VOLTAGE!

HazN

HazN

True Classic
1986 Bertone X1/9
I have noticed a link between a strange occurrence and the voltmeter reading. When the voltmeter reading is horizontal, no problem. Other than that, when it is lower than that, when I used the directional signals, it restarts my radar detector. Obviously, I have a voltage level problem. Keeping an eye on the voltmeter recently, I notice that is rather erratic. It has occasionally dropped to above the red zone while at constant cruise. I has been variable at constant cruise but not dropping so low. Am I looking at a regulator replacement or alternator (Bosch) problem?

Thanks for your input.
 
I would look at the quality of your brown wire connection to your fuse block to be sure that it hasn't overheated in the past. You may need to upgrade the connectors there or even run a second brown wire despite it being a late model.

The alt may need some attention but I would look at the supply side to the fuse block first. I would also look at the output of the alternator using a meter and have your son/wife rev the motor to see the actual voltage behavior.

The regulator and brushes I believe are one unit on this alternator so are an easy replacement with a couple screws (my recollection may be faulty).
 
Last edited:
Wiring integrity is definitely a concern - since basically the problem is that the system cannot respond quickly enough to compensate for the on/off current draw, which is always more taxing than a constant, and more of an issue with connectivity issues. I would also consider running a heavier gauge feed from the alt to the starter, as the factory supplied wire is really undersized.

You may still need a voltage regulator, as a drop in regulated voltage will make the problem more pronounced.

You could of course just move the radar detector to a circuit not related to the directionals ;).....
 
lookforjoe said:
Wiring integrity is definitely a concern - since basically the problem is that the system cannot respond quickly enough to compensate for the on/off current draw, which is always more taxing than a constant, and more of an issue with connectivity issues. I would also consider running a heavier gauge feed from the alt to the starter, as the factory supplied wire is really undersized.

You may still need a voltage regulator, as a drop in regulated voltage will make the problem more pronounced.

You could of course just move the radar detector to a circuit not related to the directionals ;).....
Click to expand...

The detector is not attached to the directionals. I believe it's a symptom of the problem. I have done the brown wire mod and also added an additional ground years ago. It's just that the variation puzzles me since it occurs during constant speed without other demands on the system.
 
I added a secondary 10ga wire from the output lug of my alternator to the starter and it did indeed improve the amount of voltage making it forward to the battery. So you may want to try that. You can route a wire any way convenient as a test. Heck, take a long 10ga wire and run it straight to the battery by taping it to the pass side of the car during a test drive. As a bonus, it will make people wonder what you are up to.

Another idea is to run a new circuit from the battery to an additional 12v outlet, just for outside accessories like a GPS or detector. I believe Tony did this because his fancy new stereo reset frequently when it was tied into the stock wiring. You can use a relay to hook it into a "key on" circuit if you want to avoid accidentally leaving a device on.
 
Drove the car Sunday. Voltmeter starts horizontal, then drops to 40% after 10 miles. Drops to above the red zone when brakes are applied. Put a hand voltmeter on the battery: when started reads 13.75 v and after ten minutes, drops to 13.53 v. Removed the alternator and (after a bit of running around) had it tested at AutoZone. (I felt odd since I was in my Auto Plus work-shirt) The alternator tested OK. According to the workshop manual, the voltage regulator specs are 13.8 v to 14.2 v. I'd be happy with that.

Any ideas?
 
The first question would be how did they test it? What load do they place on it to confirm output? Do they give you a printout?

I would still question whether the alt and/or regulator are up to snuff.
 
I would try replacing the regulator with brushes or at least take them out and inspect them.
 
Is it hot where you are? Check your coolant temperature to make sure what you are experiencing is not related to your cooling fans kicking in. I'm in Austin, TX and even though my cooling systems are in good shape, being stuck in traffic will cause the temperature to climb above 190 where the fans come on. Those fans draw a lot of current and my voltage meter will drop quite a bit until they quit.

As for your radar detector, is it a Passport? If so, they are notoriously sensitive to voltage changes. I pulled mine out of a new car (Ford Focus ST) because it was randomly beeping like crazy from voltage variations. I called Passport and they said "Oh yeah, that happens. You need to send it in and we'll refurbish it - for like $165!!!). Not happening.

Ed
 
also. Do a couple different voltage tests. (at the battery) (at the fuse block) (at the alt).

Sounds like it is charging 13.53 is a charging voltage (though a touch low) should be enough to keep the battery mostly charged.
 
Colltech said:
Is it hot where you are? Check your coolant temperature to make sure what you are experiencing is not related to your cooling fans kicking in. I'm in Austin, TX and even though my cooling systems are in good shape, being stuck in traffic will cause the temperature to climb above 190 where the fans come on. Those fans draw a lot of current and my voltage meter will drop quite a bit until they quit.

As for your radar detector, is it a Passport? If so, they are notoriously sensitive to voltage changes. I pulled mine out of a new car (Ford Focus ST) because it was randomly beeping like crazy from voltage variations. I called Passport and they said "Oh yeah, that happens. You need to send it in and we'll refurbish it - for like $165!!!). Not happening.

Ed
Click to expand...
Nope. Temperature in the low 80's. The detector is an old Uniden. I've not had the current behavior until 2 years ago. Only recently has the voltmeter become erratic.

As to the rest of the current comments, yes. Further investigation is forthcoming.
 
I had the alternator retested by the company I work for. It's a more sophisticated machine. The unit put out 16.2 v. So, I guess it's not a big buck problem. I check the eyelet that goes to the main stud and It was a rather corroded. I cleaned it up. The stud is bright metal. I will also inspect the connection at the starter. One of my coworkers mentioned that it might be a slipping belt. Before I took it apart, there was about 1 cm deflection. Considering the size of the belt, he may be right. The alternator belt was a bit scuzzy. I looked up when I last replaced them: 2014. That was about when the initial radar detector symptoms began. Even if I made a mountain out of a mole hill, I got a chance to do some "preventive" maintenance. I'll have it all back together next week and will keep you posted.
 
Haz,

It really could be your belt mine is doing that as well. I looked at the belt and it looks like its getting a sheen on it which I need to get hot and replace it. If that belt is slipping than it could be causing al sorts of voltage drops.

-Brian
 
I believe the regulator was bypassed. I think that was the way the machine was set up.
 
So, why not get a new regulator? 1cm deflection is not a large amount - you would hear it screeching/squealing if it were slipping....
 
don't be to sure of that. Shortly after getting my yellow car I have a charge fail. (turned out the belt went from snug to supper lose with no noise)

and my 79 without the belt shields would drop the Alt when it was raining (due to belt slippage) and it also never made any noise.
 
Yes! Our ongoing experiences come to light! I wont know anything until it's back together. Watch this space for further developments.
 
Well it took me awhile. Two jobs and other commitments...well you get the idea. I put it all back together and gave it a test drive to auto parts store where I work (job #2, 22 mile trip) Everything seemed perfect. On the way back, back to the original problem. It seemed that, while I had maintainer on the battery, it was fully charged. Through use the alternator .was not able to re-top off the battery. The regulator is now the most obvious problem. The photos I've included show the
installation and the result

There it is!
upload_2017-11-12_20-12-41.jpeg


Old and new compared.
upload_2017-11-12_20-14-27.jpeg


Dash result. This was a limited run at idle.
 

Attachments

  • upload_2017-11-12_20-16-6.jpeg
    upload_2017-11-12_20-16-6.jpeg
    341 KB · Views: 68
You must log in or register to reply here.
Back
Top