At My Wits End - 1998 GTX RFI -

[mmcjetski]

98 GTX RFI.....Exactly What could Be causing it then ???
Hey Guys
1998 GTX RFI

The ski has a 'hesitation' or 'bogg' at around 4000 to 4500 rpms. It runs fantastic below or above this Rpm. I understand that the raves can cause a slight surge in power in this rpm range, but that is not what is occuring. This is most definately a mis-fire or almost a stalling of sorts.
After reading a few post related to this subject I took the advice of getting the ski to the dealer to have it hooked up to the computer.

So I took the ski in yesterday to the dealer for a computer hook-up/ diagnostic check.

It came up with NO fault codes related to this problem.
The only fault code was in their words "an old" crankshaft postion sensor which they said would not be causing my current problem.
The dealer also looked at the Rave's - all checked out o.k.

So now I have spent $100 to be told they still have no idea what would be causing this very aggravating mis-fire around 4,000 to 4,500 rpm

ANY idea of where to LOOK next would be great!

Thanks

Mark

[Bill O'Neal2]

Re: At My Wits End - 1998 GTX RFI -

Look on the top of the muffler, under the water regulator. See if you see any water stains that may be from a leaky water regulator. If yes, it needs a new water regulator.

Put a multi meter or voltmeter onto the battery. See how much charge is in the battery, then do it again with the engine running to see if the battery reads higher than when it is not running. If not, it needs a new rectifier. It should read well over 13 volts when running.

Make sure the sparkplug caps are well connected to the sparkplug wires. Clip the wires and re-attach the caps. Install new sparkplugs if yours are old.

[1fastski.com]

Re: At My Wits End - 1998 GTX RFI -

somthing i cant understand , why in the world would anyone pay a shop to say I DONT KNOW { did you get to meet MR HAND} if you know the movie you know the joke lol

anyhow if i cant fix a ski or boat i wouldnt charge somone . i also wouldnt pay a penny for anyone to say I DONT KNOW . when your problem gets figured out on the fourms go charge the dealer for the info so they can fix skis the right way .

[Bill O'Neal2]

Re: At My Wits End - 1998 GTX RFI -

I wonder what that dealer meant when he said an "old" crank sensor? Is it older than the motor? Do they make a better "newer" sensor? If the sensor was bad, wouldn't it run like crap throughout the whole rpm band, not just at 4000 rpm or whatever?

I had a dealership put BUDS onto a ski I had in here. It said I had a bad crank sensor. Turned out it was a broken reed causing the problem. The crank sensor was fine.

[Denny Moran]

Re: At My Wits End - 1998 GTX RFI -

All rfi's say they have a bad crank sensor when plugged into puter.

The puter is telling the truth too, it only knows what its been programmed to know, and it knows that its not getting a signal from the crank sensor.

The reason?

Motor is not turning over, so encoder wheel is not spinning past the sensor, so no signal.

He has to enable the "start engine" function and re- check.

Definately sounds like water reg. or rave.

[mmcjetski]

Re: At My Wits End - 1998 GTX RFI -

thanks for input guys:

Dealer used the phrase "an old fault code for the crank sensor"

The engine in this ski has been recently been replaced (SBT) probably less than 10 hours on it.
I just assumed the dealer meant that the fault code occured before this new engine was installed?????

Still Baffled

Mark

[sabretooth01]

Re: At My Wits End - 1998 GTX RFI -

mmcjetski,

I'm at my wits end as well. I have the identical problem. I'd like to stay in touch with you on a solution. I've had the problem since August of 2001. See my post

http://www.sbtontheweb.com/forum/sho...t=1998+GTX+RFI

I've tried everything but take it to the dealer (I always like to have a clue what the problem is before letting someone loose on it).

Here's the list of everthing I've tried:
1) I tried gapping the spark plugs in increments from .020 to .035 - no affect
2) I checked the RAVE valves and they're operating properly.
3) I swapped coils with another RFI - no affect
4) I checked the TPS, APS and CPS sensors per the shop manual (resistance measurement). I've also "mapped" the TPS for position vs. resistance reading. I see no discontinuity.

