Offshoreonly.com - 496 beep and rpm fluctuation

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Buy a VeselView Moblie its worth every penny and way cheaper then a scanner. https://publications.brunswick.com/P...ductCode=VV-MM
Also BUP is a great guy to work with and has a ton of knowledge. He actually called me a couple days after I bought plugs and wires to make sure everything wasn't damaged during shipping and fit properly.

Quote:

Originally Posted by iaoutlaw (Post 4711948)

Thanks for the good words here. And If I recall the plugs wires did very well for your engine - I remember you text me back after running your boat and saying how much you liked the wires. Thanks again.

For OP here Hi perf 2000 and many others - His issues was NOT rare but there was more than one issue going on here. During thru out on my end I keep trying to find out why the 555 s fail more than any other ecm / pcm in the marine world. Yes they fail more than any other ecm / pcm by far. Anyways I called HP2000 back months later to see how all was going plus I had some news what else I wanted for him to change out on his engine side to help against a failure again. He reported to me that his NEW and mine repaired PCM both were doing the same thing as before.

Anyways I told him to send it back to me and I will warranty my end. Also I needed him to change a couple parts out to new on the engine side as well cause the failures will keep happening no matter if the PCM was new or a repaired PCM. Once I fixed his pcm again - He wanted me to overnite it and he would pay for that end. . I also saved him overnite shipping costs from a discount I get at Fed Ex. . End of the story, he is all fixed up and running well FINALLY.

The morel of the story here is ALL PCM failures have more than one internal issue and 80 percent of the time --- the cause was from on the engine side and or -- battery side and or - cabling side and or - VOLTAGE or a person self inflicted the damage -- all those ends need to be checked and or fixed as well. ECM / PCM s 80 percent failures are cause by something on the engine / boat / battery / person side. -- if that side goes unfixed then the ECM / PCM failures will happen again and again and again always.

Quote:

Originally Posted by Freobhoy (Post 4711907)

Hi, newbie here. I am having a very similar issue on my 2006 Mercruiser 496 mag 0W632320

I get a single short beep, drop in revs and then immediately returns and carries on ok. Usually happens shortly after starting (about first 5 minutes) and usually only once per trip although have had a couple more occasionally.

last time I went out I did a bunch of runs to try and figure out what is happening.
I noticed that when the beep occurred the revs dropped to about 600 - you can feel the boat slow momentarily- but it doesn’t sound like it is running rough or misfiring- the alarm is a single beep for about a second. Boat then carries on running as normal. This was happening shortly after starting up - within a few minutes. I did about 7 or 8 starts and it happened every time.

The revs showing on the Smartcraft tachometer drop and the digital voltage display on the Smartcraft gauge goes down to 0 volts for a few seconds but the display stays live. The analog voltage gauge doesn’t move.

I have VesselView mobile and it doesn’t give me any fault codes.

I started checking all of the connections to see if it could be a ground short but haven’t found any loose or damaged connections.
Have checked all fluids and all ok.
I checked the harness connection at the engine and that seems ok.

Strangely enough - I disconnected all of the Smartcraft gauges and just left the VesselView Mobile hooked up and the problem became a lot less frequent. I did about 5 starts and it didn’t happen but then on the last run out it happened after about 25 minutes. I’m guessing that is just coincidence that it improved when the gauges were disconnected. I’m not sure if a fault in the Smartcraft gauges or CAN cable could cause a problem.

So I think it is fair to assume that I am losing voltage somewhere in the system....the fact that the gauges stay live and show 0volts....does that mean that my ignition switch and harness are ok or is that too much of an assumption? Is the interruption so quick that the gauges don’t respond?

Noting that the previous issue on this thread was resolved by a new PCM (and the similarity in serial #) - is there an easy way to test if my issue is ‘upstream’ or downstream of the PCM?

I am based in Australia and don’t have a scanner but do have multimeter.

Thanks for any guidance, tips or ideas!

his the OP was an internal issues within the PCM 555. There is a lot involved here plus one needs software as well. I have all that -- This exact issue is not rare at all -- I fix about 3 to 4 every month with this exact issue. The exact issue in the OP video

Thanks for all the info. Is there any way to confirm if my issue is similar to the previous ones and hence needs the same PCM repair?

I’ll try and post a video.

I dont get the multiple beeps - just one beep per trip, so far.

One beep per trip ? How long is the trip ? and what kind of beep is it and what does your voltage on the gauge showing during that beep. A full engine scan would help to possible see whats going on

Quote:

Originally Posted by BUP (Post 4712114)

One beep per trip ? How long is the trip ? and what kind of beep is it and what does your voltage on the gauge showing during that beep. A full engine scan would help to possible see whats going on

single beep for about a second. Sounds like the same beep as when you first turn the key. Voltage on the digital Smartcraft display goes to 0v for a couple seconds. Analog voltage display doesn’t move. Revs go to about 600 and then straight back to where they were before. No faults show on the VesselView mobile. I don’t have a scanner, so need to get a mechanic to come out with me as the beep never happens running in neutral in the pen. Or need to buy the Diacom.

I too am experiencing a single beep with loss of RPM on my 2006 496 Mag (Not HO). Mechanic tightened a loose battery cable, replaced ignition switch, and located and tightened a loose ground ground for the starboard Buss Bar at the stud on the engine. These have not corrected the issue. I get a single beep / RPM loss one time per engine start up - sometimes right away at engine warm up, others as we are under way.

BUP, you mentioned that one of the other boaters you helped above, that you directed him to replace some parts on the engine with new. What parts should I be looking to replace? Also are your still available to repair PCMs? I would like to get mine repaired and take care of the possible items that may cause the PCM to have future failures.

-What is the process for sending the PCM to you and what is the turnaround time I need to plan for?

- I tried to PM you, but your inbox is full. If can PM me, I would appreciate it.

Josh