No spark from distributor, good spark from coil...

[moparmissus]

I'm hoping someone here can help me out. I have a 74 Barracuda with a 360 crate engine, MSD coil, Mopar distributor with vacuum advance and electronic ignition. I have very good spark coming from the coil, but absolutely nothing from the distributor. I changed the cap and rotor, as well as making sure the rotor is actually turning. Points and reluctor look good. The car was running great when I parked it for the season a year and a half ago. (Too much work kept me from being able to get it out last year.) Also, I have had a parasitic drain for several years which I believe is from the way my (aftermarket) stereo was installed... Any advice on the lack of spark? I'm out of ideas... :help:

 

[Adam]

I'm hoping someone here can help me out. I have a 74 Barracuda with a 360 crate engine, MSD coil, Mopar distributor with vacuum advance and electronic ignition. I have very good spark coming from the coil, but absolutely nothing from the distributor. I changed the cap and rotor, as well as making sure the rotor is actually turning. Points and reluctor look good. The car was running great when I parked it for the season a year and a half ago. (Too much work kept me from being able to get it out last year.) Also, I have had a parasitic drain for several years which I believe is from the way my (aftermarket) stereo was installed... Any advice on the lack of spark? I'm out of ideas... :help:

It shouldn't actually have points, does it? How are you getting a spark from the coil? if you are bypassing the dist manually to create a spark maybe the Neutral Safety switch is the problem. Check the coil wire. Check the Dist input wires for a short, corrosion, chewed by mice, ect.

 

[moparmissus]

Sorry, my bad. Not points but pickup. To check spark from coil I pulled coil wire from distributor cap , inserted screwdriver in end and placed shaft near intake (for ground) and had my son turn the engine over. Nice blue spark. Going to stop on my way home from work today for all new plug wires - maybe not enough juice from coil to spark distributor. Also, have found no signs of physical damage to exterior of input wires to distributor. Will have to check for shorts.

 

[moparleo]

Plugs should be Champion RN12YC gapped between .035-.045 larger gap with more powerfull coil.

 

[moparmissus]

Plugs are correct and gapped at .035. No burning, damage or fouling. Just slight tan discoloration on ceramic part of electrode.

Entire chain of events. Last year my cousin was visiting from Washington and wanted to take a ride. Knew the battery was dead, so he connected the charger and (unfortunately!) put it on rapid charge. Went back a short time later and top of battery was swollen. Immediately disconnected charger and noticed ECU was still buzzing. Unplugged that. Have not gotten car to start since. Replaced battery, ECU, ballast resistor and voltage regulator (parts guy said that probably got fried, too.) Nothing. Tested coil and found secondary windings bad. Replaced that. Due to the noise in my radio and battery drain, thought maybe bad alternator. Replaced that. I have good spark from the coil now, but when I check from one of the distributor spark plug towers I get nothing. I picked up a new set of wires today and will put them on tomorrow. Question: Could it be a bad pickup? Is there a way to test this? Or could one of the wires have gotten burned through when the over-charged and wiped out the ECU? Thanks in advance for the help any of you can give me.

 

[Chryco Psycho]

is the coil sparking while cranking the engine over or how are you getting spark from the coil ?
It could be a Bad coil wire ? Spark would leave the coil & not get to the rotor in the dist , the rotor could also be bad
If you are not getting coil spark cranking it could be a bad pick up coil or gap in the dist could be too wide . the Ecu may not be switching the coil ground so it could have failed , not much else could be the issue .

 

[moparmissus]

Yes, the coil is sparking while cranking. Possibly bad coil wire - will replace all wires tomorrow after work. Replaced dist cap and rotor as well as ECU. Found a way to test pickup coil online - will check that tomorrow also. Other than some small obscure wire loose or burned through somewhere I'm running out of ideas... All grounds seem tight and intact as well as hot wires. Don't know where to go next if tomorrow's projects fail.

 

[Chryco Psycho]

How can it fail , you have spark from the coil while cranking so the Pick Up coil inside the dist has to be working so does the ECU so if the spark comes out of the coil it HAS to be in the coil wire , rotor or cap the only 3 things between the coil & plug wires .

