauge while driving it seems to hit at 14 when it first starts and runs for a little bit, but then drops down to just under 13 after it's been running a while. At red lights while stopped with my foot on the brake it dips Under 12 volts. Doesn't really come up to 14 after that no matter what. Seems like if I get on it and the RPMs come up it also dips Down Under 12 volts and doesn't come back up till it's near idle. ( I understand these have a clutch on the pulley could that possibly cause a problem if the clutch is no good?) I've already checked other threads to see if I could find a similar condition and will try checking true voltage with a multimeter and grounding the case tomorrow to see if that helps. It does have underdrive pulleys but the alternator pulley was never changed. And the volts have been pretty consistent until yesterday. And besides that one hiccup where it turned over really slow and wouldn't catch it's Started every other time since. I had a Crown Victoria where I changed out the voltage regulator myself and that cured it but it wasn't behaving the same way. it just flatlined. I'll replace the unit if I have to but my gut's telling me that I may not Need to. Any diagnostic suggestions are greatly appreciated. thanks, Dave.

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[mm svt]

Check for corroded ground connections, especially at alternator and test battery, the voltage regulator is part of the alternator. As far as underdrive pulleys I’m not a fan, if they change the speed of the water pump, alt, a/c or power steering. The dress billetflow or metco are nice for idlers.

[djcrook73]

Check for corroded ground connections, especially at alternator and test battery, the voltage regulator is part of the alternator. As far as underdrive pulleys I’m not a fan, if they change the speed of the water pump, alt, a/c or power steering. The dress billetflow or metco are nice for idlers.It came with the underdrive pulleys and I do not have the originals. I heard they don't really offer anything as far as horsepower gains. The alternator grounds just by contact to the engine correct? I looked last night and the plugs Is tight and the charging or positive wire is good. That was all I could see . If the car sits for more than a month or so the battery does get weak but it's fine once I drive it again. And when you say the regulator is part of the alternator does that mean it's not replaceable without taking the alternator completely apart? I know on my older Crown Victoria it was a replaceable part on the back of the alternator itself. I don't have a problem bringing it to a shop to be rebuilt I just wanted to see if I could do some Diagnostics first to see if that's what it actually needs. I'll mess with it later on today, and thanks for the reply

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[RubberCtyRauder]

put a battery tender (less than $50) on the car when you don't plan to drive it.. these cars eat batteries when they sit..dont ask me why, repeated charging, losing charge will shorten a battery life.

[mm svt]

The regulator isn’t mounted elsewhere is what I was basically saying, Honestly tho is suspect the battery because of how old it is and suggest a battery tender

[djcrook73]

put a battery tender (less than $50) on the car when you don't plan to drive it.. these cars eat batteries when they sit..dont ask me why, repeated charging, losing charge will shorten a battery life.Unfortunately the garage where I store my car has no electrical outlet. But either way I'm figuring the voltage drop doesn't have much to do with the battery itself if the battery is not dead and sucking energy.

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[justbob]

Assuming all cables are good and tight.

I would have the battery load tested next. An alternator can not charge a battery very well with a cell on the way out.

After that I would check the alternator output when cold and also hot.

I would next check voltage at battery when cranking, then again at the starter while cranking and make sure it isn’t too much less than the battery was showing you.

Keep in mind that many cables rot out for a few inches well into the sealed ends and can not be seen unless you cut them open.

Diagnosing weak charging/starting is normally a pretty simple procedure but even I got stumped on my ‘04 F150 awhile back. In my case I was battling two different issues it turned out. My engine was starting to crank slower over a course of months and the battery was iffy on its test. I replaced it and it was MUCH better but still not what I’d call a healthy crank.

The Alternator originally tested on the low end but still good, it even picked up a good half volt after the new battery, so I went ahead and replaced the original 176,000 mile starter that looked like a pile of rust with a new high torque unit. Only slightly better change.. Now I’m stumped. I went ahead and cut the insulation back in a few places and finally found my second issue, nothing but green powder up at the battery end and even more at the starter! You couldn’t see a thing before I cut but I was getting desperate with winter approaching.

A new set of Ford cables and WOW, holy crank and charge action..

Long winded I know, but I’d like to think I’ve been around the block a couple of times and sometimes things aren’t as simple as they should be.. Especially dealing with two problems.

Basically saying these cars are getting older driven regularly or not. Start diagnosing simple and work your way through it. Just keep in mind that some parts simply can not test to their highest efficiency if other parts are holding them back.

