No start / no spark thread

[Alan73Charger]

It was suggested I start this as a new thread so perhaps guys that come along later will get some help from all the knowledgable people on this forum!  The subject car here is a 73 Charger with a 318.

When I got this car about a month ago it started and ran fine.  I noticed the champion plugs looked pretty bad so I replaced them with a fresh set of NGK plugs and also changed the oil. Went to start it and it just cranked.  Could smell the gas so went straight to a possible no spark situation.

I got a spark tester and found no spark at the first plug wire.  I threw a few parts at it, all cheap parts that were most likely 42 years old anyway.  I put a new starter relay on, a new ballast resister, new voltage regulator, and new coil.  I also put on a new period correct negative cable that has the auxilary lead that goes all the way to the frame for a ground, not one that needs another wire crimped in to get to the frame.  I also put a new ground strap on at the fire wall.

So with the key in the on position I have volt readings at both sides of the ballast resister.  (That thing gets hot)  So I pulled the coil wire off the distributor cap, hooked it up to the spark tester, cranked the engine and NO SPARK.   So the next step was the coil itself.  I pulled the coil wire off and with the help of a short piece of vacuum hose attached the spark tester to the coil.  I cranked the engine and SPARK!!  So this is great news, I think.  All the information I've been able to find says this is a bad coil wire.  Spark from the coil but not at the cap... pretty cut and dry. 

So I had wanted to put some correct orange Mopar wires on the car anyway so I've ordered them and they should be here soon.  My question is have I missed anything?  Is there anything else that could be causing me to have spark at the coil but not at the distributor cap??  Perhaps how the wires are connected to the coil? I flipped it after I installed when I realized the red wasn't going to positive.  Now I have the red to positive, and two wires going to the negative terminal.  Or could the hose going to the distributor advance cause an issue?  (This hose now comes from the new ported vacuum switch.  It used to come from a vacuum line that was connected to the carb)  I'm just trying to cover everything here because when I put these new wires on I'll go nuts if this car doesn't start!

Thanks in advance or any input and/or suggestions. 

[polywideblock]

sounds like a bad coil to dizzy  wire to me         good luck 

[Alan73Charger]

sounds like a bad coil to dizzy  wire to me         good luck 

Sure sounds like it, sure looks like it!  Just seems crazy it was fine, I change plugs, then it's fried.  But u know what they say...

[Dino]

I never noticed my ballast resistor getting hot.  How much Ohm's are you measuring on that?

[polywideblock]

try touching it after a bit of a drive   

[Dino]

I have and it was nothing more than warm.   

Can't test it anymore though, I got rid of it.

[Alan73Charger]

I never noticed my ballast resistor getting hot.  How much Ohm's are you measuring on that?

Hey Dino.  Yes it was after the key had been in the on position for sometime.  I noticed the drivers side plug a bit warm to the touch, (warmer than the passenger side for sure), then accidentally touched the top of the resister and it was hot.  As for ohms 03.7 key off, 00.0 key on position. (Divers side)  I just went and got those readings.  Honestly I have no clue when it comes to using these meters.  When I was checking before I was checking volts on the wires going into the resister and getting readings all over the place.  Just the warmth of the plugin told me power was going to the resister for sure. 

[Dino]

Can you measure ohm across the resistor?  One lead on each spade.  Just with key off.  I forget what it's supposed to be so I'll check the manual.  I think it's the same for 2nd gens.

Edit: should be 0.5 to 0.6 ohm.

[Alan73Charger]

Can you measure ohm across the resistor?  One lead on each spade.  Just with key off.  I forget what it's supposed to be so I'll check the manual.  I think it's the same for 2nd gens.

Edit: should be 0.5 to 0.6 ohm.

Mine settled in at 1.5 to 1.6 Dino, quite a bit higher than what you said.  I just took both the connections off then measured the ohms with a lead on each of the top spades.  Would that indicate something other than a bad coil wire causing my no spark?  Again I'm getting spark at the coil, just not at the dizzy.

Thanks

[440]

Is the carbon button still in the cap? Plugs at proper gap? Have you checked the plug wires for continuity?

