[V8] charging problem/ alternator
Michael Larosa Jr
Mc.Larosa at Sun.COM
Thu Apr 1 08:50:38 EST 2004
Just added this to the knowledge base, but the ascii art didn't
come out too well :( if anybody knows how to fix it, be my guest....
Can we add pics to the knowledge article ?
Michael Larosa Jr wrote:
> The dash light power comes from the battery cable between the pressed clamp
> under your passenger floor and the battery. This means it may be related
> to the dreaded green corrosion in the clamp....
> Check voltage at the alt, the jumpstart post and the battery at idle....
> how close are they ?
> This is my infamous......
> "Gory Details"
> "Troubleshooting and Correcting the dreaded
> 12.5 at the Battery - 13.7 at the Alternator"
> Some Potential Symptoms:
> A) Car starts and runs fine, The dash gage measures a little low, but
> there aren't any numbers on the voltage gage, so you don't really
> notice it's been slowly sitting more and more to the left.....
> B) Every time you run the A/C for an extended time the car won't turn
> over the next time you stop and try to start it again.......
> C) Battery dies for no apparent reason, you jump start it and leave all
> electricals off, because you wan't the battery to charge back up...
> you go to your friendly mechanic... and what does he/she do ? pops the
> hood (Not the back seat) and measures the voltage at the jump start post
> (Which is a direct connect to the alternator) and low and behold the
> output is 13.7..... they announce looks ok to me, maybe you need a new
> battery ? ) $50.- to $100.- bucks (New Battery) and a week later, it
> does it again!!! Doooooohhhhhhhhh!!!!
> Ok, The reason the A/C kills the battery in this instance is when you
> turn on the A/C it turns the electric radiator fan onto hurricane mode
> and it sucks huge amounts of juice from the battery. As it is when
> the electrical system is working properly it barely keeps up to the
> current draw. With the battery barely getting any charge from the alternator
> the battery dies fairly quickly.
> Next Ok, Why does the jump start post measure 13.7 and the battery 12.5 ?
> because the wiring harness for the charging system goes like so:
> Alternator LUG--Cable-- Jump start Post
> *** Pressed Clamp (Your problem area)
> |------- link to dash cluster gage
> The "Pressed Clamp" is a metal tube about 3-4" long in which the battery
> cable is inserted into one end and the alternator cable inserted into
> the other. Then's it's pressed together to form a connection.
> Inside the clamp it get's corroded with the green goo just like your
> battery post's used to when you owned cars where the battery was under
> the hood :-)
> Vehicles that can be affected: 5000/100/200 (likely the V8 as well...)
> Tools Needed:
> Multimeter w/point attachment (Digital preferred)
> Wrench to disconnect battery
> Seriously heavy duty wire cutters to cut battery cable
> Wire Brush
> (4) Chrome hose clamps - (3/8" wide) x 1.5dia" or so
> (with hex head preffered)
> Vise Grips
> Nut Driver w/socket that fits above hose clamps
> Grease or Lithium grease in a spray can will do
> 4" x 4" piece of 1/16" thick rubber - I used old motorcycle tube
> A Printout of these instructions when you start(Seriously)
> (You'll be taking notes.....)
> Sharp Carpenters Knife or New Razor Blades.....something good
> enough to cut the plastic of the battery cable.
> Plastic Electrical tape
> Cold Beer - (Optional)
> Everything else but the Beer is a must, I would read the procedure
> to get an understanding of what's involved and why you want all this
> stuff before you start.
> This way, If you don't have some of the tools, you may be able to
> come up with some suitable substitutes in advance.
> Background.... I've been through this on my wife's 89 100 Avant 125k miles,
> after 2 voltage regulators(1 cheapy $25.-, and a $50.- Bosch), 1 Alternator
> belt, and 2 alternators... (Don't get one from PEP Boy's, mine lasted
> 1 day then died.) and a tremendous amount of cursing.... I decided to
> devote a day to getting to the bottom of this debacle myself.
