2019 PCM Monsoon 450 Fuel Pump Relay Issue

[malibu7]

I have a 2019 23LSV with the PCM Monsoon 450 6.0L engine with about 140 hours. At the end of the 2019 summer season our fuel pump relay went out and was replaced with a new relay. Since putting the boat in the water this season the fuel pump relay has started to act up on us again. Occasionally when trying to start the boat it would crank repeatedly but not turn over (since it wasn't getting fuel), so when this happened I would pull out the fuel pump relay and put it back in which would usually fix the issue and we would be on our way. Now this issue happens just about every time we try to start the boat. The last time I started the boat it ran for about 30 seconds before dying. I have since put the old relay back in and that has worked for the time being but eventually the same issue arrises. I have ordered a few more spare relays to have on hand just in case we get stranded out on the water but my question is, what could be causing the fuel pump relay to burn out like this so frequently? I assume it could possibly be a bad/clogged fuel pump, clogged fuel filter, or an issue with the wiring harness that is providing too much amperage to the relay but I'm no mechanic. Has anyone else had a similar issue or can share some insight? 

 

*Edit: Forgot to mention one of the times the boat started up the engine was knocking/ running rough and got an error message on the screen that read "low fuel rail pressure." Again, removed the relay and put it back in and all was back to normal. 

Edited April 4, 2020 by malibu7

[justgary]

This sounds like the volkswagen issue I helped my son find on his Passat.  The official fix was to take the relay cover off and resolder all of the contacts on the relay board. 

I'm just guessing, but you could be the victim of a poor solder joint. Even if they look good, resolder all of them. 

[JBev]

Exact same issue with my 2019 23LSV. Originally PCM told dealer to bend pins on relay box to improve contact, this worked for a couple of trips. Since then, the issue started again. Now PCM is saying the wire harness needs to be replaced. What solution did you come up with?

[Rednucleus]

Same thing happening the last 2 weeks in a 2019? Nautique I ski behind. Get low fuel pressure reading, motor dies, cranks won't start. Unplug relay, plug same one back in, starts right up.

[justgary]

When you guys are pulling relays and putting them back in, are you inspecting the sockets that accept the relay pins?  You might be surprised how many engineers fail to look up the current-carrying capacity of the connector they are about to use.  If they say you need to change the harness, they really mean replace the connector in most cases. 

If anything shows signs of pushed pins, discoloration, or melting, slow down for a few minutes and *fix* something.

[JBev]

Thanks Gary. The good news is this is warranty work. If PCM claims this is the solution, let’s hope it works. Just glad it’s on their dime. It doesn’t help with the massive inconvenience of waiting for parts right now. 

[justgary]

6 hours ago, JBev said:

Thanks Gary. The good news is this is warranty work. If PCM claims this is the solution, let’s hope it works. Just glad it’s on their dime. It doesn’t help with the massive inconvenience of waiting for parts right now. 

Hopefully it does cure the issue.  You might remind them that replacing a few sockets in the harness as a first step is much simpler than installing a whole new harness, and they can always order the harness if new connectors doesn't fix it.  That way you are not waiting on a whole harness.  Odds are that the actual wire in the original harness is still good.