"PeterD" <peter2 (AT) hipson (DOT) net> wrote

I believe that Fluke has a min/max function also, so you may be able to
check for intermittent current drains. This can be a handy function.

With the engine off, you can measure the battery voltage accurately and
correlated with the temperature you can get a rough idea of the charge.
IMO this measurement is not highly indicative, but it may tell you
something.

O.K. I tested the accross the battery with the engine off and got a reading
of 12.95 volts.
With the engine running, at any RPM, I got 14.65 volts.

"42" <chris150 (AT) cox (DOT) net> wrote

At 80F the voltage with the engine running should be in the range
of 13.8-14.4.

A fully charged battery (ideally) would show a terminal voltage of
about 12.6-12.7 volts.

You might actually be running slightly "hot".

"hls" <hls (AT) nospam (DOT) nix> wrote

Sorry for forgetting the temp., it's about 85 today.
Thanks hls, maybe my voltage regulator needs to be replaced???

"42" <chris150 (AT) cox (DOT) net> wrote

Perhaps... The overvoltage is not too much, but it does appear to be
an overvoltage.

On Mon, 26 Oct 2009 14:03:18 -0700, "42" <chris150 (AT) cox (DOT) net> wrote:

Slightly overcharging. Ideally it should be about 13.7 to 13.9 volts.
14.65 in a warm/hot climate would shorten battery life. Possibly the
alternator's regulator is defective.

On Mon, 26 Oct 2009 15:46:28 -0700, "42" <chris150 (AT) cox (DOT) net> wrote:

I'd consider that were this my repair job.

Thanks guys!!!

42 wrote:
I would check the connections to the ECM first. Make sure they are
CLEAN. Also check the grounds really well. The 02 uses a signal line
from the ECM to tell the alternator what voltage to provide. The
regulator in the alternator itself doesn't control charging.

You should have one large red that connects to the battery through a
fusible link. Then on the small harness you will find a red and a gray wire.
The gray wire is the field signal to the alternator
The red wire is the sense wire to the ECM.
You should see the same voltage on the red wires and the gray wire will
change voltages as the load and temperature changes.

One thing that you can do is alter the circuit so that you can use the
internal regulator.

I would probably throw a scan tool on there and see if the ECM is seeing
the same voltage that you see on the red wire. It could be that the ECM
is failing.

--
Steve W.

"Steve W." <csr684 (AT) NOTyahoo (DOT) com> wrote


Thanks Steve W.!

Good to know. I will try to check thoses wires and connector this or next
weekend.