[Pete in NH]

Can you measure ohm across the resistor?  One lead on each spade.  Just with key off.  I forget what it's supposed to be so I'll check the manual.  I think it's the same for 2nd gens.

Edit: should be 0.5 to 0.6 ohm.

Mine settled in at 1.5 to 1.6 Dino, quite a bit higher than what you said.  I just took both the connections off then measured the ohms with a lead on each of the top spades.  Would that indicate something other than a bad coil wire causing my no spark?  Again I'm getting spark at the coil, just not at the dizzy.

Thanks

Hi Alan,


Your 73 if it still has the original factory ignition system should be Chrysler's first generation ECU. That would be a 5 pin control box and a 4 pin ballast resistor.  The one section of the ballast resistor should be around 1.5 ohms and the second section around 75 ohms. The second generation ECU is a 4 pin control box and a 1.5 ohm ballast resistor. You can use a second generation control box in a first generation system, but not the other way around.

You can use your ohm meter to measure ignition wire resistance and depending on length they will measure anywhere between 5,000 and 50,000 ohms. Longer = more resistance.

[Alan73Charger]

Is the carbon button still in the cap? Plugs at proper gap? Have you checked the plug wires for continuity?

Hi Dino,

Not sure what u mean but the carbon button.  Tell me what to look for and I'll pull of the cap.  Plugs are new NGK.  Never fired yet.  All preset at the correct .035 gap.

I hadn't checked any wires.  Key off?  I have new wires on the way anyway.  Ordered new set when the troubleshooting before showed me a spark at the coil but no spark at cap.  Seemed to be a clear case of a bad coil wire.

[Dino]

440 posed that question but I'll answer it anyway.   

The carbon button sits in the center of the distributor cap and contacts the rotor underneath.  There's a spring behind the button.

I'm glad Pete chimed in, turns out the ohm readings are different for our cars so you're good there.   

Put a new coil wire on there and see what she does.   

[Alan73Charger]

Can you measure ohm across the resistor?  One lead on each spade.  Just with key off.  I forget what it's supposed to be so I'll check the manual.  I think it's the same for 2nd gens.

Edit: should be 0.5 to 0.6 ohm.

Mine settled in at 1.5 to 1.6 Dino, quite a bit higher than what you said.  I just took both the connections off then measured the ohms with a lead on each of the top spades.  Would that indicate something other than a bad coil wire causing my no spark?  Again I'm getting spark at the coil, just not at the dizzy.

Thanks

Hi Alan,


Your 73 if it still has the original factory ignition system should be Chrysler's first generation ECU. That would be a 5 pin control box and a 4 pin ballast resistor.  The one section of the ballast resistor should be around 1.5 ohms and the second section around 75 ohms. The second generation ECU is a 4 pin control box and a 1.5 ohm ballast resistor. You can use a second generation control box in a first generation system, but not the other way around.

You can use your ohm meter to measure ignition wire resistance and depending on length they will measure anywhere between 5,000 and 50,000 ohms. Longer = more resistance.

Hi Pete,

Had never pulled off the control box connector.  It's a 4 pin.  So I guess second generation ECU?  The ballast resister is new and is 4 pin like the old one I took off.  So I guess when I touch both sides of the resister with key off that 1.6-1.7 reading is about where it should be? I tried to do each side.  With key on the 0.0 just blinked on and off.  With key off I was getting higher readings then what you mentioned.  Around 4.3 on drivers side and 5.5 on other side.  These readings were inconsistent.  I had seen them as low as 3.6 and 4.8.  

I found no resistance at the wires at all.  Maybe engine needs to be cranked when checking?  These wires are on the way out anyway.  Orange reproduction set on way from Classic Industries.  My concern is they won't solve my issue even though a fried coil wire seemed to be the problem when I ran my spark tests.

Thanks
Alan

[Alan73Charger]

440 posed that question but I'll answer it anyway.   

The carbon button sits in the center of the distributor cap and contacts the rotor underneath.  There's a spring behind the button.

I'm glad Pete chimed in, turns out the ohm readings are different for our cars so you're good there.   

Put a new coil wire on there and see what she does.   

Sorry Dino you're correct, I should of asked 440 what that was!  Thanks for replying. Well you tell me.  Here is a picture with the cap off.

