help needed for F100

[madharchod]

i have changed the comp pump ,TPS,switch,and filter plus the spring diaphragm on the low pressure pump,cleaned the VST and i have also changed the fuel line and put new primer bulb ,
all these problems was shown on the yds machine,have replaced everything but still i get intermittent stalling at high speed
compression is even in all cylinder at190kpa
fuel pressure is 100%
injector rail pressure is above 60%
have replaced new injector as well
iam too busy just need help if someone knows what else can be done to get these motors going good of will they end up being good anchor
thanks

[damirdaco]

put the new spark plugs

[99yam40]

pressure readings in % means nothing to me.
Post what the reading are.
If they do not meet specs in manual then that should tell you something is wrong in that area

If pressures were taken at same time , it would mean everything up to lift pump is good. So filters/screens after that would be where I would be looking

[madharchod]

99yamy40 i think you are an apprentice mate just stick with your kind it will help you

[rodbolt17]

ok
I am a yamaha master tech with over 30 yrs of wrench twisting with a six year stint in the US navy as an FC,means I was an electronics tech with ordanence quals.

and I am going to tell you the same thing.
there is NO % on rail pressure.

there is NO TPS switch.

dont know what a comp pump is.

when it stalls does it slow down or simply shut off?
what is required to restart?

[madharchod]

dear rod bolt i never challenged your expertise ,its just iam on water most of the time so i thought get some views on whats happening to the motors .first the tps is the throttle position sensor,and the comp pump is the the new fuel pump as i said unquote the rail pressure was measured different equipment .there is no problem re-starting its starts all the time it just cuts off at high speed some time
cheers

[rodbolt17]

you simply cannot measure rail pressure as a percent.
rail pressure on most yamaha EFI four strokes is about 42-45 PSI.
much below that and the engine shut down can be quite abropt.
unlike a carbed motor that will slow down and stumble as the fuel bowl runs dry the EFI will try all the way till it cant and bam,its quit.

that motor also uses a 12v battery powered ign system.
TCI
any loss of voltage from the main relay will shut off the pump,the ECU and the ign system.

[madharchod]

thanks for that rod
fixed the problem for now will wait and see if anything else plays up the motors running fine for the moment
cheers