Weak/No Spark

[BobsZTwins]

I just got the linkage adjusted so my secondaries on the Q-jet kick-in properly with boost at 13# and had a religious experience. Wow!

But.......next day went out to start the car and it took several minutes to catch and wouldn't run for s@#t. Blowing smoke, wouldn't idle at all, missed like crazy at all rpm.

It's a 350 with a single Rajay turbo sucking fuel through a Q-jet carb. Stock GM HEI distributor/coil, MSD ignition with boost retard box.

I pulled plugs, checked compression, no change from last time. It's getting fuel for sure.

I pulled #1 wire off the distributor, stuck a screw in the connector and set it about a 1/2" from the terminal and cranked the engine. It arced a couple times, weakly it seemed to me, and no more spark! Let it sit for a minute, tried again, same thing.

Any suggestions where/how to start checking the system?

 

Thanks!

[A. G. Olphart]

Sounds like you started with one problem and may be creating another...

 

Blowing black smoke is pretty much THE indicator of an overly rich condition, like the choke is stuck closed (your original problem?).

 

Your second problem may relate to the distance you are jumping your test spark. Some people use 75V/ mil (75Volts/ 0.001") as the actual break down voltage for air... at 1/2 inch that would be about 37500 volts, and while your ignition system should do that, the spark may have taken an easier path. If it punches through a bit of insulation it may permanently short out your ignition system. (Some ignition systems don't take kindly to open circuit testing, and I'm a bit of a wimp, so I try to hold my test sparks at about 1/8").

 

(This really should have gone in ignition and electrical)