I'm stuck. The car cranks but no spark. It is a 1970 cutlass supreme convertible. It has done this a couple times in the past but wiggling the wires near the fuse block has fixed it, but not this time. I have a HEI distributer that woks fine. I've pulled the fuse block to check for loose or broken connections and have found none. I've checked for power to the distributer and there is none there. I have also tested for power to the ign tab on the fuse block and there is none there. Everything else has power. I can run a hot wire to the distributer and the car starts and runs fine. My guess is there is something wrong in my ignition switch, or wiring connected to the column. Which column wires should I check for switched ignition power? I tried looking in my service manual but the wiring diagrams are way to blurry to read and diagrams on the web are to small.

 

Check the adjacent 20A fuses to the IGN terminal at the fuse block. I think its the turn signal fuse that powers it.

 

How about we start by you telling us exactly how the HEI is wired.

 

OMG! Just pulled the fuse, which looked fine when I looked at it installed, but turns out it was cracked behind the end cap. Replaced it and all is good. I guess the lesson here is that glass fuses will lie right to your face! LOL. I spent an hour checking wires. Thanks oldcutlass.

If anyone has a good copy of the wiring diagram that they could send me I'd still be interested in one that is legible.

 

Like I always say, it's the easy fixes that take the longest to find😀. Glad you got it 👍 though.