noods wrote:Also the more adjustment to vent to atmosphere the more it backfires...loud!!!....hmm I wonder if the exhaust is throwing flames.
This is because there's less air in the intake than the ECU expects, and it's injecting more fuel than required. Some of that fuel ends up unburned during the combustion process, and then ignites in your exhaust system.
It's doubtful that you're blowing flames though, the ignition point is generally further up the exhaust towards the engine as I understand it.