Do you mean looped back to the EGR Vacuum Modulator (like what I marked up in red)? I'm looking at the EGR system and not seeing which lines you looped back.What year 80? On my 94 I simply disconnected the vacuum lines from the top of the throttle body and looped one back to the TB and the other back to the egr valve and unplugged the temp sensor. Never had a CEL.