Another starting problem

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6pak

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Been dealing with this for a while. My car usually fires when the key is released to run.
I think I’ve found the problem, and just want an affirmation.
Believe my key switch is bad.
When I turn the key to start, run voltage goes away.
Is this normal? - I wouldn’t think so.
 
What year? Electronic or points ignition?
Did you check the ballast resistor?
"Start" and "Run" are two different circuits either feeding through (run)or bypassing (start) the ballast, and depending on year and type of ignition it could be a single or double ballast.
 
Yes normal
First column is key position.


Screenshot_20220619-230032.png


67-69 Dart Ignition Switch Pinout
 
If it will start and run with the key in the START position, but not in the RUN position, put a ballast resistor on it.
 
Dana,
Trying to understand the chart. I presume ING should be IGN? If so, seems odd to me. IGN2 duplicates START, so what does IGN2 do?
 
IGN2 power to igntion/coil when key in start
START is power to starter relay when key in start

you need these 2 to start.... 12 volts at stater relay to turn starter motor and 12 volts at coil to provide a "starting sized spark" to start
12 volts into an 8 volt coil for a short period produces a wicked good spark for starting.... it only does this during starting.

Ignition 1 is reduced power via ballast to ignition/coil in RUN

i.e when running you don't need the starter motor and you only need 8 volts for a low resistance standard 8 volt mopar coil..... its a low resiatance coil becasuse it doesn't have the in built resistance of a 12 volt coil (like those on 4 cylinders cars of the era) and depends on the ballast to limit current in coil primary and thus protect the points or igntion unit...they can only handle 2-3 amps... you are expecting them to slog along for 100s of miles.
as with all things igntion Just enough is the right amount.

You don't need a coil painted red with a lightning strike sticker on it and some big old claim about 40KVs to run a mopar.. we have sensible igntion.

why waste BHP loading your alternator up with a bigger job than necessary running an igntion that sucks 8 amps when you don't need to.

i.e you have a perfectly adequate igntion set up and your key switch is working correctly....

i think I've gone off piste....



Dave
 
Start over - ! Ha! Just wish is would start right!

73 Duster w electronic ignition.
I Disconnected starter wire from relay so it wouldn’t crank.
I put a test light on Ign2 when key on and it is half brightness.
Turn the key to start and it goes full brightness. OK
I put the light on Ign1 side of ballast and is full brightnes in run and dims when switch is turned to start.
Turning it back to run and pull Ign2 wire from ballast. Ign1 Still at full brightness. But when I turn the key to start, the light goes out.
So, when the Ign2 is connected, and turned to start, the Ign1 side is seeing voltage dropped the other way thru the ballast and the ECU being powered from that side is only seeing half voltage.

I hope this clarifies the problem. Today I’m going to jump 12v to the run side and see what happens.
*As soon as the wife gets up. Open headers. Don’t need/want to wake her up.
but looking at some diagrams I’ve found of the switch, I cannot tell if the ign switch is functioning properly.
I would think the ECU would need a full 12v.
 
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Start over - ! Ha! Just wish is would start right!

73 Duster w electronic ignition.
I Disconnected starter wire from relay so it wouldn’t crank.
I put a test light on Ign2 when key on and it is half brightness.
Turn the key to start and it goes full brightness. OK
I put the light on Ign1 side of ballast and is full brightnes in run and dims when switch is turned to start.
Turning it back to run and pull Ign2 wire from ballast. Ign1 Still at full brightness. But when I turn the key to start, the light goes out.
So, when the Ign2 is connected, and turned to start, the Ign1 side is seeing voltage dropped the other way thru the ballast and the ECU being powered from that side is only seeing half voltage.

I hope this clarifies the problem. Today I’m going to jump 12v to the run side and see what happens.
*As soon as the wife gets up. Open headers. Don’t need/want to wake her up.
but looking at some diagrams I’ve found of the switch, I cannot tell if the ign switch is functioning properly.
I would think the ECU would need a full 12v.
Simply DO what I said. Turn the key to START and hold it there. If the engine starts and runs, it NEEDS a ballast resistor. It won't hurt a thing to keep the starter engaged for a second or three, but will tell you everything.
 
If it will start and run with the key in the START position, but not in the RUN position, put a ballast resistor on it.

My car usually fires when the key is released to run


I think the op is having the opposite issue.
No voltage to the coil during cranking. Then while engine is still spinning a little the key is released to run and picks up just enough soark to fire off.
 
It runs in the run position.
Fires up when the key is backed to the run position from start.
Hardly ever starts while cranking.

Have full voltage to the coil. Half voltage to the ECU while cranking.
 
Dana,
Trying to understand the chart. I presume ING should be IGN? If so, seems odd to me. IGN2 duplicates START, so what does IGN2 do



Screenshot_20220619-230032.png



67-69 Dart Ignition Switch Pinout


This part of the chart shows what is hot FROM the battery for all key positions.

When key is in ACC - only ACC has battery voltage.

When key is OFF - no power anywhere that is key controlled.

When key is in RUN - ACC and IGN1 have battery voltage

When key is in START - IGN 2 (ballast bypass) and ST (start) have battery voltage.

