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rhersh
User
Nov 10, 2014, 1:58 PM
Post #1 of 8
(2130 views)
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charging system
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My daughters 1990 Mercury Sable 3.0 150000 miles, is having charging issues. I am on my 4th used alternator and had this one checked before I put it in the car, it tested good at an electrical shop that specializes in rebuilding alter. starters and so on.
My problem is that when I put it on the car and test it with a multimeter it only showed putting out 12.7 volts when I turned on all acc's. it dropped to 12.5 and still dropping when I remove the meter. I am sure this car has an external voltage regulator and was wondering if this could be the problem and if so how I can test it. Any other info. on what this problem could be would be greatly appreciated. Thank you for your time
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Nov 10, 2014, 3:13 PM
Post #2 of 8
(2116 views)
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Re: charging system
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? With those results for voltages it's doing something but no where near enough. IMO regulator possible but sorry my look ups weren't showing what I was after for this.
A more common reason for testing fine off car and not on car with this generation was the plug and wires you plug in to got too hot and melted up. Couldn't find those new just now.
Sorry for some mixed info but plug that was so common to fail looked like this if the dang pics show.........
Those if that type could be the trouble or any type of anything that you plug in. Find that external regulator and its plug too. Sorry - info down right now that I could believe and showed a regulator like that used lots older than this car.
Test you would ground the "F" (field) even better if just with an incandescent test light to it and volts should spike up but just test if you try for a second while watching volts or let your rebuilder test it on car for you not off car when it does test fine,
T
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rhersh
User
Nov 10, 2014, 4:02 PM
Post #3 of 8
(2108 views)
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Re: charging system
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Are you saying to ground the F-Field with the test light while having the meter hooked to the battery to see if voltage spikes? If the voltage spiked would that say that the voltage regulator is bad? And I assume this is with the car running.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Nov 10, 2014, 11:07 PM
Post #4 of 8
(2087 views)
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Re: charging system
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I'm failing again at good pictures of what I was thinking and since info is lacking please let your person just test it on car.
YES - with engine running. If you ground a field "F" terminal alternator will/should put out the max it could and voltage could spike way over what items in the vehicle could handle so using a low watt test light acts as a momentary voltage regulator such that a wild and damaging spike is less likely. There's a lot of risk here doing this wrong and I could find exact marked parts for the set up you should have so default to get help which should be quick and right while you wait.
This is the best I could find for now on what I meant in a diagram - not your exact set up TMK. Some others say in English with an arrow to "test here" right on them!
This was the idea if that shows dag nabbit!
The concept is the filament of the light bulb would be the amount of grounding and limited to that. Under load that would go low with assorted unknown probably watts of assorted test light's bulb. A hard grounding would/should spike as said but that can't stay in that mode or will burn things up is the problem and risk.
You have gone thru used alternators which are always a gamble and still say the connections are the issue with your results of just voltage and how much it dropped with items turned on. That really should have dropped a lot more with like headlights, blower for heater, rear window defroster on would not be close to showing it's charging. Pretty much if you just see voltage below 12.6 with it running it isn't charging. 11. (point) something volts it plain isn't and would continue to decline.
Again, I think this is connecting but not strong enough to allow alternator to keep powering items AND stay within the output range the items need and for it to charge battery as needed once started and run those assorted items off the alternator NOT just what's left in the battery which is really done once engine is running and alternator is your power source.
For now look at condition of the plugs for damage. New or rebuilt alternators for this suggested ALWAYS replace the plug with a new pig-tail and with external regulator just do that too for warranty if nothing else.
This is lacking triggering the alternator to work on car not the other ways of failure like overcharging or shorting out getting so hot it kills charge and overheats alternators up to dead shorts and wiring troubles you don't need and avoid causing them. They can happen alone without your help.
Again, again, again - these plugs can only take so much on about this vintage Fords. Think of it like some common household item that you plug in and remove all the time you wear out the outlet and or the item - say a vacuum cleaner's plug that gets moved all the time type deal. Only so much and the connections are weak to inoperable. Same with things on a car. You are using used parts so not hitting on the weak link is what I'm near sure is happening but not there or would be obvious to me.
Other note: If looking around and the prices for this stuff new was correct this is hardly worth going used for IMO. It's old and unless you can pick your own used parts off a car finding identical stuff possibly just replaced and vehicle junked for some other reason used isn't worth it yet. At some point you have to when new isn't available fast or a real pest to find,
T
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Hammer Time
Ultimate Carjunky
/ Moderator
Nov 11, 2014, 3:13 AM
Post #5 of 8
(2079 views)
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Re: charging system
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Unless you still have one of these in your tool box
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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rhersh
User
Nov 11, 2014, 6:54 AM
Post #6 of 8
(2064 views)
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Re: charging system
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Thank you Tom, and Hammer thanks for the pic., at least now I know what the tabs are on the regulator. The next chance I get I will check these ideas out. We just had an ice storm last night so may take awhile before I get back to it. Will let you know when I get the chance.
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rhersh
User
Nov 13, 2014, 12:09 PM
Post #7 of 8
(2017 views)
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Re: charging system
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Thanks Tom for the info.. I ended up right clicking on the second pic. that you posted and it took me to the site that the pic. came from. There I found all kinds of test to do for the reg. and other things, but from there I did the test for the vol. reg. and found it to be bad. Replaced the reg. and all is fine now. So again thank you.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Nov 13, 2014, 1:20 PM
Post #8 of 8
(2016 views)
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Re: charging system
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Good show. No problem admitting I get pics from that Autozone site or others. As said wasn't believing some info and any can, show things plain wrong like that.
Glad it's fixed and you didn't blow anything up making it worse,
Tom
(I'll lock this thread up as solved for archives and so you don't get spammed to all hell forever. Ask any moderator to re-open it if YOU wish)
(This post was edited by Tom Greenleaf on Nov 13, 2014, 1:23 PM)
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