I recently bought a diablo predator. I set it on the 85 tune and it will throw that p1093 code- low pressure in fuel rail during regiment or something. after some research on this site, i did some testing: under normal driving no code will come up, just on hard acceleration. I have not checked to see if it throws during stock tune. I also checked my oil (dipstick) and there is NO diesel smell whatsoever and oil psi is aournd 50-60 at idle 75 at in motion. been there since i have owned the truck (no crazy pressures). Oh, and I replaced my fuel filter b4 installing tuner. thanks guys.

 

it may be a dirty fuel filter or a bad fuel pump

 

well i actually installed the tuner and got the code. so i cleared the code the next day and replaced the fuel filter then made some hard accelerations and the code showed again. I cleared it and drove around town (normal driving) and checked it and no code. dunno

 

week pump lift pump maybe, on the Cummins you can suck the presser down at wot on a weak pump but dunno about the Duramax. will help all that i know how to.