wdrinnon

The vent valve can't close because there are no wires connected to it. The evap codes are tuned out for sure. i have bypassed the entire evap system. I have the tank venting to atmosphere, just for now to test, and the purge line is capped off. problems still exist. starting issues and still lean under load part throttle.

Thanks for the reply. After more investigation i have found that neither the tank pressure sensor or the the canister vent solenoid have wires connected to them. The wires are no where to be found either. is this because its an HD, did they have different style evap than the 1500 trucks? When would the purge valve be commanded to close if there is no pressure sensor reading or a way to close the vent valve?

I bought a 2003 1500HD to rebuild. Did new valvetrain, PRC Heads, TX speed cam and tuned. I noticed its running lean and has a hard time starting sometimes. I checked fuel pressure and it was a little low around 50psi key on engine off. replaced the pressure regulator(delphi) fuel filter (wix) and fuel pump (delphi). This increased the pressure to 55psi but problems still existed. i noticed when i replaced the pump that there is a pressure sensor on the top. the old pump had one and the new pump has one. The original had no wire connected to it. i assumed at some point it went out and someone just unplugged it, but i cant find the wires anywhere. i dont know if they cut them off or what. With this sensor being unplugged im assuming the EVAP system will never work. Will the purge valve ever open? and could this sensor being unplugged cause a fuel delivery problem?