alyakhim
New Member
- Joined
- May 15, 2012
- Messages
- 6
- Reaction score
- 0
- City, State
- ithaca ny
- Year, Model & Trim Level
- 1999 ford explorer xlt 4.
hello everyone. i am new to this forum and first i want to thank everyone for collaberating together to make a great explorer resource such as this. i have a 1999 ford explorer xlt with the 4.0 ohv engine and the returnless fuel system. since i purchased the vehicle in october i have been struggling with a lean condition on both banks and the cel with codes p0171 and p0174 that i just cant get rid of. i have ruled out any sort of vaccuum leak i have changed all the intake and plenum gaskets fuel injector o rings and every sensor on the intake assembly as well as the gaskets on the sensors that require them. however after doing all of that i looked into the fuel pressure and discovered that i measure only 27 psi at the rail and that is when the ignition is only in the on position and running. i have yet to monitor any major leakdown but i do know that after 10 minutes their isnt any pressure loss. i will do a longer test this evening. i have replaced the fuel pump and sending unit. the fuel filter and have recently ordered a new fuel pressure dampener but am not confident that will fix the issue because recent research led me to find this is a returnless electronic fuel system and when i purchased the dampener i thought it was a regulator. but what the hell i have already replaced everything else. the pressure measurement did not change between the old fuel pump and the new one. i am uncertain of where to go and look next as i dont really have many more parts in the fuel system for suspect. the vehicle suffers from hard starting. it may take up t0 5 to 6 seconds to start. and when veh icle is driven to become hot and it is shut off and restarted after approximately 20 min to half an hour of waiting it will run very rough and act as though it is starved for fuel and the only way to clear it out is to rev the engine for a slight amount of time and it will run and idle normal. i conclude that the engine is trying to build pressure at this time and clears up once achieved even though it only ever gets what i assume to be a bare minimum. if the vehicle were to be started after sitting say overnight. normally it will fire in only a few cranks. its normal idle speed is 1500 rpm which i believe to be very high. i do not have a fuel leak in a line and am tearing my hair out and spend every free second working on this issue. anybody with an idea on where to go next will be my hero. thanks - mike