2007 300 XS problem.

[ALE]

Out boating yesterday and motors were running OK. Stopped to do a little swimming.
Started them and the port motor went right into alarm.
When turning the ignition on, the alarm sounds and the SmartCraft indicator goes through all of it's readouts. Fuel used, temp, voltage, etc.
Continues to repeat that scenario, going through all readouts and showing all alarm indicators.
Tried to do a few re-sets, but nothing changed. It looks like every alarm that shows is reading out.
The motor starts but will only run at idle. Will not take any throttle. Give it throttle and it just bogs down and sounds like it's not getting gas.
The motor has around 125 hours on it.
Any ideas or is this another trip to the shop?

[Euroski]

Is it also giving beep codes? If so I got a chat somewhere I can find.

[bradmd]

Straight from the diagnostic manual....

[ALE]

Euroski,
Is a beep code just what it sounds like? Intermittent beeping instead of one long sound? I think it is but not 100% positive. All I can remember is that it was making a lot of noise and showed every alarm indicator the SmartCraft guage has.

bradmd,
Thanks for your post, but it looks like I'll be only able to check out the coils and a visual on the manifold. The MAP sensor and fuel pressure test sounds like a trip to the dealer.
I had a coil fail last year on one of the other motors and Mercury replaced all 6 of them under warranty. They have very low hours, but considering their age I was kind surprised.
I had to pay for labor but that was OK.

[Euroski]

PM your e-mail address. It's to large to attached here.

[ALE]

PM sent.

Thanks,

[Euroski]

PM sent.

Thanks,

Should have it, let me know if not?

[ALE]

Euroski,

I got it. Will try to figure out what happened.

Thanks.

Al

[ALE]

Thanks for all the help, but for several reasons I decided to let the dealer check it out.
After their diagnosis, I'm not quite sure which way to go, or what to think, with the problem.
They said that three faults were set. Throttle Position Switch (TPS), MAP sensor, and Water Pressure (WTR) sensor.
They test ran the motor for two hours without any issues.
I felt that this has to be a really rare and definitely strange occurrence, with high odds of it happening again. I decided to not have them replace these sensors.
I have several questions regarding this problem, mainly what are the chances of this happening again?
Should I be concerned, and just let them replace the sensors at a cost of around $750.
This problem came up when I turned the ignition on and started the motor, not while it was already running. It looks like it was just a freak glitch when I hit the
ignition switch. I don't have a key switch. It's set up with an on-off rocker and a push button to start.
If this problem were to happen again, is there any way that I could reset the faults out on the water without a computer?
Thanks,
Al

[aussiecorey]

Low battery voltage will log a mixture of phantom codes.

Hopefully that's all they were!

[HydroSkreamin]

Low battery voltage will log a mixture of phantom codes.

Correct^ Ask your dealer for a print out of the Freeze Frame buffer. This has a record frozen in time of all the parameters when the fault occurred. They (or you) should be able to figure out if voltage was a factor. Sounds like the 5V power supply was messed up, either from low battery or wiring issue. 3 sensors don't generally fail at one time without a bolt of lightening striking! If the dealer didn't clear faults they are still in there and can still be viewed.

Also of note, if the boat had any type of SystemView, VesselView, or MercMonitor, you could see what faults are for yourself as they can be viewed on their own pages, helping you self-diagnose whether it is serious enough to go to a dealer or not.

[Euroski]

Or could be a ground problem especially if all 3 sensors are to a common ground point. I would also check main grounds for engine and battery to engine grounds

[Wayne Cammidge]

Intermittent faults are always a nightmare for the dealer to find.
If it is not working, it is easy to find, but you will never find the fault once it corrects itself.
So if it was a one time glitch, you will never see the issues again. Could happen again any day.
How old are the batteries? What is their free voltage after been left for a while. They should be above 12.5v. Anything below that could cause issues. Below 12v and you are going to start seeing weird fault codes pop up.
These random fault codes will hide any real issues that you are having, and can confuse you. Once it is running make sure you have 13,8 volts to 14v only.
Then verify with the computer that the two 5 volt reference circuits are good

[ALE]

Great! This is the kind of info/help that I'm looking for.
It kills me to have to take it to the dealer to do something that I know I can do. Not just because of the $$$ but because it's just
not convenient to get to.

The batteries are 2 years old and I have an onboard 3 bank charger that's always plugged in to keep them charged. I'm not using the boat as much as I used to or would like to. This was my third trip out this season.
I will check the voltage outputs. Could be a battery going bad. I'm also going to clean all of the battery connections as a PM issue.
Don't know if this caused anything, but I added a SeaStar power steering setup this year. To spread that load, I setup the power supply for the pump from 2 of the 3 batteries, so 2 of the Perko switches are set to the "1 & 2" position. The motor that gave the faults was the only one in the "1" only position, which should have made it pretty much independent and isolated from the others. Should I put all of the switches to "1 & 2" or "ALL" to keep the voltage uniform across all 3 batteries?


If this did happen again, is there any way for me to clear the codes while out on the water?
I still have the other 2 motors to get home, but it really puts a strain on them.

Al,

[Bullet89]

The ground circuit for all these sensors is in the PCM. Mercury had a recall on all 3.0 CDMs made in China. They were shorting out the ground circuit in the PCMs. Make sure your dealer checks to make sure all the recall has been completed.