99 gsx rfi engine/fuel issues

[xc_rider08]

i have a a 99 gsx rfi with 62 hours on it. i bought it not running. Was told bad motor (checked compression and its good) but it wasnt a motor issue it was a fuel line pick up tube fall off inside the tank not allowing it to start. I got that fixed and it started right up, but never seemed to run right. Was very hard starting and just didnt pull full rpm, had sluggish top end response and would follow plugs every so often. lots of reading and research led me to check the rotary valve- it was out of spec so i had it machined down and brought back within tolerance. my starting seemed to get better but still wasnt running to performance that i think it should have and still fouled plugs at least once a trip.

Which leads me to my current situation. still trying to figure out why i cant get more then 5700 rpms/ 35 mph out of the turd and why its fouling plugs left and right. i have replaced fuel pump, fuel pressure regulator, and recently the injectors. after replacing injectors it ran great one time for 15 seconds. I started it and let warm up a bit before taking off and it ran like it should, full rpm, 45mph+.. that is until i left off the gas one time and it immediately dropped down one cylinder and fouled the pto plug and damn near left me stranded. swapped injectors around and it followed the injector. replaced that injector with another new one and same thing. didnt matter which spot i put it in when tried to run that plug when pulled would be just dripping wet with fuel. im at a loss now.. two brand new injectors both bad?? What else it could be? Computer?

sorry this is so long, but trying to give as much details as possible cause im stumped on it and very frustrated. would be nice to ride this thing before summer is over.

 

[POPPS]

could the fuel pump not be pumping enough under load…

 

[xc_rider08]

could the fuel pump not be pumping enough under load…

i guess i didnt think of that. i did have the pressure gauge on it while at the shop, but not under a load. thanks for the tip, i will give it a try

 

[TheGTIjetguy]

Definitely sounds like a rich running problem. It is suspicious that it follows the injector. That may be your clue.
Don’t count out weak spark though. Maybe running with an in-line spark tester connected to see if it drops out under load.

 

[TheGTIjetguy]

Definitely sounds like a rich running problem. It is suspicious that it follows the injector. That may be your clue.
Don’t count out weak spark though. Maybe running with an in-line spark tester connected to see if it drops out under load.

Also, dirt in the fuel can cause an injector to stick open flooding the cylinder. That issue would persist regardless of how many injectors you put on, as dirt will foul the new ones in a short time.

 

[xc_rider08]

Definitely sounds like a rich running problem. It is suspicious that it follows the injector. That may be your clue.
Don’t count out weak spark though. Maybe running with an in-line spark tester connected to see if it drops out under load.

I thought of this and ordered an inline tester. Should be here tomorrow. Plan to tackle this thing this weekend with hopefully some answers. Dang thing has been a thorn in my side all summer and its almost over

 

[TheGTIjetguy]

I thought of this and ordered an inline tester. Should be here tomorrow. Plan to tackle this thing this weekend with hopefully some answers. Dang thing has been a thorn in my side all summer and its almost over

The only thing less reliable then a jet ski is an old jet ski…. To be honest, hearing an older pwc start up and run well is worth it though. It gives a sense of accomplishment you don’t get with a new ski.

 

[xc_rider08]

The only thing less reliable then a jet ski is an old jet ski…. To be honest, hearing an older pwc start up and run well is worth it though. It gives a sense of accomplishment you don’t get with a new ski.

i agree. my last one was a 96 xp and said i wasnt gonna buy another one because of the growing family. but then this one came up for too good of a deal to pass and i had to have it.. now my wife wants to drown me and the ski. lol

i have never ridden anything newer in then a 2004 rxp that a family member owned.

 

[xc_rider08]

Well a little weekend update. had some good and had more bad.

After testing the fuel pump out again it was deemed that it wasnt working properly and I removed it and started back over from scratch. reinstalled and the old girl fired right up and held a constant 56 psi (according to the borrowed gauge) under load. put the machine all back together and took it for a ride. Burned a half a tank in 1.5 hours and fouled one plug in that time frame. Parked it on the sandbar for 3 hours and on the way back the bad happened.

Did what i normally do.. pulled off the sand bar, shook it out real good and then fired up to head back to the dock. Let it warm up for a good couple minutes before taking off. about 500 yards from the boat ramp she died. I wasnt ragging on it, Just a nice ride back to the trailer. I did notice right before it died that the tone of the engine changed and it sounded louder then normal. No warning alarms on the dash or beeps. Just died. Go to start and she is locked up tight. and on the dash i got a Hi Temp alarm. Just sick to my stomach as im swimming and pulling it back to the dock.

So over this dang thing. pic before it let me down.

 

[VinceHay]

Man I’m really sorry to hear that…sounds like you were doing everything as well as you could.

 

[NIL8er]

Well a little weekend update. had some good and had more bad.

After testing the fuel pump out again it was deemed that it wasnt working properly and I removed it and started back over from scratch. reinstalled and the old girl fired right up and held a constant 56 psi (according to the borrowed gauge) under load. put the machine all back together and took it for a ride. Burned a half a tank in 1.5 hours and fouled one plug in that time frame. Parked it on the sandbar for 3 hours and on the way back the bad happened.

Did what i normally do.. pulled off the sand bar, shook it out real good and then fired up to head back to the dock. Let it warm up for a good couple minutes before taking off. about 500 yards from the boat ramp she died. I wasnt ragging on it, Just a nice ride back to the trailer. I did notice right before it died that the tone of the engine changed and it sounded louder then normal. No warning alarms on the dash or beeps. Just died. Go to start and she is locked up tight. and on the dash i got a Hi Temp alarm. Just sick to my stomach as im swimming and pulling it back to the dock.

So over this dang thing. pic before it let me down.View attachment 59969

so what happened?

 

[xc_rider08]

so what happened?

Not sure yet. Havent looked too far into it as it still a little bit a sore spot. lol I did pull the plugs and both plugs and they looked like they got hot and it ran lean. I think its gonna be my winter project.