Another Failing Distributor? Need Some Input

[Cal2121]

I have a 68 F-250 with a 1972 390 FE. I have been running the Sniper EFI for about a year now. Previously, I had a PerTronix Flame-Thrower Plug and Play Billet Distributors (PN D133700) fail on me. I came out to start the truck and it would start but ran really erratic (i.e., rpms all over the place and stuttering despite a giving it constant gas). Summit sent me a new Pertronix and I installed it. I has ran fine for many months. Fast forward to now. In the last couple of months I've had a few times where I'm driving at a constant speed (with consistent pressure on the pedal) and I'll feel the truck losing power, rpms jump all over the place, and the engine will stutter). This happened yesterday on the freeway and lasted a few minutes. I wasn't able to check the EFI sensor readings during the event, but did when I eventually came to a stop. They were all within normal limits and I didn't have any error codes. Given the prior failure and the similar erratic nature of the engine running, I'm assuming it's the distributor but that is largely based on the similarities. Any help is appreciated.

[Ranchero50]

Without posting up how your setup is wired we're kind of pissing into the wind. That being said, low amps will kill ignitions. How much do you have drawing off of the ignition switch? What relays do you have installed? Fuel pump, EEC, Ignition? If you are pulling everything from the switch I'd lay money that's where you problem is, or overloaded old wiring.

[Cal2121]

Ranchero,

Thank you for the reply. Sorry for the lack of details. I'll have to take a look to get details. My father-in-law assisted me in installing everything. He's much more knowledgeable on those issues and likely thought of that, but I'll definitely look into it. It may be that it's all being pulled from the ignition switch.

What is the solution for not pulling it all from the ignition switch?

[Ranchero50]

Pick up a couple Bosch ice cube relays and wire them in so the coils are powered by the ignition and the load from the battery through a fuse / circuit breaker. That way the key switch is only powering the low current relay coils.

[Cal2121]

Thank you, Sir!

[GaryKip]

IF it isn't the ignition switch power, then check the coil. I believe "the amp level" may be your problem too. But without knowing if your dist. requires a resistor or resistor wire, we can't tell if the resistance of the coil plus the resistor wire is too much or not. There's been a boat load of electronic dist.s burned up when all they needed was a external resistor or the resistor wire (AKA Pink Wire)

[timachone]

+2 about the above said!

The Pertronix need constant 12V to operate properly. If not your symptoms can occur.

On my installed Pertronix I module I have a ignition switched relay in front of which give constant 12V power when activated. No problems since installation.

[Cal2121]

Thank you all for the input. I think my problem is that my dist. requires the constant 12V (i.e., bypassing the pink resistor wire) and is being supplied via the resistor wire. Going to go with the switched relay and give it a go. Thanks again.