And to answer your question, the voltage regulator is easily replaceable but rarely fail. I will take it a step further and warn you now that 80% chance or better that you will receive the wrong one when you order it. Been there.


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[Mr. Man]

Adding to JustBobs post, if I remember correctly, the Marauder alternator has a White pluginski (Motorcraft brand) and a 4g regulator. The Marquis etc. alternators use a different color which escapes me at the moment.

I often find using a terminal cleaner works wonders for slow crank. Easy and cheap good place to start.

[djcrook73]

Assuming all cables are good and tight.

I would have the battery load tested next. An alternator can not charge a battery very well with a cell on the way out.

After that I would check the alternator output when cold and also hot.

I would next check voltage at battery when cranking, then again at the starter while cranking and make sure it isn’t too much less than the battery was showing you.

Keep in mind that many cables rot out for a few inches well into the sealed ends and can not be seen unless you cut them open.

Diagnosing weak charging/starting is normally a pretty simple procedure but even I got stumped on my ‘04 F150 awhile back. In my case I was battling two different issues it turned out. My engine was starting to crank slower over a course of months and the battery was iffy on its test. I replaced it and it was MUCH better but still not what I’d call a healthy crank.

The Alternator originally tested on the low end but still good, it even picked up a good half volt after the new battery, so I went ahead and replaced the original 176,000 mile starter that looked like a pile of rust with a new high torque unit. Only slightly better change.. Now I’m stumped. I went ahead and cut the insulation back in a few places and finally found my second issue, nothing but green powder up at the battery end and even more at the starter! You couldn’t see a thing before I cut but I was getting desperate with winter approaching.

A new set of Ford cables and WOW, holy crank and charge action..

Long winded I know, but I’d like to think I’ve been around the block a couple of times and sometimes things aren’t as simple as they should be.. Especially dealing with two problems.

Basically saying these cars are getting older driven regularly or not. Start diagnosing simple and work your way through it. Just keep in mind that some parts simply can not test to their highest efficiency if other parts are holding them back.

And to answer your question, the voltage regulator is easily replaceable but rarely fail. I will take it a step further and warn you now that 80% chance or better that you will receive the wrong one when you order it. Been there.


Sent from my iPhone using TapatalkThank you.. you just set it up for me like a flowchart. Definitely some useful information for some charging system Diagnostics on any vehicle that I own. I've seen cars where a battery with a dead cell wouldn't allow it to take a jump as it would crank over too slow. I had a slow crank on the old lady's Taurus one time and it ended up being the starter, which I found out after replacing the battery. Longwinded? Nope not at all you just gave me a really great breakdown of how to troubleshoot, so thank you for the reply

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[djcrook73]

I removed battery terminals cleaned them and battery posts. Cleaned the contact for the positive/charging wire going to the top of the alternator. Then I unplugged the three pin plug and took the three pin connectors out of the plug. There looked to be a tiny bit of corrosion inside the pins so I cleaned them out and gave each pin a little squeeze so it would make better contact. Seems like it's okay now. Before I did all of this I didn't realize it but it was acting up more at night with the headlights on then during the day When I didn't need them. I didn't mention this before because I thought it was a separate problem but the car was actually bogging when I would go to stab the throttle, almost like it had a dirty maf. During the daytime I noticed it wasn't really doing it so I checked the volts and it was right about 13.5 till I turned on the headlamps. Then if I stopped with my foot on the brake and held it there for a few it would drop to below 12. So as of right now she's good but the battery is 5 years old so I'm sure it's due for a replacement. I won't be driving it much longer so I will probably do it in the spring. But she cranks right up now with authority and Spins over faster than she was before. Thank you for the replies guys I appreciate it.

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[Turbov6Bryan]

My alternator was doing the same thing for 6 months. Turns out one brush wore too much on the armature. Went to www.car-part.com and that alternator is staying at 13.8 volts and never dips into the 12s with lights on and rolling up the windows

If your interested in a pic of what happened to mine pm me

[johnjamis]

My alternator was doing the same thing for 6 months. Turns out one brush wore too much on the armature. Went to www.car-part.com and that alternator is staying at 13.8 volts and never dips into the 12s with lights on and rolling up the windows

If your interested in a pic of what happened to mine pm me

Did you replace the worn out brush or the whole alternator?

[Turbov6Bryan]

I purchased a used alternator using that site, the seller was 16 miles away and the alternator was 53.00. Then I returned a Buick 60 amp alternator core for 10.00
Total was 43.00

Parts to rebuild mine were going to be over 100 bucks...

If I get 20k out of it I'll be ecstatic!

[johnjamis]

Thanks for the details.