2004 HPDI cutting out

Hi Everyone,
I have 320 trouble free hours on my 2004 250 HPDI. I know that's hard to believe. Over the last 10 hrs, the motor has developed an intermittent stall/cough..in other words, it will cut out completely for a brief instant at higher RPMS (3500-4500). At first it seemed to be when I hit a wave or boat wake, and now it happens on acceleration and the boat is barely useable. So far, I have visually inspected the battery concetions, key switch and main wiring harness. I recently changed the plugs.

I copied this post from someone who wrote it back in 05...There were no responses then. I was wondering if someone else has experienced this problem. I have a mechanic coming to look at the engine this week but was hoping to give him a better idea of what was going on.

Any help would be greatly appreciated.

Thanks

Mike Bruno

[boats.net]

Could be a bad main relay.

Thanks..I'll mention that.

[Mdelgado]

Thanks..I'll mention that.

Any update on this?

I have the same issue with my 300 cutting out, mainly when hitting waves hard. Already had to replace my fuel pump relay. So the main relay wouldn't be a bad guess.

[rodbolt17]

my guess would be debris in the VST.
but what do I know.

[Mdelgado]

my guess would be debris in the VST.
but what do I know.

This happens before and after new filters (vst/canister/HP pump filters) are installed. This is more of an electrical issue, where it's a real quick off/on.

I would still be able to run flat out 5600 rpms. When my filters start getting build up, performance declines for obvious reasons..

I see a lot of people with this issue in forums, but no one follows up to say how it was resolved

[Mdelgado]

Could be a bad main relay.

Do you happen to have the part # for the main relay?

[rodbolt17]

other than a few that the protective sleeve on the power tap wire at the starter that were to long, electrical issues with the z250 are incredibly rare.
however if fuel pressure drops much below about 900 PSI it will shut down almost like you flipped the keyswitch.
nice thing about it is YDS will record the last 13 min of operation.

[Mdelgado]

other than a few that the protective sleeve on the power tap wire at the starter that were to long, electrical issues with the z250 are incredibly rare.
however if fuel pressure drops much below about 900 PSI it will shut down almost like you flipped the keyswitch.
nice thing about it is YDS will record the last 13 min of operation.

Mines a z300 and these past couple years I've been chasing electrical issues, but all due to corrosion and bad relays so far. I've run it on yds and when it cuts out the software acts as if it lost connectivity to the ECU and goes back to the main screen.

[rodbolt17]

if you get the communication error msg, most likely for some reason the ECU lost 12v.
look carefully at the wiring diagram concerning how the main relay gets turned on.

[Mdelgado]

I wanted to follow up on my issue in case anyone was following. As I was going through my electrical system and replacing my battery combiner and switch with a new blue seas unit, i found my issue. The + cable from the outboard to the battery selector was very loose. Even with a lock nut, somehow it backed off. Haven't had the issue again this season tightening all connections and replacing switch. I probably wasted $300 on the new switch/combiner, but it is nice...

[rodbolt17]

why do folks waste money on combiners?
the engine has a battery isolator built in.
you paid for it when you bought the motor.

like turn signals, you paid for it why not use it?

[boscoe99]

why do folks waste money on combiners?
the engine has a battery isolator built in.
you paid for it when you bought the motor.

like turn signals, you paid for it why not use it?

1. Less costly.

2. Easier installation.

3. Just as effective.

Would be three of my guesses.

Now a bigger question is why does Yamaha US offer combiners for sale?

2014 Yamaha MRP Catalog

[rodbolt17]

dunno.
BUT ALL V6 Yamaha from about 1992 have a built in isolator to charge a second battery.
most 4cyl 150 and up also have the isolator.
MOST riggers have no clue the isolator is there.
it works and works well.
you paid for it, why not use it?

[boscoe99]

dunno.
BUT ALL V6 Yamaha from about 1992 have a built in isolator to charge a second battery.
most 4cyl 150 and up also have the isolator.
MOST riggers have no clue the isolator is there.
it works and works well.
you paid for it, why not use it?

Almost all.

Agree about the riggers. But every one can't know all things about all Yamaha motors. Too much stuff to know.

It does work well.

If the optional lead was paid for (part and installation) then certainly I would use it. Now if it costs extra (part and installation) which it does, then I for one would go down the combiner route as it is cheaper, faster to install and just as effective. IMO.