2005 Mercruiser 5.0 MPI - ECM - recorded information and solid alarm issue

[Mustang_Sally]

2005 Mustang 2200 ClubSport (LOA 27.7)
5.0 MPI
Bravo II
Closed cooling system
name : Sally (Mustang Sally!)

G'Day!


We are having an issue that could be related to each other

Our 2005 Mustang - 5.0 MPI -Bravo II had been sitting in the water for 5 years, we took her out without starting - have changed out her risers, checked manifolds, changed out leg impeller, gimbal ok, fuel and oil changed out - filters changed
plugs and leads all tested fine. - no osmosis and antio fouled - now stored in a SeaPen

She idles perfectly, although her taco and volt meter do not work.

On her first run- 0-5knts -fine

6 knots- and on throttle up- runs for 5-10 seconds and we get a solid alarm

the handheld read- 100% available power- just before the solid alarm the Guardian feature kicked in and she hesitated until almost stalling....handheld read 4% available power...pulled back to neutral and back in gear at low idle - no alarm

Fuel pressure before start up 40-solid no fluctuation

when Guardian mode kicked in it raised to 50...then we lost fuel pressure for 2 minutes..then it returned.. so we changed out the fuel pump today- hooked her up to the handheld.....same issue!.. 5-6 knots..Guardian mode.- sits on 180 (closed cooling system)

Any ideas what it could possibly be?

This is where it gets interesting- the dash hour meter reads 89, but the ECM reads 268

The previous owner - has owned the boat since new - and assures me nothing has been changed out - hour gauge or ECM.- no reason to doubt him -

This leads me to my next question - When we hooked up the handheld it does not give us any serial numbers we can tie up to the boats engine, leg or VIN, is there any mode that does this, or can Mercruiser extract serial numbers, -( we are in Australia, but my Mechanic is heading back to California on Wednesday for 3 weeks, I am thinking about him taking the ECM for testing in the US, for faults and to extract any serial numbers to confirm boat of origin)and tell me if the ECM is original or has been swapped out for a defective ECM (with higher hours) and my low hour ECM put into another vessel.

Any help on wither questions would be greatly appreciated.

 

[alldodge]

The serial number identifies what parts where used to build the motor. Don't remember ever seeing it loaded in the ECM

For the motor to go into guardian mode there would have been a code and should be seen on the scanner

changed out leg impeller

The Bravo has a belt driven water pump, there is no impeller in the leg

The number one failure and cause for steady alarm is the water pressure switch, and is on the power steering cooler. Other things which can cause guardian and loss of full power are
TPS
Battery voltage
Overheat
Low oil pressure
Oil pressure switch failure

 

[Mustang_Sally]

Hi AllDodge

Thanks for your reply

you are correct- changed out entire water pump ( was thinking about my bowrider - long day!) :sleeping:

hand held was unable to produce a code -it just dropped to 4%

oil pressure shows normal on the gauge and handheld and water temp normal as well

will check water pressure switch and TPS

is there anyway to prove if the BCM is original - the hour gauge is original so no idea why the BCM is throwing out a higher hour usage ( 260-270) ?

cheers for the reply

If anyone has any other experiences with this issue and the BCM ( anyway we can prove the BCM is the original in there - would be much appreciated

 

[scoflaw]

270 hrs is crazy low for a 17 tear old boat. Like said ECM is not going to get linked to your engine #

 

[alldodge]

Could be your scanner may not have up to date software.

Connect the scanner and with the motor running find the water pressure reading, see what it shows.

 

[QBhoy]

Sw pressure sensor and TPS would be on my hit list.
Likely the cap is bad too, but would not alarm or guardian.

 

[Mustang_Sally]

Just want to thank AllDodge, scoflaw, and QBhoy for your help, going to look at all the sensors and your advice tomorrow- I'll let you know how we go :joyous: :yo:

 

[Mustang_Sally]

Update: We changed out the SW pressure sensor which my mechanic had from his 383 MAG and no change- Scanner stated guardian 4% when rpm reached 2000+ and stayed at 4% until rpm's decreased. Scanner stated fault unspecified.

Block pressure on scanner 0.0

This is when we decided to unplug from the SW pressure sensor itself - We immediately got the 2 chirps and scanner read available power 89%.

We took her out and gently took her to 35 mph with no issue- except of course for the two chirps every minute.

-oil pressure normal
-water temp normal

So at this stage - ordered a new sensor and will fit tomorrow - if it faults again with no block pressure do we think the issue is with the loom or BCM?

Will update tomorrow with new sensor installed.

 

[alldodge]

Might be the gear switch. If the motor thinks its in neutral there will be an alarm. Disconnect it and see if that fixes the issue. You won't have the interrupter switch

 

[QBhoy]

Keep us posted

 

[Mustang_Sally]

Will do QBhoy

and thanks AllDodge

I will check the gear switch as well - i know the scanner was acknowledging when in neutral and when in gear and what %

- didn't get a chance today- will tomorrow arvo

:joyous:

 

[Mustang_Sally]

UPDATE: Sunday 31st March

Issue fixed!:thumb: - replaced SW pressure sensor (as suggested)

Took her out for a short sea trial yesterday (1 hour) and a longer one today (2.5 hours) with no issues at all.

I would like to take this opportunity to thank every one who gave input and knowledge in helping me on this one.

- very much appreciated- you are all awesome :joyous::joyous::joyous:

:yo: