99 GTX RFI No Start when Hot

[Aena06]

99 GTX RFI with only 94 hours
Bought last season and have never been able to button start without throttle. This season I’ve had issues with it starting cold and on trailer, but once we shut off and try to restart, it takes several long crank attempts to get it going again.

Compression 170 in both cylinders
Replaced fuel filters
Replaced injectors
New plugs
New rectifier
New starter relay
Resistance test good on crank, tps, air sensors
New/good battery
New fuel check valves for in and out venting
Calibrated at shop for when tps/new idle set
Wet plugs but I always assume it’s because I have to throttle it to get it going

At a loss - what to check next? Trying to understand why this is only a hot problem?

Thanks

 

[hellz_wings]

I have the same issue as you 99 gsx rfi. I can start when cold and also out of the wayer easily. Ive also had the RV cover machined to spec and replaced all those gaskets, replaced fuel pump/regulator/filters and put on a 4tec rectifier. What I havent done yet is replace starter, stator, mpem or any of the engine sensors. Debating whether I should try that.

 

[etemplet]

I'd check the Rotary Valve surfaces. What you are experiencing is typical for that kind of issue.
Check the 3 prong plug that is going to the coil. Very small plugs. After I cleaned one I got a stronger more consistent spark. Did you trying checking the spark with spark checkers? They are great to use on these ski because you can see the quality of the spark at all time. You might find a bad coil which I doubt buy you gotta check.

I wouldn't go replacing sensors. You can change everything on a RFI and it will still not run correctly. Been there a few times. I have a lot of spare parts including a computer and I've changed everything with no relief. Gotta find the problem.

Did you pull the #4 mpem plug and check the sensors? Are you positive you have the electrical plugs in the correct location. 2 can be swapped. One is the PTO fuel injector and the Rave solenoid. The other is the TPS and Air Pressure sensor. You can unplug the TPS, Air Pressure, and Air Temp sensors and the ski will start.

Stick with it !! Good Luck !!

 

[hellz_wings]

What did you do to clean the 3prong plug to the coil? When using the spark plug checkers, do you crank it with plugs off and one wire grounded while the other in this spark checker? How do you check if coil is bad?

 

[burtshaver2021]

This is so basic I feel I shouldn’t even mention it but just in case it helps... I also have a 99 GSX RFI that I just got last fall and started riding this year. I was finding it hard to start when the engine was warm. I was stopping the engine with the start/stop button then when I was going to start it again it was a little hard to start. If I pulled the dess key off and put it back on it would start easily even when warm. I could be wrong but I figured it was cycling the fuel pump and providing the engine with start up fuel? Also came to realize that I need a real good battery for it to start easily.

 

[hellz_wings]

This is so basic I feel I shouldn’t even mention it but just in case it helps... I also have a 99 GSX RFI that I just got last fall and started riding this year. I was finding it hard to start when the engine was warm. I was stopping the engine with the start/stop button then when I was going to start it again it was a little hard to start. If I pulled the dess key off and put it back on it would start easily even when warm. I could be wrong but I figured it was cycling the fuel pump and providing the engine with start up fuel? Also came to realize that I need a real good battery for it to start easily.

Interesting i always press the start/stop button to stop the engine. I’ll try pulling the DESS key and test to see if that makes any diff. Not sure why it would but who knows maybe there’s some kinda signal sent to the computer that’s fuel related when the key is pulled vs button.

 

[burtshaver2021]

J

Interesting i always press the start/stop button to stop the engine. I’ll try pulling the DESS key and test to see if that makes any diff. Not sure why it would but who knows maybe there’s some kinda signal sent to the computer that’s fuel related when the key is pulled vs button.

just to be clear, I can still use the start stop button to stop the engine if I want to, but when I go to start it back up if I pull the dess key and put it on right before I’m ready to go again then I get the 2 beeps, fuel pump cycles and it starts up. If I stop it with the start/stop button and go to start it again when warm without removing and replacing the dess key it rolls over longer without starting. Are you still able to get out on the water where you are? Season is pretty much over here, I’m interested to find out if this makes a difference for you

 

[hellz_wings]

J

just to be clear, I can still use the start stop button to stop the engine if I want to, but when I go to start it back up if I pull the dess key and put it on right before I’m ready to go again then I get the 2 beeps, fuel pump cycles and it starts up. If I stop it with the start/stop button and go to start it again when warm without removing and replacing the dess key it rolls over longer without starting. Are you still able to get out on the water where you are? Season is pretty much over here, I’m interested to find out if this makes a difference for you

Im up in canada north of montreal and its still roughly 20 celcius in the day and 10 celcius at night. It’s definitely a warm autumn compared to previous years. We have already gotten snow on sept 30th one year - that was early though. I’m going to try this out for sure before I put her away. I have to run fuel stabilizer, top off tank, etc. pretty soon. Will report back once I try this.

