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Intermittent engine miss.

3K views 11 replies 6 participants last post by  galaxiex 
#1 ·
New to the site looking for answers. Have a 68 Mustang with a 5.0L, had installed Pertronix ignitor 3 kit on 4 years ago still using the resistor wire and had no problems until this year. When starting the engine it would kick back on the starter, removed coil wire, it turned over fine, bought a pig tail without the resistor wire and that did not eliminate problem so pertronix tech website said module had failed, so went an HEI style system, along with a new coil and the missing started, reused the old coil, eliminated the fuel system, removed the HEI system, purchased another Pertronix system and still have the same concern. I have research a lot of topics saying that you can use the solid wire which takes of the place of the resistor wire in the pigtail as your 12 volt power, but could I have another concern within the wiring harness or the ignition switch or should I use a different wire within the switch for my power source ?
 
#2 ·
Try a new ignition switch. I had a similar problem with my pertronix ignition that first occurred at high rpm and progressively got worse. One day I could start the car and when I let go of the key the engine would stop. The "light" in my head went on and I realized what the problem had been all along and got a new switch.
 
#4 ·
Kicking back on the starter is often a sign of a timing related problem in the high voltage system. Could be cracked cap, rotor, spark jumping from wire to wire (bad wires) or the firing order is not correct. A miss could be any of the above including possibly a bad plug- insulators sometime crack. Check all the grounds including the coil to the engine and the connections.
 
#5 ·
Kicking back on the starter is often a sign of a timing related problem in the high voltage system. Could be cracked cap, rotor, spark jumping from wire to wire (bad wires) or the firing order is not correct. A miss could be any of the above including possibly a bad plug- insulators sometime crack. Check all the grounds including the coil to the engine and the connections

Thanks for the reply, never a problem until the original Pertronix module failed and everything has been replaced since then with new. Another member mentioned that there could be a fault within the ignition switch and that's what I'm going to replace next.
 
#7 ·
Have even retarded the timing, which made no difference and as stated before everything is new. Had miss with the HEI, which was a new distributor, new has another Petronix 3 system, new ignition switch, resistor wire has been eliminated, have added additional grounds, etc and etc.
 
#10 ·
Have you replaced the wires? What is the age and condition of the distributor? I once had issues with a missfire related to a broken coil - distributor wire. Another time I has ignition issues was when the distributor shaft bushings were worn out and that caused the dwell to disappear completely at times. I think your issue is with the distributor, or the wires, not with the module.
 
#11 ·
Have you replaced the wires? What is the age and condition of the distributor? I once had issues with a missfire related to a broken coil - distributor wire. Another time I has ignition issues was when the distributor shaft bushings were worn out and that caused the dwell to disappear completely at times. I think your issue is with the distributor, or the wires, not with the module

Thanks for the reply, problems started with the failure of the original Pertronix system, went with a HEI system (complete, new distributor, cap, wires, coil, etc) and the miss was there, removed that system, installed a new Pertronix unit with a known good distributor, new Pertronix wires, cap, 45 volt coil and plugs. Have also replaced the pigtail less the resistor wire and even installed a new ignition switch and it's still there.
 
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