1999 GSX RFI loose crank sensor

[commando_j]

Hello,

Here is my story if you want to read it. If not, the abbreviated version is in bold.

Been trying to diagnose a "no idle in water" issue for the past year. Ran last year for the first time in water in 4 years. Ran it on land each summer over the four years and winterized it.
Only 44 hours on seadoo.

When taken out in 2013 it would die at speed, I could restart it right away. Second time I went out with new fuel mixed with old fuel. Same issue. Third time out had all new fuel (drained old fuel) and same thing, to the point that it would not start anymore on water. On land it would start only with some throttle and not idle without some throttle.
During winter I did the following:
- Fixed cracked oil tank
- changed oil filter.
- New oil, bled system.
- New fuel pump and filters, cleaned tank.
- Checked injectors (not cleaned).
- New battery

This spring it still did the same out of water; needs throttle to start and won't idle.
- Checked all sensors. Found dead air pressure sensor. Replaced. Still the same result.
- Found ground screw for a bunch of sensors completely loose. Fixed. Found power wire for starter in main power box loose. Fixed. Still same result.
- Took it to dealer to read codes and zero TPS. No codes found and TPS was not really bad. Idle adjusted to 1900rpm with hose connected and finally would idle on land!
- I took it out on water and still the same issue. Also noted that it bogs when accelerating.

Brought it home today discouraged, but checked all connections again and battery voltage. The battery is showing 13.x volts at 3000 rpm and barely dips on start. Looks good.
Found that the screw holding the crank position sensor was backed off about 1/4"! Tightened it down. I am hoping this is the issue.

I am asking you experts what might be the symptoms of a loose CPS. It seemed to be seated properly but I could wiggle it. It starts, idles, and runs really strong out of the water at the moment. Could a loose CPS allow for seemingly good idle and running out of water but not idle and bog down in the water?

I'm going to check the compression in the next day or so and hopefully take it back out next weekend.

Thanks for any answers. This site has helped me a lot to do what I've done already.

 

[jammin777]

yes i believe it can, a crank position sensor reads the speed and position of the crank that play a role in timing of spark and when the fuel injectors fire. with the sensor loose and if the sensor was upseated causing a greater gap between the sensor and flywheel gear, may cause a miss read to no read and malfunction a bit to cause it to run rough, backfire and loss of power, especially in the water with a load. it wont run with a bad or no sensor at all. the crank position sensor is one of the parts in the ignition system that takes place of the distributor.
keep us posted.

 

[commando_j]

Didn't have time to do the compression test yet, but decided to check the oil pump cable alignment. Found it to be off by about 1/4" (the red line in the attached picture was where the line marker was before). Meaning it was not giving any or not enough oil on low throttle. Not sure if this would cause bogging but could cause long term wear on engine I guess. Adjusted it and thought it was fine until I took the attached picture. I'll do the fine tuning tomorrow night.

 

[commando_j]

Compression test:

No Throttle: 145-150 on MAG side, 155 on PTO side
Full throttle: 150 on MAG side, 160 on PTO side.

So it looks like I have about 10psi difference. That's about 6-7% between the two. Any feedback on these numbers is appreciated.

Also, an FYI, if you get a compression tester, try to find one with a flexible hose. Mine is braided SS. Looks nice but doesn't flex very much. On the GSX RFI you gotta turn the whole hose while in an "S" shape and it's not easy. I'm putting so much pressure to flex the hose and turn it, I don't have a strong feel if I am screwing it in straight.

 

[commando_j]

Finally took it out tonight. Better but not stable.

- I still need to put some throttle to start it when in water. On land it doesn't need it.
- Once started it will idle, generally around 1800 (it was set to 1900 out of water).
- But if left to idle it will slowly reduce down to 1500 RPM. Once below 1500, it quickly goes to stall. I can be quick on the throttle to keep it going. Once I let go it is stable again and the cycle will repeat.
- I did get 12V low warning twice at first. But it went away at one point on its own and didn't come back for the last 5-10 minutes I was testing it. Not sure if it is an issue.
- I can bring it up to full speed and it feels strong above 4000 RPM. Below 4000 it seems ok but it's been so long since I've used it I may be just paranoid.

