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glennstar67

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I have a 74 Duster. It has electronic ignition. It started running rough, almost like it was running on 7 cyl or something. Eventually it wouldn't even start anymore. Would just backfire through the carb and then finally it just quit. No power at all. No headlights, domelight, nothing when you turn the key. I figured it was the ign module box.. When I took the old one off there was a hole in it. I'm figuring problem solved. I install a new one. All power comes back. I turn the key, I get one click and all power is gone again. Could it be the starter is bad and drawing too many amps? I've replaced the starter relay as well. I would appreciate any advice. Thank you all in advance.
 
Don't guess learn how to troubleshoot. You can download a 73 shop manual for free from MyMopar. That manual and several others over there came from the efforts of guys right here

Also "somewhere" is a poor quality wiring section for 74.

Free service manuals

You need "at the least" a multimeter which you can buy at any auto parts store, hardware store, Lowe's or HD or even Horrid Freight

Start by examining the condition of the ignition system. Pull the cap and rotor and examine for dirt, moisture, foreign materials, "tracking" around the inside of the contacts, and damage and "punch through" of the rotor. Examing the reluctor and pickup for damage, heavy rust and debri

Next get/ rig yourself a spark tester. I use a Lisle as it is adustable, less than 10 bucks

lisle 50850 spark tester - Google Search

WHEN TESTING THE SPARK it is IMPORTANT to do THREE things minimum

1....Do not test by jumpering the starter relay to crank the engine. This changes the power path to the ignition system and leads you astray

2...Do not use the existing coil wire, as it might be a resistance wire and could be defective. Put your spark tester connected to the coil tower to the engine block

3.....Take your multimeter and connect to the coil + and watch it when you crank the engine USING THE key. You should show AT LEAST 10.5 V or more as it is cranking or more

The system should produce nice blue snappy sparks at least 3/8" and more typically 1/2" long

It is much more likely that the coil is going "somewhat bad" than the ignition module.
 
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Don't guess learn how to troubleshoot. You can download a 73 shop manual for free from MyMopar. That manual and several others over there came from the efforts of guys right here

Also "somewhere" is a poor quality wiring section for 74.

Free service manuals

You need "at the least" a multimeter which you can buy at any auto parts store, hardware store, Lowe's or HD or even Horrid Freight

Start by examining the condition of the ignition system. Pull the cap and rotor and examine for dirt, moisture, foreign materials, "tracking" around the inside of the contacts, and damage and "punch through" of the rotor. Examing the reluctor and pickup for damage, heavy rust and debri

Next get/ rig yourself a spark tester. I use a Lisle as it is adustable, less than 10 bucks
Actually used a multimeter on it. Everything was good, replaced cap, rotor, and coil as well
 
I found the 74 wiring scan in my computer. I don't remember where or if it ever got put on line. Send me a pm and if you can receive a somewhat less than 10mb file I will send it I scanned this, it is poor but I think readable
 
"Everything" is not a word that computes. You have to be specific. I cannot tell what you are doing

1...Make sure the meter works. Check the battery voltage.
2...Is there anything supplied by the ignition switch that does not appear to work? That would be a clue
3....Do you have a 2 or 4 wire ballast resistor? If you have a 4 wire, there should be one end with both terminals jumpered together. That comes from the ignition switch in "run". Hook your meter to that, put the key in the "run" position and see what you have

4....Double check the above by checking the blue wire feeding the alternator field. With the key in "run" it should be very close to "same as battery."

5...It is IMPORTANT to understand that the circuit CHANGES between "run" and "start" positions of the key. The test in (4) only works in 'run'. The 'run' voltage GOES DEAD when you twist the key to "start"

Hook the meter to coil positive, and twist the key to "start." You should have at least 10--10.5V or more
 
Very good suggestions. I will try all of these tomorrow. Thank you very much for all of your help this evening. I really appreciate it
 
Thank you for responding. There is nothing. Completely dead
Okay, well if the box is good,coil is good, ballast is good and the magnetic pickup works and its sparking plugs and cranking till battery goes dead...you may have lost a timing chain gear.
 
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id check starter relay be sure its grounding good! had the same issue on my D150 other day!! if no power on the start and run wires with key switch on id bet its the electric switch in the steering column the key switch works!!
 
Okay, well if the box is good,coil is good, ballast is good and the magnetic pickup works and its sparking plugs and cranking till battery goes dead...you may have lost a timing chain gear.
Are you saying that the distributor is not rotating at all? I am just following this thread to learn.
 
