ECM CODES on 350 MAG MPI during Survey.

Randy Coleman

Member
May 28, 2021
49
Boca Raton FL.
Boat Info
Kay-LinSea
2005 340 Sundancer
8.1 Horizons with Vdrives.
Engines
8.1 merc V drive
Hello All.

Looking for some feedback from others that know a thing or two about these engines.
Boat is a 2004 320 DA, V drives, 4 blade props.
We had the mechanical survey/sea trial yesterday and the survey showed up some peculiar items in the ECM memory.
The mechanic suspects that the wiring harness needs to be replaced however, the boat ran perfectly during the Sea Trial.
Running gear needs to be cleaned but bottom was clean.
4 guys onboard with full water and half fuel load.
4500 rpm at WOT at 29mph
3700 rpm for cruise at 23mph

Here's a list of the codes that were shown. (Indicates results from Fault)
PORT ENGINE 614hrs.
Steer CKT LO (Stall)
SEA TMP CKT HI (Stall)
FUEL LVL2 CKT H (Stall)
PITOT CKT LO (Stall)
OVERSPEED
FUELPUMP RLY CK (Stall)
ECT OVRHT (STALL)
GUARDIAN
SEA PUMP PSI LO

STARBOARD ENGINE 618hrs
STEER CKT LO (STALL)
FUEL LVL2 CKT H (STALL)
PITOT CKT LO (STALL)
FUELPUMP RLY CK
OVERSPEED
IAC OUTPUT (STALL)
SEA PUMP CKT LO

I have both downloads if anyone is interested in seeing them?

Has anyone seen or had these issues on their boat?
If so, could this all be caused by a bad wiring harness or bad ECM?

Your input is greatly appreciated.

Randy
 
Those codes are over the life of the engine. At what hours did that happen? This boat is what about 17 years old? If that is all it had I wouldn't worry. Plus the overspeed is not a fault, that just means the boat was light and it touched the rev limiter. It would have had a beep but reset with cycling the eng off and back on.
 
I get pitot ckt hi/lo because we have v-drives, there is no pitot sensor. I somehow reset my smartcraft, and I get these codes. Just ignore. Fuel pump relay code, boat will not run, common issue, I keep backup relays on my boat, and replaced the harnesses as well. Sea pump psi, engine will run, but I think goes into guardian mode, 1k rpm or less(?), I carry backup water pressure sensors as well, they get clogged, or fail to make good electrical contact. IAC, same, keep spares, these are all super easy to replace if I can do it.
I have been replacing IACs annually now, no more issues failing on trips.
 
On a separate note, what are the specs on those 4 blade props? Maybe see if the broker can get that from the previous owner?
 
Thanks for the responses.

I've asked about the props but the owner doesn't know as he bought the boat with the 4 blade props.
This boat will need a bottom job so I'll need to send the props out for repair and tuning.
I'll report back once completed.

I ran the boat for about 2 hours and had no new faults.

This particular surveyor thinks that both engines need a new wiring harness.
He says that I can do this myself.

Seems fairly easy to change out?
Has anyone done that themselves?
 
Funny you say that because I asked the same thing.

The surveyor says the most recent codes are common to harness issues.
 
Again the ecm should log the hours at the fault time. Was it even recently?
I wouldn't worry about the codes that much. If it runs within spec now then it's good. Now that doesn't mean something won't break in the future. It could blow an engine the second you take delivery. You just don't know. I like to say it's good till its not. That is why it's important to have the funds to correct problems as they arise.
 
Unless you are seeing frequent false alarms I doubt you need new harnesses.

These alarms may have accumulated over time. If he pulled the full data there should be a snapshot around each error if I remember correctly.

Regardless I don't see any troublesome alarms so if you buy the boat I would just monitor.

-Kevin
 
Thanks for the replies.
Several of the codes were very recent and had to deal with low CKT's on steering, pitot, fuel LVL and sea TMP, according to the download from the engines.

I'm thinking of having all the codes cleared and then running the boat for a few hours to see if any pop up again.

Thanks again.
 

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