2004 rxp sc mpem buzzing

[rxp04]

Hi, I have a 2004 rxp sc , I just rebuilt the engine on / supercharger. After the install found out that as soon as I touch hot wire on battery the mpem starts making a buzzing sound but no fuses are blowing. The only thing it will do is buzz , someone told me it could be bad battery? Any ideas ? Thanks

 

[devonte007]

I have experienced this before on my boat when I did not have both (or all) the negative leads connected to the battery. My boat has 2 negative cables and 1 positive cable (some boats/skis are different). I once forgot to hook up one of the negative cables (slipped down under the engine) after installing the battery. As soon as I hooked up the positive cable I got a weird buzzing sound coming from the mpem/fuse block, it obviously would not start either. I then realized my mistake and hooked everything up proper and no problems since.

Not sure if this in your issue, but good to start with something simple first. Hopefully it is not something more serious.

 

[rxp04]

Thank u for reply. I just followed the wires on negative cable the big negative cable is hooked up but there are 2 other small negative leads that are not hooked up . I have no clue where they hook up to though.

 

[devonte007]

Sounds like you found the problem, glad it is something simple. I do not have that machine and i am not familiar with the wiring layout. Do you have a shop manual you can refer to? If not you should be able to get a PDF version through this site, just click on "manuals" up at the top.

If that does not help I'm sure someone else with more knowledge of your particular ski will chime in and help you get the info that you need.

 

[ski-d00]

The small ground wires attach to the front of the motor just below the engine info plate. There should be 3 separate screw bosses in a horizontal line and there are 3 or 4 wires on that model if I remember correctly.

 

[rxp04]

Ok, I hooked up the ground wires on front of engine block . I hooked up the battery and the same thing happened mpem started buzzing again, fuses look good but have not tested them yet. As soon as I touch the power to it, it starts buzzing and no power is getting to gauges.

 

[ski-d00]

The LCD gauge won't come on until you put the proper key on the lanyard. Sounds like you still have a ground missing. How many small ground wires do you have connected to the front?

Are you sure it's the MPEM buzzing? Disconnect the TOPS after you check all your grounds and see if it still buzzes.

 

[Coastiejoe]

In almost all cases, buzzing is caused by lack of voltage.

That said, the lack of voltage can be caused by wires not connected, battery issue, or poor connections. Your grounds must be near perfect condition. You want to feel the wires and make sure they don't "crunch" when you bend them (sign of corrosion within the wire). That the ends are super clean as it the mounting area they attach to.

 

[rxp04]

I have 3 ground wires on front engine. I disconnected tops switch still buzzing . I pulled 30 amp fuse off hot wire on stater relay buzzing stopped. I was told to change starter relay because it could be stuck in open position. I have another one so I will try that to.

 

[ski-d00]

You were told wrong. The 30A fuses on/near the starter relay has nothing to do with the starter relay. It basically powers your whole electrical system so the buzzing should definitely stop since it is the same thing as disconnecting your battery.

Are you sure your battery is good? When you jump the solenoid, does the engine turn over at proper speed?

After looking at the wiring diagram, you should have 5 separate black wires connected to the 3 ground bosses at the front of the motor, two will be doubled up and another single wire.

 

[rxp04]

Ok , I jumped the starter relay and the starter barely turned over. I done a load test on battery and it's bad. Will low voltage cause it to buzz ? Oh and the ground wires as you described 5 wires to 3 bosses.

 

[Coastiejoe]

Ok , I jumped the starter relay and the starter barely turned over. I done a load test on battery and it's bad. Will low voltage cause it to buzz ? Oh and the ground wires as you described 5 wires to 3 bosses.

Yep Yep...
Low volts is a major issue. As noted in my above post (#8). Buzzing is ALMOST always poor voltage. It can be a battery or poor connection, but it comes down to a voltage/amperage issue.

 

[rxp04]

Well I got it running finally new battery and then I swapped plugs on mpem on top of intercooler fired right up. . Thanks for all the replies.

 

[ski-d00]

You mixed up the A and B connectors on the ECU? I guess that would do it. I've never even heard of that happening. SeaDoo normally keys all their connectors so they can't be mixed up although there is a giant "A" and a giant "B" on the connectors and on the ECU so I don't think keying it would be necessary.

Glad to hear it's running!!