MY problem is: Alternator discharging Battery.
My purpose is: To find out why (and also to fix it).
I have researched a lot of posts with similar symptoms but no answers.
All input with the problem is appreciated.

1. Recently I replaced the front head gasket on a 1944 Plymouth Voyager SE.
The Engine(3.3L V6) now runs OK except The battery will drain in about an hour
to where the engine stops.

2. Here is data after a fresh battery charge.
All measurements are between battery neg post & pos post.
Before starting engine, battery voltage = 12.88v
After starting = 12.22v (Idle, 800rpm through-out test)
0-26 minutes 12.16v-11.75v
27-45 minutes 11.7v-9.00v (Dash voltage gage going down)
28-48 minutes 8.5V-7.88V
49-50 MINUTES 7.63V-6.8V
51 MINUTES 6.00V (engine stops, after-which, turned off ignition)
0-8 minutes 11.67v-11.82v (voltage building back up)
9-35 minutes 11.9v-12.06v
36-157 minutes 12.06v-12.10v (engine will NOT turn over)

3. The test was repeated later using 2000rpm
Before starting engine, battery voltage = 12.45v
Afterstarting = 11.90v
5 min 11.88v
10 min 11.65v
15 min 11.63v
20 min 11.56v (turned off engine)
------------
10 min 12.19v
20 min 12.21v
30 min 12.23v
40 min 12.23v (engine turned over - car started)

4. The next question is: What are the possible causes of the problem?
4.1. Battery
A new battery is one of the first things tried but is seldome the solution.
4.2. Alternator
A rebuilt alternator is usually tried but is seldom the solution
4.3. PCM Logic Module(voltage regulator)
4.4. Harness Connectors
Two connectors from alternator to PCM module reconnected(no solution).
4.5. Open Circuit
4.6. Circuit Short

 

hehe mmm ok get a few indiscretions out of the way so we are all on same page for who reads this.
1 1984,1994.2004 minin van not a 1944 one they were not made then which year is it?

Second who did this work on your van was it and issue before the work was done?

third an alternator does not discharge the battery the running of the vans system is which the alternator is not charging up the battery is killing it.

More then likely power wire has no voltage on it to the alternator or not connected or fuse link or wire broken to the alternator from pcm.

 

Check my postings this website on this very subject as to how to test for alternator backleak. Be about a year ago now.

Leedsman.

 

(this is my first post and the post is as much a problem as the problem
at hand)

First: 1944 should be 1994

Second: I did the work on the van, me and the haynes manual. The electrical
system was OK before I started.

Third: I thought the "Alternator Discharging the battery" would best describe the
problem.

A wire from the alternator B+ to the battery Positive shows no voltage while
running.

Is it possible to jumper the Alternator B+,Gnd and the two Field terminals in a way to check out
the alternator?

 

I am not able to find the thread you refer to but I have checked the amps with the
battery negative post removed and it measures 0.02 amps.

 

You are not measuring the alternator back-leak that way. You must detatch the main power lead from the alternator, and check with a milliammeter between the lead you've you've just removed and the connector on the alternator you've just removed it from. You don't need to switch on ign. or anything else. Be careful with this lead as it's capable of setting fire to something if you short it. It's at +12volt ALL THE TIME. The back-leak should be zero. The alternators use silicon solid-state diodes times 6 and these kind have no back flow at all. Infinity. Measuring the parasitic current in the battery -ve lead is what you've been doing.
The alternator power terminal is directly connected to the battery +ve. with a thick wire, and there is nothing in the way, no fuses, no nothing.
If you are not reasonably au fey with auto-electrics, best consult someone with experience. It is a specific job in motor engineering. DO NOT SHORT ANYTHING TO GROUND. This is how fires are started around the main battery circuit.

Leedsman.

 

The tests in #1 should always be carried out with everything electrical full whack - A/C - lights, stereo, wipers, fans, everything on. You should get 14v on the battery terminal with a bog standard multimeter set at 20v @ 1500-2000RPM, anything less that 13.7v at the battery and you will never charge the battery. Why not just take it to someone who can do a free test my friend?

 

The B+ connection is awful hard to get to. I can get a wire clamp on it so I can get a
continuity check to the main connector pins between the alternator and the PCM module.
Also taking the battery loose so as to get to the connectors and PCM module.
It may take awhile.

 

We know the battery is not being charged. As I stated at the beginning my purpose is
to learn why. When the cause is determined, then we search for a fix.
Do you have any idea what the cause is?

 

your answer from my orginal post
More then likely power wire has no voltage on it to the alternator or not connected or fuse link or wire broken to the alternator from pcm

get you volt meter on the red big wire at the alt see if three is 12 on it or not.

Because you did the work yourself IM gonna say something is not connected and or pinched somewhere during the re install process.