2000 GTX RFI after rebuild issues

[Eavedesian]

Hope someone can help.

Getting my ski back on the water after fixing some annoying post assembly issues. Did the rebuild because my inner seals were TOAST! Had great acceleration and 6800 max rpm...

Anyway after fixing my exhaust hose issues and my loose clamp on my bellows the thing will stay running long enough to come down to the 2 final issues.

Had a hard start before the rebuild in water, still have that, last 200 rpm or so is gone? And bottom end sucks now. Also, ever so slight surging while cruising mid throttle.

I have a beefy rectifier, new injectors, fuel pump filters changed inner and outer, and pressure is in specs. TPS reset with candoo and no codes are set. Raves are spotless.

So questions are if rotary valve is off by 1 tooth or flipped over (180 degrees out) could that cause this? Also, when it is cold I get a bit more acceleration for like the first 5 minutes and maybe 50 more rpm and then when it heats up fully rpm goes back to 6600 max rpm and weak off the acceleration.

Also, if you were chasing a sensor which one/s would you go after?

Thanks in advance.

 

[etemplet]

Air pressure sensor is worth doing a double check
Rotary valve can cause problems starting. I moved the timing on a 1998 GS that was difficult to start. Try to put the timing in the MIDDLE of the tolerance. Did you measure the clearance on the rotary valve??

How did you adjust the Throttle Postion sensor? did you back the idle screw all the way out allowing the butterfly to close fully. Then did you "set" the idle screw. Just about every ski I work on, the idle screw is frozen or broken off. I've had to drill a couple. I find if you don't idle the ski up enough it will be difficult to start because people tend NOT to give a fuel injected skis throttle when starting.

As for your upper RPM, check your Water Control Valve on the exhaust water canister. Make sure they line isn't plugged at all to the pipe. Those dirt divers will quickly plug lines up that are sitting out in the open.

Did you check your fuel pressure and.... how "broken-in" is the engine? Some don't get up to speed till they loosen up. I don't measure performance by RPM only... I use top speed. 6900 is bad azz on the RFI.

You are narrowing down to problem and finding out what it "isn't" which is how I like to call it. LOL Good Luck man....

 

[Eavedesian]

You rock. Thanks for the suggestions.

Yep, did the tps correctly just like the manual said. I loosened the locking nut and then the screw all the way til it didnt touch the arm at all. Then flicked the throttle a couple times to make sure it closed. Then did the reset with candoo.

Water control valve was just pulled apart and cleaned. It was actually pretty much spotless.

Fuel Pressure was good and new filters put In.

I'll check the timing but the air pressure sensor sounds like my first plan of attack.

 

[etemplet]

Good job on the TPS. I tell ya though... I think it's overrated. I swapped computers twice in one ski and never checked anything. No TPS adustment at all. Turn and burn... and no issues. LOL I'll think of more stuff. LOL What about the Coil? Got a spare?

 

[Eavedesian]

Yep have spare....I'll check that too. I never noticed a diff with a tps reset either

 

[Eavedesian]

Air pressure sensor didn't do anything. Coil didnt either.

Im going to advance my rotary valve timing a bit but it will still be within the lines on the case from the factory.

I'm going to check the gap on the cover. The rebuilder blew off the scratches in the cover and said it's nothing so I guess I'm going with his experience.

One thing I did notice is that the o-ring looks a little on the skinny side. How far should it protrude from the groove? Should I barely be able to see it with the naked eye or should it be obvious?

 

[Eavedesian]

Rotary valve cover clearance was excessive so I got a beautiful new one. Starting is easier. Had the smaller 717 o-ring on it. Was hoping that was it...NOPE. Tried new water temp sensor that didnt work either.

Mid range is still strong but 6600 rpm is max and still boggy acceleration.

Surges ever so slightly while cruising mid range.

If I cut the raves back too much after the rebuild could this cause these issues or would I be better off going after a new tps?

 

[Eavedesian]

Anyone?

 

[etemplet]

Did you check the water control valve for leaks and it's operation?? I don't like how you keep replacing stuff on the ski but I guess that is a method . It can be daunting and frustrating but throwing money at these skis generally doesn't work. You have to find the problem which isn't easy sometimes.

 

[etemplet]

Do you know anyone with a ski like yours? Swap the computer. It only takes a few minutes. Sometimes the computers get issues.

Have you taken the OHM readings on terminal number 4 plug. I'm assuming you checked or replaced the little check valve off the engine that goes to the rave solenoid. I'd pressure test the rave lines and make sure you have no leaks. How's your spark plugs? They'll get ya everytime if you don't replace them. About here is where I'd make sure you have the correct impeller and no drag on the drive system. You've certainly done a lot of troubleshooting... kudos for all that. Keep chugging.

