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787 RFI limp mode? The Service center says it doenst exist?

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nicolajjetrider

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Hi

I have a 787 RFI, it has been at a service center to erase failures on the MPEM because it didnt go over 2400RPM.

It didnt help :(

But at the service center the people sayed: There is no Limp mode at seadoo GSX 787 RFI ? I was verry supriced to hear that.

Know im confused and i think the problem is the MPEM.

But does the 787 RFI has a limp mode?

Nicolaj
 
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The RFI skis don't really have a "Limp Mode". Only the Di skis have a true limp mode that will shut off one cyl. BUT... the nature of a fuel injection system is... if it's not working... it will have a hard time getting full power. Also... with SeaDoo... 2400 isn't a limp RPM. 3500 is.

All I can say, is that you will have to go over the senders methodically, to find what's wrong. Also... the injectors need checked, along with the fuel pressure.
 
So stupid Danish people understands it ;) What is the Senders?

? Sensors? Or?

Dr Honda said:
The RFI skis don't really have a "Limp Mode". Only the Di skis have a true limp mode that will shut off one cyl. BUT... the nature of a fuel injection system is... if it's not working... it will have a hard time getting full power. Also... with SeaDoo... 2400 isn't a limp RPM. 3500 is.

All I can say, is that you will have to go over the senders methodically, to find what's wrong. Also... the injectors need checked, along with the fuel pressure.
Click to expand...
 
Strizzo said:
assuming that your mechanic has already checked the rectifier that is a known issue on RFI skis.
Click to expand...

yes Nikolai, the SENDERS are the parts in the MPEM that send the electronic signal to the fuel injectors. the RECTIFIER is what the spark plug wires are connected to, it makes the spark the engine runs on.

hope that helps, i had a foreign exchange student from denmark about two years ago.

held og lykke!
 
Nope, he just erased all the failures on the computer and changed the TPS sensor, and took 450US for it. And it didnt help the problem.

So i will my self fix it know.

Where is the rectifier?

Issue is this:
787RFI engine
Engine compression: 12Bars on both cylinders
New Coil
New Sparkplugs
New TPS

both Injectors are spraying.
when I check for spark both are fine and blue, but when i start it the front spark i cold ( not firring ) and the engine take max 2400RPM in the water ( on the trailer it runs OK ).



Strizzo said:
assuming that your mechanic has already checked the rectifier that is a known issue on RFI skis.
Click to expand...
 
DSchmidt54 said:
yes Nikolai, the SENDERS are the parts in the MPEM that send the electronic signal to the fuel injectors. the RECTIFIER is what the spark plug wires are connected to, it makes the spark the engine runs on.

hope that helps, i had a foreign exchange student from denmark about two years ago.

held og lykke![/QUOTE]

Mange tak ;)

Thanks, I will check it all again. My previus topic was this:

Hi

Im looking for some help here

I have a GSX RFI 787

It will max run 2400RPM
No Failures in the computer
New TPS Sensor
New Sparkplugs
New Coil
RAVE Valves cleaned

When i check spark there is on both. But when it is sailing its only the rear sparkplug there is getting hot.

Is it a new computer and key?
----------------------
Click to expand...
 
i dont know what causes excessive compression, but stock for that engine should be around 135 - 150 psi so 9-10 bar
 
liquid in the engine is usually the culprit to high compression, if your injectors are DUMPing too much gas into the cylenders that could likely be the culprit, also , has the ski been rolled , or has water gotten into the engine bay recently?
 
The RFI does have a "LIMP MODE" if the battery voltage goes too low. The MPEM will limit the RPM's to 4480 rpm's.
 
Too much fuel will cause both higher compression as well as reduced RPMs.

Either the computer thinks the engine is cold and dumping tons of fuel and or the carbs need rebuilt. If it is injected, then the injectors should be test for both pop off pressure and a leak test.

If old style fuel (grey) lines crumbled they can clog the pointless in injectors and hold them open.
 
FI skis don't have the grey lines but i agree with getting the injectors cleaned and tested.
 
Unfortunatley, I am not up on what ski has what items just yet,,,

That said, I do know the how and why of things in regards to running and running issues.
Certified diesel mechanic, gas engine, small engine, A/C and refrigeration...

I can normally get a good clue based on my past...

Thanks for the info..
 
Last edited by a moderator:
Hi guys

I will go test the ski again systematickly tomorrow.

The fallowing things I will do is:

New Compression test.
Check the injectors.
check the sparkplugs ( but they are new )
check the rejichter? How??
Check fuellines
Check - connections to battery and engine and +
Rave's ( They are cleaned )
I will make a video and youtube it so you guys can see it runing and the foolwing things i do to it.

You know have 29 hours to come with good ideas to what it can be? And what to check

Nicolaj - Denmark :)
 
nicolajjetrider said:
Hi guys

I will go test the ski again systematickly tomorrow.

The fallowing things I will do is:

New Compression test.
Check the injectors.
check the sparkplugs ( but they are new )
check the rejichter? How??
Check fuellines
Check - connections to battery and engine and +
Rave's ( They are cleaned )
I will make a video and youtube it so you guys can see it runing and the foolwing things i do to it.

You know have 29 hours to come with good ideas to what it can be? And what to check

Nicolaj - Denmark :)
Click to expand...

I recommend you take a look at this link for testing the rectifier. http://www.seadooforum.com/showthread.php?31491-Testing-the-rectifier you can check the voltage at the battery while the engine is running to see if it is working properly at idle, it should be betwee 12.8 and 13.9 volts and fairly steady.

another test is to disconnect the red wire, this takes the rectifier out of the system basically, if the problem clears up with this, the rectifier needs to be replaced. Seadoosource sells a plug & play heavy duty rectifier as well http://www.seadoosource.com/hdrectifier.html
 
Well, you can be sure all of your ski is in great shape after all you have gone through,,,,

Glad you have it working, congrats,,
 
Thanks mate :) Its a total good feeling.

I have be doing following:

Checked mpem
Checked all wires
Cheked battery
Changed tps sensor
Cheked the other sensors
Compression testet
Cleaned raves
New sparkplugs
New coil

And finaly it was the rejectifier :)

I Will Go ride it this weekend. Video will follow:)

Cant Thanks you enough for all help!
 
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