Sunday afternoon and no spark.... 440 6 bbl

[P Dubya]

I haven't been this aggravated in quite a while.... I'm now 2 Sunday afternoons into this no spark problem and made no progress. From everything I can see it looks like I'm not getting the step up in voltage while I crank the engine over. With the key on I have about 3.5 volts on the + terminal of the coil (seems low but thats what I have, maybe that is enough to run after starting?) Negative terminal shows about 1.5 volts. While cranking the voltage never jumps up enough to light up a test light (incandescent bulb). Air gap at the reluctor/pickup coil is .008''. Orange ECU/transistor box is well grounded to both the firewall and I also added a dedicated ground wire to the intake for assurance. Ceramic resistor is fed at the top 2 spades by two blue ( I think) wires. Bottom 2 spades have 3 wires connected which I presume feed the coil. One of them is blue and is connected to the + terminal. Tested for continuity and seems to be fine. What am I missing?

 

[eldubb440]

What am I missing?

 

[Road Grabber]

Have you tried bypassing the ignition switch and run 12 volts to the battery? You should have full voltage when cranking to the ballast resistor.

I’m assuming you have looked up a wire diagram or have checked that you are using the correct wire connections.

Even if you provide 12 from the battery for a temporary test it won’t harm anything.

Others can comment on this but I would run direct line to the coil just to see if it fires.

You can even unplug the coil wire and see if spark jumps to the terminal.

If you are getting a spark from the coil to the distributor cap you know you aren’t getting enough voltage and something in front of the distributor is a problem. If you get spark from the coil wire to the cap you know the distributor is not doing its job.

If you get spark at the cap you can take a plug , ground it and see if it sparks and so on.

If you had another ECM around to swap you can try that too but the low voltage could be a bad connection at the bulkhead or your ignition switch. They have a bad habit of getting corrosion.

Hope this may help

 

[Daves69]

Mine is a single ballast but as I understand it, you should be getting battery voltage to the ballast from the ignition switch.

Disconnect BOTH connectors at the ballast.

Ign 2 connector (red) should have battery voltage with key in "start" position.

Ign 1 connector (green) should have battery voltage with key in "run" position.

 

[Road Grabber]

Don’t rule out a bad or damaged fusible link that may limit voltage going to the ignition switch and dash harness

 

[P Dubya]

View attachment 1629983

Mine is a single ballast but as I understand it, you should be getting battery voltage to the ballast from the ignition switch.

Disconnect BOTH connectors at the ballast.

Ign 2 connector (red) should have battery voltage with key in "start" position.

Ign 1 connector (green) should have battery voltage with key in "run" position.


View attachment 1629991

Both connectors disconnected at ballast resistor.

View attachment 1629983

Mine is a single ballast but as I understand it, you should be getting battery voltage to the ballast from the ignition switch.

Disconnect BOTH connectors at the ballast.

Ign 2 connector (red) should have battery voltage with key in "start" position.

Ign 1 connector (green) should have battery voltage with key in "run" position.


View attachment 1629991

Both connectors disconnected from ballast.
Red circled area has battery voltage in key on position.
Green circled area has no voltage.
The only place I can get battery voltage is on both of the wires that go to the top of the resistor. See picture attached.

 

[P Dubya]

A couple more pics of testing resistor with ohm meter.

 

[Road Grabber]

When you crank are you getting voltage at the coil? Put a test light there.
From what you have said there should not be voltage at the resistor in the Run position.

According to the diagram given you should have voltage at the ballast at the green circle with the key in the run position.

You may have a bad ignition switch or connection if the voltage it not reaching the ballast resistor. Check if the voltage is coming from the ignition switch at the under dash connection from your steering column.

You can back probe the ignition switch connector under the dash and see if you are getting voltage to the proper wire leading to the bulkhead.
If the voltage is coming out the switch see where it ends cause it’s not getting to the run position on the ballast resistor.
Back probe the bulkhead connector connection leading to the ballast resistor too.

Just a suggestion….

 

[P Dubya]

I think this may all stem from a possible problem at the bulkhead or fusible link as I just lost power to the oil pressure idiot light... With key on it no longer illuminates.

 

[Road Grabber]

A poor fusible link connection at the bulkhead/corrosion or loose ammeter connection can cause an electrical fire as well.

I have had dash harnesses fry because of poor connections at the bulkhead and loose ammeter connections. Mopars are known for having that problem. Built up resistance makes for a very hot connection under load.

The fusible link can look fine from the outside but they can disintegrate inside the insulation.

 

[Daves69]

Do the check on the Leads, NOT the resistor.

From MP ...........

 

[Road Grabber]

This is consistent with the above diagram and discussion. If you don’t have voltage during the test there’s a problem with harness, connections, ignition switch, power supply etc. preventing voltage from reaching the ballast resistor.
That’s my guess without being there. You can start from ballast and work back or from the supply end.
You will still need to see if voltage has reached the coil if you get voltage at the ballast resistor connectors. Let us know of the voltage test.

