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496 HO - Engine Sensor Problem - HELP Needed!

JacqueW

New member
Was driving boat fast, had slowed down to idle for about five minutes then heard two beeps. Raised the engine cover and smoke came out. Engine was at 160 degrees (not hot). Oil pressure was at 40. Isolated it to the winterizer pump that was melting as it had fallen out of its holder and was touching the serpintine belt. The smoke did not cause the fire extinguisher to come on. Have not gotton boat past idle since but upon starting engine, but hear two beeps immediately (even with cold engine) and every three or so minutes the two beeps reoccur.

Talked to the marine shop we bought boat from and they said that melted pump might be the problem and just need to take boat in, put on computer and shut sensor off. However, he said he doesn't think that is the problem and just a coincidence that it occurred at the same time of some other problem.

What sensor is in alarm with two beeps when engine is hot or cold? What causes this sensor to go off? Do you all think the problem is just the melted pump caused the engine sensor to go off or should we examine other items? Is there a way to shut off the engine sensor without going to marine shop and hooking up to computer?

Items we have checked without the marine looking at it are:
1. Fluid level in stren drive oil is and was full
2. Disconnected CO'2 sensor - didn't stop the beeps
3. Oil filter was hot to touch and if left hand on it, think it would have burned me.
4. Exhaust manifolds (when looking at engine) left side was cooler than right side. Neither were so hot that you burned yourself.

Any guidance would be appreciated. Once fully resolved, I will update this forum with the root cause. Thanks!!!
 
Marine shop, put on hand held computer reader and said impeller problem and code was a overheat code. Said 8 weeks before they could work on it... :(

Bought impeller and we are tearing down as I type. Hope this is it.
 
Do you experts out there think the smoke inside the engine could have set this sennsor off and we really don't have an impeller problem?
 
The two beeps is a typical indicator that something is "wrong" based on what the PCM receives as inputs from its sensors...the list is pretty extensive. Low flow from the raw water pump is very possible....did the shop tell you which DTC(s) was set?

BTW, changing the impeller in a pump won't always restore its operation...you need to ensure no obstruction at the in/outlets and nothing else is worn in the housing.

Smoke in the engine housing should do Nothing to any of the engine sensors...depending upon its makeup, density, and quantity, it make impact engine operation.
 
We replaced impeller (nothing wrong with first one) and tried to take boat out and two beeps were still there... tried to run the boat and it went into guardian mode and then produced a long beep noise. We took it to our normal repair guy and he put it on the computer. System type is MerCrusier PCM555. Printout error codes read as follows (I have the full printout)...

Fault Log Data
Fault Descriptions

Block Pressure is Low: 472
Guardian Strategy: 482

All this guy did is clean out all hoses and flush the system. The alarms are no longer going off. We took the boat out on the 4th and it ran okay. Did notice the two exhaust pipes were pretty warm. Engine temperature while running the boat fast stayed at 160 degrees. As soon as we slowed down to idle the temp raised to about 175 degrees and stayed at 175 for about 10 to 15 minutes.

We are really nervous with the temp fluctuating like that. Do you think we still have a problem? We read a different post indicating some hose in the lower unit might that initially pulls in the water could have a pin hole in it. On a side note, we have been taking water for about a year now. If the boat sits in the water for about 2 to 4 hours the bilge pump will come on and take the water out. Do you think this is related to our issue?

Thank you so much for responding and offering your guidance!

Jacque
 
Decided to type in the whole report results so you can see the whole picture:

Performance Data

Engine Speed 0 RPM
Available Power 100%
Coolant Temp 111.20 degrees Far
Fuel Flor Rate 0.00 GPJ
Port Exhst Cool Temp 111.20 degrees
Sea Pump Pressure 0.04
Starb Exhst Cool Temp 113.00
IAC Duty Cycle 0.00
Manifold Absolute Pressure 13.76
Trim Position 1018
Baro Pressure 13.77
Trim Volts 4.97
Manifold Air Temp 113.00
Pitot ADC 0
Oil Pressure 0.33
Paddle Wheel 0 Hz
Thorttle Position 0.00
Sensor Power 5.03
Throttle Sensor Voltage 0.53
Lake/Sea Temp 429.80
Spark Advance 6.00
Fuel Level 1022
Battery Voltage 12.68

3. Trouble Code Status
Current ECM Codes
Sensor Fault, click Read Fault button for details
Freeze Frame Data:
0 BLK PSI LO

---------------------------------------------------------------------------------------
FF Faro Pressure 13.81
FF Battery VOlts 13.97

FF Sea Pump Pressure 0.00
FF Boat Speed 0.00
FF Manifold Air Temp 123.80
FF Coolant Temp 165.20
FF Demand 14.55
FF Engine Speed 2490
FF Engine State RunningFF FPC Totlal 21.5 counts
FF Frequency Count 14
FF Fuel Level 0.00
FF Gear Position Neutral
FF Lake Temp 431.60
FF Engine Load 7.15
FF Main Pwr Relay Requests YES

FF Manifold Air Pressure 5.93
FF Oil Level 0.00
FF Port Tab Pos 0.00
FF Available Power 5
FF Run Time 670.60
FF Starbord Tab Pos 0.00
FF TPS Percent 14.55
FF Trim Position 0.00

