First, I have been chasing a high speed miss issue. Bass boat ... jumps up on plane, but as soon as I get up around 5000 rpms I feel a miss. Boat normally will get up to 71 mph gps, but now can only get 67. It will not loose rpms or speed but the miss is evident and constant. If I come off the throttle to around 4500 rpms miss is gone. to give some history, power head has about 11 hours on it, (miss was there before rebuild) #2 piston broke at the exhaust port side.... All new internals except for crank and rods, bored all cylinders .020 oversize. I have replaced all fuel filters ( VST, fuel water sep, medium pressure filter, see through can filter, fuel regulator and filter, High pressure filter baskets 4ea., injectors sent off cleaned and tested with new filter baskets) new low psi fuel pumps. Medium psi fuel is at 50 psi, YDS high pressure is around 987 to 1017 psi.... I have turned my attention to the electrical side.....All 6 motor coils ohm the same, all plug boots ohm the same and test good according to Yami Service manual. I found a couple of things that I need advise or insight on.
I noticed that if I'm running my YDS to monitor sensors while running wide open my high pressure fuel reading stays above 950 to 1017 psi, but if I switch screen a look at the MPA fuel reading in the diagnostic screen it shows that I dropped fuel MPA to 5.68 which would equate to below 800 psi on fuel pressure.... is this normal.
2nd issue, I notice that if I trim up while getting on plane my Medium pressure drops to around 42 psi but stays at 50 psi if not using the trim.
I started to check my voltage because I thought maybe I was pulling power from the electric fuel pump when using the trim switch causing the psi drop on fuel....
3rd issue.... checked the red (pink) wires unplugged from the back of the fuse block from the voltage regulator, 1 side reads 14.45 volts, the other reads 7.23 v. according to the service manual both are supposed to have 14.5 volts..... could this be my problem. I worked the trim switch while testing the voltage at the fuel pump and it does make the voltage drop to 12.65 at the pump red terminal.
4th issue, my electric oil pump under the VST does not pump oil into the VST tank when motor is running..... has 12.5 volts going to it, but no ground, I see it receives a ground signal from either to pulsar coil or the ECM..... if I run a jumper ground wire to the pump, I can make it pulse oil on and off with a ground.....
With this last issue, I'm wondering if maybe I have a bad ECM causing all these issues..... or does this " pulse" electric oil pump only work at certain RPMS, manual says it should work any time the motor is running.....I'm tired of chasing, and spent some serious cash already, appreciate some help and all ideas are welcome.
I noticed that if I'm running my YDS to monitor sensors while running wide open my high pressure fuel reading stays above 950 to 1017 psi, but if I switch screen a look at the MPA fuel reading in the diagnostic screen it shows that I dropped fuel MPA to 5.68 which would equate to below 800 psi on fuel pressure.... is this normal.
2nd issue, I notice that if I trim up while getting on plane my Medium pressure drops to around 42 psi but stays at 50 psi if not using the trim.
I started to check my voltage because I thought maybe I was pulling power from the electric fuel pump when using the trim switch causing the psi drop on fuel....
3rd issue.... checked the red (pink) wires unplugged from the back of the fuse block from the voltage regulator, 1 side reads 14.45 volts, the other reads 7.23 v. according to the service manual both are supposed to have 14.5 volts..... could this be my problem. I worked the trim switch while testing the voltage at the fuel pump and it does make the voltage drop to 12.65 at the pump red terminal.
4th issue, my electric oil pump under the VST does not pump oil into the VST tank when motor is running..... has 12.5 volts going to it, but no ground, I see it receives a ground signal from either to pulsar coil or the ECM..... if I run a jumper ground wire to the pump, I can make it pulse oil on and off with a ground.....
With this last issue, I'm wondering if maybe I have a bad ECM causing all these issues..... or does this " pulse" electric oil pump only work at certain RPMS, manual says it should work any time the motor is running.....I'm tired of chasing, and spent some serious cash already, appreciate some help and all ideas are welcome.