ecu losing voltage

[Mike Dieterle]

Hello my name is Mike and my wife and I are not new to boating but new to the yachting side. We have a 1996 320 voyager with twin 350 crusaders. We are frustrated at the moment due to the starboard engine dies randomly. Here is what I have done and found so far, installed new OEM electric fuel pump, new OEM anti syphon valve, new ECU unit. On to the trouble shooting part, at this time I have wired in a green light from the ECU to the fuel pump so I know when it looses voltage. Once it looses voltage you can turn the key off for a minute or so and restart the engine just fine, it may stay running for a minute or the rest of the day. At this time I feel like the problem is before the ECU and that's where I need advise on what to check next. I have cleaned what grounds I can reach and wiggled what wires I can reach as well, I keep hearing people comment of fuel and ignition relays but I can not fine them. I want to say thank you in advance for your all's help.

[km1125]

I would check the ignition switch. You might put a second "green light" on the "RUN" contact on the ignition switch to see if that loses power at the same time.

[Viper]

Welcome aboard Mike.
The ignition switch as mentioned is a good one. Check the oil pressure switch, if it is faulty or intermittent, the fuel pump won't run properly or at all. This is a safety feature. So I assume you have confirmed that indeed the fuel pump looses power?

You have the benefit of two engines, I recommend you stop throwing new parts at it unless you know for sure they are faulty otherwise you could be spending a fortune replacing perfectly good parts. If you suspect a part, swap it to the other engine and see if the fault follows the part. Swap only one part at a time so you know which part is causing the problem.

Post your engine's model number so we can look up some diagrams.

[Mike Dieterle]

I apologize I did say new on the ECU when in fact I did swap the port side over and the problem stayed with the engine. I was reading on this year model to see what fail safes these engines had and could never find if they have a engine temp or oil psi fail safe, not to sound rude or dis respectful in any way but are sure about the oil psi sending unit being tied to the fuel pump as a fail safe and if so I will buy one of them due to it be not that expensive anyways. I want to say as a new member I appreciate the quick response to my issue at hand. I posted in other groups and got a lot of smart ass answers which in turn I left the group.

[Midnightsun]

not to sound rude or dis respectful in any way but are sure about the oil psi sending unit being tied to the fuel pump as a fail safe and if so I will buy one of them due to it be not that expensive anyways.

I am with you on this as it does unusual however coming from Viper I would take this as fact.

[bud37]

There is one other part I would inspect very, very closely....the engine harness connector plug.......look at all the pins for some corrosion or broken/damaged wiring. They can be the source of much grief...you may have already done this......good luck man...


To add, anything with an electric fuel pump will or should have a safety shut-off in case the engine fails, you don't want the fuel still pumping.

[Mike Dieterle]

I want to say thank you so much in such a short time for the helpful advice, as I stated earlier on other sites I would be more frustrated by now due to the un wanted advice or sarcasm. I have a few leads from this group that I will try and with any luck one of them will fix our issue. I will keep everyone posted as we go along to may be help future boaters of a similar situation.

[Viper]

Source of the post There is one other part I would inspect very, very closely....the engine harness connector plug.......

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