So it looks like the loose crank sensor and/or the oil cable position was/were the main issue. Now I need to find out why I need throttle at start and why it eventually stalls.
I'll check the plugs again since they may be a bit fouled up. They were new after the dealer adjusted the idle but I took it out once for testing with the loose crank sensor.

Any ideas?

 

[commando_j]

Update:

- Cleaned some shavings off the magnet of the crank position sensor.
- Checked the spark with an in-line spark checker. Seems ok. Slight fouling on the new plugs but should be ok.

Will take it out again this week end. Noticed that it idles high now, around 2K to 2.5K and it can vary over time. It was stable when the dealer started it up to show me that it was at 1900RMP. Possibly tightening and cleaning the crank sensor and adjusting the oil pump cable changed the behavior of the idle??

The 99 GSX RFI is supposed to idle on one cylinder from what I read. BUt the spark checker showed that it was using both cylinders, but my idle is high above 2K. If it does idle on one cylinder, is there a preset RPM at which the MPEG determines that it needs to go to one cylinder? Like 1500RPM? Or would it be the 1900RPM at which the dealer set it at?

 

[jammin777]

any updates? i;m having the same issues

 

[commando_j]

Took it out on the 5th. Basically the same thing. Needs gas to start. But need to be careful not to flood it so there's a delicate balance as to how much and how long you try. Once started it did the same as the last time. I stayed out for about 15 minutes. Above 3000 RPM it feels great. below 3000 when accelerating it kind of feels a bit under-powered but that could be me being paranoid. At that point I did everything I could think of without spending more money. Like I could buy an in-line fuel gauge and stuff, but it was easier to just bring it to the dealer. So Saturday the 12th I brought it in and told him to take it out himself and try to find the problem. I hate doing that since it's almost like writing a blank check but I've spent too much time on it and I got other things falling apart around the house.
I should have an answer by Friday, hopefully good news.

 

[martyx11]

Have a look for a tooth missing. When this happen to my 99 GTX RFI everything under 3000 rpm was all over the place. It would start fine and run great above 3000 rpm. If you don't want to take the cover off the front of the motor you can remove the spark plugs and remove the crank position sensor and look though the hole and turn it over by hand.

 

[commando_j]

Martyx11,
How many hours did you have on yours when this happened? I considered checking the teeth when I cleaned off the sensor but didn't think that could happen. Wish I had it in my hands right now but it's at the dealer.

 

[martyx11]

commando__j
My GTX had 280 hours The dealer wanted $1000 bucks with tax for the new flywheel. I found a used one for a $100 bucks with low hours on it.

 

[commando_j]

I'm lucky to only have 44 hours on mine. But that means I didn't enjoy it as much I guess. My issues have so far been related to not maintaining it properly over the past 5 years, besides winterizing it. Not checking if everything is tight, and letting it sit with old fuel. I'm positive the final piece to the puzzle is still related to this.
Still waiting for the answer from the dealer.

 

[grinditout]

Have you teset the tps?

 

[commando_j]

On the first trip to the dealer he did it. But not after I found the crank sensor loose and the oil pump cable adjustment off. Still waiting on the dealer to give me feedback.

 

[commando_j]

Finally got some feedback from the dealer as to what the problem is.
I didn't push them over the weeks since I was too busy with other things. I wanted to make sure they took the time to really find the problem. I called in mid August and told me that after changing the plugs all was good. I ask "in the water, or out of the water?" They said out. I repeated that the problem with starting and idle was in the water.
So they called me today. They checked compression, fuel pressure, and some other things, all ok. The mechanic also noticed that the plugs were fouling quickly. So quickly in fact that a new set that never ran in the water and were only used a little on land had already fouled and became hard to start. Changing them again to new ones made it start right up.
So they tested the stator. Pretty sure they did resistance test and some kind of voltage check and it was not good.
They gave me the quote. 1K$ all-in to change the stator, flywheel (not sure why exactly), and labor. I can't blame them for the price, they are working with BRP pricing for the parts. So I said I will just pay for the 2.5 hours of labor and fix it myself. At least now I know where to start looking again. I will test it myself to confirm what they found. If it is the stator, then I saw new ones on ebay for 100$ plus 35$ shipping to Canada.
I don't know when I will get around to working on it. But for those of you with the same issues, check the stator. When I googled stator and bad idle on RFI, I saw some people had a working stator but metal shavings were attached to it causing problems.

