chasing spark 74 cuda

[CU-DUH!]

using an inline spark tester, I get spark directly from the coil. Is it safe to say the ECU, reluctor gap, ignition coil are all working properly? continuing.... when I connect the coil wire to center of cap, the spark seems to end there?!?!? I rotated the engine to  power stroke of #1 cylinder, rotor looks like its in correct position to fire there ..but no spark at plug wire. Cap and rotor were replaced, but same problem remains. what am I missing?

[Brads70]

The coil wire itself? 

[HP2]

Is the carbon button in the center of the distributor cap present? Is the tab on the rotor tall enough to contact the button?

[CU-DUH!]

purchased new plug wires, got same results, thought about rotor height, uncertain how to accurately check that. The distributor shaft does move up and down about an 1/8 of an inch, is that normal?   

[CU-DUH!]

so set to TPC, marked rotor position, and put cap on. is this WAY out of time?

[HP2]

I'm guessing thats' about 10* off. However, while the spark firing would not be timed correctly, that would not stop the spark from going down the plug wires. Even if the distributor was installed 180* off, it would still shoot spark down the  to the plugs. Its a simple matter to twist the housing back the 10* to get the rotor to align with the #1 position on the cap. The rotor position is fixed. Only the housing and cap move.

You can always try bending the tab on the rotor up a bit to make it contact the cap button. The cap is installed with its tab in the matching notch in the distributor housing?

Interior of your distributor looks kind of crusty. IS the interior of the cap similar?

[usraptor]

How is your ground?  Has the car been painted recently?  Is there paint or corrosion between the K frame and frame rails?  Have you cleaned the end of the neg wire where it attaches to the block and made sure there is no corrosion on the negative cable or head where it bolts to?  I added a second ground strap from the engine block to the K frame bolt when I was having similar issues.  I also added a small braided ground wire from the back of the block to the ECM on the firewall.  All is good now.   Good luck!

[CU-DUH!]

new cap, so looks good to me...new coil and plug wires. ...did have better spark then before... bent rotor center tab up a bit. took marker to underside of cap to see if an imprint would show on rotor top when I put together ...had wife crank engine while turned disb forward and back..still nothing past new coil wire

[mopar jack]

Did you pull the distributor before this happened? Got to ask did you set it to top dead center on the compression stroke? 

[Chryco Psycho]

Having the spark go to the correct plug is not the issue , if you are getting no spark down any wire wether it is at the correct time or not is not the problem .
So coil wire is known to be good & so if you hold the wire close to ground while cranking you get good spark ?
Really it has to come down to 2 things , either the coil is not putting out enough voltage under load , or the condenser is grounding it if you still have a condenser off the negative side . really the condenser was more to protect the points & Is not nessisary with electronic .
or the cap is bad even if it is new & looks fine , possibly the spark is not getting through the center carbon terminal .

[CU-DUH!]

How is your ground?  Has the car been painted recently?  Is there paint or corrosion between the K frame and frame rails?  Have you cleaned the end of the neg wire where it attaches to the block and made sure there is no corrosion on the negative cable or head where it bolts to?  I added a second ground strap from the engine block to the K frame bolt when I was having similar issues.  I also added a small braided ground wire from the back of the block to the ECM on the firewall.  All is good now.   Good luck!

thought about needing an extra ground, will add another for sure ...all new batt cables thou, found short braided one on backside of head going to firewall, will clean that up too. Originally there was a short lighter gauge wire neg wire running from neg post to..well...dont really recall 

[CU-DUH!]

Having the spark go to the correct plug is not the issue , if you are getting no spark down any wire wether it is at the correct time or not is not the problem .
So coil wire is known to be good & so if you hold the wire close to ground while cranking you get good spark ?
Really it has to come down to 2 things , either the coil is not putting out enough voltage under load , or the condenser is grounding it if you still have a condenser off the negative side . really the condenser was more to protect the points & Is not nessisary with electronic .
or the cap is bad even if it is new & looks fine , possibly the spark is not getting through the center carbon terminal .

I'll double check coil wire spark after cleaning so other ground connections. As my cap and coil were purchased new at local auto store, can you (or anyone else)recommend a reputable quality  parts retailer? thx for responding!!

[mopar jack]

Did you change the reluctor? when you point the rotor at # 1 on the distributor a tooth on the reluctor should be just passing the pick up. The reluctor has two locations depending if it's turning clockwise or counter.

[Chryco Psycho]

Roseville sells only good parts so that is an option .
Hold the end of the coil wire near ground & crank the engine , you should have a blue spark ,not yellow, that will jump at least 1/4 " , if not the wire  or coil is bad .
You should be able to test the center terminal on the cap with an ohm meter  for continuity but it will not be zero Ohms as the carbon terminal will have resistance .

[CU-DUH!]

Did you pull the distributor before this happened? Got to ask did you set it to top dead center on the compression stroke?

no...but hasn't ran since 1986, it was running rough when I parked it then.....