 

[AUSTA]

coil

Yes, the coil is sparking while cranking. Possibly bad coil wire - will replace all wires tomorrow after work. Replaced dist cap and rotor as well as ECU. Found a way to test pickup coil online - will check that tomorrow also. Other than some small obscure wire loose or burned through somewhere I'm running out of ideas... All grounds seem tight and intact as well as hot wires. Don't know where to go next if tomorrow's projects fail.

I had a similar problem found the coil wire had a different fitting on each end & the brass end was not going into the coil electrical but rather sitting on the edge of the insulated section of the coil squashed the brass a bit so it would go all the way in all fixed.

 

[moparmissus]

Thanks, Austa. I replaced the coil wire and now I don't even have spark from the coil! Made sure it was clipped on, but no good. I was going to change all of the wires, but the set I got was too short. So much for "exact replacement" and "custom fit". Even if I don't use the loom to keep the wires off my valve covers they are too short. On the plus side my pickup does seem to be working. That's a good thing because I can't seem to find anyone who sells them for Mopar Performance distributors! Back to the drawing board....

 

[AUSTA]

Thanks, Austa. I replaced the coil wire and now I don't even have spark from the coil! Made sure it was clipped on, but no good. I was going to change all of the wires, but the set I got was too short. So much for "exact replacement" and "custom fit". Even if I don't use the loom to keep the wires off my valve covers they are too short. On the plus side my pickup does seem to be working. That's a good thing because I can't seem to find anyone who sells them for Mopar Performance distributors! Back to the drawing board....

Back to basics
Your saying your coil is not providing a spark to earth when cranking.
check your resistor is plugged in ,also your ECU ,disconnect your tacho wire if you have one sometimes it can drag down the coil voltage also check the coil supply pin on the firewall connector i have seen corrosion at that point causing poor or intermittent spark .
First you need to get a spark from the coil then plug in the coil lead & check for spark to earth once established you can plug into cap then check spark at plug connectors

 

[moparmissus]

How do I check the coil supply pin at firewall connector? And I do have a tach - it's all over the place when I'm cranking the engine. I think I may have over-crimped the coil wire when changing the terminal for the coil and damaged the wire. I run an MSD Blaster coil which takes a special terminal and I was having problems with it. The new wire set I got are MSD and came with a crimping tool, Will try again with new coil wire also.

 

[Chryco Psycho]

The coil feed is the blue 12v feed , it goes to the ballast resister , voltage regulator , alt field etc , it should have a steady 12v from the ign switch . The ballast could be bad though but the ballast is bypassed while cranking so the brown wore from the ballast should feed to coil directly & should also have 12v while cranking

 

[AUSTA]

How do I check the coil supply pin at firewall connector? And I do have a tach - it's all over the place when I'm cranking the engine. I think I may have over-crimped the coil wire when changing the terminal for the coil and damaged the wire. I run an MSD Blaster coil which takes a special terminal and I was having problems with it. The new wire set I got are MSD and came with a crimping tool, Will try again with new coil wire also.

Try plugging a plug lead into the coil & fit a spark plug on the end & crank over some of the suppression type leads dull the spark

 

[moparmissus]

Okay, so I replaced all of the wires including the coil wire making sure I had a good tight fit. Had to spread a couple of the terminals a bit for the distributor, but otherwise no problems. Turned the key and.........nothing. So I started looking (again) for anything loose, broken or disconnected. I found one wire under the hood I missed reconnecting (green to negative coil), and one inside the passenger compartment that had come loose (black used as a ground to metal on dash). Kept looking and discovered that one of the terminals that plugs into my ballast resistor has broken. I probably happened one of the times I had the cap off. Going to try to find a new one (I don't have one for two wires) and see if that takes care of things.

 

[moparleo]

You can check spark by bridging both sides of the ballast. Just run a jumper wire across to both sides.

 

[moparmissus]

Not having any luck finding the disconnect I need for my ballast resistor... (No good junk yards around here!)

 

[moparleo]

Just connect the wires together from both sides of the ballast as a test. Also lets try to hotwire it. This is a very simple ignition test. Run a wire from the battery to the Plus side of the coil. Now crank the engine and if all of the ignition parts are working, it should start right up.