No spark from coil

[510revisited]

I know this topic has been beat to death like its owed money, but i now suffer from this fatal situation. Small rundown. 1969 datsun 510, ei dizzy, ir alternator. Was in the process of doing a compression test. Inadvertently arced my wrench against the white/black wire going into the alternator. Mind you that wire was unplugged. Blew a 20a fuse (flasher fuse i believe) replaced it. Car started and ran fine. Took it out for a spin and on the way to park it, it died INSTANTLY. Got it to start again, then parked and let it idle, and it died INSTANTLY again. Could not get it to restart. Pushed it into the garage and started to diagnose everything i could think of. Checked all fuses with a vom. All have continuity. Checked primary and secondary on the coil for resistance, thats ok. Have power at the wires going to the coil. Checked for spark coming out of coil lead, nothing. Checked ign module on ei dizzy (e12-80) and that seems to be the culprit (i think), checked it as per this i have NOT traced the wiring to the ign switch due to my vom leads falling apart and pure frustration. Question is, is the ign module crapping out possible? Im reading that those things are more or less invincible. I dont mind buying a new one, but i dont wanna just throw money at the darn thing. I see the wiring diagram shows several fusible links for that system, but i cannot locate them. Im darn near ready to pull the whole harness out and diagnose that way. Any ideas on what else it could be. I checked the relay at the radiator. It works. Any and all help is greatly appreciated. I just wanna get the damn thing on the road, AGAIN.

[datzenmike]

Ignition ON. Check that there is 12 v on the coil positive terminal AND while cranking the engine with the starter. Make sure terminal screws and nuts are tight.

 

1/ Yes to both go to 4/

 

2/ Yes 12 volts but only when cranking

Ballast resistor is bad.

 

3/ No 12volts ON or  START. Check ignition switch or fusible link. Check battery cables are clean and tight at the battery posts and on the head and the starter.

 

4/ Put an old plug in the coil wire and place on a grounded surface. Crank engine... got spark???

 

5/ YES.... you'll have to drive around till it quits. Can't fix what ain't broke.

6/ No spark... Turn the ignition ON. Briefly touch a grounded wire to the coil negative side and release. You should have a spark

 

7/ No spark.... Coil is bad or intermittent

8/ Yes there's spark. Go to 9/

 

9/ Coil is not getting the ground and release signal from the EI module.

 

For the module to work all coil power must ground through the distributor case to the block.

Check that the distributor is tightly bolted down and is well grounded. Some EI have a ground terminal for this.

Make sure the matchbox is securely mounted (grounded) to distributor case.

Make sure there is 12v at the B terminal on the module and the C and B wires are secure and making contact.

With distributor cap off make sure distributor turns during cranking.

 

 

 

 

 

[510revisited]

     Datzenmike, your the man. Any chance you can make it out to my neck of the woods and build my car for me. Ill pay you in trident layers!! Thanks for the help.

     I will follow your procedures in a couple days when i get my new test leads. I did read through and had one guestion. Where would the fusible link be? I know what they generally look like and dont see ANY. I cant imagine nissan putting one inside the harness, under the tape. Keep in mind im about the second, third or more owner. Ive already changed a few wiring issues, i.e. grounding points. But in reality the harness is pretty well preserved. 

     However, I am seriously thinking of taking all the wiring out and redoing it all anyways. Using more modern plugs, new wire and all. I do know,  or more suspect, a lot of the issues are from bad connections, or grounding. I do plan to start at the tail lights and work my way forward cleaning all connectors and grounds. Couldnt hurt unless i fu€£ up again, right?

[510revisited]

Sit rep. Got off me lazy bum and tinkered. Had 12 volts at both terminals. Yeah! Took a plug and wire (coil wire was a loose fit on the plug) and plugged into coil. Yeah SPARK! hooked it all back up, turned the key. nothing. It cranked and cranked. Nothing. Took it apart again, tested everything again. 12.?? At positive when ON, 9.3 when starting. To clarify battery was dying. Charging battery now. Checked for spark, nothing. Both wires coil lead and plug wire. Still nothing. And at the time when i checked the plug again the cranks were strong before the battery started going and still no spark. Saw a spark at the neg side of the coil and 12 volts at b terminal on ign module.  WTF?

 

Edit. No ballast resistor. Removed by po.

Edited October 7, 2018 by 510revisited

[datzenmike]

 You will have 12v on the positive side of the coil and somewhat less on the negative side because power will flow through the coil resistance. Ground the negative side and release and it should spark. If it does, the coil can be considered ok.