F225 TXRC bogging down - fuel rail pressure question

[Crazy Train]

The high pressure fuel pump pressure at key on should be measured within 5 seconds. Reason being is that the pump only runs for about this amount of time.

Specified pressure at key on is 42 psi. At idle RPM the fuel pressure reference value is 37 psi. As the throttle is opened up the fuel pressure will rise until it gets near, but not at, 42 psi.

Your pressure values seem on the high side. Is the gauge new or known to be accurate?

What I would try is to have someone mist some gasoline into the air intake system at the time the motor starts to bog down. If it picks up and runs that indicates a lack of fuel. Problem could be the injector filters are clogged. If so, you will have fuel pressure to the injectors but insufficient fuel can get through the injector filters into the intake manifold.

Thanks boscoe. Great point: the gauge is brand new and, in comparison to your pressure values, seems to be reading consistently high at about +4 to +6 psi. (I will figure out if the gauge is accurate. That is, I need to test the test equipment.) If I assume the gauge is inaccurate and reading high, then rail pressure is likely sufficient and points to clogged injectors/injector filters. Thanks again.

[rodbolt17]

last thing I would suspect with those symtoms is a regulator.
I would suspect a VST filter or an injector filter or both.
the HP filter on that motor is about the size of a pencil eraser.

[99yam40]

If the pressure gauge is correct/accurate, I would think the pressure regulator could cause it also, and too much fuel is bad for proper combustion just like too little what do the plugs look like?

[boscoe99]

The high pressure fuel pump pressure at key on should be measured within 5 seconds. Reason being is that the pump only runs for about this amount of time.

Specified pressure at key on is 42 psi. At idle RPM the fuel pressure reference value is 37 psi. As the throttle is opened up the fuel pressure will rise until it gets near, but not at, 42 psi.

Your pressure values seem on the high side. Is the gauge new or known to be accurate?

What I would try is to have someone mist some gasoline into the air intake system at the time the motor starts to bog down. If it picks up and runs that indicates a lack of fuel. Problem could be the injector filters are clogged. If so, you will have fuel pressure to the injectors but insufficient fuel can get through the injector filters into the intake manifold.

[Crazy Train]

2004 F225TXRC on a Parker 25SE. The motor starts easily and idles nicely. However for the past few months, the motor has been bogging down when I try to accelerate to high speed to the point where I can barely get on plane at around 4200 RPM. The motor then begins to fade out, or wants to die out until you chop the throttle and return to idle speed, at which point, the motor idles fine. To attempt to troubleshoot this issue, I obtained a fuel pressure gauge to read fuel rail pressure, as this technique has been discussed on this forum many times. So today, at key on/engine off, rail pressure was 46 psi then dropped off to 40 psi after about 15 seconds. At idle of about 1100 RPM, rail pressure was 42 psi. At 4200 RPM, the rail pressure was reading between 48-50 psi. I was able to make it to and maintain 5300 RPM where the rail pressure maintained its reading of around 48-50 psi. The boat was still slightly sluggish but not as bad as earlier this year. Honestly, I suspected an issue with my HP pump filter in the VST so I was expecting below-normal rail pressures to be indicated. However, the pressures of 48 to 50 psi seem excessively high. Does anyone know if these rail pressures are 'normal'? Thanks!