I just have to say there is no ill intent on my part. But I am pretty sure this is a different read for the people reading than it is for the poster.
When you hear hoofbeats, think horses not zebras. All signs point to a timing issue. You can continue to throw money at it, but until the timing is addressed, it is just a frustrating exercise. Continuing to throw parts at it only increases the odds of some issue arising with the new parts to compound the problem.
Second. Insanity is doing the same thing over and over, but expecting a different outcome the next time. Point being, you set the timing to 4 BTDC with the timing connector disconnected, and it sort of runs. Then you connect the timing connector, and it falls flat. Meaning there could be something in your application of the setup routine that is causing this, and therefore the symptom keeps repeating itself.
It is popping back through the TBI. Meaning the timing is too early for the position of the valves.
I can think of two possibilities that would explain this.
One, is the correct mark for 4BTDC being used on the harmonic when you set the original timing? There are four marks on that harmonic. Are you using the big indented mark or a mark 3 notches over from that one? This also could be the whole basis of the distributor being off. Are you 100% percent certain the piston is at TCD when putting the distributor in, or are you using that timing mark as the indicator that the engine is at TDC. After all you keep mentioning the harmonic slipping on the crank. That simply does not happen with shearing the key.
Second, the engine has jumped time and the valves are no longer in time with the piston. This very much will cause poor ignition and popping because the valve is opened when the engine fires. As you mentioned earlier, pull the valve cover and watch the valve train actuation as the engine is barred over. Also, a compression test would tell you somewhat if the engine were out of time.
I am not criticizing you, please don’t read it that way. There is benefit in having a third party looking over your shoulder to identify what may be going on.
I think you are in Florida from your profile. Where? If you are close, and I live in Inverness, would you be open to on site help?
