GTX RFI bogging and not reaching full rpm

[Minton33]

Really needing some help so I can get this thing back on the water before it gets cold.

So I picked up a 2000 Seadoo GTX RFI for a good deal in spring. It had an sbt engine put in it last summer and for whatever reason it had lost compression when my coworker bought it. I work at a Seadoo dealership and he is the main Seadoo mechanic. He put a fresh topend on it and never could get it started again so i bought it from him. turns out he had the injector and rave solenoid plugs swapped as well as the map and tps sensor. Which ruined the mpem so I replaced the mpem and swapped the plugs around and it ran.

Since then for the last few months it has had a miss/stumble from 4000 to 4500 rpm and occasionally misses between 2 and 3000 rpm. Aside from that it has ran fine until the other day and now it will not go over 6400 rpm and if held there for 10 seconds or so it will slowly start loosing rpm and then bog down to about 5400 or so and start missing worse and worse until you let off for a bit and then you can do it all over again. It gets worse the more you ride it. It also completely falls on its face when jumping it and will bog when turning hard left. the idle has also dropped to between 900-1100.

List of things I’ve done since I got it.

•replaced battery and starter

•replaced mpem

•replaced fuel pump with I believe it was a quantum kit

•drained tank and wiped out. Although it was a few months ago

•replaced one injector

•properly reset tps and idle multiple times.

•clipped back plug wires

•cleaned raves as well as replaced orings in them and are now sealed good. They were covered and full of black oil.

•cleaned rave check valve as it was clogged

•replaced rave solenoid

•replaced oil lines.

•removed and cleaned crank pos. sensor

•rebuilt jet pump and new wear ring

•replaced plugs multiple times

•exhaust hose on top of waterbox was leaking so adjusted and tightened it

•disconnected red wire to rectifier-made no difference

•I noticed the water regulator was backed almost 3 turns out from flush. From what I’ve read it should only be 2 clicks from flush or 3 full turns out from all the way in. Tried both and it got rid of the low rpm miss but still does it at 4500 and did nothing for the bog it’s doing now.


•it has no codes.

tonight I am going to check fuel pressure again and set up the other ecm I have to see if it helps any. After that I am out of ideas and am really needing some advice.

 

[etemplet]

There is a CDI behind the MPEM that can cause problems. If you have the old MPEM I'd swap it back and see what happens.

You could also have a mechanical issue like and hopefully not, a rod bearing on the crankshaft seizing up. Did you do a recent compression check? I got tons of hours troubleshooting RFIs. Good old fashioned troubleshooting always gets it done.

Did you do the sensor checks on the 4th plug? Check your grounds, check the wire/plug connections. Look at the plug for the MAG. Is the mag putting out proper voltage for charging? You can unplug the rectifier and the ski will run fine. I wish I could tell you a fast path but there isn't one. Be methodical.

 

[Minton33]

There is a CDI behind the MPEM that can cause problems. If you have the old MPEM I'd swap it back and see what happens.

You could also have a mechanical issue like and hopefully not, a rod bearing on the crankshaft seizing up. Did you do a recent compression check? I got tons of hours troubleshooting RFIs. Good old fashioned troubleshooting always gets it done.

Did you do the sensor checks on the 4th plug? Check your grounds, check the wire/plug connections. Look at the plug for the MAG. Is the mag putting out proper voltage for charging? You can unplug the rectifier and the ski will run fine. I wish I could tell you a fast path but there isn't one. Be methodical.

I appreciate the response. I didn’t get to mess with it last night since it stormed pretty good and the power went out. but I will try the old cdi and do the sensor checks tonight. Tbh I just kinda assumed the sensors are fine since it has no codes but it never hurts to check. And I tried unhooking the plug with red and black wires to the rectifier the other day and it made no difference. I have not checked the mag to see what it’s outputting, I will try that tonight also as well as rechecking the compression. For a fuel pressure test, while researching I saw some saying you need to ride it while checking it. How do you feel about that?

 

[etemplet]

Perhaps in some instances putting the ski on the water to test fuel pump pressure would be appropriate but I've never had to do that. Whenever I had weird electrical problems it was always the MPEM. One ski would develop a miss and I noticed one of the electrical plugs was getting hot. I swapped the MPEM (whole black box) and the problem went away and the ski ran perfectly. Another ski wouldn't get over 4100 RPM on the water then at times I would take off from there and run great as long as you kept it over 4100 RPM. If you let it drop... same problem. (I keep that MPEM as a spare to test with, I believe the rev limiter is bad on that one) I had one mpem that kept the PTO injector open. That thing was like a pressure washer. I figured that out when I pulled the fuel rail and watch them fire. Diligence and Perseverance get's it done. I have every spare part for the RFI which is nice but that rarely solves a problem. They laugh at parts changers.

