2006 F225 fuel issue

[pstephens46]

apparently my verbiage on the diagram legend is confusing.

"driver" means relay - a "remote con*****ed switch"


the relay itself provides the ground for the LP pump to run - when it is switched "on"

the ECU provides the ground to switch the relay (which then "switches on" the pump!)

Got it. My weekly electrical lesson. No more for a few days.

[fairdeal]

The driver has nothing to do with the HP pump.

Boscoe is momentarily forgetting this particular Yamaha model idiosyncrasy?


The part pictured earlier in the thread controls both the Low and high pressure pumps -

it contains two separate electronic relays.


The ECM grounds the B/W wire to switch on the LP pump

it grounds the L/R wire to switch on the HP pump

[boscoe99]

Boscoe is momentarily forgetting this particular Yamaha model idiosyncrasy?

The part pictured earlier in the thread controls both the Low and high pressure pumps -

it contains two separate electronic relays.

The ECM grounds the B/W wire to switch on the LP pump

it grounds the L/R wire to switch on the HP pump

Boscoe went brain dead.

[boscoe99]

fairdeal, double check me on this diagram.

[marchmadness]

I was reading this post. why think its electrical right away. Does the vst have fuel when it dies?? Squeeze the ball until hard and fill the vst ,run the engine . When the low pressure pump cycles you can hear it and feel it. Also the first time it died at 4100 rpm, clogged vst filter?

[Hooked Up]

marchmadness, I am going to start with the vst filter and such tomorrow. I had thought low pressure pump because it would run fine for 3 to 5 minutes after priming with the primer bulb (assumed this was filling the vst) before it started to die. I thought if the vst was clogged, it would run like crap from the get go. Thanks for the input. At this stage I am not sure where to start to isolate the root cause and all input is much appreciated.

[fairdeal]

I had thought low pressure pump because it would run fine for 3 to 5 minutes after priming with the primer bulb (assumed this was filling the vst) before it started to die.

I like that thinking - the pump itself, or some other restriction (either on suction or pressure side) or a suction side air leak

have you inspected the F-shaped filter at the inlet to the VST?
the pressure-regulating valve that is zip-tied to the LP pump?

I thought if the vst was clogged, it would run like crap from the get go.

ehh - I would think most likely limiting at high load/high rpm
and pumping the bulb wold have no influence whatsover

[Hooked Up]

I have replaced the fuel/water separator, bowl fuel filter, and F shaped filter between LPP and VST. Tomorrow I am replacing the HPP filter and checking out the VST tank. I will then button everything else and run the motor and throw the gauges on and see what i get for pressures and pump operation to either isolate or rule or that end of the problem.

[Hooked Up]

Ok, VST HP pump filter is replaced. It had some particulate but far from clogged. Put the system back together and t'd the vacuum pump just before the fuel filter and placed the high pressure gauge on the shrader to the to the right of the VST. Started motor after pumping primer bulb to fill VST. Motor started and ran smooth for about 30 seconds before it started to sputter and died. 4 to 6 Hg on the vacuum gauge and 40psi in the high pressure side. I did the clear tubing on tube going into the VST from the low pressure pump. No air in line.

I am beyond lost at this point. I also moved a gauge to the fuel line coming out of the LP pump and verified pressure out of the pump.

Unless I am missing something it appears as though (at least into the VST) the fuel pumps are providing fuel to the motor...I just dont know where to go next.

Any tips, pointers, something I am not checking or verifying.

[boscoe99]

Ok, VST HP pump filter is replaced. It had some particulate but far from clogged. Put the system back together and t'd the vacuum pump (gauge?) just before the fuel filter and placed the high pressure gauge on the shrader to the to the right of the VST. Started motor after pumping primer bulb to fill VST. Motor started and ran smooth for about 30 seconds before it started to sputter and died. 4 to 6 Hg on the vacuum gauge and 40psi in the high pressure side. I did the clear tubing on tube going into the VST from the low pressure pump. No air in line.

I am beyond lost at this point. I also moved a gauge to the fuel line coming out of the LP pump and verified pressure out of the pump.

Unless I am missing something it appears as though (at least into the VST) the fuel pumps are providing fuel to the motor...I just dont know where to go next.

Any tips, pointers, something I am not checking or verifying.

Vacuum looks excessive. At WOT the vacuum should not exceed 5.9"Hg. At idle it should not exceed 3.14"Hg. Lower is better, but too low can indicate an air leak.

[fairdeal]

Started motor after pumping primer bulb to fill VST. Motor started and ran smooth for about 30 seconds before it started to sputter and died.

ok, that's puzzling me.

The VST holds ~8 ounces of fuel - that's enough to run (idle) for quite a few minutes - far more than 30 seconds.

I would fill it with the primer bulb and then drain it and measure what comes out

(there is a Shrader on the VST cover which must be pressed so it will drain completely.

[Hooked Up]

I guess it would be handy if I noted that the 4 to 6Hg was sucking out of the external fuel tank.

[Hooked Up]

Ok, after setting for the last 30 minutes, and after looking for obvious disconnected things or something I missed, I turned it over again. Same thing, idel for 30 or so seconds, and then dies. This time I noticed an alarm from the helm. Single tone beep, and motor dies. Is there a list of what the tones mean?

[boscoe99]

I guess it would be handy if I noted that the 4 to 6Hg was sucking out of the external fuel tank.

If you are seeing 4 ~ 6" Hg at the tank then it is even worse at the primary fuel filter inlet. You got a fuel flow restriction big time. Not sure if that is your main problem but that needs to be fixed first.

[99yam40]

Ok, after setting for the last 30 minutes, and after looking for obvious disconnected things or something I missed, I turned it over again. Same thing, idel for 30 or so seconds, and then dies. This time I noticed an alarm from the helm. Single tone beep, and motor dies. Is there a list of what the tones mean?

what was the HP gauge showing when it dies?
If the HP pump is still providing pressure as it dies then running out of fuel is not the problem