HPDI Z250 TXRD Cuts out

[Paul Gaines]

My 2005 HPDI Z250 TXRD cuts out under load. It needs to warm up for about 20 min. Then from a idol when I give it 3/4 to full throttle it gets up onto plane then cuts out for 1-2 seconts then takes off again.
I took it to the shop they said it had 6 overheats and one low fuel pressure codes. they had it 2 months looking for the problum and no luck.
any sugestions would be great.

[boats.net]

With 6 overheat alarm codes and low fuel pressure code you are dealing with different at the same time. There are 3 fuel pressure readings on that engine low, medium and high and they all need to be checked, if it was a low fuel pressure code that means a problem with mechanical fuel pump or a restriction in fuel lines or filter going to engine, simply the engine is not getting enough fuel, then need to do a fuel vacuum test on mechanical fuel pumps and lines as per the service manual. The overheat codes are different problem, it could be the motor is mounted too high on boat, jack plate adjusted too high, running motor in weeds in water, running engine on a garden hose flusher will sometimes make engine overheat (I connect the 6 cylinder engines to 2 garden hoses at same time earmuffs and flush hose adapter).

[Paul Gaines]

All three fuel pressures were within spec. also vacuum test was fine. We replaced the fuel separator on the transom, pulled up the deck and inspected the fuel tank, lines, and fuel pick up. All were fine, clean and clear of obvious contaminants. We ran about 30 min both at *****ing speed and wide open and still the same cut out.
Could it be a relay? It has a main, fuel and I’m not sure what the third does. When it cuts out its like hitting the kill switch and releasing it really quick. On/off it kills for maybe 1 second.
Also to address the overheats we lowered the engine as for as it would go.
It may have been run without the flush hose connected. No alarm. Cut out problem started after that.
Engine has never been run on earmuffs

[Ken]

Paul,
During this 1-2 sec cut-out at 3/4 throttle, are you hearing any alarm? Also, have you noticed if you are losing power/signal to the console gauges, as if you had turned the ignition completely off?
Ken K

[Paul Gaines]

No alarm, and a slight drop on the volt meter.
I wish it would throw a bell then at least I would have a code to start with.
I spent the day going through more rigging. the boat is a 2000 with a re-rigged 05 HPDI. All new yamaha riogging. I did notice some "hokie" wiring near the key, a few grounds that they love to jump from gauge to gauge, but other then that nothing that stood out. Sooooooo thursday I take it to a shop with a dyno, I will sit with a glass of cold ice tea and wait.......

[boats.net]

The main relay and injector driver relay or even fuel pump relay (if it didn't loose fuel pressure at VST then probably ok) could cause a loss in voltage if faulty, more so in rough sea's. The main and driver relay (located under fuse cover) are easier to replace than test but can be tested with an analog voltmeter and test adapters. Check all ground wires on engine for loose or bad connections.