Clean all the plugs on the MPEM especially the large blades. I use 180 emery gently, a gentle wire brush, and "deoxit" I've taken the large plugs apart for cleaning and bent the large tabs to give better contact. Onetime I found the CDI plug was wet inside the MPEM box. Cleaned that up, dried it out and it ran great.

Clean all the electrical plugs, especially the one that plugs into the coil and make sure the black wire on the coil has a good ground. Check your grounds. My last battle with the RFI I purchased a wiring harness but never installed it (MPEM was the problem).

Problem with these skis is that you never know what they've been through. Eliminate fuel issues first, they are the easiest. Good Luck !!

 

[Minton33]

Perhaps in some instances putting the ski on the water to test fuel pump pressure would be appropriate but I've never had to do that. Whenever I had weird electrical problems it was always the MPEM. One ski would develop a miss and I noticed one of the electrical plugs was getting hot. I swapped the MPEM (whole black box) and the problem went away and the ski ran perfectly. Another ski wouldn't get over 4100 RPM on the water then at times I would take off from there and run great as long as you kept it over 4100 RPM. If you let it drop... same problem. (I keep that MPEM as a spare to test with, I believe the rev limiter is bad on that one) I had one mpem that kept the PTO injector open. That thing was like a pressure washer. I figured that out when I pulled the fuel rail and watch them fire. Diligence and Perseverance get's it done. I have every spare part for the RFI which is nice but that rarely solves a problem. They laugh at parts changers.

Clean all the plugs on the MPEM especially the large blades. I use 180 emery gently, a gentle wire brush, and "deoxit" I've taken the large plugs apart for cleaning and bent the large tabs to give better contact. Onetime I found the CDI plug was wet inside the MPEM box. Cleaned that up, dried it out and it ran great.

Clean all the electrical plugs, especially the one that plugs into the coil and make sure the black wire on the coil has a good ground. Check your grounds. My last battle with the RFI I purchased a wiring harness but never installed it (MPEM was the problem).

Problem with these skis is that you never know what they've been through. Eliminate fuel issues first, they are the easiest. Good Luck !!

I really appreciate all the info. I really hope the mpem is not bad considering I already had to replace it a few months ago due to it only sparking once then stopping. I will clean all the plugs tonight as well as a few other things and then lake test it tomorrow after work and let you know how it goes. One more thing is have you ever had any issues with the water regulator? I read somewhere that it can cause it to not go to full rpm and bog and I’m wondering what would be the best way to test it as well since the manual had pretty much no useful information on it aside from don’t touch it

 

[Minton33]

Okay I had assumed the sensors were all good being as no codes were being thrown. I just checked all the sensors through the 4th plug on the mpem and when I checked the map (aps) sensor I had no continuity between one of the circuits. I pulled the plug off the sensor and checked at the sensor and it still had no continuity. I pulled the aps sensor off and then rechecked once more and now it has continuity. I plug it back in and it also now is in spec at the mpem plug. All other sensors tested in spec.

I realize now I do not have the proper fittings to run the ski while checking fuel pressure but when I put the key on it jumps to 60psi and immediately falls back down to 10psi then slowly bleeds the rest of the way down.

I would now assume the APS sensor is my issue but I’m wondering if the fuel pressure should fall that fast. I’m going to try and pull the aps sensor off of one of the junk RFI that we have at work tomorrow and see what happens. Not sure how to feel about the fuel pressure results though

 

[etemplet]

Fuel pressure should hold so your regulator is bad. I hope you have good luck finding the proper regulator. Perhaps Quantum will have the correct one. I bought one off Amazon and ended up with a regulator that would hold 48psi and I contacted the vendor who told me they couldn't guarantee if I would get the regulator with the correct setting. My Regulator being bad didn't seem to affect the operation of the ski I was restoring. On the test after shutting off the engine the fuel pressure dropped to 20psi from 58 in less than 10 seconds. It was hit or miss if it held at 20psi or went lower
I'll be interested to find out if your APS sensor is/was the problem but you are on the right track. Perseverance. Good Luck !!

 

[Minton33]

Fuel pressure should hold so your regulator is bad. I hope you have good luck finding the proper regulator. Perhaps Quantum will have the correct one. I bought one off Amazon and ended up with a regulator that would hold 48psi and I contacted the vendor who told me they couldn't guarantee if I would get the regulator with the correct setting. My Regulator being bad didn't seem to affect the operation of the ski I was restoring. On the test after shutting off the engine the fuel pressure dropped to 20psi from 58 in less than 10 seconds. It was hit or miss if it held at 20psi or went lower
I'll be interested to find out if your APS sensor is/was the problem but you are on the right track. Perseverance. Good Luck !!

