Can't find the problem. What would you do? Replace VR?

[tirwin]

Ok... I need some of you "Click and Clack" types to help me with this puzzler.

I've been chasing a problem for months and I cannot find the smoking gun.

I'll try to recap the events as best I can.

About 9 months ago (last spring) I noticed the headlights would not come on full power on the way home one night. Brights were fine. Just the dims. Dash lights flickered a bit on the drive home. Put the battery (Optima Red Top) on the battery minder. Problem went away. Also JWest headlight relays are installed. Turn signal stalk was replaced 2 years ago.

Some time later, same problem. Tried swapping relays. No affect.
Battery minder again, problem went away.

Series of little things happened that I didn't think we're related and the time but now appear to be.

- stereo shut itself off
- parking brake light randomly came on (parking brake NOT on)

These things were random over the course of weeks and months. It wasn't until I read another thread on here that it occurred to me they could be related.

And then my CDI box failed.

After I replaced the CDI and coil I backed the car out of the garage at night, shut the garage door and turned on the headlights. The light output varied (surged) with RPMs.

So I'm thinking the VR is shot. Pull the alternator and discover I have a Valeo and not the original Bosch. Great. Didn't look very old and I have no record of when it was replaced. Took the alternator to an old-school rebuilder recommended by a local Pelican and explain what's going on. Seems like a great shop but they can't find any problem with alternator or VR and suggest maybe it's the battery.

Take the battery to the local FLAPS and get it tested. They say it tests clean. I bought a new yellow top because the red was 2008 vintage and I figure it's just time.

So... No smoking gun found. Wiring looks good. Grounds look good. I just can't seem to find anything wrong.

Before I put the alternator back in I'm wondering if I should just replace the VR anyway for peace of mind?

What would you guys do next? I'm stumped...

[Vereeken]

Have you installed and tested the yellow top?

I had last year a problem with the Varley Red top in a race car. You could charge it, it would hold charge but during the race it would short cicruit. Everyone told me alternator, but I replaced the battery and all was well. The battery seller claimed that the battery was fine and even suggested that buying a new battery was a waste of money....

I have the impression that batteries are not very transparent when it comes to internal problems...I beleive this is one of the reasons why you see so much effort in hybrid and electrical cars put into wiring each bank of batteries and cells independently...

Give it a try.

[zippy_gg]

I would not put too much weigh on having the battery tested at a chain store. When I took my battery to Auto Zone they put it on a charger for a couple of hours and it "tested" OK because it kept the charge.
I told them that the fully charged battery would go flat after a few days. They "tested" again and found the battery would not charge past 52%, no matter how long they kept it on the charger (I had to insist they let it on overnight).
My battery was effectively dead...

[pors1968]

Did you check the connection on the starter the red wire that goes to the alternator.

[pete3799]

I don't see anywhere in your post that you've monitored the voltage out put.

[MBAtarga]

^ +1 - but I bet it's your VR.

Hook up a DVM to your cigarette lighter jack - or somewhere else convenient that can be monitored from the driver position. I've used an old cell phone plug modified with wires that hand out for easy access.1

[tirwin]

zippy,

Roger that. I guess I was just hoping for that smoking gun. Would a bad battery throw an intermittent voltage spike?

pors1968,

Good call. I will double-check.

Pete,

Good catch. I posted some numbers in another thread. I'll go dig them up. Voltage with car off, idle and at 2k RPM was fine. I could never catch a spike in the act but I had many of the same symptoms as a bad VR.

[LJ851]

The voltage reg can fail intermittently, mine did. I would rig a temporary volt meter in the interior so you can watch what is happening when you drive.

[JAR0023]

2nd the cheap voltmeter so you can monitor what's going on. The one below worked well for me. Voltage at the lighter socket may be a little less than at the battery but I found the unit to at least be consistent.

I had the tell tale signs of a spike once. Radio blinked off, seat belt light came on. I bought a gauge and started monitoring voltage output. Took another six months to show a spike. One thing I noticed in hind sight was the old alternator/regulator would show wild swings. 12.5 - 14.0 - 13.0 etc. Constant fluctuations of a volt or more. Once I bit the bullet and replaced the alternator/regulator with a new Bosch unit I found that voltage fluctuations would be in tenths or hundreths of a volt not whole volts. Yes voltage still varies based on load and output but the wild, constant fluctuations stopped. -J


ETA - When they actually have them in stock Amazon sells new(not reman) Bosch alternators for $250-$300. That's about half what they sell for at most other vendors.

INNOVA 3721 Battery and Charging System Monitor : Amazon.com : Automotive

[tirwin]

Originally Posted by Vereeken

Have you installed and tested the yellow top?

I had last year a problem with the Varley Red top in a race car. You could charge it, it would hold charge but during the race it would short cicruit. Everyone told me alternator, but I replaced the battery and all was well. The battery seller claimed that the battery was fine and even suggested that buying a new battery was a waste of money....

I have the impression that batteries are not very transparent when it comes to internal problems...I beleive this is one of the reasons why you see so much effort in hybrid and electrical cars put into wiring each bank of batteries and cells independently...

Give it a try.

Somehow I missed your post earlier. I was reading from my phone so maybe I missed it.

I just picked up the battery today and haven't had a chance to install it yet. I'm going to get a DVM for the cig lighter as others have suggested. I'm just wondering if I should trust the alternator/VR before putting it back in.

[wwest]

Open the alternator and look for burned insulators, stator winding standoff insulators.

[tirwin]

LJ851 & JAR0023,

I've got that Innova DVM on order. And good to know on the Bosch from Amazon! I might just do that. The guy at the alternator shop did not speak highly of the Valeos which is consistent with just about everything I've read here.

[tirwin]

Originally Posted by wwest

Open the alternator and look for burned insulators, stator winding standoff insulators.

Any idea how to separate the fan from the alternator?

[rusnak]

Just check the battery posts with a multimeter. You should have around 13v. I'd also check and clean your battery connections, the starter motor connections, grounds, etc. If other electrical accessories are going strange, (windows dont work, car won't shut off) then you can have a bad ignition switch.

[JAR0023]

Separating fan from alternator. I took a tip I found in a thread here. There is a circle of 5 or 6mm holes around the hub of the fan. Tap two opposite each other and use screws to press the fan off the alternator shaft. IIRC the size of the holes is such you get a half depth thread. Very easy to tap and still strong enough to press the fan off. -J

[drleah]

Tap gently around the edge with rubber mallet and should drop down enough to get the key out of the shaft.


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[tirwin]

The old battery checked out fine with a multimeter.

The ignition switch and the turn signal stalk were the first things I fixed when I bought the car in 2011. Also added an in-line fuse to the instrument panel circuit.

[NathanR]

Multimeter will not detect bad cell in battery, only the voltage of the good cells. Need to charge battery fully and put on a load bank battery tester.

[NathanR]

I just replaced my VR with whatever is spec'ed for an 87 Carrera. I'm still getting 1/4 to 1/3 volt voltage swings. Is the new VR crap?

[K Sykes]

Did you check all the grounds? Particularly the braided engine to body one underneath?

Wire is pretty cheap, I'd be tempted to replace the one I mentioned and disconnect and celiac all the others. If the shop says the alt is ok, and the batt is holding a charge, I'd re think connections and wires.