Occam’s Razor is the problem solving principle that suggests the simplest solution is most likely the right one. That’s true in detective work as well as figuring out why your old Corvette won’t run.
Q. I have a 1969 Chevy Corvette, last year I replaced the points, distributor cap and ignition rotor and the engine ran great. This year now that the weather has gotten better I went out to drive it and it won’t start.
When I jumped it with my other car it did backfire once. I sprayed a little starting fluid down the carburetor and it still won’t fire. I pulled off the coil wire and there is a decent spark.
I know that you need spark, fuel and compression for an engine to start. The only thing I haven’t checked is the compression. Do you think that the timing chain jumped when it backfired and it is causing the engine not to start?
A. Just because you have spark at the coil doesn’t mean it is getting to the plugs.
Start with pulling a plug wire off, if you have a spark tester (looks like a spark plug with a alligator clip on it) use that to check for spark. If you don’t have a spark tester test it the old fashioned way. Use a screwdriver inserted into the plug wire and with someone cranking the engine hold insulated handle and position the metal shaft screwdriver over something metal and see if the spark jumps to ground. A good ignition system should have a solid blue spark that can jump half an inch.
My suspicion is the ignition rotor is allowing the spark to go to ground through the center shaft of the distributor. If you are like most people with old cars you saved the old parts. I would start with replacing the rotor and perhaps the distributor cap.