key on not running draw

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DART66GT

DART66GT

62 Lancer GT - B Body 8 3/4
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I was having a problem with my lancer starting for the first time. I checked everything and everything is fine. What I did find was when the key was on but not running the voltage would draw down to 11.7V. When cranking was even worse. I removed the field wire + (blue) and the car started right up and had full battery voltage to the coil. I put the + (blue) wire back and removed the green field wire. Full battery voltage and starts easy. Put the green field wire back on no start 11.7V. removed plug from voltage reg. 12.6V and starts easy. With key on not running both the green and blue field wire are at 12.6V. Tried new voltage reg. same thing. Ground is definitely good on the V.R. had alt. shop test diodes and they are good. What am I misssing??
 
With both field wires removed do
an ohm test between the field connections on the alternator.

And do an ohm test between each field contact on the alternator and the body of the alternator, seperately

By the way, if the key is in the run position, and the points (assuming you have points) is closed there will be a draw on the battery. Electronic ignition would also have a draw but probably not as much
 
DART66GT said:
I put the + (blue) wire back and removed the green field wire. Full battery voltage and starts easy. Put the green field wire back on no start 11.7V. removed plug from voltage reg. 12.6V and starts easy.
Click to expand...
Sounds like a short in the field circuit. (On a Lancer charging system, green is also positive, but its regulated.)

Assuming the difference between this
DART66GT said:
What I did find was when the key was on but not running the voltage would draw down to 11.7V.
Click to expand...
and this
DART66GT said:
With key on not running both the green and blue field wire are at 12.6V.
Click to expand...
is that in the second test the field wire was not connected to the alternator, something is drawing a lot of current or the battery is very weak.

DART66GT said:
I removed the field wire + (blue) and the car started right up and had full battery voltage to the coil.
Click to expand...
In start, the resistor is bypassed. Because battery voltage can drop as low as 9.5 under starter load.
 
With an alternator with one field terminal grounded, lets think of a way to check for a short in the field circuit.
Ok. First. Measure the resistance between the two brushes.
Its should be very low, maybe not even measureable. Don't think I ever measured a resistance of note.
upload_2020-5-17_16-52-36.png


Then remove the ground brush. This one.
upload_2020-5-17_16-56-51.png

Measure the resistance from the field terminal brush to the case. It should be infinite. If not, there's an internal short to ground.

Then remove the field terminal brush and insulator.
It slides out.
upload_2020-5-17_16-57-47.png

There should be an insulating washer under the screw head.

Check brushes and insulators visually.
 
Im sorry I did not mention in first post I have an alternator with the 2 field terminals and a later electronic voltage regulator. It is the squareback type.
 
I have electronic ignition also....HEI and the ballast resistor has a wire soldered across with no resistor.
 
Well then you can check for internal short to ground without removing the brushes.
 
DART66GT said:
removed plug from voltage reg. 12.6V and starts easy
Click to expand...
In which case, seems like the VR may not be wired correctly.

The rotor's feed wire and the VR 'sense' wire should both be on the ignition feed.
The rotor's 'ground' wire goes to the VR plug's lower right corner. The VR opens and closes the connection to ground depending on the sense wire voltage.

upload_2020-5-17_17-47-0.png
 
Dana67Dart said:
With both field wires removed do
an ohm test between the field connections on the alternator.

And do an ohm test between each field contact on the alternator and the body of the alternator, seperately

By the way, if the key is in the run position, and the points (assuming you have points) is closed there will be a draw on the battery. Electronic ignition would also have a draw but probably not as much
Click to expand...

Between the 2 field terminals I got 10.6 on the 200 ohm setting. There was no continuity between either field terminal and the case.
 
Others can chime in but that sounds good. The 10.6 ohms would be the field coil and only a bit over 1 amp . No connectivity to ground is also good
 
I think "we" are on the wrong track here. I think you have a defective terminal/ device in the path to the ballast resistor/ ignition. Generally, the path is battery.....starter relay "BIG STUD.".............FUSE LINK........through the BULKHEAD CONNECTOR.......(on RED ammeter wire).........through the AMMETER.......out on BLACK to the under dash WELDED SPLICE..........branch off to IGNITION SWITCH connector, through the switch, and out on DARK BLUE.........out through the BULKHEAD CONNECTOR....into the engine bay and junction at the ballast resistor, branch off to feed the VR and the alternator field.