> _____________________ These spots are for you to write down
> your findings as we explore the problem.
> - Take out the back seat.
> - Open the hood.
> - Front of car on ramps helps, but is not required. Remember to block
> tires and use emergency brake, unless of course you have bad emergency
> brake levers on your rear calipers, then DON'T grab the emergency brake,
> just block the tires :-)
> 1) Measure battery with the car OFF ______________
> Your Target is (12.8 +/- .1)
> -If it's below target, it's not being charged sufficiently or
> the battery is on the way out. How far along is the battery
> in it's projected life span ?
> (Believe it or not I had Sears check the battery with a Bear machine
> of some sort that put a load on it, looked ok, then they charged it
> and gave me a loaner battery for a few day's... whilst mine sat around
> for a few day's to see if it discharged. It didn't, battery was ok)
> Keep reading...
> 2) Measure at Jump start post with car OFF ____________________.
> Your Target (12.8 +/- .2)
> -If battery measures 12.8 and jump start post is at 12.5 or
> less your losing voltage from a bad connection in the
> cable somewhere.... Keep Reading...
> START YOUR ENGINES!!!!, Imagine checkered flag waving... sorry, getting
> off track...
> 3) Grab the multimeter with a pin point end. Measure voltage at the
> jump start post with car RUNNING ___________________.
> Your Target (13.7 +/- .2)
> -If voltage fluctuates wildly, as in more than .5 volts, possible
> regulator. $25.- (Cheap..) to $50.- (Bosch)
> -If voltage less than 13.7, I'd bring it somewhere reputable and have
> the alternator tested. It should put out an easy 13.7, could be as
> easy as new brushes.
> -KEEP READING, you may have more problems.... let's get 'em all
> checked out while where here.
> 4) Measure at Battery with car RUNNING ______________.
> Your Target (13.7 +/- .2)
> -If 3) meets target, but you fail here with less than 13.5,
> keep reading.....
> SHUT THE CAR OFF.
> How'd you do ? you probably failed somewhere or you wouldn't be
> doing this on a sat/sun instead of watching the ball game with
> a frosty beer in hand... :-)
> OK, If you failed and got the dreaded 13.7 Alt - 12.5 Bat, again...
> Keep Reading.....
> The Fun Part...
> Follow the Positive cable from the alternator, it travels across
> the top of the passenger side frame rail into the firewall at the
> passenger side foot well.
> Pull up the carpet on the passenger foot well.
> On the top of the foot well on the right side, you'll see the
> cable coming through.
> Start up the car and poke that positive side pointy end on the
> Multimeter through the cable to check the positive voltage. Check it
> before and after the "Pressed Clamp". The "Pressed Clamp" Looks like
> a 3 - 4" long by maybe .5" thick shrink wrap section on the cable.
> On the wife's car it measured 13.7 on the alternator side and 12.5
> on the battery side.....
> If this is what you get, go grab a frosty out of the fridge, you've
> just figured out the problem :-)
> Whilst drinking said Beer, you get to decide do I go out and buy a
> new cable from Audi for $430.- bucks or do we fix this puppy
> right know with all the Tools/Supplies outlined above ?
> I vote we get it over with and continue.
> - First things first, DISCONNECT THE BATTERY!!!!!!!!!!!
> - Back to the passenger footwell... pull on the cable and see if
> there is any slack.
> - Your gonna need about 3-4 inches.
> - If NOT, there is a clamp near the alternator where the cable is
> bolted in. Unbolt it from there and you'll get the slack.
> Back in the car at the passenger foot well....
> - Once you have the slack, get the Big wire cutters and cut out the
> Dreaded "Pressed Clamp". Making sure to cut as close to the clamp
> as you can.
> - Strip approx 2" of insulation from both sides.
> - Put the 2 Chrome clamps on each cable loosely.
