Why is it missing now ?

[bighealeysource]

Hey all,
Had to trace an electrical problem on my 100M when I completely lost power. Ended up being the white wire from the fuse box to the coil had come loose at the fuse box. Fixed that and started right back up. Of course in the meantime before I found that thought the Petronix module had given up the ghost as engine was turning over and pump was working. So, replaced the module with a new one I keep as a spare. When that did not work I went through the wiring and found that white wire mentioned above. Now that I have put the original module back in getting a miss at lower speeds, the intermittent type burbling - where I had none before and car was running perfect. The module only goes in one way, no adjustment, but I did not check the timing out as felt it would not have changed. Kinda stumped as have not touched the carbs or the timing but did take the module out and then put back in. Any advice on what to check or to do ?
Thanks,
Mike:confusion:

 

[Bob_Spidell]

I've had one of the early Pertronix units in my BJ8, probably for close to 15 years. A couple years ago I bought a new one as a spare, but learned, to my dismay, that they have 'improved' the unit and the mounting has changed. Because of this I cannot just swap the spare in if the old one fails; if it fails on the road I'll have to put it in and set timing by trial-and-error (set for a decent idle, then be alert for ping and retard if necessary; hmmmmmm ... maybe I should throw the advance meter in the boot along with the thousand tools and hundreds of spare parts).

Doubt this is your problem--you probably would have noticed the differences in the units--but throwing it out there anyway.

 

[bighealeysource]

Hey Bob,
Thanks for getting back on this. Could be exactly the problem as the older petronix unit is over 10 years old. Going to just get out the timing light and makes sure that is right as "not gonna touch them carbs" as was running perfect before the electrical issue !
Regards
Mike

 

[Ed_K]

It could be the coil. Check primary side of the coil with all wires disconnected for 3 ohms.
If a lot more or less than three ohms, replace the coil.
But since the white wire came loose, it may have damaged the hall effect transistor
inside the petronix pickup before it came all the disconnected.
Or since you have restored full power to the igntion circut, the rotor is starting to
arc if you have one of the black plastic modern rotors that doesn't work very well.
Try one of Moss's red colored rotors.

 

[bighealeysource]

Hey all,
Thanks for all the hints on what to look for. Turned out to be very simple - dizzy was apparently not tightened down enough ( stupid on my part) so when I was taking the Petronix off and back on, managed to turn it enough to advance the timing way too much. Re-timed and runs like a charm. Had forgot how bloody small the timing "hole" on the pulley is and hard to find. But located it, remarked and good to go!!!
Regards
Mike