Mercruiser 4.3 MPI 220HP

[pfarnan]

My Mercruiser 4.3MPI 220HP engine management system is intermittently throwing a diagnostic code causing the audio alarm to beep twice. The 3 possibilities are: low engine oil pressure (oil levels are ok and oil is clean); drive oil low (level is ok); engine temperature too hot (engine temp running consistently at 1/4 on the gauge which is apparently where it's supposed to sit). Thermostat has been tested and it's working correctly - opening at approx 71C (160F), and closing at lower temps. Tested the temp gauge was working correctly by earthing the sensor - all ok. Interestingly, whilst doing this the two beep alarm was activated. Tested whilst flushing and all ok. Tested under load on the water and all was ok until we came in and the alarm started again. Timed the alarm - goes off every minute without fail, at speed or idling. Turned engine off, restarted and no more alarm. I suspect the sensor. Thoughts from the forum? Thanks, Peter.

 

[QC]

Re: Mercruiser 4.3 MPI 220HP

Welcome aboard pfarnan!!! I moved this over to the Mercruiser I/O section. You were in the Mercury OB section. I'm sure we'll be able to help you out over here. Good luck

 

[pfarnan]

Re: Mercruiser 4.3 MPI 220HP

Thanks

 

[Don S]

Re: Mercruiser 4.3 MPI 220HP

The oil pressure, temp and low gear lube would give you a steady alarm, not an intermittant 2 beeps per minute that you are getting.
There are MANY problems that could cause your problem. Do you happen to have a mercruiser serial number for your engine. Year of your boat also doesn't help.

 

[pfarnan]

Re: Mercruiser 4.3 MPI 220HP

Don,
Engine serial number: OM647724, manufactured 2004.

Thanks, Peter

 

[Don S]

Re: Mercruiser 4.3 MPI 220HP

Below is a link to the list of alarms for your engine.
If you plan on doing your own repairs, you are going to need a diagnostic tool such as the Rinda scan tool, a DVM, and the OEM service manual to find the problem.

http://www.4shared.com/account/document/wQ5qgap8/555_Audio_Alarm_chart.html

 

[pfarnan]

Re: Mercruiser 4.3 MPI 220HP

Thanks very much Don.

 

[pfarnan]

Re: Mercruiser 4.3 MPI 220HP

Don,
I haven't mentioned that I changed the battery after purchase. The alarm wasn't evident before this, but occurred not long after installing the new battery. Leads are connected to the correct terminals. Could there be any connection with the alarm problem?

 

[Don S]

Re: Mercruiser 4.3 MPI 220HP

Are the cable connections clean and tight on the battery? I don't mean tight with those wingnuts, remove them things, use real nuts and a wench to tighten them. The cables also have two ends that need to be clean and tight. DO NOT assume, check them.
One other possibility, you need to use a starting battery, not sa deep cycle with EFI.

 

[pfarnan]

Re: Mercruiser 4.3 MPI 220HP

Don,
battery leads/terminals all ok. Tried a new water pressure sensor but still getting the alarm, so resorted to putting engine on a diagnostic tool. Computer reported 109 Guardian faults. The mechanic could not find anything mechanically wrong with the engine which was as expected. However, he found the switch that monitors in-gear and neutral was always set to neutral, regardless of being in forward or reverse. Looking at the chart you supplied I'm guessing the last fault listed 'Shift Switch' is the fault. The tool unfortunately didn't drill down that far. The explanation seems to make sense as at times when the boat is cruising at a steady 20 - 25 mph, followed by a rapid acceleratioin will cause the alarm to be thown. The mechanic has cleand and adjusted the switch so that it now reads correctly when in gear or neutral. Water test in a couple of days. Keep the fingers crossed.

 

[pfarnan]

Re: Mercruiser 4.3 MPI 220HP

Don,
problem fixed. It was definitely the issue mentioned in my previous post. No more beeps! And this was a relatively inexpensive exercise. Hope this helps other forum users.

 

[QC]

Re: Mercruiser 4.3 MPI 220HP

Thank you for the follow-up!!!