i have a 496 ho that keeps stalling the second I attempt to give it any throttle above an idle. Sometimes it runs fine, ill launch it drive around for a while, anchor the boat, but when I go to leave the second I give it any gas it dies. I thought maybe bad fuel, replaced the fuel, still does it. If anyone could help me out id appreciate it. I bought the diacom software but am having trouble figuring out what it all means.





4 5 VDC PWR LO
--------------------------------------------------------------------
FF Baro Pressure 9.66 PSI
FF Battery Volts 11.95 VDC
FF Sea Pump Pressure 7.32 PSI
FF Boat Speed 0.00 #
FF Manifold Air Temp 50.00 °F
FF Coolant Temp 50.00 °F
FF Demand 2.40 %
FF Engine Speed 0 RPM
FF Engine State Stall
FF FPC Total 0.0 Counts
FF Frequency Count 168
FF Fuel Level 0.00 %
FF Gear Position In Gear
FF Lake Temp 431.60 °F
FF Engine Load 0.00 %
FF Main Pwr Relay Requests YES
FF Manifold Air Pressure 10.73 PSI
FF Oil Level 0.00 %
FF Port Tab Pos 0.00 %
FF Available Power 100 %
FF Run Time 376.23 hrs
FF Starboard Tab Pos 0.00 %
FF TPS Percent 2.40 %
FF Trim Position 52.25 %

5 MAP INPUT LO
--------------------------------------------------------------------
FF Baro Pressure 9.41 PSI
FF Battery Volts 14.32 VDC
FF Sea Pump Pressure 6.52 PSI
FF Boat Speed 0.00 #
FF Manifold Air Temp 105.80 °F
FF Coolant Temp 150.80 °F
FF Demand 0.88 %
FF Engine Speed 708 RPM
FF Engine State Running
FF FPC Total 9.0 Counts
FF Frequency Count 1
FF Fuel Level 0.00 %
FF Gear Position In Gear
FF Lake Temp 429.80 °F
FF Engine Load 3.20 %
FF Main Pwr Relay Requests YES
FF Manifold Air Pressure 3.92 PSI
FF Oil Level 0.00 %
FF Port Tab Pos 0.07 %
FF Available Power 100 %
FF Run Time 375.98 hrs
FF Starboard Tab Pos 0.00 %
FF TPS Percent 0.88 %
FF Trim Position 21.61 %

6 MAT CKT HI
--------------------------------------------------------------------
FF Baro Pressure 9.41 PSI
FF Battery Volts 14.11 VDC
FF Sea Pump Pressure 5.63 PSI
FF Boat Speed 0.00 #
FF Manifold Air Temp 105.80 °F
FF Coolant Temp 147.20 °F
FF Demand 0.12 %
FF Engine Speed 626 RPM
FF Engine State Running
FF FPC Total 18.7 Counts
FF Frequency Count 0
FF Fuel Level 0.00 %
FF Gear Position In Gear
FF Lake Temp 431.60 °F
FF Engine Load 4.49 %
FF Main Pwr Relay Requests YES
FF Manifold Air Pressure 6.51 PSI
FF Oil Level 0.00 %
FF Port Tab Pos 0.38 %
FF Available Power 100 %
FF Run Time 375.95 hrs
FF Starboard Tab Pos 0.00 %
FF TPS Percent 0.12 %
FF Trim Position 0.00 %

7 TPS1 CKT LO
--------------------------------------------------------------------
FF Baro Pressure 9.41 PSI
FF Battery Volts 14.22 VDC
FF Sea Pump Pressure 5.86 PSI
FF Boat Speed 0.00 #
FF Manifold Air Temp 102.20 °F
FF Coolant Temp 141.80 °F
FF Demand 1.65 %
FF Engine Speed 727 RPM
FF Engine State Running
FF FPC Total 19.3 Counts
FF Frequency Count 0
FF Fuel Level 0.00 %
FF Gear Position In Gear
FF Lake Temp 431.60 °F
FF Engine Load 5.29 %
FF Main Pwr Relay Requests YES
FF Manifold Air Pressure 6.49 PSI
FF Oil Level 0.00 %
FF Port Tab Pos 0.19 %
FF Available Power 100 %
FF Run Time 375.92 hrs
FF Starboard Tab Pos 0.00 %
FF TPS Percent 1.65 %


