If you have fuel, spark, timing is correct, and COMPRESSION, it has no choice but to run. The only thing you didn't check is compression. See if you can get a gauge from a parts store that rents tools. If you have everything else, I need to know that the compression is within spec. However, as wrenchtech mentioned, double check the firing order to make sure. That will cause a backfire. So can a partially open valve.
Tuesday, February 14th, 2012 AT 10:21 PM