 

[hfgreg]

bump......

 

[hfgreg]

Re-opening post.

 

[commando_j]

Thanks for the re-open!

So a bunch has happened in the last 3 years of trying to get this GSX RFI running properly. My goal is to resolve the issue completely so that others can have a guide to fixing the same problems.
I did change the stator coil from one I bought on ebay in 2015. Guess what? Still would not idle. So now I also have a spare coil! Lots of spare parts now.
I didn't do anything to it in 2016 except new plugs, again, and ran it on the water just to say I drove it in 2016. That year my local dealer closed down so I couldn't get their help anymore.
In 2017 I was moving more and more towards buying a CandooPro. I couldn't justify the cost though if I was feeling more and more like I was just going to get rid of it because of the frustration. In the spring of 2017 we had a new local dealer and decided to take another chance with the TPS reset, especially since the last dealer set my RPM high, then I also changed the coil. I figured the TPS reset may not have been done properly the first time. So I took it to the dealer and 3 days later I went to pick it up. After telling them specifically what I wanted done, they told me that they did fix the RPM and it runs smoothly now (out of the water). I said great, you reset the TPS and the idle? They then shocked me with "Uh, no, there is no way to hook up to the seadoo, so we adjusted the idle manually." After a few seconds of shock from what I heard, I repeated back twice what he said and he confirmed it twice. Unfortunately at that very moment I was not aware that the DESS post was the way to communicate. If I had I would have said something. Knowing at that point that they probably made it worse, I paid the 40$ and took the seadoo and knew I wouldn't be going back there again for help. Note: I have recently seen posts about some dealers not having the equipment (or experience) anymore with dealing with older seadoo models. I would give them a pass if they at least realized this themselves and didn't charge me 40$ to turn an idle screw.
I had one more chance with someone local to look at the seadoo. There's a guy who has a repair shop with good reviews. I take it to him and ask for a TPS reset. Later that day I come back and see the raves dissasembled. He shows me that one of the raves is seized! It was the first time a mechanic actually found a real problem! I was encouraged at that point. I gladly paid him 30$ since he found something that I can fix. I took it home and pulled the raves off. I did note that they had never been taken off or checked, since the screws were still brand new. That includes when the dealer was supposed to have checked them way back when I owned it under warranty and paid extra for the extended service stuff.Nice.
So one rave was covered I guess in oil. Cleaned it off easily. The other one that was seized was dry and I would say a bit gummy. That's why it wouldn't move. It seemed to be stuck in the lower position. The shaft of the valve was corroded so that the plating of the valve was coming off. I cleaned it as best as possible and reassembled it, making sure that it glided enough that it was not binding. I knew I had to replace the valve but at that moment it was good enough. I took it out on the water. Well at this point I couldn't tell if it worked, because the damn dealer had set the idle so low that it would stall right away.
At that point I had some hope. I decided that instead of trusting a dealer to reset the TPS and pay them to do it incorrectly, I would buy a Candoopro. Worse case is I can resell it at a decent price. I got the Candoo, reset the TPS, made sure the oil pump markers lined up, tightened it all down and took it out. At first it wouldn't idle. I said screw it. Even though I did the 2-3 turns on land, I would adjust it higher in the water till I got something. I actually had to turn it about 2 more turns. At around an idle of 1600rpms, guess what, it was stable!!! And because of the rave fix I had no more stutter through the RPM range. I could get full rpm and it was responsive. After a about 20 minutes of riding I got worried because I thought it came back, but I noticed the idle screw had moved back because I didn't tighten the lock nut. Fixed that and it was ok.
I was still left with fouling plugs very quickly. New plugs start right up, but 10 minutes later it was very hard to start, and after 30 minutes it was no luck in starting. Changing the plugs got it back up but again, fouling was an issue.
After researching these forums I saw the info about going down a number on the plugs. So I tried the BR7ES. With these plugs I went for about 1.5 hours on the water. I restarted the seadoo at least 10 times. Much better. I still had issues starting it so I knew fouling was occurring. After I was done, one plug was fouled as before, but the other was only half-fouled. So I consider this a big improvement. At least now I could use the seadoo, and just carry a spare set of plugs when I go out just in case (I bought a pneumatic plug cleaner on Ebay, so I won't need to keep buying new ones.).
Issues that remain:
1) I have to set the idle a bit high, around 1600-1700rpm. If it goes lower with the current fouling it will begin to stall. This is better than before since even at an idle of 1800rpm, it would die after about 2 minutes.
2) It takes time for the rpm to come down to the right idle speed. When I let off the throttle, it will be around 2200rpm. After 20-30 seconds it will begin to go down to where it should be. I could make it go down quicker if I sit further back on the seat which likely blocks the exhaust a bit and causes the affect of lowering the rpm.
3) I could idle all day at 1600 rpm. But if I do two things I could make it stall. If I sit further back on the seat, and turn the bars all the way left or right to go in circles while idling, it will want to stall out.
4) I do need to change the corroded rave valve stem.
5) I need to flush the oil I have and put XPS oil in. Right now I have synthetic Nautilus 2T oil in it. I changed it out with the filter when I changed my cracked oil tank a few years ago. I didn't do a full flush at the time. So #1, I mixed the two oils (not the worst since both synthetic but not recommended), and I cannot confirm if the oil I used is good enough, and can be contributing to the fouling plugs.
6) I need to check the water valve on the exhaust and inspect the exhaust for any debris or buildup. this could have a negative impact on the idle.

