98 GTX RFI won’t turn over 4200 rpm

[Blacknsilvr]

Hi all!!

As the title states, ski won’t turn over 4200 rpm. I’m assuming it’s in a fail safe mode, because it stutters like a rev limiter. I’ve verified that the stator, and my osd heavy duty rectifier are both operating as designed.

This is a new problem and that popped up after I rebuilt the engine due to a rod bearing failure. (Engine was turning 6800 ish rpm at the time of the failure).

Fuel injectors have been cleaned and flow tested.

Verified the rave valve solenoid and lines are functioning properly.

TPS has been reset and idle speed adjusted.

Crank position sensor checks to be good.

So my question is, is there a possibility that the ski is actually charging correctly, but the mpem is not recognizing that it is, and throwing it into fail safe?

I’ve traced my powers and grounds to the mpem, all are showing battery voltage, and good grounds.

I’m open to any and all ideas on this deal, it’s got me stumped pretty good.

Thanks in advance!!!

 

[Blacknsilvr]

Bump??

 

[shamrock246]

Are the rave valves opening?

 

[Blacknsilvr]

Are the rave valves opening?

Yes. I have thought about taking the caps off the next time out, to see if that changes anything.

 

[etemplet]

I had one that did that. Right under 4200 then evey now and that it would take off and run 6900. Once I let it drop back down below 4000 rpm it wouldn't rev. It was the rev limiter in the MPEM. I swapped MPEMs and the ski ran great. I kept the MPEM for testing.

 

[Blacknsilvr]

I had one that did that. Right under 4200 then evey now and that it would take off and run 6900. Once I let it drop back down below 4000 rpm it wouldn't rev. It was the rev limiter in the MPEM. I swapped MPEMs and the ski ran great. I kept the MPEM for testing.

I read several of your replies that said it fixed yours. I did try another mpem, and it did the same thing. But it’s exactly like yours did. If I hold it long enough, it will push through and go to max rpm’s.

I did clean out the rave valve solenoid, and the vent line that goes back to the rear of the ski. Vent line was stopped up, but I doubt it fixes the problem. This ski has been a PAIN. IN. MY. ASS……..

 

[etemplet]

When I swapped MPEMs mine responded right away. Hmmmmm..... Check your wiring from the mag, three yellows and black and red. You may have a bad ground. I also found bad connections to the ground and the wiring under seat (the coils) I didn't read it all but did you swap the coils out. I'm lucky as I have lots of spare parts but I have to say... swapping parts is no way to fix these skis. gotta figure out what is wrong. Have you check the timing? clean the plugs and points of contact on the number 4 plug on the MPEM. You might have a plug issue Be gentle they break real easy. Good Luck !