Fuel pump fault

[Eme2685]

Hello all,

So during this season I had an intermittent soft alarm (2 beeps/min).This alarm would only occur over 4000 rpm and did not happen every time exceeding 4000 rpm. No noticeable performance issues. I took it to a local marine mechanic and they pulled the codes. They stated the code stated "fuel pump" and nothing more and couldn't further diagnose it. I just purchased this boat and did not replace the fuel water separator after last season due to it being stuck. I plan to swap it out during winterization this year though. Would this cause a fuel pump fault code? Possibly, restricting fuel pressure at higher rpms resulting in a fault code to be created in regards to the fuel pump? I am just at a loss and confused how the mechanic had zero idea what it could be. He stated mercruiser no longer uses fault code number? And the code stated nothing more than "fuel pump" is this an actual fault? If so what could it mean?

2003 4.3 mpi mercruiser

 

[alldodge]

What is the motor serial number?

 

[Eme2685]

What is the motor serial number?

The motors S/N is 0M370012

 

[alldodge]

Motor has 555 ECM
Not seeing a 2 bp/min for fuel pump or pressure. There is a 2 bp/min for
Fuel injector open or short

Might be seawater pump open or short
What was the code number?

 

[Eme2685]

Motor has 555 ECM
Not seeing a 2 bp/min for fuel pump or pressure. There is a 2 bp/min for
Fuel injector open or short

Might be seawater pump open or short
What was the code number?
View attachment 351569

That's the thing. The mechanic stated that Merc did away with the code numbers supposedly. He stated that when he ran the diagnostics it simply said fuel pump and nothing more. Which from what I have read is not an actual code that I have seen. And am unsure how there would not be a specific number for the code to give more information..

 

[alldodge]

mechanic stated that Merc did away with the code numbers supposedly.

Haven't heard that one before, or seen one without a number. Here is the same with numbers

 

[alldodge]

Think your going to need a scanner and have it attached when it goes off again. If its something like low voltage then weird things can happen

 

[Eme2685]

Think your going to need a scanner and have it attached when it goes off again. If its something like low voltage then weird things can happen

Okay, thanks for the tip. I tried getting it tested on the water, but the marinas diagnostics for the old type of connection that I have didn't work any more.. go figure. And I had the other mechanic test it off water and he said that was all that was stored unfortunately. I guess I will keep an eye on it next season and hopefully come to a conclusion.

 

[Eme2685]

Would there be any chance that a clogged fuel water separator filter cause a strange fault to occur? The beeps only seemed to occur when the boat is loaded down, never when it's just two people or so.

 

[alldodge]

According to your serial number the motor doesn't have a fuel pressure sensor. Having a boat heavier causes it to burn more fuel, so may be in the fuel supply side, but just not pressure

 

[Eme2685]

So could possibly be a clogged filter not supplying the fuel demands necessary for proper operation while loaded down resulting in the computer assuming a failing fuel pump or other fuel delivery issues just trying to think of the possibilities at the moment since it will be a while until I get the boat back on the water unfortunately. Just still unsure why I was getting a 2 beeps /minute soft alarm with no other stores codes besides the "fuel pump" then mechanic mentioned.

 

[alldodge]

My thought is the scanner that was used (if it was used) may not have updated software. It does have a problem, just don't think its fuel pressure.

I would think a water pressure sensor issue only because they fail quite often. Not saying replace it without knowing.

 

[Eme2685]

I just wouldn't think a water pressure sensor fault would be dependent on the physical load on the boat though. I guess I won't be able to tell until I get another diagnostic on it. But I'd rather not waste another $100 if it's going to come back the same. I couldn't imagine a reputable mechanic having our of date diagnostics software.

 

[alldodge]

My thoughts in a simplistic example
There are 4 rooms, and only 3 light switch's and 3 lamps. Each light switch goes to one lamp, one in each of the 3 rooms. There is no light or switch in the 4th room. If someone says the 4th switch was flipped and turned on the light in the 4th room, what would you think?

I have no idea what the Mech actually saw, I only know what is being said and what the parts are that make up the motor. Guess I'm not the right guy to help, maybe someone else can.

 

[Eme2685]

I was simply trying to bounce some ideas around. I never meant to discredit your attempts to help out, nor did I feel like your ideas were wrong, I was just trouble shooting the way I know how, building ideas and sharing thoughts. My apologies. I appreciated your input.

 

[achris]

Hmmm... Lots to unpack in this thread.

Okay, thanks for the tip. I tried getting it tested on the water, but the marinas diagnostics for the old type of connection that I have didn't work any more.. go figure.

Merc haven't changed the connector type.

The mechanic stated that Merc did away with the code numbers supposedly.

Nope. Depending on what is used to scan (PC with Diacom running or a 'techmate' scanner) you'll get either the code numbers or a list of the faults.

He stated that when he ran the diagnostics it simply said fuel pump and nothing more. Which from what I have read is not an actual code that I have seen. And am unsure how there would not be a specific number for the code to give more information..

Here's a print of a listing I did on my engine when I had an IAC fault. (The other 'faults' are inherit because I don't have sensors for those items).

As AD said, there's no sensor on your 4.3MPI for the fuel pump. There is for fuel pump relay, but not for the pump itself (or the rail pressure).

My suggestion would be to buy (I know it's expensive, but might actually be cheaper than taking the boat to a service centre each time, ultimately), and run the scan yourself, post the file here and we can analyze it...

The other thing to be aware of is that Merc have made the original pumps NLA, if that's what's faulty, then it's a whole new pump assembly, and $pendy! See service bulletin 2004-05R1

Chris........

 

[Eme2685]

Hmmm... Lots to unpack in this thread.


Merc haven't changed the connector type.

Nope. Depending on what is used to scan (PC with Diacom running or a 'techmate' scanner) you'll get either the code numbers or a list of the faults.

Here's a print of a listing I did on my engine when I had an IAC fault. (The other 'faults' are inherit because I don't have sensors for those items).
View attachment 351584
As AD said, there's no sensor on your 4.3MPI for the fuel pump. There is for fuel pump relay, but not for the pump itself (or the rail pressure).

My suggestion would be to buy (I know it's expensive, but might actually be cheaper than taking the boat to a service centre each time, ultimately), and run the scan yourself, post the file here and we can analyze it...

The other thing to be aware of is that Merc have made the original pumps NLA, if that's what's faulty, then it's a whole new pump assembly, and $pendy! See service bulletin 2004-05R1

Chris........

For my 2003 4.3 MPI they stated the 4 pin connector was for diagnostics at the first shop I took it to. I attached a pic of what it was, I have seen on newer models the diagnostic port does not look the same as the one on my boat. The mechanic who just ran diagnostics on it stated he used a laptop for the diagnostic scanning. I will have to look into a diagnostic scanner I suppose...

 

[achris]

Same DLC port as mine. The standard Diacom kit comes with the right adaptor for that connector.

That's the 94006 adaptor. (And comes with the 'barebones' Diacom software)

Rinda Technologies Inc. Marine and Industrial Engine Diagnostic Tools

 

[alldodge]

The comment about a different connector was that there are 12 different adapters and the adapter that comes with the SW or Techmate is chosen at time of purchase. Unknown if the shop had the right connector or not. There was also a SW update a few years ago and I have yet to get mine updated. When I bought mine I picked up 3 different connectors

 

[achris]

The comment about a different connector was that there are 12 different adapters and the adapter that comes with the SW or Techmate is chosen at time of purchase. Unknown if the shop had the right connector or not. There was also a SW update a few years ago and I have yet to get mine updated. When I bought mine I picked up 3 different connectors

Yeah, me too.