Sudden no-spark situation

[chaseincats]

Hi guys,

While taking the car out today, everything was running great until I went to wide-open throttle.  After about 20 feet, the car flat out died and refused to start.  The car was low on gas, so after pushing it to a gas station and refilling it, it started right up 3x in a row and was able to drive it home.  I just went down to try and start it and it is now dead.

I pulled the coil wire off of the distributor cap and grounded it against the body - and it seems I am not getting any spark now.  I used a multimeter to poke the 2 coil poles and got less than 1.8ohms so according to the FSM it means the coil isn't bad.

Any ideas as to where I should start to look?  It seems like this is the result of an electrical part that was on its last legs or something...

 

EDIT: I just checked for continuity at the end of the two pick-up coil wires (in the black box where they are bolted to the harness) and did not get continuity.  Could that be the issue?

Box on the right is what I'm referring to: https://www.classiczcars.com/uploads/monthly_2017_02/Screenshot_2017-02-21-14-44-04.png.07517510cbd3dcbe526420d18fa8092e.png

 

-chase

Edited August 31, 2020 by chaseincats

[Zed Head]

35 minutes ago, chaseincats said:

EDIT: I just checked for continuity at the end of the two pick-up coil wires (in the black box where they are bolted to the harness) and did not get continuity.  Could that be the issue?

Could be.  Supposed to be continuity and a certain resistance.  It's in Engine Electrical and the "Bible".  

The breaker plate moves the wires to the pickup coil and sometimes they fatigue and break or short out.

[chaseincats]

7 hours ago, Zed Head said:

Could be.  Supposed to be continuity and a certain resistance.  It's in Engine Electrical and the "Bible".  

The breaker plate moves the wires to the pickup coil and sometimes they fatigue and break or short out.

Update: I removed the distributor cap and the front of the pickup coil seems to be scratched, (almost like its been rubbing on the rotating portion of the distributor) there are also very small metal shavings magnetized to the back of the pickup coil.

I tried to shake the main shaft around and it can be moved somewhat but is still very much connected to the engine (not sure if any of this information helps).

Video I just filmed: https://youtu.be/N8R1Ps-r3Pk

Would the pickup coil's outer casing being rubbed against ruin the internals?  Also, if that is indeed what happened, it would probably be a good idea to purchase a new distributor, correct?

 

-chase

[Zed Head]

That looks worn out.   I don't think I've seen one that bad before.  I think that some people have devised ways to repair that bushing surface but it takes some work and proper tools.

[chaseincats]

4 minutes ago, Zed Head said:

That looks worn out.   I don't think I've seen one that bad before.  I think that some people have devised ways to repair that bushing surface but it takes some work and proper tools.

Definitely agree but I just don't get how my pickup coil can be dead from that (isn't that block just a huge magnet)?  I checked all of the wiring and there aren't any visible breaks, even under the cap.

Edited August 31, 2020 by chaseincats

[Zed Head]

Your air gap is uncontrollable.

[chaseincats]

16 minutes ago, Zed Head said:

Your air gap is uncontrollable.

Ah, do you mean if I move the coil, continuity should appear if it is the proper distance from the center shaft?

[Zed Head]

If you're not getting continuity then a/the wire(s)  in the pickup coil probably broke from the vibration of the reluctor wheel beating on it at high RPM.  There's more than just a magnet in there.

I don't know the construction of the Nissan unit but here's a typical diagram from the interwebs.  Not my forte...

[chaseincats]

19 minutes ago, Zed Head said:

If you're not getting continuity then a/the wire(s)  in the pickup coil probably broke from the vibration of the reluctor wheel beating on it at high RPM.  There's more than just a magnet in there.

I don't know the construction of the Nissan unit but here's a typical diagram from the interwebs.  Not my forte...

It seems the re-manufactured ones are NLA.  Is there a different distributor that is currently made that is swappable that you know of? 

[Zed Head]

ZX distributors.  123 ignition.  Someone probably has a used one.  If it's the bushing in the body that's worn you might just get a body and swap your parts in to it.

[Captain Obvious]

On ‎8‎/‎30‎/‎2020 at 7:44 PM, chaseincats said:

I just checked for continuity at the end of the two pick-up coil wires (in the black box where they are bolted to the harness) and did not get continuity.

Reluctor wheel grinding against the pickup face is never a good thing, but before you convince yourself that the pickup is dead, you need to ditch the "continuity" reading on your meter and use Ohms.

The spec from the FSM is 720 Ohms. I don't know if that's high enough of a resistance that the "continuity" scale on your meter might not pick that up. In other words, the pickup coil could be just fine but resistance of the coil may be high enough that your meter won't consider it a connection (and won't beep on continuity).

[chaseincats]

6 minutes ago, Captain Obvious said:

Reluctor wheel grinding against the pickup face is never a good thing, but before you convince yourself that the pickup is dead, you need to ditch the "continuity" reading on your meter and use Ohms.

The spec from the FSM is 720 Ohms. I don't know if that's high enough of a resistance that the "continuity" scale on your meter might not pick that up. In other words, the pickup coil could be just fine but resistance of the coil may be high enough that your meter won't consider it a connection (and won't beep on continuity).

Just headed down to the garage to try that and unfortunately no luck on with the multimeter on any of the resistance settings