Moses, thanks for your detailed and quick response. I forgot to mention that this engine was rebuilt a year ago. O2 sensor is brand new NTK. All other sensors have been tested either with OBD tool or with scope and seem to operate properly. In some cases I had spare ones that return same values.
Based on part number I installed proper fuel pump. I tested for bleed down and it held pressure for more than 30 mins. I will preform the test at fuel filter. Can I simply remove fuel filter and put tee instead of it?
What bothers me is that with both old and new regulator there is fuel odor in