Also from my testing the IGN1 and IGN2 have a slight overlap as the key is turned.

Meaning IGN1 comes live just before IGN2 goes dead as the key is turned from START to RUN ( the propper term is "make before break")
 
It runs in the run position.
Fires up when the key is backed to the run position from start.
Hardly ever starts while cranking.

Have full voltage to the coil. Half voltage to the ECU while cranking.
Ok so it sounds like it's missing IGN2. My bad...as they say. lol Doesn't that come from the starter relay?
 
I believe Wire to the relay and and Ign2 (assuming that is the ballast start side wire) are two separate paths from the switch.
Because when I jump 12v to the Ign2 side of the ballast, the starter relay doesn’t click.
 
even if it doesn't normally, and i don't know... perfectly viable place to take it from or (indeed off the only live when starting, starter) ... run wire from there to inner end of ballast. job done.... you nick 12 volts for starting direct to coil, which is gone when in run.

I think this what you do when you run a denso on an earlier car if you want to carry on with full ballast functionality
there is a tech note on one of the denso sites outlineing how to use their starter with only 2 connections on a car that had 3 at the starter connection point, for if you had the need to connect up a special 12 volt feed for starting on a car that ran a ballast resistor.

no idea where i saw this but noted it at the time when hunting for oddly specified pinion gears for mopars that use 9 tooth 25 mm i.e not 35 mm like a dakota truck

Dave
 
Yes. Was my plan.
I’ll let you know.
 
What you need to have is 12 volts while cranking and 8 volts when running. 12 volts while running will ruin the coil.

When cranking the 2 blue wires on the one side of the ballast are a bypass and direct 12 volts to the coil. When you leave off the cranking position the brown wire on the other side of the ballast is now the feed and when going through the ballast it reduces the 12 volts to the blue wire that goes to the coil to 8 volts.
 
6pak
This is most likely what you have.

If you have a dual ballast resister and a try 5 pin ECU there is another wiring diagram for that but it is very much the same.
Screenshot_20220620-080042.png


The ECU gets power from IGN 1 when in run and from IGN2 back through the ballast resister in Start.


The coil gets power from IGN1 in run through the ballast resister.

The coil gets power from IGN2 directly during cranking.
 
so it sounds like it's missing IGN2. My bad...as they say. lol Doesn't that come from the starter relay
The starter relay is fed from the ST pin of the ignition switch. IGN 1 AND IGN 2 are isolated from the ST pin. But all three come from the ignition switch.

Sounds like you need to get a wiring diagram from myMopar.Com (free) or classicarwiring.Com ($20.00ish, colored and laminated)
 
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You are leading yourself down the wrong path with your test procedure, because the two circuits feed back into each other. When the key is in "run" the power goes from IGN1 "run" through the ballast and to the coil. AT THE COIL + terminal, the IGN2 is essentially "that point" electrically. So the IGN2 line back to the ignition switch "sees" the run voltage AND THAT CHANGES some because of the load on the coil through the ballast, and because of the charging voltage. "Running," coil + will vary somewhere between 10-12V when the system is running at nominal 14V With key "in run" but engine stopped, it will be somewhere from 5-8 or maybe 10V, because the battery is down around 12

IN START the IGN2 is "supposed" to be "same as battery." That is, if when cranking, the starter pulls the battery down to 11V, then IGN2 should be about 11. This will show at coil+ AND THAT NOW will feed "backwards" through the BALLAST and show up on the IGN1 line. There may be loads on the IGN1 line which will pull the ballast "down" and so on the "key" side of the ballast, that voltage will / might be quite low

ON NEWER CARS with factory breakerless ignition, THIS BACKFEED from IGN2 (in start) --through the ballast "back" towards IGN1 NOW IS THE STARTING POWER SOURCE FOR THE electronic ignition box!!! IT MUST BE there or the box will not operate in "start."
 
67Dart273;

“backfeed” was the word I was looking for.
I jumped 12v from the battery to the IGN1 side of the ballast and it started right up and ran.
And wouldn’t cut off! Oh yea, the jumper!

Apparently the load in the IGN1 side is pulling the voltage down.
I the DkBlu goes to pin 1 of the instrument cluster.
what does that go to?
 
Found a diagram of the cluster.
Thanks. I think I can handle it from here.
 
Thanks to the guys who answered my query about IGN2. So, in a points car, IGN2 supplies the coil & starter relay, during cranking. Correct?
 
Thanks to the guys who answered my query about IGN2. So, in a points car, IGN2 supplies the coil & starter relay, during cranking. Correct?
No.
The ignition switch Start terminal supplies power to trigger the starter relay.
Ignition 2 terminal supplies the coil.

Wire S2 (yellow) carries current to the relay.
Wire J3 (brown) carries current to the coil when the points are closed.
upload_2022-6-21_8-46-40.png

System voltage is noticibly drawn down when the starter engages.
 
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Dana proved here that the Start and I2 terminals are not connected to each other, at least in the dash mounted switches used through 1969.
Those terminals are independently connected to the B terminal when the key is in Start position.
 
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