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Alternator charging/voltage regulators blowing

Tiny
MATTHEWBOUX
  • MEMBER
  • 2008 FORD EXPLORER
  • 4.6L
  • V8
  • 4WD
  • AUTOMATIC
  • 205,000 MILES
Hello,

For about a year and a half now I have had a problem with my charging system.

I have been through 6 alternators.

Seem to keep blowing the voltage regulators on them.

The charging system is fine for a few weeks then I get a battery light and the charging system stops working entirely (have to replace alternator) or it becomes intermittent (off/on) and will throw the system into limp mode, or the voltage spikes
upwards of 16.50 to 17 volts on my gauge and throws the system into limp mode.

No codes, just a battery light.

This issue is driving me absolutely insane and is costing me $280.00 every time to change the alternator.

I have tried 3 different brands and the same thing keeps happening.

Please help.
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Friday, January 31st, 2020 AT 9:53 AM

21 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good afternoon,

These alternators should be warranty. $280.00 per time? Where are you buying these alternators?

https://www.2carpros.com/articles/how-to-check-a-car-alternator

What I am afraid of is since the voltage went so high, it may have damaged the ECM. That is what turns the regulator on and off.

Roy

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Friday, January 31st, 2020 AT 12:05 PM
Tiny
MATTHEWBOUX
  • MEMBER
  • 24 POSTS
The alternators I use are factory approved re-manufactured units by Wilson. From a friend that works in the automotive parts store.

I would like to add the voltage spikes only happen at a higher rev (over 4,000 to 6,000) and then go away. Sometimes normal operation resumes or I lose all charging all together. I have a new battery, no bad cells, it has been tested multiple times.

When I change the alternator the issues go away for a week to several months. How can I test the ECM?

I have tested the ECM's 12 volt supply wire to alternator field wire and it has 12 volts.

I have checked for fuses but am not finding any listings regarding an ANL fuse or likewise or even soldered in units.
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Friday, January 31st, 2020 AT 12:53 PM
Tiny
ASEMASTER6371
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It is not a fuse at all. It is all about the control of the regulator.

I would replace the ECM and the alternator together.

Roy
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Friday, January 31st, 2020 AT 12:59 PM
Tiny
MATTHEWBOUX
  • MEMBER
  • 24 POSTS
The ECM is delivering a consistent 12 volts to the alternator so I don't see how the ECM could be relevant?
Even if I run 12 volts from battery to alternator field wire it still will not charge.
If I change the alternator the issue goes away for a time, only to re appear eventually.
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Friday, January 31st, 2020 AT 1:08 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
The ECM controls turning on and off the regulator. It is very important in the charging system. Do not dismiss the ECM as the issue.

Applying 12 volts to the field is not a way of testing the alternator at all.

If that was the case, then the factory would have run a jumper from the big red wire to that terminal.

Roy
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Friday, January 31st, 2020 AT 2:21 PM
Tiny
MATTHEWBOUX
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  • 24 POSTS
Okay Roy, I have an ECM module on order programmed for my VIN.

I will change the ECM and (replacement) alternator at the same time when it arrives.

Will report back with the results of this.

Thanks for your time.
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Friday, January 31st, 2020 AT 2:45 PM
Tiny
ASEMASTER6371
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You are welcome.

Always glad to help.

Roy
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Friday, January 31st, 2020 AT 3:19 PM
Tiny
MATTHEWBOUX
  • MEMBER
  • 24 POSTS
Okay, I have the new alternator and brand new ECM unit from Flagship1 which is programmed for my VIN and has all the current updates.

Before I install these two new items, is there anything I should do or any procedures to follow?

And, worse case scenario, this does not solve my issues what else could this issue be caused by in the system?
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Thursday, March 12th, 2020 AT 3:29 PM
Tiny
ASEMASTER6371
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One step at a time.

Install them and let us see what happens.

