I purchased an e8902 fuelpump and was advised it works on postive or negative ground,when installing power {negative} to the tan wire and grounding the black wire to the positive ground pump will not work,if I take the pump directly to the battery will not pump......if I put the tan {power wire} on the positive of the battery and goundig black wire it works fine,after snding several emails to airtex all they state is it should work.....any ideas ?