Bad Ground on HPDI

[Br3ttc@hotmail.com]

Folks,

I have had all of the standard filter/HP Pump issues with my HPDI but when I took the boat out today and after hitting some rough seas the 150 lost power intermittently. If I shut the motor down she would run normal for a time then start loosing power.

I had just changed one of the batteries and when I first fired her up the gauges took a few seconds to come on and it motor stopped twice at the dock.

Maybe it's wishful thinking but I live 90 minutes from Key Largo and am hoping I created a bad ground and the ECM is cutting out when the ground is knocked a bit loose.

Is this possible? Obviously I need to check the gas and filters too. Just wondering if a loose ground could cause this type of behavior.

[Sequoiha]

hit rough seas and started running bad, sounds like junk in the vst being sucked into the filter..

[Br3ttc@hotmail.com]

Folks. fixed the electrical issues, replaced the fuel/water separator w/ a new 10 micron filter and boat ran great for an hour and re-emerged.. Ran a gauge and low pressure is fluctuating between 47-50 off the VST so I assume this is likely the High Pressure pump which has been rebuilt twice in the last 20 hours or running by Flagship.

Is is possible the pump is just bad and can't be rebuilt. Flagship is suppose to be about the best.

Thanks,

Brett

[rodbolt17]

HP pump sensor can be monitored with a volt meter.

[Br3ttc@hotmail.com]

Thanks! Will check it.

Being that it is a mechanical pump if there was an electrical problem would it cause the pump to act like it was failing? Reason I ask it that it's been rebuilt twice in the last 20 hours of operation and I am wondering if this might have been the issue all along.

The other strange thing is that if I restart the motor it seems to reset the HP pump for a short time. It runs better for 20-30 minutes. Then begins to drop from 740 PSI to 360 back up and down to 420 etc.

Just wondering there is a bad control wire etc and pump thinks it's suppose to shut off?

I'll be darned if it is a electrical problem vs mechanical :-)

[99yam40]

If the filters are clean and VST is not running out of fuel,
have you check the pressure regulator?

monitoring the amps the HP pump is pulling or the voltage should tell you if pressure drop is due to it loosing electrical connection

[Br3ttc@hotmail.com]

Thanks 99Yam40

If we hook it up the computer will it also show the draw for the HP Pump? Just trying to sort out how to monitor the pump while under way :-)

I have enough trouble trying to view the VST pressure gauge :-)

[Br3ttc@hotmail.com]

If the filters are clean and VST is not running out of fuel,
have you check the pressure regulator?

monitoring the amps the HP pump is pulling or the voltage should tell you if pressure drop is due to it loosing electrical connection

99 Yam. Where is the pressure regulator? Is it after the VST before the High Pressure Pump?

[rodbolt17]

ok
lets all get on the same page with terminology.
the low pressure system is the primary filter cup,2 lift pumps and the line feeding the VST, should maintain 3-6 PSI at all operating RPM.

medium pressure system is the liquid in the VST the electric boost pump in the VST the filter in the VST the VST 50 psi regulator and the inline canister between the VST and the mechanical high pressure pump.

the high pressure system is simply the mechanical belt driven pump its 625 PSI regulator and internal non field serviceable filters.

now that that is over.

dirt simple to test.
monitor BOTH medium and high pressure AT the same time and AT the failure RPM and load.

if you maintain 50 psi on the medium and cannot maintain 625 PSI on the HP then its either a clogged inline filter or a HP pump issue.

if BOTH medium and HP pressures fall its either the lift pumps or the VST or a fuel restriction/air leak on the lift pump intake side.

see ho easy this is.
each subsystem is totally dependent on the next.
if one fails the others may and the engine doesn't run correctly.

[99yam40]

If the filters are clean and VST is not running out of fuel,
have you check the pressure regulator?

monitoring the amps the HP pump is pulling or the voltage should tell you if pressure drop is due to it loosing electrical connection

well as you can tell I did not know what I was talking about, so forget about what I posted