4.3L MPI Mercruiser Alarm Twice a minute with no fault codes given on code reader

[mitchellmc]

I have a 2006 Crownline with a 4.3L MPI mercruiser, it is giving the typical 2 beeps a minute and it will limit top end power I can get about 4000rpm where normally I can get 4800rpm. I checked all the normal fluids, temp is good has a new impeller in it. It seems to be running fine but still get the alarm. Over the winter I had changed the Oil, gear lube, put in new plugs and a cap and rotor just because I thought it might need it... It is setting in my local boat shops garage and they hooked it up to there code reader and get nothing except the alarm beep...???????

 

[alldodge]

I have a 2006 Crownline with a 4.3L MPI mercruiser, it is giving the typical 2 beeps a minute and it will limit top end power I can get about 4000rpm where normally I can get 4800rpm. I checked all the normal fluids, temp is good has a new impeller in it. It seems to be running fine but still get the alarm. Over the winter I had changed the Oil, gear lube, put in new plugs and a cap and rotor just because I thought it might need it... It is setting in my local boat shops garage and they hooked it up to there code reader and get nothing except the alarm beep...???????

Howdy and :welcome:

Do you get the beep at idle or just when you get the rpms up?

 

[mitchellmc]

All the time

 

[alldodge]

Without your serial number I'm going to guess you have a MEFI-4 computer using the 555 CANBUS. With this there should be a code set. Mentioning that the shop put the scanner on it and could hear the beep but could not find a code is puzzling. The beep is controlled by the ECM and not a given switch/sensor. I wonder if the shop has version 6 software and the 555 connector. Here is the list which can set codes, and note the ones with 2 beeps and 90%. These are the ones which can cause a power reduction

Warning system Faults, SC1000 Yes/No, Audio Alarm, Available Power %, Description.

(1) Cam Sensor Yes 2 Bp/min 90% Open or short, engine must be cranking to set this fault code.
(2) ECT CKT HI Yes 2 Bp/min 90% Open
(3) ECT CKT LO Yes 2 Bp/min 90% Short
(4) ECT Coolant Overheat Yes Constant 6-100 % Engine guardian overheat condition
(5) EST 1-8 Open Yes 2 Bp/min NA Coil harness wire open
(6) EST 1-8 Short Yes 2 Bp/min NA Coil harness wire short
(7) Fuel Injector 1-8 Open Yes 2 Bp/min NA Fuel injector wire open.
(8) Fuel Injector 1-8 Short Yes 2 Bp/min NA Fuel injector wire short
(9) IAC Output Yes 2 Bp/min 90% Only with rpm
(10) Knock Sensor 1 Yes 2 Bp/min 90% Alarm sounds for 20 seconds in NEUTRAL and indefinitely in gear.
(11) Knock Sensor 2 Yes 2 Bp/min 90% Alarm sounds for 20 seconds in NEUTRAL and indefinitely in gear.
(12) Low Drive Lube Strategy Yes Steady Bp 0-100% Low oil in sterndrive.
(13) Low Oil Pressure Strategy Yes Constant 0-100% Low oil pressure strategy.
(14) MAP Sensor 1 Input High No 2 Bp/min 90% Short, no visual on SC1000.
(15) MAP Sensor 1 Input Low No 2 Bp/min 90% Open, no visual on SC1000.
(16) MAT Sensor Yes 2 Bp/min 90% Open or short in MAT circuit.
(17) Oil PSI CKT Hi Yes 2 Bp/min 90% Short, defaults to 51.7 psi.
(18) Oil PSI CKT Lo Yes 2 Bp/min 90% Open, zero oil pressure.
(19) Overspeed Yes Constant RPM Limit Engine over rpm limit
(20) Port EMCT CKT Hi Yes 2 Bp/min 90% Open, defaults to 32 degrees F.
(21) Port EMCT CKT Lo Yes 2 Bp/min 90% Short, defaults to 32 degrees F.
(22) Port EMCT CKT Overheat Yes Constant 6-100% Overheat condition, 212
degreesF(100 degrees C) limit.
(23) Sea Pump PSI Lo Yes Constant 6-100% Low water pressure strategy, defaults to 43.4 psi.
(24) Sea Pump CKT Hi Yes 2 Bp/min 90% Open.
(25)Sea Pump CKT Lo Yes 2 Bp/min 90% Short.
(26) STB EMCT CKT Hi Yes 2 Bp/min 90% Open, defaults to 32 degrees F.
(27) STB EMCT CKT Lo Yes 2 Bp/min 90% Short, defaults to 32 degrees F.
(28) STB EMCT CKT Overheat Yes Constant 6-100% Overheat condition, 212 degrees (100 degrees C) limit.
(29) Steer CKT Hi Yes No No Open and short.
(30) TPS1 CKT Hi Yes 2 Bp/min 90% Short, signal to 5v+, engine will not start. Refer to data monitor screen.
(31) TPS1 CKT Lo Yes 2 Bp/min 90% Open.
(32) TPS 1 Range Hi Yes 2 Bp/min 90% Above 4.8v, 994 counts.
(33) TPS 1 Range Lo Yes 2 Bp/min 90% Below 0.5v, 35 counts.
(34) Trim CKT Hi Yes No No Short, high range, visual warning on SC1000 only.
(35) Trim CKT Lo Yes No No Open, low range, visual warning on SC1000 only.
(36) 5 VDC PWR Low Yes 2 Bp/min varies Short any 5v+ to ground.

A week battery or bad connections can cause the beeping, but they also have fault codes

 

[Faztbullet]

The IAC will do this and have no codes...