1 TRIM CKT HI
--------------------------------------------------------------------------

FF Baro Pressure 13.77
FF Battery VOLTS 12.71
FF Sea Pump Pressure 0.04
FF Boat Speed 0.00
FF Manifold Air Temp 113.00
FF Coolant Temp 111.20
FF Demand 0.00
FF Engine Speed 0
FF Engine State Stall
FF FPC Total 0.0
FF Frequency Count 15
FF Fuel Level 0.00
FF Gear Position Neutral
FF Lake Temp 431.60
FF Engine Load 0.00
FF Main Pwr Relay Requests Yes
FF Manifold Air Pressure 13.76
FF Oil Level 0.00
FF Port Tab Pos 0300
FF Available ower 100
FF Run Time 670.60
FF Starboard Tab Pos 0.00
FF TPS Pos 0.00
FF Trim Position 0.00


2 FUEL LVL2 CKT H
-----------------------------------------------------------------------
FF Baro Pressure 13.77
FF Battery Volts 12.68
FF Sea Pump Pressure 0.04
FF Boat Speed 0.00
FF Mainfold Air Temp 113.00
FF Coolant Temp 111.20
FF Demand 0.00
FF Engine Speed 0
FF Engine State Stall
FF FPC Total 0.0
FF Frequency Count 13
FF Fuel Level 0.00
FF Geat Position Neutral
FF Lake Temp 431.60
FF Engine Load O.00
FF Main Pwr Relay Requests YES
FF Manifold Air Pressure 13.76
FF Oil Level 0.00
FF Port Tab Pos 0.00
FF Available Power 100
FF Run Tme 670.60
FF Starboard Tab Pos 0.00
FF TPS Percent 0.00
FF Trim Position 0.00


3 STEER CKT HI
--------------------------------------------------------------------------------------
FF Baro Pressure 13.77
FF Battery Volts 12.68
FF Sea Pump Pressure 0.04
FF Boat Speed 0.00
FF Mainfold Air Temp 113.00
FF Coolant Temp 111.20
FF Demand 0.00
FF Engine Speed 0
FF Engine State Stall
FF FPC Total 0.0
FF Frequency Count 14
FF Fuel Level 0.00
FF Geat Position Neutral
FF Lake Temp 431.60
FF Engine Load 0.00
FF Main Pwr Relay Requests YES
FF Manifold Air Pressure 13.76
FF Oil Level 0.00
FF Port Tab Pos 0.00
FF Available Power 100
FF Run Tme 670.60
FF Starboard Tab Pos 0.00
FF TPS Percent 0.00
FF Trim Position 0.00


4 Fuel LVL CKT HI
-------------------------------------------------------------------------
FF Baro Pressure 13.77
FF Battery Volts 12.68
FF Sea Pump Pressure 0.04
FF Boat Speed 0.00
FF Mainfold Air Temp 113.00
FF Coolant Temp 111.20
FF Demand 0.00
FF Engine Speed 0
FF Engine State Stall
FF FPC Total 0.0
FF Frequency Count 12
FF Fuel Level 0.00
FF Geat Position Neutral
FF Lake Temp 429.80
FF Engine Load 0.00
FF Main Pwr Relay Requests YES
FF Manifold Air Pressure 13.76
FF Oil Level 0.00
FF Port Tab Pos 0.00
FF Available Power 100
FF Run Tme 670.60
FF Starboard Tab Pos 0.00
FF TPS Percent 0.00
FF Trim Position 0.00

5 PITOT CKT LO
FF Baro Pressure 13.77
FF Battery Volts 12.68
FF Sea Pump Pressure 0.04
FF Boat Speed 0.00
FF Mainfold Air Temp 113.00
FF Coolant Temp 111.20
FF Demand 0.00
FF Engine Speed 0
FF Engine State Stall
FF FPC Total 0.0
FF Frequency Count 12
FF Fuel Level 0.00
FF Geat Position Neutral
FF Lake Temp 429.80
FF Engine Load 0.00
FF Main Pwr Relay Requests YES
FF Manifold Air Pressure 13.76
FF Oil Level 0.00
FF Port Tab Pos 0.00
FF Available Power 100
FF Run Tme 670.60
FF Starboard Tab Pos 0.00
FF TPS Percent 0.00
FF Trim Position 0.00

6 NEUTRAL OVERSPE
-------------------------------------------------------------
FF Baro Pressure 13.81
FF Battery Volts 13.76
FF Sea Pump Pressure 0.00
FF Boat Speed 0.00
FF Mainfold Air Temp 123.80
FF Coolant Temp 163.40
FF Demand 26.07
FF Engine Speed 1962
FF Engine State Running
FF FPC Total 43.9
FF Frequency Count 942
FF Fuel Level 0.00
FF Geat Position Neutral
FF Lake Temp 431.60
FF Engine Load 18.87
FF Main Pwr Relay Requests YES
FF Manifold Air Pressure 10.67
FF Oil Level 0.00
FF Port Tab Pos 0.00
FF Available Power 5
FF Run Tme 670.60
FF Starboard Tab Pos 0.00
FF TPS Percent 26.07
FF Trim Position 0.00

