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got a nightmare 2017 pathfinder 3.5 direct injection. alldata does not offer much info about operations or diagnostics. history on car it has been to several shops before coming to me(do not want to hear should have passed on this one please). not sure what original problems were but from what i am told dealer recommended timing chains, another shop installed new chains. still having problems. has had a rebuilt pcm installed, new cam sensors, new crank sensor and probably other items as well. went back to dealer and they found aftermarket gps installed poorly with bare wires rubbing and refused to work on it. came to me with customer stating it just was not getting fire at the spark plugs. i scanned and found security codes with security light flashing. had locksmith come and reset. security light now off with no more security codes. would crank but no start. code p0087(low fuel pressure at rail). installed pressure gauge at rail and only getting about 75 psi cranking at rail. low pressure side tested good before installing new high pressure pump. ran through some checks and found is getting fire at the plugs now, will hit on brake cleaner sprayed in throttle body. ran through the tests for code alldata has and came to high pressure fuel pump faulty. got one from dealer and still have the same problem. i am thinking either timing chains out of time(since pcm controls fuel pump pressure by controlling solenoid on high pressure fuel pump) or problem with pcm control of solenoid on pump. need to know how to test signal at solenoid on pump(what voltages to look for and what types of signals) and how to test if it is timed right(have to pull engine to access timing chains so looking for cam/crank signal correlation with lab scope). i have a snap on vantage lab scope to check signals if i just knew what i was looking for.
The rail pressure is controlled through pulse width modulation. The fuel control solenoid on the inlet of the hp pump is fed with battery/system voltage and then pulled to ground through the pwm control signals by the control module.
There are normally open and normally closed designs. One will have no fuel pressure at all without a working solenoid while the other one will go full gorilla.
Apart from the corresponding circuit tests you always could activate the control solenoid manually to test it's condition.
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