 

[Eavedesian]

Did you check the water control valve for leaks and it's operation?? I don't like how you keep replacing stuff on the ski but I guess that is a method . It can be daunting and frustrating but throwing money at these skis generally doesn't work. You have to find the problem which isn't easy sometimes.

I'm with ya. But I have 2 DI skis so swapping stuff back and forth is free. Lol.

Water control valve is spotless. I pulled it apart and cleaned it.

 

[Eavedesian]

I'm about the do the MPEM and ECU with the neighbors ski. I've done 6 sets of plugs so far this year. Lol.

The impeller was verified in the spring when I did the jet pump oil. 1

Do you know anyone with a ski like yours? Swap the computer. It only takes a few minutes. Sometimes the computers get issues.

Have you taken the OHM readings on terminal number 4 plug. I'm assuming you checked or replaced the little check valve off the engine that goes to the rave solenoid. I'd pressure test the rave lines and make sure you have no leaks. How's your spark plugs? They'll get ya everytime if you don't replace them. About here is where I'd make sure you have the correct impeller and no drag on the drive system. You've certainly done a lot of troubleshooting... kudos for all that. Keep chugging.

Terminal 4 plug? Not sure I'm following you...

Anyway I pulled the fuel rail yesterday and cranked ski to look at injector spray...for like 3 seconds it was nice and full..
.then gradually it looked like the spray got finer and finer. Almost like an undetectable mist. I've never been able to get this ski started in the water unless I hold the throttle open a bit. Not even after the rotary valve cover replacement.

Would that be an indication to you that the MPEM is wonky?

 

[etemplet]

On the MPEM or Computer Module there are 4 large plugs. Generally the plug marked Number 4 is the one that connects to the engine systems such as, throttle position, Air Pressure Sensor, fuel injectors, crankshaft position and such. Simple oh checks on the proper terminals can reveal a problem with the sensor or the communication with the Computer. I merely suggested to run those tests. They are in the Repair Manual.

Swapping the computer is a cool idea if you have one. That can be very helpful in troubleshooting Good Luck

 

[Eavedesian]

Oh. I understand now. Derrr. Sorry. Yeah I did those checks I'm going to try another tps before I go yanking my neighbors computer. Lol.

But honestly after all these checks, outside of ringing out every wire that's what it seems to be leading to.

 

[etemplet]

I wouldn't waste my time with another TPS. Nice to have another computer to stick in there. Swap the whole box it is easier and will tell you more. I think the RFI is the best 787. I love that fuel injection. Good Luck with the computer.

 

[Eavedesian]

Ok. One last question.

If I pull the fuel rail and crank the ski for the first 2 or 3 seconds there seems to be a nice spray then it gets lighter and lighter.

Does that indicate computer problems or is that normal?

Yeah I'll do the entire computer swap.

 

[etemplet]

I am far from a guru on these skis. I don't know how the computer thinks but it would make sense for the injector to spray more fuel at the initial start up and less after the engine turns over. This would avoid flooding the engine with fuel. The fact that both are firing properly would tell me they are working and the system is working. If you have to go further with that at some point then do so. Keep it simple. If you didn't send out the injectors then there really isn't a way to know they are working properly.

 

[Eavedesian]

Both injectors are brand new.

 

[etemplet]

dang CAN'T say you take the cheap route. I sure hope you get this thing cadillac-en

Edited... changed can to CAN'T LOL

 

[Eavedesian]

Nah some things ya gotta do....ya know like when you take your injectors in to the local shop to get cleaned and they smash one of them and say it's bad and when you get the new ones it runs the same.....yeah.....it happened. Lol.

 

[etemplet]

I like to use professionals of course that doen't mean they are all on the up and up either. LOL found an Injector shop in New York which is closer to you guys than Florida.. I contacted the owner, I believe, who seems very friendly and thorough. I am going to give him a try with my next set of injectors.

 

[Eavedesian]

I tried a shop in ohio as well. He didnt work out for me.

 

[Eavedesian]

I wouldn't waste my time with another TPS. Nice to have another computer to stick in there. Swap the whole box it is easier and will tell you more. I think the RFI is the best 787. I love that fuel injection. Good Luck with the computer.

Well the computer was good. So the only things left are the wiring, TPS, and the rave system. However before the rebuild I cant remember if it was a dog like this. Lol.

I guess i need to verify the charging circuit again.

 

[Eavedesian]

The tps was changed and same....