[Diy_efi] CS Failure

Tue Nov 29 15:33:55 UTC 2005

Tom,

That's the best help I've had on this issue.  The E-39 discussion group I
listen in on doesn't have any solutions when I ask on this one.

I'll take a look at those two solutions.

Thanks!

Dan Nicoson

  -----Original Message-----
  From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org]On
Behalf Of Tom Visel
  Sent: Monday, November 28, 2005 11:07 PM
  To: diy_efi at diy-efi.org
  Subject: Re: [Diy_efi] CS Failure

  Most likely you have a bad Lamp Control Module.  It's located in the
forward power distribution box under the hood, and it's about the size of a
box of cigarettes, with a 32-pin connector.  It controls current flow to all
of the exterior lights that aren't headlamps, so if you're smoking bulbs,
it's probably the culprit.  If you have non-stock HID headlamps or
high-wattage bulbs in your headlamps, it tends to kill this idiot box, which
gets its power from the headlamp system.

  Bad news:  The modules cost mega bucks, and there are many different part
numbers to make JY hunting harder.  Good news:  You can install LED
replacements for your taillamps, for less money than the module.  The LED
lamps will have a current limiting resistor in them so they won't accept
extra current and die if the module is getting stupid.  You have an
electronic flasher (hope it never dies, it's spendy too!) so your bulb flash
rate shouldn't vary; however, if it does, you can get a 6 ohm, 50W resistor
and place it in parallel with the LED turn signal bulb and restore your
previous flash rate.  I buy LED lamps from
http://www.superbrightleds.com/1157.htm   Good service, good product, good
selection, haven't had one die yet.
  .
  Hope this helps!
  TomV

  Daniel R. Nicoson wrote:
    Tom,

    I have a 1998 BMW 540 that eats one or two rear taillights each month.
I've never seen anything like it in over 20 years of car ownership and 19
cars.  The battery is in the trunk, I assume all power goes forward to the
engine before coming back to the taillight assemblies.

    I did put my oscilloscope on the car once to see if there were any weird
spikes, didn't see anything.

    I've cleaned all the bulb sockets, cleaned the multipin connectors, even
tried conducting grease at the contact points.  Still loose one or two bulbs
each month.  Any ideas here?

    I'd drive it into your shop and pay for a proper diagnosis if you're
anywhere close to western Pennsylvania!

    Thanks,

    Dan Nicoson

      -----Original Message-----
      From: diy_efi-bounces at diy-efi.org
[mailto:diy_efi-bounces at diy-efi.org]On Behalf Of Tom Visel
      Sent: Monday, November 28, 2005 12:38 PM
      To: diy_efi at diy-efi.org
      Subject: Re: [Diy_efi] CS Failure

      I own a repair shop specializing in electrical and driveability
diagnosis and repair.  If my shop had no overhead, I could probably retire
on the income I make from alternators which other shops (or customers)
installed and had die on them due to high resistance in the output circuit.
Intermittent or poor lamp circuit (L terminal) connections will cause
intermittent no-charge problems.  Poor or no connection at the sense (S
terminal, the big one in the regulator connector) may cause the alternator
to undercharge, but rarely to overcharge or burn out.  What burns out
CS-series (and indeed, all) alternators is heat.  Internal heat, cause by
overwork because the alt can't charge the battery properly and/or can't
monitor the battery's state of charge.  To diagnose your vehicle:

      With a fresh known good alternator and a fully charged battery (12.66
V or better) installed, check the voltage drop on the positive and negative
sides of the charging circuit.  To do this, get the alternator under a good
load: engine running, lights on, heater blower and A/C running, cooling fans
going if you have them.  If you have an ammeter, clamp type or no, measure
the current flow through the system.  Positive or negative side will be the
same, and be sure to include all of the wires at the battery in your
measurement if using a clamp-type probe.  Note the reading.

      While the engine is still running, using your DVOM, measure the
voltage between the alternator case (the case thru-screws are good
candidates) and the battery negative terminals.  Note the reading.  Now
measure the voltage between the battery positive terminal and the alternator
output stud.  Note the reading.  If you got negative readings, ignore the
sign.  It's the number that counts.

      Total your two voltage readings.  This is the "voltage drop" in the
charging circuit.  It is a reflection of the resistance in the circuit -
resistance which will put a long-term strain on your alternator's diodes and
overheat and kill them.  If you get a total of greater than 0.1 Volt per 10
Amps of alternator output, that is too much voltage drop and the connections
and/or wires and cables will need to be improved.  For a standard 105 amp
CS130, 10 gauge wire straight to the battery, with a 14 gauge fusible link,
is sufficient.  For a "high output" alternator, 8 gauge with a 12 gauge
fusible link is recommended.  Also, you can't have too many grounds.
Besides keeping your alternator alive, quality grounds (less than .050 volts
drop) will help stave off computer stupidity.  You would be astonished at
the number of vehicles that leave my shop with a sub-$150 repair (diagnosis,
labor, parts, tax) when other shops told the customer that s/he needed a new
ECM or a stack of new sensors.

      TomV

      Clayton Martiniuk wrote:
        Hello, I have an 1994 Chevy 350 that Keeps eating alternators for
some reason. They seem to work for about two days and then shit out. I have
a cs series alternator powered with one exciter/indicator wire at the F
terminal. Looking at the indicator bulb, I'll start the truck, the light
will go off for a while but turn back on intermittently. I heard that these
years of trucks seem to have a problem. Some say to ground the back of the
case to the batt but I dont see how on mine. I am probably close to duty
cycle but no major power drains. It gets very cold here around -20 to -50. I
am running an electric fuel pump. I am running an red top optima with 800
cca. Does this Battery require special needs? Is the answer an larger
amperage generator or am I doing something wrong?
        I am sick of buying alternators and no one can seem to figure out
whats happening.
                                                        Thank you for your
time
                                        Clayton Martiniuk
------------------------------------------------------------------------
_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
http://lists.diy-efi.org/mailman/listinfo/diy_efi
  --------------------------------------------------------------------------
--
_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
http://lists.diy-efi.org/mailman/listinfo/diy_efi

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.diy-efi.org/pipermail/diy_efi/attachments/20051129/f64722ad/attachment.html 