Optimax dies randomly. Code: Engine Data Bus

[iammarcuse]

2004 Optimax 225 on a 21' Ranger. The motor will cut out instantly while underway. No sputtering or loss of rpm first. It literally just dies completely like you turned off the key or hit the kill switch. Sometimes 10 times a day, sometimes not at all. The smartgauge reads "Engine Data Bus". The diagnostic computer shows no faults. When you go to turn the key again sometimes it will start right up, other times nothing for a minute or 2. Sometimes if you hit the trim switch it will then start up. Either way it always starts up again. The gauges are still lit up so I know the key power is still on.
It has been to two different dealers 5 or 6 times. They replaced the entire computer for $5000 and nothing changed. They have done new lift pumps, fuels lines and filters and screwed around endlessly at $120/hour. They say that there is nothing wrong with it, but they are not the ones driving it in the middle of the lake when it quits. Super frustrating.
Anyone have any experience with this problem? Any help will be appreciated.

 

[alldodge]

Have they replaced the relays yet?

 

[schematic]

Check all grounds. even the heavy cables from battery to engine...

 

[iammarcuse]

All the grounds at motor and battery have been checked.

Alldodge - What relays?

 

[alldodge]

Most all EFI motors (OB, IB and I/O) have at least one relay, and the Optimax manual I'm looking at has one, the Main Power Relay. Where it is I don't know but may be next to the trim relays

 

[iammarcuse]

There are 3 identical next to each other. 2 trim and one engine. I will swap with one of the trim ones and see if that helps. I saw that mentioned on another forum. Thx

 

[iammarcuse]

Swapped the relays. Thought I had it beat. Ran great for half a day and then back to stalling. Any other ideas.

 

[alldodge]

This is a hard one to find, but look for corrosion/loose connection somewhere. Might even be a bad ignition switch, loose or corroded contact on a relay or other item. Bad ground

 

[jamescerano5]

2004 Optimax 225 on a 21' Ranger. The motor will cut out instantly while underway. No sputtering or loss of rpm first. It literally just dies completely like you turned off the key or hit the kill switch. Sometimes 10 times a day, sometimes not at all. The smartgauge reads "Engine Data Bus". The diagnostic computer shows no faults. When you go to turn the key again sometimes it will start right up, other times nothing for a minute or 2. Sometimes if you hit the trim switch it will then start up. Either way it always starts up again. The gauges are still lit up so I know the key power is still on.
It has been to two different dealers 5 or 6 times. They replaced the entire computer for $5000 and nothing changed. They have done new lift pumps, fuels lines and filters and screwed around endlessly at $120/hour. They say that there is nothing wrong with it, but they are not the ones driving it in the middle of the lake when it quits. Super frustrating.
Anyone have any experience with this problem? Any help will be appreciated.

Same problem, 2005 Optimax 175. The problem started around 500 hours. First noticed while under hard acceleration after a 10 minute idle. No alarm just dies. Has anyone ever solved thisone?