And yes that's the plan.  New coil wire with a new set of wires at hopefully we have all the spark we need.

Thanks

[Dino]

The blade on top of the rotor is what contacts the carbon button in the cap.  See if it is still spring loaded and look for burn or wear marks.  It's probably fine but it doesn't hurt to check!

[Alan73Charger]

The blade on top of the rotor is what contacts the carbon button in the cap.  See if it is still spring loaded and look for burn or wear marks.  It's probably fine but it doesn't hurt to check!

Yes she springs right back up when I push down and looks to be in great shape.  I guess it's pointed correctly too with that "1" right in front of the number one plug.  Inside the cap looks good to.  I clean it up some and snap it back on.  Thanks for your help.

[440]

Interesting, you get spark off the coil high tension lead but none from the plug wires?

Even if you accidentally mixed up the plug wires you'd still get spark.

[ws23rt]

I had a similar problem years ago that turned out to be a microscopic hole or crack right under the blade on the rotor. The spark from the coil would pass through this crack to ground in the distributor shaft. --Try a different rotor?--

[Alan73Charger]

Interesting, you get spark off the coil high tension lead but none from the plug wires?

Even if you accidentally mixed up the plug wires you'd still get spark.

I get spark directly from the coil.  I hooked the spark tester up to it with the help of a small piece of vacuum hose and saw spark when cranking engine.  When I attach the wire and attach the spark tester to the end of that wire, (that would go on the dizzy), I have no spark present.  I haven't changed any plug wires so no issues there.  That's the next step!!

Thanks

[Alan73Charger]

I had a similar problem years ago that turned out to be a microscopic hole or crack right under the blade on the rotor. The spark from the coil would pass through this crack to ground in the distributor shaft. --Try a different rotor?--

Hey thanks for this suggestion.  You never know.  I sure don't mind throwing a rotor for under 10 bucks at this and see if it does the trick.  Car already has new plugs, a new starter relay, voltage regulator, ballast resister, coil, and new wires on the way.  I'll pick one up today.

[Pete in NH]

Can you measure ohm across the resistor?  One lead on each spade.  Just with key off.  I forget what it's supposed to be so I'll check the manual.  I think it's the same for 2nd gens.

Edit: should be 0.5 to 0.6 ohm.

Mine settled in at 1.5 to 1.6 Dino, quite a bit higher than what you said.  I just took both the connections off then measured the ohms with a lead on each of the top spades.  Would that indicate something other than a bad coil wire causing my no spark?  Again I'm getting spark at the coil, just not at the dizzy.

Thanks

Hi Alan,


Your 73 if it still has the original factory ignition system should be Chrysler's first generation ECU. That would be a 5 pin control box and a 4 pin ballast resistor.  The one section of the ballast resistor should be around 1.5 ohms and the second section around 75 ohms. The second generation ECU is a 4 pin control box and a 1.5 ohm ballast resistor. You can use a second generation control box in a first generation system, but not the other way around.

You can use your ohm meter to measure ignition wire resistance and depending on length they will measure anywhere between 5,000 and 50,000 ohms. Longer = more resistance.

Hi Pete,

Had never pulled off the control box connector.  It's a 4 pin.  So I guess second generation ECU?  The ballast resister is new and is 4 pin like the old one I took off.  So I guess when I touch both sides of the resister with key off that 1.6-1.7 reading is about where it should be? I tried to do each side.  With key on the 0.0 just blinked on and off.  With key off I was getting higher readings then what you mentioned.  Around 4.3 on drivers side and 5.5 on other side.  These readings were inconsistent.  I had seen them as low as 3.6 and 4.8.  

I found no resistance at the wires at all.  Maybe engine needs to be cranked when checking?  These wires are on the way out anyway.  Orange reproduction set on way from Classic Industries.  My concern is they won't solve my issue even though a fried coil wire seemed to be the problem when I ran my spark tests.

Thanks
Alan

Alan,

When using an ohm meter your ignition key should always be off. Ohm meters don't like voltages in the circuit you are trying to measure and you can damage your meter.