Charge the battery, or replace with one known good.
Clean the battery terminals and cable connections, particular " + " one.
 
Are you saying that the distributor is not rotating at all? I am just following this thread to learn.
Oh no... it can still rotate and Spark, see it can even rotate somewhat less than engine speed at cranking because in such a scenario the chain driven by the crank just slipped and re settled on the cam gear setting the cam timing out enough not to run.

A lot of times they only finally slip in 2 ways "most of the time"... and that's under hard acceleration and more under deceleration, inertia takes over at a point when the chain and gear is just too loose and worn.

Hope that sheds some light.
 
Oh no... it can still rotate and Spark, see it can even rotate somewhat less than engine speed at cranking because in such a scenario the chain driven by the crank just slipped and re settled on the cam gear setting the cam timing out enough not to run.

A lot of times they only finally slip in 2 ways "most of the time"... and that's under hard acceleration and more under deceleration, inertia takes over at a point when the chain and gear is just too loose and worn.

Hope that sheds some light.
But he says there is no spark at all. (Post #9) I understand if a gear slipped he would spark but not at the right time. Without a spark at all, either there is no signal to send a spark or there is a broken component to generate the spark, be it coil, wire or Dist. If the shaft of the dizzy is broken or the drive for it (timing gear) then no signal to generate a spark would be sent, thus no spark. To test that the dizzy is turning at all take the cap off and crank it and watch it spin. Unlikely, but an easy check.
 
I have a 74 Duster. It has electronic ignition. It started running rough, almost like it was running on 7 cyl or something. Eventually it wouldn't even start anymore. Would just backfire through the carb and then finally it just quit. No power at all. No headlights, domelight, nothing when you turn the key. I figured it was the ign module box.. When I took the old one off there was a hole in it. I'm figuring problem solved. I install a new one. All power comes back. I turn the key, I get one click and all power is gone again. Could it be the starter is bad and drawing too many amps? I've replaced the starter relay as well. I would appreciate any advice. Thank you all in advance.

But there is no spark. No power at all

Thank you for responding. There is nothing. Completely dead

So I'm a little confused;
We went from rough running engine to no ELECTRICAL POWER did we?
As in does not even crank over?

If everything reads 1.0 on your meter, then either;
it's on the wrong scale,or
on the wrong setting,or
the leads are in the wrong holes,or
you are using it wrong,or
the battery juice never made it to the circuit you are testing, or
it's just not working at all, else it would read something different on every circuit.
 
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But he says there is no spark at all. (Post #9) I understand if a gear slipped he would spark but not at the right time. Without a spark at all, either there is no signal to send a spark or there is a broken component to generate the spark, be it coil, wire or Dist. If the shaft of the dizzy is broken or the drive for it (timing gear) then no signal to generate a spark would be sent, thus no spark. To test that the dizzy is turning at all take the cap off and crank it and watch it spin. Unlikely, but an easy check.


My post was a general "if these things work, then it's.."
I know how it works.
 
check the bulkhead wiring ...had same problem with 73 Duster....the 3 plugs on the firewall....they will corrode ....wiggle the plug everything worked....wiggle again and everything is dead..
 
I have a 74 Duster. It has electronic ignition. It started running rough, almost like it was running on 7 cyl or something. Eventually it wouldn't even start anymore. Would just backfire through the carb and then finally it just quit. No power at all. No headlights, domelight, nothing when you turn the key. I figured it was the ign module box.. When I took the old one off there was a hole in it. I'm figuring problem solved. I install a new one. All power comes back. I turn the key, I get one click and all power is gone again. Could it be the starter is bad and drawing too many amps? I've replaced the starter relay as well. I would appreciate any advice. Thank you all in advance.
If you had no headlights or dome light that has nothing to do with your ignition or ignition system. There is something wrong with your battery or wiring. If you try to jump start the car and you get the same result then your wiring is faulty.
 
I have a 74 Duster. It has electronic ignition. It started running rough, almost like it was running on 7 cyl or something. Eventually it wouldn't even start anymore. Would just backfire through the carb and then finally it just quit. No power at all. No headlights, domelight, nothing when you turn the key. I figured it was the ign module box.. When I took the old one off there was a hole in it. I'm figuring problem solved. I install a new one. All power comes back. I turn the key, I get one click and all power is gone again. Could it be the starter is bad and drawing too many amps? I've replaced the starter relay as well. I would appreciate any advice. Thank you all in advance.
Is your amp meter working?
Check the connections on it. Common problem.
 
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