8 MPRLY OUTPUT
--------------------------------------------------------------------
FF Baro Pressure 5.27 PSI
FF Battery Volts 7.28 VDC
FF Sea Pump Pressure 3.75 PSI
FF Boat Speed 0.00 #
FF Manifold Air Temp 60.80 °F
FF Coolant Temp 93.20 °F
FF Demand 0.00 %
FF Engine Speed 0 RPM
FF Engine State Stall
FF FPC Total 0.0 Counts
FF Frequency Count 2
FF Fuel Level 0.00 %
FF Gear Position In Gear
FF Lake Temp 431.60 °F
FF Engine Load 0.00 %
FF Main Pwr Relay Requests YES
FF Manifold Air Pressure 4.60 PSI
FF Oil Level 0.00 %
FF Port Tab Pos 0.23 %
FF Available Power 50 %
FF Run Time 376.13 hrs
FF Starboard Tab Pos 0.00 %
FF TPS Percent 0.00 %
FF Trim Position 0.00 %

9 CAM SNSR

FF Baro Pressure 6.73 PSI
FF Battery Volts 10.49 VDC
FF Sea Pump Pressure 4.78 PSI
FF Boat Speed 0.00 #
FF Manifold Air Temp 50.00 °F
FF Coolant Temp 50.00 °F
FF Demand 0.00 %
FF Engine Speed 854 RPM
FF Engine State Running
FF FPC Total 23.7 Counts
FF Frequency Count 43
FF Fuel Level 0.00 %
FF Gear Position In Gear
FF Lake Temp 431.60 °F
FF Engine Load 4.25 %
FF Main Pwr Relay Requests YES
FF Manifold Air Pressure 4.94 PSI
FF Oil Level 0.00 %
FF Port Tab Pos 0.33 %
FF Available Power 74 %
FF Run Time 376.10 hrs
FF Starboard Tab Pos 0.00 %
FF TPS Percent 0.00 %





ETC Motor Open: 0
ETC Motor Short: 0
Fuel Pressure Sensor Input High: 0
Fuel Pressure Sensor Input Low: 0
Guardian Strategy: 0
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: 33
MAP Sensor 1 Idle Rational: 0
Oil Pump Output: 0
Overspeed: 1
Port Clnt Overheat: 0
Starboard Clnt Overheat: 0
Warning Horn Output: 0
Water In Fuel: 0

IS it totally random or does it do it more one time over another? Does it do this when its cold? After it has been driven around for a while and its hot?

Also are you getting any beeps going off?

5 VDC LO there is a short in the 5V circuit feed - Bat showing 11.9V
MAP INPUT LO shows 3.92 psi
MAT CKT HI showing 105 degrees F
TPS CKT LO open in the Throttle position sensor
MPRLY OUTPUT motor stalled/quit
CAM SNSR open or short in cam sensor showing 10.9V
Overspeed 1

I'm thinking you have a bad ground somewhere, you loosing solid power to the PCM and the computer is going off the rails

Bad or loose kill switch?

Yes, to me it appears random. I'm unable to connect any common occurrences between it happening... It'll do it after I drive it out to a bay and anchor and been sitting for a while trying to come back. So the motor will be cold.... I'll finally get it back to the house, and fire it up on the trailer on muffs and won't be able to duplicate it.... But no beeps I don't think, there's no active code it's not in guardian just the stored codes in freeze frame...

one is you need a new cranking battery with a min of 12.7 Volts and with the currect MCA amps recommended by the OEM. Or you have very poor connections - loose or corrosion issues for power connections.

Also your 5 V sensor(s) are reporting low voltage - they need to be reporting 4.8 to 4.9 min on the scan.

YOU HAVE A IN Gear report on the scan tool so was this scan after a stalled engine in gear ???? If not you have a problem with the shift in gear swtich.

You have mainly VOLTAGE issues - you have to fix all of that first - and whatever bad grounds and testing on possible sensor themselves to make sure they are still good

Is this a salt boat ??? has any part of the engine got wet especially sensors and connections ??? Corrosion issues - they hurt voltage inputs and outputs all the time and will set crazy fault codes.

YOU NEED TO LOOK into history and write down all that info with engine hour timeframes when they all took place.

YOU NEED TO LOOK IN HISTORY AT WHAT RPM the cam sensor fault reported and at what engine hours to see if it happened before the 376 hour mark as well ???

5 V sensor low voltage is stalling the engine. THAT FAULT CODE is plain as day from the scan report showing.

A scan tool can possible lead you to the problems or hopefully point in that direction - reading it and understanding is a whole different story - kind of like playing doctor - SURE we all can take X rays and draw blood but how many NON doctors can read all of that correctly and in depth. I know I could not. Trying to make a point as sometimes buying scan tool can be a boat owners waste of money.

You are absolutely right about understanding the data it delivers, I was hoping itd lead me to something simple like a faulty sensor and I could just replace it. I thought that because it mostly ran fine with intermittent issues.. I saw others stories about hooking it up and it telling them exactly the issue, clearly this is something... I greatly appreciate the assistance in reading the data.