I really appreciate the help. Was a good idea to go through and actually check the sensors. You’d think it would have thrown a code. Hopefully I’ll be able to find a functional one and take it to the lake tomorrow. I’ll let you know how it goes. I suppose I should go ahead and find a regulator to order as well

 

[Minton33]

Fuel pressure should hold so your regulator is bad. I hope you have good luck finding the proper regulator. Perhaps Quantum will have the correct one. I bought one off Amazon and ended up with a regulator that would hold 48psi and I contacted the vendor who told me they couldn't guarantee if I would get the regulator with the correct setting. My Regulator being bad didn't seem to affect the operation of the ski I was restoring. On the test after shutting off the engine the fuel pressure dropped to 20psi from 58 in less than 10 seconds. It was hit or miss if it held at 20psi or went lower
I'll be interested to find out if your APS sensor is/was the problem but you are on the right track. Perseverance. Good Luck !!

We have a new APS in stock from a 4-tec engine that appears exactly the same but the part number is 0 261 230 049 instead of 0 261 230 061. As far as I can tell it’s exactly the same except for the sticker being blue. turns out the Bosch part number on it is different from the Seadoo number. Being as according to the brp website the one on the rfi was also used in 4tecs. I’m wondering if it will work or if I’d be better off finding a used one out back off an rfi for now.

 

[etemplet]

I'd go with the exact part number just because you are having problems. No sense in chasing your tail.

 

[Minton33]

I'd go with the exact part number just because you are having problems. No sense in chasing your tail.

Okay the used aps did nothing for it unfortunately. The fuel pressure regulator was missing the lower o ring somehow even though I had never had it out. It now primes to 60 and then drops to 53ish and sits there. Neither made any difference in the problems. Still tries to throw me over the handlebars every time I jump it. Tbh I feel as though it may be more of a mechanical issue being as it pulls good to 6300 and then sits there fine for 10 seconds or so till it starts bogging. but I’m not sure what else I could check.

 

[etemplet]

Did you check the water control valve. Also, check the raves even if you checked them 5 times already (did you replace the orings? I generally blow into the rave hose and determine if it is holding pressure. They leak.. If they drop off, the ski will bog. Sometimes the smallest detail is the real problem. Keep plugging.

Could be a crank bearing seizing up but it would do that for very long before it locked up. Check your jet pump. We may have discussed all this ut I'm not going back to reread... Ha ha.

 

[Minton33]

Did you check the water control valve. Also, check the raves even if you checked them 5 times already (did you replace the orings? I generally blow into the rave hose and determine if it is holding pressure. They leak.. If they drop off, the ski will bog. Sometimes the smallest detail is the real problem. Keep plugging.

Could be a crank bearing seizing up but it would do that for very long before it locked up. Check your jet pump. We may have discussed all this ut I'm not going back to reread... Ha ha.

I couldn’t find anything in the manual regarding how to check the water valve.
And yes I replaced both of the orings on both raves. They are now sealed when I blow. The check valve was completely plugged off. I cleaned it and got it working.
I just rebuilt the pump and replaced the wear ring within a ride or two before it started boggingbefore this started happening

 

[Minton33]

I removed all gas from the tank. Wiped the tank out. Disassembled water regulator and found nothing wrong so reinstalled. Replaced plugs again. And the problem is gone. It runs out to 5780 with no bog which is good enough for me atm.

Now if I could just figure out why it’s missing so bad between 4,000 and 4,400 rpm. It starts slightly missing around 3,500 and by 4,200 it’s pretty rough and then completely gone by 4,400

 

[Stevie96xp]

I removed all gas from the tank. Wiped the tank out. Disassembled water regulator and found nothing wrong so reinstalled. Replaced plugs again. And the problem is gone. It runs out to 5780 with no bog which is good enough for me atm.

Now if I could just figure out why it’s missing so bad between 4,000 and 4,400 rpm. It starts slightly missing around 3,500 and by 4,200 it’s pretty rough and then completely gone by 4,400

We had one do that I would check the voltage regulator. Must do it while riding and if that’s not a problem you might have to get the tps reset that can cause that

 

[Minton33]

We had one do that I would check the voltage regulator. Must do it while riding and if that’s not a problem you might have to get the tps reset that can cause that

Okay I have not tried checking the voltage regulator while riding. Will try it next time I have it out. Thanks for the suggestion

 

[Stevie96xp]

Okay I have not tried checking the voltage regulator while riding. Will try it next time I have it out. Thanks for the suggestion

Yep good luck