> - Put the 2 cables side by side so that the bare ends both touch
> each other's plastic sheathing. I'd try to make an ASCII drawing
> but the picture would be more confusing than helpful......
> - Here is where we'll need the Nut Driver and the Vise Grips, Line up the
> Chrome clamps on the exposed cable a 1/4 inch or so from the ends.
> So that there is a 1/4 inch of cable showing between the clamp and
> the plastic sheathing. Hopefully this makes sense...
> - Use the Vise Grip to hold the clamp in place, this will also give you
> some leverage when your tightening it with the Nut Driver.
> - When it's tight. Put the Rubber section over the area and loosely clamp
> it on.
> Here's where we get to start the car up and re-measure with the
> multimeter :-) Just make sure the cable is not exposed anywhere!!!
> Don't forget to hook up the battery.....
> I'm going to assume success......
> - Ok, NOW DISCONNECT THE BATTERY!
> - Take the rubber off the cable.
> - I put a piece of cardboard behind the working area of the cable and
> sprayed it heavily with Lithium Grease. It's all I had at the time.
> - I think a good heavy hand applied grease might work better here, glop
> it on thick. This will hopefully slow down the corrosion enough that
> next time it happens, you won't own the car :-)
> Where in the home stretch......
> - Put the rubber section back over the cable and make sure it's big
> enough to cover the whole thing and then some. Secure it with the
> other 2 cable clamps.
> - Wrap nice and tight and completely with Plastic Electrical tape, This
> will help keep out any moisture as well as keep it all in a nice bundle :-)
> RECONNECT BATTERY AND TRY IT AGAIN.
> - Wouldn't want to put everything back together and find we missed
> - Everything working ok ? Yes, Excellent, put it all back together,
> sit back have a couple more beers!!!
> Hopefully my anguish over this will help somebody else save some time, money
> and frustration. I know other people on the list over the years have
> saved me lot's of both :-)
> Steve Kramer wrote:
> > Guys, I'm having an intermittent problem with the voltage coming off of
> > channel 11 in the diagnostic. here's the story
> > - 1990 Audi v8 157k original alternator
> > - replaced battery in January with a Sears International Battery ( had
> > great success with this battery over Audi's battery)
> > - just added a subwoofer
> > - checked battery connections yesterday - vent was not hooked up
> > a couple weeks ago, I noticed that the cat , battery and brake light were
> > dimly lit. There is no squealing noise on the belt, however, the engine is
> > making more noise than before.
> > As a non techie - my thinking is basically when you turn on the car - these
> > lights turn on until your car turns over - then they go out. In this
> > situation I believe the alternator is not giving enought voltage Revving the
> > engine cause these dim lights to go out - as if the alternator is reving up
> > and providing the proper voltage.
> > Sometimes , the car starts up normally and these lights are out . Head
> > voltage is 13.8 . When the lights are dim - the voltage is 11.8
> > Another possibility is that when this happens is with my temp / gas guage
> > goes dead. .
> > Any thoughts
> > Steve Kramer
> > 1990 V8 q
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> _/_/_/ _/ _/ _/ _/ Mike LaRosa
> _/ _/ _/ _/_/ _/ TSE - HAS
> _/_/_/ _/ _/ _/ _/ _/ 1617 Southwood Drive
> _/ _/ _/ _/ _/_/ Nashua, NH 03063
> _/_/_/ _/_/_/ _/ _/
> S U N Phone: 781/442-1250
> S E R V I C E S Fax: 781/442-5488
> Email:mc.larosa at sun.com
_/_/_/ _/ _/ _/ _/ Mike LaRosa
_/ _/ _/ _/_/ _/ TSE - HAS
_/_/_/ _/ _/ _/ _/ _/ 1617 Southwood Drive
_/ _/ _/ _/ _/_/ Nashua, NH 03063
_/_/_/ _/_/_/ _/ _/
S U N Phone: 781/442-1250
S E R V I C E S Fax: 781/442-5488
Email:mc.larosa at sun.com
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