Re: 225 ox66 problems...
throw the trim sender in the creek and fuggitaboutit.
the trim sender on an OX 66 motor DOES NOT affect the oiling system in anyway.
that was only used on 2.6L V6 from 1990 to 95.
96 and up V6 uses the V76 3.1L control for the PBS system.96 and up V6 use a pulser coil signal to tell the control module the engine is running and oil transfer is allowed.
no run signal no oil transfer via automatic.
I would check the inline check valve and the oil pump shaft seals as they can fail and can be replaced.
max fuel vacum at the lower lift pump is 6" Hg on that engine but I like less than 4" HG.
the resistor was NOT your problem.
the resistor is used to drop pump voltage slowing the pump at speeds below about 1400 RPM, above 1400 or so the pump ground bypasses the resistor and takes it out of the circuit. above 1400 or so you can throw the resistor overboard and save weight.
on the O2 sensor, test the heater voltage at the blue connector for battery voltage with the key on.
test the green connector with the gray wires for a varying voltage between about .35 and about.6 v after a 15 min run above 3000 RPM.
voltage should vary rapidly between .3 and .6 at 3000 RPM.
.1 indicates very lean,.9 indicates very rich and the ECU will alter fuel delivery regaurdless of if its a correct signal or not.
if you dissconect it the ECU will fix fuel rich at idle and lean above 4000 do not run above 4000.
if this engine is anything but a VX225 it incoperates CCS.
means below about 500 RPM all six spark, from about 550 to about 2000 #5 DOES not spark, from about 850 to 2000 #2 does NOT spark.
VX motors DO NOT incorperate this feature.
when I say the ECU on that motor wont store a code it means this.
if the code is active it will register,however if the code is inactive it wont leave a record that it was ever set.
so if at idle my winky is showing code 1 doesnt mean at 4800 I wont be blinking a code other than 1.
this system only shows a code if the code is currently active, if its not you get code 1.
fuel rail pressure MUST maintain at 35 PSI at ALL rpm ranges or something is broke or clogged.
always remember how the PBS transfer system works for the particular engine your working with.
for others reading this always be aware that the replacement 84-89 v6 oil control modules now tap a pulser signal for normal transfer as well as the replacement V4 modules and the V4 from about 2004.
that way they got to eliminate the mercury switch. V6 2.6L from 1990 to 1995 still use the trim sender.
the OX66 system does NOT inject oil into the crankcase like all other yamaha systems. it adds all oil to the VST via a manifold. the check valve simply keeps oil from draining back OR keeps gravity from forcing oil into the VST when sitting.
the only way we can get oil into the airbox on that engine is via the vent line, serveral causes of oil tank overflow the most common is an incorrectly installed engine tank screen.
now a certain amount of fuel/oil spit back is normal and then the fuel will evaporate and leave the oil.
the gray hose on the lower port side of the airbox to the intake should remove this for combustion.
if the hose is dissconected,clogged or missing you will see it drip.
on that engine 225 OX66 any sensor other than the thermosensor and O2 sensor, if they fail out of range OR are dissconected timing will be fixed idle speed increases usually to about 1100 and top speed cannot be reached.
however a loose knock sensor can drive you nuts
