4.3L MPI 2007 Searay Sport 185. Single Alarm at 20 RPMs and higher

[Nord2903]

I'd be interested to see spark advance pre and post guardian mode at similar rpms. Most of that info isn't particularly interesting. What's the value below oil pressure? Water pressure? Was the boat warmed up? Water temp is cold and didn't rise.

It is water pressure.

 

[Nord2903]

It is water pressure.

Is that what the correct water pressure should be? I checked the impeller the other day and it was perfectly fine.

 

[dubs283]

Is that what the correct water pressure should be? I checked the impeller the other day and it was perfectly fine.

That water pressure number is too low, should definitely be more than .4 psi at idle, more like 3+. And at 2000k+ rpm it should be more like 10 psi or more. Most likely the water pressure sensor is faulty or the impeller is faulty

Guaranteed when connected to a system that can read freeze frame (stored) faults there will be one or more related to sea water pump pressure

 

[achris]

. What's the value below oil pressure? Water pressure? Was the boat warmed up? Water temp is cold and didn't rise.

Sea water temp is irrelevant as there isn't a sensor for it.
And here's part of the problem with VesselView, great data for users, not enough for diagnosers...
I'd be interested in things like IAC cycle, TPS position, Sensor voltage, MAP and MAT.

That water pressure number is too low, should definitely be more than .4 psi at idle, more like 3+. And at 2000k+ rpm it should be more like 10 psi or more. Most likely the water pressure sensor is faulty or the impeller is faulty

For the old stiff vane low volume impellers, yes. But these impellers work just fine at those low pressures. The ECU is set to throw a fault if the pump pressure is lower than 0.5psi (or higher than 15psi). My engine is only making 9.44kPa at 1,000rpm.. (1.37psi, 'Murica. You guys really need to get into the 20th century!)

Chris......

 

[Nord2903]

I also thought the water pressure was low especially with a load. Here's my concern though, clearly the water pressure sender is working as its providing a reading. I checked the impeller and even though its "formed" (which I have a new one and can change), if the pressure was too low or even too high, would I receive a hi or low pressure code?

 

[achris]

I also thought the water pressure was low especially with a load. Here's my concern though, clearly the water pressure sender is working as its providing a reading. I checked the impeller and even though its "formed" (which I have a new one and can change), if the pressure was too low or even too high, would I receive a hi or low pressure code?

Correct, and don't worry about there being a 'set' in the impeller. They all get that after about a month in the housing. If you pull it out and leave it on a bench overnight, next morning it looks like a new one again.

Chris..

 

[Nord2903]

Correct, and don't worry about there being a 'set' in the impeller. They all get that after about a month in the housing. If you pull it out and leave it on a bench overnight, next morning it looks like a new one again.

Chris..

The follow up question I have is, if the water pressure is that low-no code is being thrown-could my circulating water pump be the issue? and it not throwing a code?

 

[Nord2903]

I also checked the thermostat (and tested it putting it in hot water) and the cap and rotor which all looked great.

 

[achris]

The follow up question I have is, if the water pressure is that low-no code is being thrown-could my circulating water pump be the issue? and it not throwing a code?

Circ pump has nothing to do with water pump. That pressure is the incoming pressure from the impeller, not a block pressure reading... Here' what the flow diagram looks like... The water pressure sensor is in the end of the power steering cooler (h).

I also checked the thermostat (and tested it putting it in hot water) and the cap and rotor which all looked great.

Unfortunately those crap caps can't be determined as 'good' just from a visual inspection. They are almost a case of 'put a new one on and if that solves the problem, the cap is faulty'.... (Thanks GM!)

Chris.........

 

[Fun Times]

1012-24: Engine or drive trim position. The input circuit for the sensor is above the valid limit.

1031-25: Steering position. THe input circuit for the sensor is below the valid limit.

701-24: Level sensor tank A. The input circuit for the sensor is above the valid limit.