I think you have a bad connection somewhere in that path. Do some voltage checks with ignition on. Start with the large feed into the ignition switch, and the "ignition run" coming out, and check both sides of that connector. If that blue (output) seems OK concentrate on the bulkhead connector If the feed TO the switch is low, also concentrate on the bulkhead. Check the voltage on the fuse link going into the pass compartment.
 
DART66GT said:
Im sorry I did not mention in first post I have an alternator with the 2 field terminals and a later electronic voltage regulator. It is the squareback type
Click to expand...
That would be the correct alt for the VR
 
Did you have the battery checked, just ruling out the easy stuff.
 
What happens if you do what you need to get it to start then while it is running reconnect the wire removed to get it to start?
 
Also, it's a simple matter to check the current draw on the alternator field. It's a simple 12V circuit. Ground one field after checking for opens to the case, and check the draw through the field, that is jumpered to battery---through the field---your ammeter---and to ground.
 
67Dart273 said:
Also, it's a simple matter to check the current draw on the alternator field. It's a simple 12V circuit. Ground one field after checking for opens to the case, and check the draw through the field, that is jumpered to battery---through the field---your ammeter---and to ground.
Click to expand...

Bottom line seems to be this:
Key in run, the voltage (at battery post?) drops from 12.6 to 11.7 Volts.
Removes the triangular connector from regulator, and the voltage comes back up.

Didn't say what the ammeter indicated.
 
67Dart273 said:
I think "we" are on the wrong track here. I think you have a defective terminal/ device in the path to the ballast resistor/ ignition. Generally, the path is battery.....starter relay "BIG STUD.".............FUSE LINK........through the BULKHEAD CONNECTOR.......(on RED ammeter wire).........through the AMMETER.......out on BLACK to the under dash WELDED SPLICE..........branch off to IGNITION SWITCH connector, through the switch, and out on DARK BLUE.........out through the BULKHEAD CONNECTOR....into the engine bay and junction at the ballast resistor, branch off to feed the VR and the alternator field.

I think you have a bad connection somewhere in that path. Do some voltage checks with ignition on. Start with the large feed into the ignition switch, and the "ignition run" coming out, and check both sides of that connector. If that blue (output) seems OK concentrate on the bulkhead connector If the feed TO the switch is low, also concentrate on the bulkhead. Check the voltage on the fuse link going into the pass compartment.
Click to expand...

I did go thru every wire from the battery following the whole path. With the battery at 12.60 volts, the voltage will only drop to 12.56 at the coil and field with key on and the green field wire disconnected.
 
Did not check for amperage yet. But will tomorrow. Can I set up the ammeter between the field terminal and green wire?
 
Disconnect both field wires so the alternator is isolated. Check both field terminals to the case make sure they are open to ground. then jumper ("clip lead") to either field, through the meter on 10A scale to ground. Loosen belt, turn pulley slowly. It should draw somewhere in the 3-6A range I forget exactly. Look in the service manual
 
Op tested fields to ground. OPEN

OP tested field resistance 10.5 ohms, @12v would draw just over an amp

Post 9
 
upload_2020-5-18_9-38-7.png



Pretty sure revised squarebacks draw more field current, if that's what is on the car.
I don't know what year those introduced, late 70s?
 
Mattax said:
Pretty sure revised squarebacks draw more field current, if that's what is on the car.
I don't know what year those introduced, late 70s?
Click to expand...

That's right. 1976 electrical service section does not break them down by specific amperage ratings, it simply says "4.5--6.5 amperes @12V all except 100A 4.75--6.0A @12v
(The 100 and 100+ units are the HUGE frame units introduced in mid 70's)
 
Let's break this down simply. There could be one or MORE problems

It could be either or BOTH.......

A......Something drawing excessive current, due to either a component failure, or due to a short or partial short. One example would be a partially shorted field winding in the alternator

B.....Something allowing excessive voltage drop in the supply path, which I covered above

C....A combination of BOTH THESE THINGS, that is, something drawing more current that should be, and that is sucking down the voltage due to a poor connection, thus showing up the poor connection

Bear in mind that depending on year and model/ options of the vehicle, there are different components fed by the "ignition run" circuit
Don't discount something ADDED by a previous owner

Ignition system, alternator field, voltage regulator power, electric choke if used, and on some years a smog doo-dad or two. All fed off the "run" IGN1 line and by the way NOT FUSED
 
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