Strange Issue

[1project2many]

So this is a tough situation to help with. It's tough b/c as an experienced mechanic I've gotten used to seeing and thinking of problems in ways that help diagnose the what's wrong. Your description may be right but it doesn't match up well with what I'm used to seeing.

Sucks that you had a fire. Hopefully it didn't result in other damage! I think a fuel pressure test might be a good idea. Low fuel pressure can cause hard star, no start, and backfire. I'm not sure what else to recommend at this point.

[Resin]

Can a vacuum leak possibly cause backfiring? I will throw my fuel pressure gauge on it tomorrow. No damage, I had a fire blanket at the ready and threw it over immediately.

[steveo]

no even a massive vac leak will not cause a fire. a fire in your throttle body could only be a severely leaking injector (unlikely) or a timing or valvetrain issue. is it possible that while messing around diagnosing the previous issue you have clocked the distributor improperly

[Resin]

It is certainly possible. Would the rotor being backwards cause that? I.E. pointing at wire 1 when #6 is at TDC?