Jump to content
Ultimate Subaru Message Board

FIXED!!! Gremlins running amok or low volts problem, help needed.


Recommended Posts

OK I am fresh out of ideas, so its time to ask some advice.

My problem is as follows:

 

My car is not outputting the correct voltage. This is universal across the entire electrical system as everything is dim (from headlights to dash lights). With the car off battery reads at 12 V, and with a full load the bat terminals read 10-11 Volts or sometimes as low as 9V. The alternator does not seem to be charging the system, as it requires as jump next time you turn

on the car (most of the time).

I cannot for the life of me figure out what is causing this.

Steps I have tried so far:

 

swapped alt

swapped bat (known good)

swapped coil

new battery terminals and fresh wires to starter and grounds(pos and neg)

Cleaned up every ground to sparkly and cleaned all terminals

Wired alt directly to battery with fresh wire

 

No change.

 

Help?

oh and btw its an 1983 EA81 wagon

Link to comment
Share on other sites

not to up on various names for volt testing

is that checked by placing a lead on bat neg and another the alt positive charge wire?

 

if so, yes checked out ok, reads at 11.86 (same output I am currently getting with engine on when testing pos neg bat terminals, but this is with new bat)

 

 

Not a clue. Should have been the alt+grounds.

 

Did you check the positive charge wire from the alt to the batt for resistance?

Link to comment
Share on other sites

just got done running through snowman's tests for voltage drop

found here

 

this is with the NEW battery and cleaned grounds etc. seems like there was several probs going on as when I tested prior to doing any replacing numbers were lower and grounding problems were apparent

 

1. open circuit voltage: 12.12

voltage on pos/neg terminals with full load: 11.56

 

2. one lead on the alternator case and one on the terminal on the alternator 11.56 (indicates alt prob)

 

3. one lead on the battery positive and one on the terminal on the alternator, .0 (connection is now fine this was prior .6)

4. Place one lead on the battery negative terminal and one on the alternator case .0 (this was prior .8 grounds are now good)

 

I guess this means the THREE alts I have swapped in must be all bad. unlikely but possible. Tommorow i will swap in a KNOWN good alt and see what happens.

 

Will of course post an update.

Link to comment
Share on other sites

suggest testing the alternator(s) at auto parts store to verify they are bad. If a bench tested good alt fails to produce 14 volts at 2000 rpm then there has got to be a wiring problem-make sure ground wire between engine and frame is good,and trace wires from other terminals on alt (F, S?) and make sure they are not pinched, broken, or otherwised hosed up by a blown fuse, or burned out charge indicator light , etc. Consult a detailed schematic of your specific car.

 

Let us know and good luck...

Link to comment
Share on other sites

run wire from bat+ term on alt to battery +

run wire from alt case screw to battery -

run wire from battery + to terminal of fuse link box

check fusible links, IIRC a green one haldles the charge

check 15a fuse, should have low voltage when NOT running

Link to comment
Share on other sites

two quick thoughts

 

you have a external voltage regulator alt

on a car built for an internal VR

(yes early EA81's had an external VR

it also ran the fuel pump on some early Gen I's)

 

Or vise-A-versa

 

or a bad fusible link (must be tested with a multimeter)

possibly a burned out "charge" lamp.

Link to comment
Share on other sites

subiemech85: I will try running fresh wires to everything you suggested, little to hungover today though, will have to wait until tommorow

 

Skip: how could i tell which is the case? if there is an external regulator where is it located? btw fusible links tested ok

 

how would a burned out charge light affect the situation?

 

known good alt also goes in tommorow, if that dosen't work and the new wiring dosen't pan out. I will have the alts tested at the auto parts store.

 

thanks for all your advice to all who responded.

 

updates as they come.

Link to comment
Share on other sites

Captain,

I got out the 83 FSM, it says you should have an internally regulated alternator

 

Hitachi model LR155-15C

 

might check the number against yours.

 

It is acting like a non internal regulator alternator

without it's external regulator.

or

The charge lamp provides the excite voltage for the internal IC voltage regulator.

If the lamp is burned out or missing the regulator will not excite the field winding

an thus

the alternator will not charge.

 

This excite circuit travels through fuse # 4 in the fuse box

might check it also.

 

Note: I have seen these type alternators with the excite terminal (small terminal on back of alt) directly connected to an ignition switched hot wire.

 

Hope this helps.

  • Like 1
Link to comment
Share on other sites

thanks for looking that up Skip, good to know

 

I have just put in the known good alt, model LR155-15C.

 

still no change.

 

However throughout the duration of this problem the "charge light" has not come on, fuse is fine but no light.

 

So....

couple questions:

first, if someone could explain the purpose of the wires on the alt. I know the one connected by a nut is a hot wire, and i have tried running it directly to the pos bat post. BUT what about the t-plug? One hot and one ground?

secondly

Skip, can i bypass the excite circuit by running the hot wire you mentioned? is that the larger of the t-plug wires?

 

or

 

how do i repair or replace the charge light? not familiar at all with it. I am assuming there is a bulb in the dash, but have no idea how to get to it.

 

run wire from bat+ term on alt to battery + done (as long as alt + is the wire with the nut)

run wire from alt case screw to battery -

run wire from battery + to terminal of fuse link box done

check fusible links, IIRC a green one haldles the charge done

Link to comment
Share on other sites

SUCCESS!!

You nailed it Skip. After wiring up a spare t-plug directly to pos bat terminal, started her up and guage immediatly jumped up to where it should. Quick multimeter test showed 14.56 outputting from the bat while running. YES!!!!!

 

So.........whats your advice now?

Just wire t-plug connections to igg-switched hot wire? (any suggestions for a wire near the alt I can tap into?) or try and fix the charge lamp?

 

My eternal gratitude to all who helped me with this, especially Skip.

Link to comment
Share on other sites

You're most welcome,

as for my help...

put this under the blind squirrel and the nut catagory

 

I would attempt a proper repair as

something else could be knackered.

 

The close by ig switched hot wire?

 

The main feed for the head lights is always hot

when the ig switch is on.

Link to comment
Share on other sites

:grin:

put this under the blind squirrel and the nut catagory

 

a quick update:

wired both t-plug connections into the headlight assembly and took her for a thorough test drive. Voltage seemed fine on startup but seemed to drop after driving around a bit (at one point back down to 8V, at least according to the in dash gauge, kinda hard to stick a voltmeter on the battery while driving....)

I could tell the alt was charging though...as it climbed sporadically with the RPMS.

 

Further investigation is required,

Of course another battery of voltmeter tests is in order. Then I am going to double check those t-plug connections and secure the wires down nice and tight, and maybe run an extra ground off the alt like subiemech suggested.. an extra ground or two off the bat woulden't hurt either...

Link to comment
Share on other sites

I had one on the red w/ blue stripe, but the other on the red w/ white. I have corrected the problem, and according to the voltmeter everything checks out.

 

However the in dash guage still reads low sometimes (prob just the guage itself)

 

and I havent had a chance to take it for a test drive yet, we will see how she does..........this time I am taking the voltmeter with me!

 

Capt'n you are sure you got the hot feed to the

headlamps?

 

It is the only one with full battery voltage

when the key is on.

 

FSM says it's a Red with Blue stripe on the driver's

side

Link to comment
Share on other sites

Nicky do as you like but the red with white is the high

beam ground

It may cause some problems.

 

It may look like it has voltage until you hit the high beams

 

at that point it goes to ground

 

good luck,

Skip -- over and out

Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...