451-25: Pitot Pressure. The input for the sensor is below the valid limit

Just to double check the trim fault, on the outside of the boat on the gimbal ring of the transom assembly, how many trim sensor pucks are mounted on the ring… 1 or 2?
1 on Starboard side and 1 on port side? Both have 2 wires?
Or is there 1 puck and if so, how many wires are showing?

Rev testing on the trailer isn’t going to tell you much and it will set an RPM limit and will sound the alarm..,
Does this happen when in gear on the water??

 

[Nord2903]

Just to double check the trim fault, on the outside of the boat on the gimbal ring of the transom assembly, how many trim sensor pucks are mounted on the ring… 1 or 2?
1 on Starboard side and 1 on port side? Both have 2 wires?
Or is there 1 puck and if so, how many wires are showing?

Rev testing on the trailer isn’t going to tell you much and it will set an RPM limit and will sound the alarm..,
Does this happen when in gear on the water??

2

 

[Nord2903]

Circ pump has nothing to do with water pump. That pressure is the incoming pressure from the impeller, not a block pressure reading... Here' what the flow diagram looks like... The water pressure sensor is in the end of the power steering cooler (h).
View attachment 359863

Unfortunately those crap caps can't be determined as 'good' just from a visual inspection. They are almost a case of 'put a new one on and if that solves the problem, the cap is faulty'.... (Thanks GM!)

Chris.........

ill give it a go

 

[Fun Times]

2

Then the trim fault shouldn't be affected in this case.

Does this happen (2K limit) when in gear on the water?

 

[QBhoy]

I'd be interested to see spark advance pre and post guardian mode at similar rpms. Most of that info isn't particularly interesting. What's the value below oil pressure? Water pressure? Was the boat warmed up? Water temp is cold and didn't r

The follow up question I have is, if the water pressure is that low-no code is being thrown-could my circulating water pump be the issue? and it not throwing a code?

the sea water pressure is always dead low at idle on a trailer. There is no back pressure at all sure.

 

[Nord2903]

So follow up. Boat being looked at by a mechanic. They’re are “thinking” it’s the rotor because the metal tab was broken. My concern is that there isn’t a plug that attaches that communicates with the ECU. Would this trigger an alarm with no electronic connection?

 

[achris]

It could be captured as a 'misfire' event.

 

[dubs283]

My concern is that there isn’t a plug that attaches that communicates with the ECU.

Again, as stated very early in thus thread all mercruiser efi engines are equipped with a diagnostic harness connection to communicate with the ecm. Unless someone has for some weird reason abated the plug, it is there. My WAG as to why your mechanic does not see one is that they don't know what they are looking for.

Your engine would use a four pin connection for diagnostics. This would be used in conjunction with Mercury's CDS diagnostic system which unfortunately they no longer support. One can still use diacom to communicate with the ecm, it's what many repair shops use these days as it communicates with several different manufacturers systems.

It's possible your mechanic only has mercury G3 and is looking for that proprietary connection?

 

[Nord2903]

@dubs283. I found the connection to the ECM to have it scanned as I hooked up the vessel view to it. I just got off the phone with the boat mechanic and he said that he has never had to do this before but he is tapping out cause he can't solve the issue. He spoke with mercury technicians and they said they believe it is a low voltage issue, but he is not getting that with any of his scans or reads with a multimeter. He also stated the issue has become worse as it is stumbling at idle (which I didn't have) and the alarm is now going off more often.

 

[Nord2903]

It could be captured as a 'misfire' event.

Hes also not getting any codes with his marine reader.

 

[dubs283]

Hes also not getting any codes with his marine reader.

Find a new mechanic. With the alarm going off that means there is an active fault and should be present with a scan tool. Either he doesn't know how to use the scanner or it's not the proper scan tool.

One time I had a mercruiser that would randomly shut off, then beep. No active faults when it happened and no stored faults. Came to find out the motor had been removed for a coupler and when reinstalled the main ground for the harness/ecm was on the opposite stud from the main battery ground. Got the grounds stacked together on the same stud and issue went away.