Roy
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Thursday, March 12th, 2020 AT 3:32 PM
Tiny
MATTHEWBOUX
  • MEMBER
  • 24 POSTS
Okay, new alternator and new ECM installed.

Now I have a no start issue? Will not start at all.

I guess the PATS system has disabled my starter etc. I now have to go through the process of having a scan tool to reset/pair the original keys to the new ECM unit?
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Friday, March 13th, 2020 AT 5:32 PM
Tiny
ASEMASTER6371
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Yep. You have security issues

Do you have the IDS scan tool?

Roy
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Friday, March 13th, 2020 AT 8:58 PM
Tiny
MATTHEWBOUX
  • MEMBER
  • 24 POSTS
I do not have the IDS scan tool.

My dad has a few scan tools but they do not support Ford PATS.
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Friday, March 13th, 2020 AT 9:06 PM
Tiny
ASEMASTER6371
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I would call a locksmith and have him come to you and program the key.

Roy
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Friday, March 13th, 2020 AT 9:08 PM
Tiny
MATTHEWBOUX
  • MEMBER
  • 24 POSTS
The ECM needs to have the PATS system reset with a scan tool with key in on position to relearn the keys correct?

A mobile locksmith will have this type of scan tool?

Or is this a dealer only type scenario?
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Friday, March 13th, 2020 AT 9:23 PM
Tiny
ASEMASTER6371
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Yes, a locksmith does have the correct scan tool.

Roy
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Saturday, March 14th, 2020 AT 3:26 PM
Tiny
MATTHEWBOUX
  • MEMBER
  • 24 POSTS
Okay.
Locksmith came and did a parameter reset of the PATS.

Both my keys now work. Vehicle starts with new ECM and new alternator.

The new ECM is throwing codes that were not present before.
- PO135
- PO141
- PO155
- PO161
- PO443

The charging system is working. When cold voltage reading is 14.6 or so, and as it warms up to operation temperature it slowly drops down to 13.8 or so and holds.

I did a 1 hour test drive and have had no other issues other then the trouble codes mentions and charging system seems to be alright.

I guess time will tell.

Any other suggestions or testing that I should be doing since these new items have been installed?
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Saturday, March 14th, 2020 AT 5:27 PM
Tiny
ASEMASTER6371
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Okay, I doubt that all the O2 sensors circuits have failed at once.

Verify your connections at the new ECM.

Roy
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Saturday, March 14th, 2020 AT 5:51 PM
Tiny
MATTHEWBOUX
  • MEMBER
  • 24 POSTS
How do I verify the connections?

They ECM has 3 big plug in ports from wire harness, all 3 have a lever latck/lock system.

The O2 sensors have never been done on this vehicle over its entire life.
So in my mind, it could be possible that the old ECM was faulty and not detecting any of these issues as well as creating issues with the charging system. Causing all of these failed alternators since the initial voltage spike that happened when the first alternator initially went out.
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Saturday, March 14th, 2020 AT 6:31 PM
Tiny
ASEMASTER6371
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Okay, check the connectors again. Make sure that all the pins are seated and nor backing out when the connectors are latched.

Roy
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Saturday, March 14th, 2020 AT 6:42 PM
Tiny
MATTHEWBOUX
  • MEMBER
  • 24 POSTS
Have been driving the vehicle for just about a week now. No issues.

Today was driving down the road at about 60 kmh. Lost all accelerator pedal control, no gas pedal response at all. Vehicle was just idling and coasting.

Pulled over, pressed the gas pedal to the floor multiple times, no response at all. Wrench light came on dash, engine light on. No codes were given (SCT tuner on board so can check on the fly )

Shut off, restart. Everything working again.

Get maybe 300 ft down the road, same thing. No gas pedal response at all. Kit idling and coasting. Kept happening after 300 - 500 ft of driving.

Had to shut off and restart maybe 7 times to limp it home.

Still no codes, kit wrench light and engine light on dash.

Any suggestions Roy?
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Monday, March 23rd, 2020 AT 10:46 PM

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