Alternator

[Tiara_Austin]

Hi all! It seems that i haave a huge problem with my alternator and it's electrical system. It's a long story and it started for about 3-4 years ago. The original alternator needed to be changed out, and it's normal i thinck after more than 10 years and close to 150000 miles. I changed it with an 130 amp alternator from Unipoint. The new alternator works fine for about 6 months, but then it's seems to go down in amp production and it ends up dead after a while. I got an new one but after a year, the same happend.

I bought me an new one installed it and this third one also run god and normal for almost an year, but right before this christmas i died, i got it checked at an auto part store, but the only thing they could tell me, was that my alternator was dead. So nr 4 goes in, a brand new 130 amp alternator from Unipoint and a set of new batteries.

It seems to run good and i conected an digital voltmeter inside my truck so that i can always have an control on the voltage. For the first 10-20 miles it was normal, 14.2 v output . Sudenly the voltage drops to 11,9 and the alternator seems not to work again. I stopped and started to check my conections while the engine was running. The output wire and the 4 smal wires that controls the regulator. When i did that, suddenly the alternator starts up again and 14.2-3 output on voltmeter. It was good for about 5 min, it died again. So i thought it was an problem whith the plug that holds 3 of the smal wires. I cut it of and made me an new one but the alternator was still working only in short periodes. Then i did some readings from the 3 wires which is called A S I. I started with the I wire, it's reading was 14.3 when the alternator works fine and 11.5-9 when it dont. So i thought i had an solution on my problem so i made me an new wire that repleaced the one from the starting switch. Everything run's good, 13.9 to 14.2-3

I was happy and thought this was it but .... after about 3 weeks, suddenly my voltage meter show me an voltage as high as 18, oh my god what is this..... I took my fot of the trotle controller and the voltage drops back to normal again, i stopped and pushed the rpm a bit and the voltage runs up, more rpm gave me higher voltage. I left my car and started to write this post. This forum have helped me a lot with other problems and i realy hope that some of you have an solution on this problem to

thanks anyway
Terje
Norway

[arthurgoboom]

Does yours have the external voltage regulator, or is it internal to the alternator? This sounds like regulator issues to me...

[cdnsarguy]

93 should have internal Vreg.......

TA PM me your email.......... I can forward a test for over voltage and do some follow up with you on this problem.......

Try this small test......... first record the base voltage of the batteries.


l KEY ON, engine running, blower motor on high and headlamps on high beams.

l Increase engine speed to 2000 rpm and check voltage reading.
Voltage reading is 0.5 volts above base voltage
The charging system is operating normally.
Voltmeter reading continues to rise above base voltage
PERFORM the «Over Voltage Tests» in this section.
Voltmeter reading is less than 0.5 volts above base voltage
PERFORM the «Under Voltage Tests» in this section.

[Tiara_Austin]

hi and ty for replying....
Yes it is an internal regulator and here is some small test's i have done since i got the issue.
1. Voltage at batteries is 12.2 and 12.1
2. At idle (700 rpm) voltage drops to 11.7-8 ???
3. At 2000 rpm i go as high as 17.5 - 17.8 v
conclution out of this tells me: higher rpm, more voltage

[farmfuel]

I did a 130 alternator w/ internal regulator swap on my 89 with V-belts. Here's the way I wired it in:

I took the "A" wire to the battery + post. The "S" wire pluged back into the alternator (maybe this is the field wire??? Not sure, don't care) After that, the "I" wire is running to my key on current- as opposed to constant current, like the "A" wire.

My charge wire is a 4 gauge wire running from the alt. post to the solenoid, with a 175 amp inline fuse that I got from the stereo shop. I am also running a 8 gauge ground wire from the back of the alternator to the fender ground next to the solenoid.

I'm sorry to hear of your troubles, but my thinking is- if you remove all of your factory ford wiring, and wire it yourself, (like above); the only thing it could be is a bad alt/reg from your shop. Around here, if I buy a remanufactured product from an auto parts store, I give them the three strike rule. If the third unit that I got from them fails, I get my money back for the unit, plus the core charge. I take my business somewhere else, and try to steer clear of electrical parts bought online.

[Tiara_Austin]

I have now run the tests i got from "cdnsarguy". And the results are as following.

1. There is no difference in voltage from the starter solenoid and the regulators A screw. Both on 12.6

2. Second test I did was difference in voltage at A and F screw on the regulator with ignition off. A screw has an voltage at 12.6 and F screw is at 0.

Does this mean that my regulator is broken? As I understand from the papers I got, it says so.

Since this is alt nr 4 from Unipoint and al of them go down after a while, what can make an alt to be damaged? Is there anything I should do to prevent another shutdown on alt?

Can I do any damage to the alt or anything else by using my car until I get an regulator replacement?

Greetings and ty
Terje

[cdnsarguy]

Just checked with the guys at the shop....... were thinking the damage was done before you repaired the wires...... consider getting a new regulator and brush pack....

check the slip rings for condition....... One other question are these NEW alternators or rebuilt. If rebuilt the armature has probably been turned and may be too small.

Will check in tonight......

[Tiara_Austin]

Hi and ty! The alternartor is new, not rebuilt. I have ordered a new regulator, hope that will do it. It will be here tomorrow and i will also do the tests i got when the new regulator is in place.

[Tiara_Austin]

uppdate.... changed the regulator today, nothing happend, still 11.8-9 v idle and rising up to 16-17 v when at 1800 rpm

[cdnsarguy]

That sucks..no change.

I will dig deeper tomorrow and see where the problem is......... still have to test mine yet, but its.. -30*F today.. without windchill. Will be busy in the morning, but will try to find some answers after lunch.

[Tiara_Austin]

Yes it realy do same here -25 degres below here so it's hard to be outside doing any repair.