no spark from coil

[irish]

Rebuilding a 1961 sprite, engine in good shape, new plugs, wires, cap, rotor, coil etc, and have converted to negative ground and installed an ignitor in distributor but still can not get spark from the ignition coil. From ignitor have red wire to coil's + or sw terminal and black to -or cb terminal. From sprite's harness (to coil), the white (w) wire attached to coil's cb term (instead of sw, as when pos. ground) and the white/black(wb) wire to sw term. When I do a lamp test on the cb terminal, the light does not pulse as it should and I get no spark from the coil.I suspect that I have not correctly attached correct wiring. Suggestions appreciated, muchly...

 

[Dave Russell]

Irish,
Sorry that you are still having trouble.
Assuming that you have a Pertronix which was made for a negative ground car,
I think that it should be wired just like the previously referenced wiring diagrams;
White wire to coil + (sw), red wire from pertronix to coil + (sw), black wire from pertronix to coil - (cb). The white/black wire not connected.

I think that you have the white wire connected to coil - and to the Pertronix black. Move the white harness wire to coil + where the Pertronix red is connected, & leave the white/black harness wire disconnected. I hope that the Pertronix isn't damaged, it could be damaged by the white wire being connected to the Pertronix negative black wire. The white wire on your reversed ground car is now a positive wire.
Good luck.
D

 

[irish]

D,

I had the red and black wires hooked up correctly and the white to + (sw) also. I do have 2 white/black wires however. Before converting to ignitor, one of the white/back was hooked to the coil and the other to the distributor LT term. Now I have both not attached to anything; perhaps they should be wired together? I assume they were ground wires?
Unfortunately, still not getting spark despite on going checklist; receiving current to the + term of coil but getting no pulsing on the - side so thinking it is a secondary ignition problem...hmm, from always learning...irish

 

[Dave Russell]

Hi Irish,

A couple of things don't add up to me.

First - If the coil is original for positive ground, it should be marked SW which is negative & CB which is positive. If a later coil has been substituted, it could be marked SW which is positive & CB which is negative. Or it may be correspondingly marked + & -. It isn't clear to me which you have. In reality it should not keep the ignition from sparking with either coil.

Second - To my knowledge, there is only one black/white wire. It originally went from the distributor low tension terminal to the coil CB terminal. Is it possible that your two B/W wires are the two ends of the same wire. If not, I don't know where the second B/W wire comes or goes.

Do you have a wiring diagram of the car. If not, you can find a similar diagram here;
https://www.gerardsgarage.com/GarageContent/Tech/WiringDiagrams/buegeywiring.htm

If the white wire from the ignition switch (should now be + with respect to ground) is connected to the same side of the coil as the Pertronix red wire & the Pertronix black wire is connected to the other side of the coil it should work. I repeat, your Pertronix may be damaged.

Maybe Jeff - Bugeye 58 can jump in here & help?
D

 

[Bugeye58]

Irish, it sounds as though you have everything hooked up right. There is only one white/black wire, and you are seeing both ends of the same wire. It is redundant to the Pertronix installation. Have you ohm checked the coil? I'm afraid that Dave's suspicion may be correct, in that you may have damaged the unit.
Heres a link that shows the proper way everything should go together, and hopefully the problem is something simple, rather than a damaged unit.
https://www.mgcars.org.uk/electrical/pertronix.html

Jeff

 

[irish]

D & Jeff,

About the "2" white/black wires, you're correct, I am simply just seeing 2 ends of the same wire...About the coil, have a new Lucas sports coil and will do ohm check but doubt that's the problem, of course...About the ignitor, don't think it is damaged since wires have been placed correctly since start. Isn't the ignitor basically a magnet and circuit breaker (a electromagnetic device). I'm curious why it seems to be so easily damageable?
I do have a wiring diagram for the car but will check the website you suggested. I noticed while comparing my sprite's wiring with the diagram that I don't have a red/white wire included among the 3 wires that connect to the ignition switch (red/white, white, and brown/blue). So, will delve more into the wiring aspects...thanks, irish

 

[Dave Russell]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by irish:
D & Jeff,
About the ignitor, don't think it is damaged since wires have been placed correctly since start. Isn't the ignitor basically a magnet and circuit breaker (a electromagnetic device). I'm curious why it seems to be so easily damageable?
irish<hr></blockquote>
Irish,
A quote from your original message;
"From ignitor have red wire to coil's + or sw terminal and black to -or cb terminal. From sprite's harness (to coil), the white (w) wire attached to coil's cb term (instead of sw, as when pos. ground) and the white/black(wb) wire to sw term."
=================================
The wires were not "placed correctly at the start" according to your original message. You had the white harness wire connected to the Pertronix black wire. The white wire should connect to the Pertronix red wire.

The Pertronix is a Hall effect sensor amplified & switched by electronics. The rotating magnets are in the sleeve that you put over the point cam. If the wrong power polarity is connected to it there is a danger of damaging the electronics.
D