2005 Volvo Penta 8.1 GXi intermittent beep over 1400 RPM

[Aaron K]

2005 Chaparral 256 SSi

Engine 8.1 GXI-E 3869285 4012149875 Drive Unit DP-SM 1.78 (M22) 2868912 4202133431 Transom Assembly TSK SX-MHP 3868850 4151085733

This weekend we were cruising along at 3000 RPM when I go t a constant beep and it cut power. Beep turned into long intermittent beep when I put the throttle in neutral then went away completely after about 20 seconds. All gauges reading normal, shut off engine, raised engine hatch, not hot, nothing out of the ordinary. Checked all fluids, they were all normal. Started the engine up, once I get past 1400 RPM it starts an intermittent beep. It will cruise "all day" as long as it stays under 1400 RPM. I can put the throttle at WOT and it will run up to 3000 for about 3 seconds then constant beep, cuts power, down to about 2200 RPM, intermittent beep until I power down to 1400 RPM. If I leave it in WOT, it will go from 3000 RPM down to 2200 RPM and back to 3000 RPM, over and over until I change throttle position. The whole time it is a constant beep. I only did that once just to see if it would help diagnose the problem.

I am not sure if the marina has the proper scan tool to tell me exactly what it is or if their scan tool just says it is a faulty sensor, faulty ???. I hate to pay them to scan it if it won't give me a definitive answer and now I just become a parts changer until I find the right sensor, etc.

Thank You all in advance!!

 

[alldodge]

The intermittent beep below 2500 rpm means the ECM has detected an active code

The steady beep above 2500 rpm means the ECM has activated engine protection mode

Low oil pressure
Engine temp above 200* F and stays above 180*
Exhaust temp above 210*F and stays above 160*

The ECM uses preset pressure and temp switches. If oil pressure gauge can look good, but the switch may be telling the ECM its low. Same with the engine and exhaust temps

Use a IR temp gun to verify temps

 

[muc]

From your owners manual......

Engine Protection Mode
In a low oil pressure, low voltage, engine overheat, or
lack of exhaust cooling water situation, the Electronic
Fuel Injection (EFI) system will enter an Engine Protection Mode (EPM). In such cases, if an acoustic
alarm has been installed with your engine, the alarm
(located beneath the dashboard) will sound to notify
you of a malfunction.
Under these conditions, engine operation is limited to
2500 RPMs or less. When the EFI system switches on
the EPM, there will be a temporary reduction in power
until the problem is resolved. In this mode, ignition timing is also adjusted in response to the situation. If the
engine drops below 1200 RPMs, normal injector operation and spark timing resume. The engine may now
be operated normally, as long as engine speed remains below 2500 RPMs.
For anything above 2500 RPMs, the engine will display poor running characteristics. If the engine is run
above 2500 RPMs without any load or with the drive
in neutral, the engine will exhibit surging.
NOTE! Continuing to run the engine in this mode
without correcting the cause may result in
further engine damage.
Use the oil pressure and water temperature gauges to
verify a problem exists, then inspect the engine crankcase for proper oil level and check the water inlets for
obstructions. The low oil pressure/engine overheat
problem must be corrected before the engine will return to normal operation.
To reset the Engine Protection Mode after the problem is corrected, allow the engine to cool and then
continue with normal operation.
NOTE! If the problem continues, contact your Volvo
Penta dealer and have the engine inspected.

A scan tool won't be of much help with this. It will only speed up testing of numbers 2+3. Knowledge of how the system works is what is needed.


It will be one of these 4 things.

1. The oil pressure switch can be unplugged for testing.
2. The voltage at the ECM can be tested with a voltmeter.
3. The engine coolant sensor can be tested with an ohm meter.
4. The 2 exhaust temp switches can be unplugged for testing.

Further information and a wiring diagram can be found in Workshop Manual EFI Diagnostic #7742218