Even Experts Gets Stumped

[Capt Ken]

Just to let y'all know, even us so called trained experts gets stumped and this one has my tech advisor stumped also.
HPDI 150, will run in start position but not in run. First thoughts would be ignition switch but I'm running it with a breakout box. Wired key in start position, disconnected wire to starter solenoid to keep it running with starter disengaged and found diagnostics won't work with key in start position. No trouble codes showing in static mode.
History of engine was water in fuel system. Just replaced the pump in the VST and pressure is good. Running off my portable tank with non ethanol. Still trying to decide if it's fuel or ignition. Digging into the HP pump and injectors this morning.

So you know your day isn't going well when your Official Tech guy says HUH?

 

[99yam40]

Re: Even Experts Gets Stumped

Is there 12+ getting to pumps and ECU in the on position?
Trying to remember if the yellow wire had a splice in the harness.
Seems I remember reading about something like this before, but killed those brain cells already

 

[Capt Ken]

Re: Even Experts Gets Stumped

12 volts to fuel pumps and VST pressure is holding at 50psi even when engine stops. Main relays check out good. Just got off the phone from the tech rep again and after I studied the wiring diagram last night, the start circuit throws 12 volts to the ECU on start up but runs off its own juice after that. In start mode, it runs off all 6 cylinders but when the key is released back to run, it goes in to sequencel firing and only fires 4 until shifted in gear. No splices in the wiring and everything looks good and tight. I'm starting to lean more toward fuel this morning being it has begun to not run but a few seconds in the start position now. I have determined I'm in uncharted waters.

 

[Grub54891]

Re: Even Experts Gets Stumped

If it runs off its own juice,could the charging systym be bad? No juice from the systym itself= no run....?

 

[Don S]

Re: Even Experts Gets Stumped

I would sure be asking the owner what happened before this became a problem. Did he work on ANYTHING on the engine, and on the boat, if so what, and no matter how minor.

Had a customer that had a problem with his windshield wipers blowing fuses. Found the problem (eventually without asking) but took the boat apart looking. Found he hung a small good luck charm above the cabin door, and don't you know the wires were right behind where he put the screw in and shorted the wires. After that, I always ask a lot of silly sounded questions to the owner. Many times it has paid off with a hint to where the problem was.

 

[Capt Ken]

Re: Even Experts Gets Stumped

Comedy of errors it appears but now running fine. Removed the HP pump and disassembled. Cleaned and replaced the filters in both pump and injectors. Retried and the engine would run when key released but maybe on two cylinders at best. Replaced sparkplugs and it ran fine.
So here is what caused the problem and solution. Ethanol fuel got water in it and phased out. Water/alcohol mixture corroded the inlet valve of the VST tank to where it barely let any fuel in. Fuel pump failed due to not keeping enough fuel in VST tank to cool it. Water/alcohol solution went through fuel system and screwed several spark plugs.

So after cleaning VST and replacing the fuel pump, I used shop fuel tank but the results was what happened above. The cleaning of the HP pump and changing filters got it close to running but being several spark plugs was drowned by water/alcohol, they didn't fire. In the start mode, all six cylinders fired which meant the two or three that wouldn't fire, was carried by the extra two cylinders upon startup. When the start mode was exited, cylinders 2&3 cut out and the engine is suppose to run on the other four. But being some of them wasn't firing, the engine would go dead when 2&3 cut out. I might add that the filter inside the HP pump was full of crap whereas the injector filters was clean.

The boat has no filter inside the boat so I'm surprised this hasn't happened before. Gotta install a big 10 micron filter tomorrow in a small hole.

 

[99yam40]

Re: Even Experts Gets Stumped

I would recommend the tank be drained and cleaned also, still stuff hanging around it there and will just cause problems later on even with the filter installed.

Fuel pressure reading should have showed loss if filter/screens were plugging.

Did the plugs show any visual sign of problems?
Carbon or moisture shorting them out or other type of contaminates, should they be visible if spark is kept from jumping?

 

[Capt Ken]

Re: Even Experts Gets Stumped

Can't read the HP pump without laptop and the diagnostic program won't read unless engine is running. But once running, the HP pump was within specs. Around 730 psi. The alcohol / water mixture saturates the ceramic center of the spark plug and grounds internally. So one can check fire all they want and everything will check normal. You can use an ohm meter and can sometimes find the grounded plug.
I'm deciding on if I want to pump the tank or instruct the owner. Not like I have somewhere to put 60 gallons of bad fuel. A bit much for my used oil tank.

 

[99yam40]

Re: Even Experts Gets Stumped

Not just pumped , but cleaned would be my recommendation. And it is up to him , but at his cost to dispose of it.

I guess a KV tester would have worked, as a shorted plug should not show up as high of voltage as it did not have to jump the gap, but I am not sure on that but makes since to me.
not sure if voltmeter would read HP if not running even if diagnostic could not

 

[Capt Ken]

Re: Even Experts Gets Stumped

Something I did learn. A HPDI will run at idle without the help of the HP pump. The VST pump will provide enough pressure for the injectors. Also, with the engine filter, VST filter and inline filter, how in the heck did anything get past them to lodge in the HP pump filter?

 

[99yam40]

Re: Even Experts Gets Stumped

agree with all the filters and screens it would seem impossible to get there.

Maybe just being under a different pressure and heat causes stuff to drop out of suspension in the tank

Seems like I have heard that before on running at idle