7 GUARDIAN
-----------------------------------------------------------------------------------
FF Baro Pressure 13.81
FF Battery Volts 14.00
FF Sea Pump Pressure 0.00
FF Boat Speed 0.00
FF Mainfold Air Temp 122.00
FF Coolant Temp 165.20
FF Demand 14.55
FF Engine Speed 2484
FF Engine State Running
FF FPC Total 21.7
FF Frequency Count 15
FF Fuel Level 0.00
FF Geat Position Neutral
FF Lake Temp 429.80
FF Engine Load 7.21
FF Main Pwr Relay Requests YES
FF Manifold Air Pressure 5.96
FF Oil Level 0.00
FF Port Tab Pos 0.00
FF Available Power 5
FF Run Tme 670.60
FF Starboard Tab Pos 0.00
FF TPS Percent 14.55
FF Trim Position 0.00

8 MAT CKT HI
-----------------------------------------------------------------
FF Baro Pressure 13.77
FF Battery Volts 12.68
FF Sea Pump Pressure 0.04
FF Boat Speed 0.00
FF Mainfold Air Temp 114.80
FF Coolant Temp 111.20
FF Demand 0.00
FF Engine Speed 0
FF Engine State Stall
FF FPC Total 0.0
FF Frequency Count 0
FF Fuel Level 0.00
FF Geat Position Neutral
FF Lake Temp 431.60
FF Engine Load 0.00
FF Main Pwr Relay Requests YES
FF Manifold Air Pressure 13.76
FF Oil Level 0.00
FF Port Tab Pos 0.00
FF Available Power 100
FF Run Tme 670.60
FF Starboard Tab Pos 0.00
FF TPS Percent 0.00
FF Trim Position 0.00

9 BLK PSI CKT HI
------------------------------------------------------------
FF Baro Pressure 13.77
FF Battery Volts 12.68
FF Sea Pump Pressure 31.45
FF Boat Speed 0.00
FF Mainfold Air Temp 114.80
FF Coolant Temp 111.20
FF Demand 0.00
FF Engine Speed 0
FF Engine State Stall
FF FPC Total 0.0
FF Frequency Count 0
FF Fuel Level 0.00
FF Geat Position Neutral
FF Lake Temp 431.60
FF Engine Load 0.00
FF Main Pwr Relay Requests YES
FF Manifold Air Pressure 13.76
FF Oil Level 0.00
FF Port Tab Pos 0.00
FF Available Power 100
FF Run Tme 670.60
FF Starboard Tab Pos 0.00
FF TPS Percent 0.00
FF Trim Position 0.00

Fault Log Data
Fault Descriptions Seconds
Battery Rang High: 0
Battery Range Low: 0
Block Pressure is Low: 472
Compressor Temp Overheat: 0
ETC Motor Open: 0
ETC Motor Short: 0
Fuel Pressure Sensor Input High: 0
Fuel Pressure Sensor Input Low: 0
Guardian Startegy: 482
Knock Sensor 1: 0
Knock Sensor 2: 0
Low Oil Pressure Strategy: 0
Low Oil Remote Strategy: 0
Low Oil Reserve Strategy: 0
MAP Sensor 1 Input High: 0
MAP Sensor 1 Input Low: 0
MAP Sensor 1 Idle Rational
 
MAP Sensor 1 Idle Rational 0
Oil Pump Output: 0
Overspeed: 0
Port Clnt Overheat: 0
Starboard Clnt Overheat: 0
Warning Horn Output: 0
Water In Fuel: 0

While it looks like we have 670.60 hours on this boat.. we don't.... blew the engine in 2009 and put a new engine in. We had 518 hours on the boat when it blew.... so on this engine we now have 152.60 hours on it.....

Engine Run Time History:
Total engin run time 670.60
0 - 749 RPM: 60.22
750 - 1499 RPM: 50.65
1500 - 2999: 8.28
3000-3499: 6.90
3500 - 3999 RPM: 6.88
4000-4499 RPM: 11.12
4500-4999 RPM: 8.58
5000-5499 RPM: 0.00
Over 5499: 0.00
 
hours are stored in the PCM so what you see is its time of use.

Glad your horn isn't beeping.

The boat shouldn't be taking on water when sitting; those leaks should be fixed promptly.
 
So with all those readings I posted, all this guy did is clean out all hoses and flush the system. The alarms are no longer going off. We took the boat out on the 4th and it ran okay. Did notice the two exhaust pipes were pretty warm. Engine temperature while running the boat fast stayed at 160 degrees. As soon as we slowed down to idle the temp raised to about 175 degrees and stayed at 175 for about 10 to 15 minutes. IS THIS NORMAL? We are really nervous with the temp fluctuating like that. Do you think we still have a problem?
 
a brief rise in temp, when the engine is returned to idle after a long run at cruise, is normal...the 10-15 minute part is a little long but not knowing the specific environment, it is hard to say.

try a few minutes at fast idle after the next run and see if the temp doesn't drop faster. I only saw luke wam to 165 in your posted data.
 
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