So that's where I'm at. I'm at the point of taking it to the dealer to have them check for touble codes and check the "mapping" of the TPS.

Please let me know what you find on your end.

[John Kubiak]

Re: At My Wits End - 1998 GTX RFI -

Take it to someone who has am MPEM progammer, dealers have them, as do many of the better independents who specialze in Sea-Doo. I sounds as though you need to have the TPS "zeroed" to the idle stop or re-mapped, and possibly have the ignition timing offset adjusted as well.

[1pcdoc4u]

Re: At My Wits End - 1998 GTX RFI -

I had a similar problem with a 1999 gtx limitted it is carb moddle but the symptoms are the same. Turns out the problem was in the fuel system. I replaced the fuel valve and things cleared up you might give that a try.

[sabretooth01]

Re: At My Wits End - 1998 GTX RFI -

Thanks John. You convinced me to bring it to the dealer. I think you're on the right track.

Dave
Hey 1pcdocu, it's an RFI (Rotax Fuel Injection). It's not carburated. The symptoms might be the same, but the solution will not be.

[Johnnylaw]

Re: At My Wits End - 1998 GTX RFI -

Not all dealers are the same. I know of at least two Sea Doo dealers that I would not let touch my PWC's again. Just a heads up.

[sabretooth01]

Re: At My Wits End - 1998 GTX RFI -

mmcjetski,

I think I have a solution for you. (checkout my post earlier in this thread)

Yesterday I took my GTX RFI to the dealer and had them check the ignition timing and re-calibrate the Throttle Position Sensor (TPS). They did both. The ignition timing was fine. Regarding the TPS, the dealer can only re-calibrate it, he can't see if it's out of calibration. So, he followed the seadoo procedure (below) to re-cal the TPS, and returned the PWC to me. Today my sons ran it in the water and they say it no longer mis-fires @ ~4500 PRM. It's running great again.

Hope is helps you!

Dave

Here's the Seadoo TPS procedure:

The adjustment of the TPS is performed using the MPEM programmer.

CLOSED TPS
To perform this adjustment, proceed as follows:
Access the BOSCH SYSTEM in the MPEM programmer. Then, select ADJUSTMENT in the sub-menu.

Choose CLOSE TPS in the ADJUSTMENT menu.

The screen will display the actual adjustment of the TPS in degrees and it will offer to adjust it

(do not select "yes" until the idle speed screw is loosned to allow the throttle plate to close)

Lossen the lock nut of the idel speed screw.

Loosen the idle speed screw until it does not contact the throttle plate stopper.

Slelcting "yes" will instantly readjust the close throttle position adjustment to the new setting.

IDLE SPEED ADJUSTMENT
Turn idle speed screw until it touches the stopper.

Turn idle speed screw 2-3/4 turns as a preliminary adjustment.

For precise adjustment of the idle speed, it should be finalized in the water.

Idle speed in water is 1400 +/- 50 PRM

[ntelligent]

Re: At My Wits End - 1998 GTX RFI -

Wow!


I have a 2001 GTX RFI that we just received back from the shop. It has a reman SBT engine installed and we were running through the break in process today. After riding for about an 1hr in the 1500-3000RPM range we let the ski rest for about 20 minutes and then started on our second hour of riding. Amazing enough when I reached 4150-4500RPM there was a strange hesitation. I called the dealer about it and he indicated to continue the break in process. I will follow up with this timing issue with him next week!!!

[mmcjetski]

Re: At My Wits End - 1998 GTX RFI -

Dave,


Thanks for the heads up. I assume the tps adjustment has fixed your problem? Have you had it out a few times to see if the hesitation is no longer there?

Weird thing is, when I took it to the dealer 5 months ago, they acted like they werent even familiar with a TPS setting or adjustment. I will print off your step by step and show it to them


Again thanks for the reply!!!:emoticonb

mmc

[sabretooth01]

Re: At My Wits End - 1998 GTX RFI -

mmc,

The mis-fire I was getting at ~4500 RPM has been fixed by the deal re-calibrating the TPS. I took it out myself the other day and while there was an occational mis-fire, I consider it fixed at this point. It has power again in the 4000-5000 RPM band, where it didn't before.

Good Luck on your side,

Dave