350 Mag goes into Guardian Mode - Help Please
 

I've got a 350 Mag that goes into guardian mode about 3000 rpm. The computer is not showing any error codes. Any one have similar issues or thoughts?

Re: 350 Mag goes into Guardian Mode - Help Please
 

Check for a bad neutral safety switch. If they see neutral they will not go over 3000, and will not code. Unplug the switch and see if it fixes it. If it does it may be that the lever that switches the switch is over-traveling and the switch is dropping off the back side. Don't ask me how I know this :D

Re: 350 Mag goes into Guardian Mode - Help Please
 

Are you sure it's going into Guardian Mode? Is there an alarm when this happens? What codes are currently in memory? What is the frequency count for each one?

You could try clearing the Freezframe memory and retesting. If you get an alarm/Gaurdian Mode again, it should be easy to figure out why after rechecking the memory and reveiwing the newly stored faults.

If you get an alarm and there are no faults stored, there may be a problem with the ECM, but thats not very common.

Taking a wild guess, it sounds like a possible problem with the shift position switch. If the ECM thinks the engine is in neutral, it will limit RPM to 3500. But you should have a stored Neutral Overspeed fault if that was the case. Again, this is just a guess, there are other faults (ECT Overtemp, Low Drive Lube, Low Oil Pressure) that could be causing the power reduction.

Dave

Re: 350 Mag goes into Guardian Mode - Help Please
 

Thanks for the feedback. I'll let you know what I find.

J

Re: 350 Mag goes into Guardian Mode - Help Please
 

I had a 350 Mag in my old boat and it did something similar at 3000 rpm. Sounded like the rev limiter kicked in or something. Turned out to be a loose plug wire. Check those, all of them including the main one. That's what it was for me.

350 mag issue no start
 

hi , ihave a boat with 2 engines 350 mag the 02 engine do not want to turn on i scanned the engines i have the following code on both of them

Current ECM Codes

Sensor Fault, click Read Fault button for details

Trouble Code List:
PITOT CKT LO Code is active
FUEL LVL CKT HI Code is active
STEER CKT LO Code is active
SEA TMP CKT HI Code is active
TRIM CKT HI Code is active
i test the injectors with the diacom from 01 to 04 injector test good, but from 05 to 08 i cannot test them ,the same result on the 02 engines,please let me know if you have any suggestion.
engine 01:
Parameter Description Value Unit

Engine Speed.......................................... 0 RPM
Available Power..................................... 100 %
Coolant Temperature............................... 75,20 °F
Fuel Flow Rate..................................... 0,00 GPH
Port Exhst Cool Temp.............................. 32,00 °F
Sea Pump Pressure.................................. 0,00 PSI
Starb Exhst Cool Temp............................. 32,00 °F
IAC Duty Cycle..................................... 0,00 %
Manifold Absolute Pressure........................ 14,80 PSI
Trim Position...................................... 1023 #
Baro Pressure..................................... 14,80 PSI
Trim Volts......................................... 4,99 VDC
Manifold Air Temperature.......................... 78,80 °F
Pitot ADC............................................. 0 #
Oil Pressure....................................... 0,38 PSI
Paddle Wheel.......................................... 0 Hz
Throttle Position.................................. 0,00 %
Sensor Power....................................... 5,06 VDC
Throttle Sensor Voltage............................ 0,63 VDC
Lake/Sea Temp..................................... 32,00 °F
Spark Advance...................................... 8,00 DEG
Fuel Level......................................... 1023 #
Battery Voltage................................... 11,25 VDC

3. TROUBLE CODE STATUS

Current ECM Codes

Sensor Fault, click Read Fault button for details

Trouble Code List:
PITOT CKT LO Code is active
FUEL LVL CKT HI Code is active
STEER CKT LO Code is active
SEA TMP CKT HI Code is active
TRIM CKT HI Code is active
engine 02


2. PERFORMANCE DATA

Parameter Description Value Unit

Engine Speed.......................................... 0 RPM
Available Power..................................... 100 %
Coolant Temperature............................... 75,20 °F
Fuel Flow Rate..................................... 0,00 GPH
Port Exhst Cool Temp.............................. 32,00 °F
Sea Pump Pressure.................................. 0,00 PSI
Starb Exhst Cool Temp............................. 32,00 °F
IAC Duty Cycle..................................... 0,00 %
Manifold Absolute Pressure........................ 14,57 PSI
Trim Position...................................... 1023 #
Baro Pressure..................................... 14,57 PSI
Trim Volts......................................... 4,99 VDC
Manifold Air Temperature.......................... 78,80 °F
Pitot ADC............................................. 0 #
Oil Pressure....................................... 0,54 PSI
Paddle Wheel.......................................... 0 Hz
Throttle Position.................................. 0,00 %
Sensor Power....................................... 4,99 VDC
Throttle Sensor Voltage............................ 0,64 VDC
Lake/Sea Temp..................................... 32,00 °F
Spark Advance...................................... 8,00 DEG
Fuel Level......................................... 1023 #
Battery Voltage................................... 11,11 VDC

3. TROUBLE CODE STATUS

Current ECM Codes

Sensor Fault, click Read Fault button for details

Trouble Code List:
PITOT CKT LO Code is active
FUEL LVL CKT HI Code is active
STEER CKT LO Code is active
SEA TMP CKT HI Code is active
TRIM CKT HI Code is active

there is pressure on the fuel pump the startor good spark plug new the fuse good thank you to help me
best regards