 

[P Dubya]

All 3 connectors at bulkhead pulled and while they show their age nothing seems to be burned. Fusible link is good and passes battery voltage through it. ECU is welled grounded, test light lead to + battery terminal shows good ground and lights the test light right up when touched to ECU.
Still have very low voltage on negative terminal of coil and no flash when cranking/test light on negative terminal.
Is there any resistance value I should look for at the distributor plug/2 wire harness that can tell me of the pickup is good?

 

[Sixpactogo]

Have you tested the plate coil in the distributor? They have a tendency to fail without warning.

 

[Road Grabber]

More information please

- what year and car?

-were any components added or changed before this problem?
-I’d like to know there is not a wiring error. The engine ran previously using this ignition setup and wiring?

-what is the voltage reading at the positive side of the coil while cranking? You mentioned the negative side but not positive side.
- check that the wiring connections are correct leading to the coil. Maybe reversed them by mistake?
- previous reply mentioned that ECM go bad. I agree. They can look brand new and be faulty. I carry an extra ECM in the trunk just because of that.
- if you unplug the distributor check for continuity at the plug connections. Then touch ground from each side of the distributor plug checking for a short.

If the engine ran before but then quit or didn’t start again I would suspect the ECM.

If you are not getting voltage to the positive coil or the “start” connection of the ballast resistor you have a bad connection to the ballast from rhe ignition switch or leading up to the ignition switch. That would be my suggestion

 

[Daves69]

....Still have very low voltage on negative terminal of coil and no flash when cranking/test light on negative terminal....

Sooooooooo,

What voltages are you getting to the two ballast leads in start and run positions?

 

[P Dubya]

Have you tested the plate coil in the distributor? They have a tendency to fail without warning.

Nothing has been done under gap except set reluctor to pickup coil gap. .008'' How do I test? IS there a certain resistance I should look for at the 2 wire plug for the distributor?

 

[Road Grabber]

I agree with Daves69. I believe you said you didn’t have voltage at both connections?

If you don’t have voltage in the start and run position then you have a problem.

There shouldn’t be resistance at the distributor plug.

I would start with the basics and check the ballast connections for voltage.

 

[Sixpactogo]

Nothing has been done under gap except set reluctor to pickup coil gap. .008'' How do I test? IS there a certain resistance I should look for at the 2 wire plug for the distributor?

I would put the meter on ohms and test between both wires. I don't know what it should read but it is a coil so should read something. If it reads zero or open, it is junk. Might not be your problem but it could be. Could also be a broken wire somewhere in the circuitry or bad connection at the firewall.

 

[P Dubya]

More information please

- what year and car?

-were any components added or changed before this problem?
-I’d like to know there is not a wiring error. The engine ran previously using this ignition setup and wiring?

-what is the voltage reading at the positive side of the coil while cranking? You mentioned the negative side but not positive side.
- check that the wiring connections are correct leading to the coil. Maybe reversed them by mistake?
- previous reply mentioned that ECM go bad. I agree. They can look brand new and be faulty. I carry an extra ECM in the trunk just because of that.
- if you unplug the distributor check for continuity at the plug connections. Then touch ground from each side of the distributor plug checking for a short.

If the engine ran before but then quit or didn’t start again I would suspect the ECM.

If you are not getting voltage to the positive coil or the “start” connection of the ballast resistor you have a bad connection to the ballast from rhe ignition switch or leading up to the ignition switch. That would be my suggestion

1969 440 6BBL Roadrunner clone - Started out life as a 318 Satelite from what I can tell.

Nothing added or changed recently. Engine was completely rebuilt last fall and has run flawlessly until this issue happened about 3 weeks ago. Literally started engine to go for a drive and did not make it out of garage. Engine died within first minute and has not started since.

I have not checked to see what (+ terminal) voltage I have while cranking, at least not that I can remember.

ECM - I have been thinking about upgrading to the FBO ECM. Any experience with them?

Pretty sure I ran ohm meter tonight on the distributor side of the 2 wire plug although I don't remember what I found there. I don't recall there being continuity from one wire to the other though.... Is there any resistance value that I should look for from one wire through the coil and back to the other wire?

Engine ran great before all this so the ECM could very well be the problem, part of the reason I am looking to upgrade to the FBO ECM.

I get some voltage to positive side of coil but I think I may be lacking the bump up in voltage while cranking. When I use a test light on the negative terminal while cranking there is no flash from the bulb. This leads me to possibly think that the coil in the distributor is not signaling the ignition coil to send a spark at each passing point on the reluctor. Is there any safe way to bypass the vast majority of the ignition system ? 12V directly to ignition coil, crank engine and see if coil throws a spark?