CARSmith56 Posted December 8, 2011 Share Posted December 8, 2011 (edited) Unit ran fine; dropped a valve; new head; ran poorly; replaced turbo; roadtested great; then quit on the way back to the shop. No codes; we've swapped ECU's with running trucks; replaced plugged EGR cooler; pulled apart all harnesses looking for wiring problems - no luck. Two new fuel pumps; cranks over good, then instantaneously starts and quits. Corporate Mack magicians are stumped, anybody out there with any ideas where to look next?! Heeeeeeelp!! Edited December 8, 2011 by CARSmith56 Quote Link to comment Share on other sites More sharing options...
Mackpro Posted December 8, 2011 Share Posted December 8, 2011 When you turn the key on, does the red X and yellow lighting bolt come on for 2 seconds the go out? And also does it have a Auto-shift or Ultra-shift (automatic) transmission? I have seen the EUP (unit pump)harness short out against the block and cause this problem Quote Link to comment Share on other sites More sharing options...
CARSmith56 Posted December 9, 2011 Author Share Posted December 9, 2011 Thank you! We'll check out that harness first thing Monday! Quote Link to comment Share on other sites More sharing options...
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