The original Orange ignition wires on your 73 were resistance wires to keep down ignition noise in the car radio. Those wire sets are still available from Chrysler and hopefully that is what Classic is sending you.  Handle them gently as they are fiberglass cores with carbon impregnated in them to give you the resistance. Pulling on them too roughly can break the cores internally.

ws23rt's rotor suggesting is an interesting one- you never know! If I were changing the plug wires , I think I would treat the engine to a new distributor cap as well.

On spark plugs , your car left the factory with Champion plugs. I know today many guys don't like Champions but they have always worked well in my Mopars over the years.

[Alan73Charger]

Can you measure ohm across the resistor?  One lead on each spade.  Just with key off.  I forget what it's supposed to be so I'll check the manual.  I think it's the same for 2nd gens.

Edit: should be 0.5 to 0.6 ohm.

Mine settled in at 1.5 to 1.6 Dino, quite a bit higher than what you said.  I just took both the connections off then measured the ohms with a lead on each of the top spades.  Would that indicate something other than a bad coil wire causing my no spark?  Again I'm getting spark at the coil, just not at the dizzy.

Thanks

Hi Alan,


Your 73 if it still has the original factory ignition system should be Chrysler's first generation ECU. That would be a 5 pin control box and a 4 pin ballast resistor.  The one section of the ballast resistor should be around 1.5 ohms and the second section around 75 ohms. The second generation ECU is a 4 pin control box and a 1.5 ohm ballast resistor. You can use a second generation control box in a first generation system, but not the other way around.

You can use your ohm meter to measure ignition wire resistance and depending on length they will measure anywhere between 5,000 and 50,000 ohms. Longer = more resistance.

Hi Pete,

Had never pulled off the control box connector.  It's a 4 pin.  So I guess second generation ECU?  The ballast resister is new and is 4 pin like the old one I took off.  So I guess when I touch both sides of the resister with key off that 1.6-1.7 reading is about where it should be? I tried to do each side.  With key on the 0.0 just blinked on and off.  With key off I was getting higher readings then what you mentioned.  Around 4.3 on drivers side and 5.5 on other side.  These readings were inconsistent.  I had seen them as low as 3.6 and 4.8.  

I found no resistance at the wires at all.  Maybe engine needs to be cranked when checking?  These wires are on the way out anyway.  Orange reproduction set on way from Classic Industries.  My concern is they won't solve my issue even though a fried coil wire seemed to be the problem when I ran my spark tests.

Thanks
Alan

Alan,

When using an ohm meter your ignition key should always be off. Ohm meters don't like voltages in the circuit you are trying to measure and you can damage your meter.

The original Orange ignition wires on your 73 were resistance wires to keep down ignition noise in the car radio. Those wire sets are still available from Chrysler and hopefully that is what Classic is sending you.  Handle them gently as they are fiberglass cores with carbon impregnated in them to give you the resistance. Pulling on them too roughly can break the cores internally.

ws23rt's rotor suggesting is an interesting one- you never know! If I were changing the plug wires , I think I would treat the engine to a new distributor cap as well.

On spark plugs , your car left the factory with Champion plugs. I know today many guys don't like Champions but they have always worked well in my Mopars over the years.

Thanks for the info when measuring ohms.

Here is what classic industries is sending.

http://www.classicindustries.com/product/mopar/parts/mn1124.html

Cap sounds like a good idea.  And I agree on the plugs.  I pulled champions out.  Since the car was starting great then I wish I would of just left them in even though they looked like they needed changed.  The car hasn't started since I pulled them!  I'm sure the car would run fine with Champions or NGK's.  But your right most guys into performance do consider the NGK a better plug.  My neighbor said he would run champions in his mower but never in his BMW.  But hey he drives a BMW, not a Charger!

[Barfyspitz]

Did you fix it yet? I'm experiencing similar issues.

[Alan73Charger]

Did you fix it yet? I'm experiencing similar issues.

I did, but I was looking in all the wrong places!  Ended up being carb related.  The screw that held in the Acc pump lever was loose so the accelerator pump wasn't functioning correctly.  If you have spark check for fuel issues.  I'm still battling my carb, started flooding after I got it running.  I'm about to ditch it for a 4barrel.  Good luck.