Ignition Depression

[jfrmach]

I have a 69 Mach 1 w/ a 351W and 4sp toploader. I have owned the car for almost 20 years, but only drive about 500 miles a year. Recently had some hesitation and then car just died at 35 mph.

Using a timing light, I see spark only when I come off the key to start, often accompanied by a backfire. No spark during cranking.

Since time has gotten away from me on some of the ignition components and many are original as far as I know, I have changed the following over the last couple weeks of troubleshooting:

Mallory E-Spark Module + Rotor (i.e. no points on this car, although distributor is stock)
Dist Cap + Plug Wires
Coil
Solenoid
Ignition Switch (along with connector + pigtail because it was melted - I thought for sure this was my problem d'oh!)
I even disconnected the tach just in case

I am basically out of ideas at this point. Where do I turn? Drinking has only helped temporarily.

Any words of wisdom?

[bmxmon]

Do you have power to the coil while cranking? Might have wired your ignition switch wrong. Google up a wiring diagram, I found one for a 69 pretty quick but it was pretty crappy. A little more digging and you should find a decent one pretty quickly.

[jfrmach]

I found the problem. I and a friend spend a couple of hours with a wiring diagram and could not find a problem last night. After buttoning things up for the night I thought of something that turned out to be the problem:

The aftermarket Mallory shutter-wheel rotor is a tight fit. When I installed it, it was tight enough that I thought it had bottomed, but it needed to go down another 3/16" or so and was not engaging the notch on the distributor shaft. As a consequence, the rotor appeared to turn OK with the cap off but, when the cap was on, the rotor hung up at the nearest terminal. My guess is that the slight motion of the rotor when the key was turned and let off from the start position caused it to fire, giving me spark then, but not while cranking.

Once the rotor was turned to the proper alignment and pushed down far enough to engage the notch, the car fired up instantly.

The moral, besides don't be stupid is to pay attention to aftermarket parts. Nothing wrong with the part, per se, it just didn't behave like a stock rotor and fooled me.

I think the original problem was caused by my melted ignition switch connector. The rotor problem was my own doing.

[bmxmon]

Well congrats on getting her running again! Welcome to MW, better post up some pics of your car!

[jfrmach]

Thanks for the good wishes. I will get some pictures up ASAP.

--John