My season is done here in Montreal. So over the winter I'll do the oil flush, new oil filter, new rave valve, inspect water valve and exhaust.

Right now with the BR7ES plugs, the seadoo feels like new at full throttle. I get it up to 6930rpm, The lake was ruff, so top speed was hard to judge but it was at least in the high 80's (55mph). It registered 96kph top speed but that was likely from the rough waters. The other trick I do to help is that I always wait a minute at idle before shutting it off. And then when I start, I do the trick of holding the throttle all the way down, plug the key, then start the seadoo. This ensures no gas is injected and I burn off any that might be there. After a few seconds I slowly release the throttle allowing gas to come in and it starts right up. (Most of the time!). At least this prevents me from flooding the engine, like I used to do all the time.

So thanks for sticking around and reading this novel. Hopefully it helps some of you with these wonderfully designed RFI engines. I'll likely update again in the spring when I take it back out.

 

[motodug]

If your spark plugs are oil fouled you most likely have Bad center seals on your crankshaft. The center cavity on the 800 RFI motor is filled with oil to lubricate the rotary valve gear and bearings. It has a virtually endless supply as it is fed by the big oil Jose coming from your oil tank. Usually this problem is caused by bad crank bearings. You said it sat for awhile. If it wasn’t fogged well before storage, the bearings develop rust pits. Once you start running it. The bearing retainers break and the debris gets into the seals. I’ve rebuilt RFI motors where 5 of the crank bearings completely fell apart when the cases were separated, but they still started right up before the tear down. The only symptom was that they fouled spark plugs.

 

[commando_j]

If your spark plugs are oil fouled you most likely have Bad center seals on your crankshaft. The center cavity on the 800 RFI motor is filled with oil to lubricate the rotary valve gear and bearings. It has a virtually endless supply as it is fed by the big oil Jose coming from your oil tank. Usually this problem is caused by bad crank bearings. You said it sat for awhile. If it wasn’t fogged well before storage, the bearings develop rust pits. Once you start running it. The bearing retainers break and the debris gets into the seals. I’ve rebuilt RFI motors where 5 of the crank bearings completely fell apart when the cases were separated, but they still started right up before the tear down. The only symptom was that they fouled spark plugs.

I ran it each year on land with the hose. And fogged it also each year. Hopefully something like that is not the case. I'll see next season once I remedy the last few things listed above.