 

[burtshaver2021]

Im up in canada north of montreal and its still roughly 20 celcius in the day and 10 celcius at night. It’s definitely a warm autumn compared to previous years. We have already gotten snow on sept 30th one year - that was early though. I’m going to try this out for sure before I put her away. I have to run fuel stabilizer, top off tank, etc. pretty soon. Will report back once I try this.

Well I feel like a wuss, I’m in Ontario as well, about 1.5 hours west of Montreal along the St.Lawrence. Yeah, it’s still plenty warm here in the afternoons, about 23 or so lately but feels warmer. I would actually be out a lot of these day’s if I wasn’t busy.

 

[hellz_wings]

Last year i put it away at 4 degrees but had a wet suit on that made all the difference. This year ive got wet shoes, gloves and goggles and a ski mask type wet suit hat thingy. Whatever, I’m prepared for the cold water if I fall in lol.

 

[burtshaver2021]

Last year i put it away at 4 degrees but had a wet suit on that made all the difference. This year ive got wet shoes, gloves and goggles and a ski mask type wet suit hat thingy. Whatever, I’m prepared for the cold water if I fall in lol.

Lol, it’s not so bad in the fall even on a cool day, water is still warm. When I’m testing a machine I’m working on, nothing can stop me, lol. Last fall in October I was trouble shooting my 97 GSX so I went out to the water, it was raining, probably around 7 or 8 degrees and forgot my life jacket, so out I went anyways. Same thing this summer, was trouble shooting my 95 XP, when I got to the launch there was a thunderstorm off in the distance and raining where I was, out I went. Come to realize I actually like riding in the fall when the air is cooler and like riding in the rain as long as it’s not a pelting rain but I hate spring riding when the water is freezing. Even when it’s 30 degrees out it’s still cold out on the water. I’ve thought about getting a wet suit too but haven’t pulled the trigger yet. Anyways, have a good night

 

[POPPS]

99 GTX RFI with only 94 hours
Bought last season and have never been able to button start without throttle. This season I’ve had issues with it starting cold and on trailer, but once we shut off and try to restart, it takes several long crank attempts to get it going again.

Compression 170 in both cylinders
Replaced fuel filters
Replaced injectors
New plugs
New rectifier
New starter relay
Resistance test good on crank, tps, air sensors
New/good battery
New fuel check valves for in and out venting
Calibrated at shop for when tps/new idle set
Wet plugs but I always assume it’s because I have to throttle it to get it going

At a loss - what to check next? Trying to understand why this is only a hot problem?

Thanks

Most often, your symptoms are from xcessive rv clearance, as the following posts have suggested.

 

[Purksy]

J

just to be clear, I can still use the start stop button to stop the engine if I want to, but when I go to start it back up if I pull the dess key and put it on right before I’m ready to go again then I get the 2 beeps, fuel pump cycles and it starts up. If I stop it with the start/stop button and go to start it again when warm without removing and replacing the dess key it rolls over longer without starting. Are you still able to get out on the water where you are? Season is pretty much over here, I’m interested to find out if this makes a difference for you

Going threw the same thing with my ski. Just noticed today it starts better when unplugging and replugging, cycling the pump.
Still doesn’t want to idle under load though.

 

[burtshaver2021]

Going threw the same thing with my ski. Just noticed today it starts better when unplugging and replugging, cycling the pump.
Still doesn’t want to idle under load though.

Yes, I notice a huge difference when I plug the Dess key in right before I’m ready to start it, it starts right up however if I leave the dess key on the post and come back and just Press the start button it needs to roll over longer to get started. It seems to make good sense to me that the fuel pump cycles when the dess key is inserted on the post. With your low idling issue, I’m not sure at all, I’m pretty good at putting the carbs back to stock settings but don’t even know if the fuel Injected models have any type of idle screw or way to set the idle. Until you get it the low idle issue figured out I would be Leary of driving it much in case it is not getting enough fuel? There is a really good thread all about the RFI’s . I will copy and post the link here for you. The only things I can think of are checking your fuel pressure and possibly having the injectors tested and cleaned? But maybe you will find something on this thread that I will post The RFI (Rotax Fuel Injection ) Spot

 

[POPPS]

Idles on injected machines are usually set at the factory to mesh with the TPS.