frankensammi. sure.
pinch return and 60psi happens. (the shunt test) this makes pressure 2 times normal and over injects same so is a valid test.
fpr does this. (this is normal , as you advance the throttle the vacuum drops and fuel pressure rises the same amount,
https://fixkick.com/INJECTORS/PUMP/reg-graph-mpi-g.jpg
that test proves the injector x4 are clogged.
or proves ECU underjects (pulses to the 4injectors)
THE MAF weak or only dirty is first.
LTFT will reflect the fact that fueling is lean. and slam trim full rich. (if 02 shows it going lean LTFT goes rich correcting this state. if not controllable it rails the LTFT and sets a DTC error for going off the rails, I call it.
forget STFT it moves faster than humans can see, only LTFT matter, slow and usefull to track.
the O2 sensor failing , most times cause rich not lean. (0v O2 causes full rail rich)
MAF tops list of causes, this is the primary fueling device here, #1 top dog.
The ECT needs to be at 300 ohms or 180F degrees hot, the scans show what it is.
the ECU scans show maf air flow too, but is a chicken and egg test. very hard to test. most times cleaning it works best.
one trick is to unplug the mAF and the MAF simulator inside the ECU (firmware) , causes more FAKE maf air flow and engine wakes up. DTC errors happen now dead maf, and limphome effects.
https://fixkick.com/sensors/92-95MAF/92-...sting.html
pinch return and 60psi happens. (the shunt test) this makes pressure 2 times normal and over injects same so is a valid test.
fpr does this. (this is normal , as you advance the throttle the vacuum drops and fuel pressure rises the same amount,
https://fixkick.com/INJECTORS/PUMP/reg-graph-mpi-g.jpg
that test proves the injector x4 are clogged.
or proves ECU underjects (pulses to the 4injectors)
THE MAF weak or only dirty is first.
LTFT will reflect the fact that fueling is lean. and slam trim full rich. (if 02 shows it going lean LTFT goes rich correcting this state. if not controllable it rails the LTFT and sets a DTC error for going off the rails, I call it.
forget STFT it moves faster than humans can see, only LTFT matter, slow and usefull to track.
the O2 sensor failing , most times cause rich not lean. (0v O2 causes full rail rich)
MAF tops list of causes, this is the primary fueling device here, #1 top dog.
The ECT needs to be at 300 ohms or 180F degrees hot, the scans show what it is.
the ECU scans show maf air flow too, but is a chicken and egg test. very hard to test. most times cleaning it works best.
one trick is to unplug the mAF and the MAF simulator inside the ECU (firmware) , causes more FAKE maf air flow and engine wakes up. DTC errors happen now dead maf, and limphome effects.
https://fixkick.com/sensors/92-95MAF/92-...sting.html
http://www.fixkick.com