Newbie with question

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Water Crafts
02 GTX DI, 04 GTX supercharged
#1
Hello All, new to the Seadoo world. I just bought two, 04 GTX supercharged and 02 GTX DI. The DI came with the understanding that it had developed an intermittent miss so I got it for what I thought, pretty cheap. The engine had 40 hours on a rebuild. The story I got was they were riding and it developed an intermittent miss at mid throttle, brought it into shore, the dad (also the mechanic) rode it and decided to put it away for the day. Got home, wouldn't start, no beeps no power. Checked fuses all good, read internet thought mpem was bad, put it away for winter. Sold it to me, hooked up dess key, got the two beeps, fired right up, ran great for about an hour then started misfiring. came home read internet. So here we are, question is could a dess post going bad cause this? MPEM? and of course fuel pump. It does have an external fuel pressure gage on it but did not check it when it was misfiring and the weather hasn't been cooperating the last couple of days. I did check it prior to start and it is very close to 27 psi and while running on the hose is just over 100 psi but it wasn't misfiring. I'm thinking heat related?? thanks!!
 


mikidymac

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Water Crafts
2003 GTI
2001 XP
1997 GSX
1996 XP
1996 HX
1996 SPX
01' Superjet
#2
It has to be exactly 107 psi. Good luck my friend, the DI can be a pain to diagnose.
 
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Water Crafts
02 GTX DI, 04 GTX supercharged
#3
Thanks for your reply, I don't know how accurate the gage is, it doesn't have a calibration sticker on it. Im going to try and ride it without the front seat and see if I can see any needle fluctuations, just waiting on another nice day that I'm actually off work. If it is the pump where do I find a replacement? I was reading a bunch of old posts that said they were really hard to find but then noticed they were from 2012. Thanks again!
 

mikidymac

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Water Crafts
2003 GTI
2001 XP
1997 GSX
1996 XP
1996 HX
1996 SPX
01' Superjet
#4
You have to bite the bullet and use an OEM pump. Some have had luck cleaning the old one though.
 
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Location
Westchester NY.
Water Crafts
current
2001 GTX DI
2007 GTX LTD
1998 Speedster

old
98 XP LTD
98 Kaw 800
#5
Don't use an aftermarket pump.

I put an aftermarket fuel pump in my DI and it would not run. I bought a pressure gauge and found out not enough pressure. I sucked it up and bought a Sea Doo fuel pump and it works now.
 
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96
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Location
Catawissa pa.
Water Crafts
2001 gtxdi,2002 gtxdi
#6
27 psi when putting on the lanyard is perfect. So the fuel pressure regulator is working like it should. If you haven’t done so yet make sure to change the internal fuel filter which is on the bottom of the fuel pump and the External in-line fuel filter. Don’t waste your time and money on an aftermarket fuel pump- I only got two hours out of mine. your air compressor may not be adding the additional 80 psi like it supposed to. In the manual there is a fuel delivery diagnostic flow chart which can be very helpful. If you don’t have a manual you can download one from seadoomanuals.net or something close to that? The intermittent miss you have could also be from The regulator/ rectifier. And easy way to check that is to simply unplug the connector at the rectifier and if the miss goes away you found the problem. Of course don’t run it too Long unplugged because will not be charging the battery. If you do find the unplugging of the regulator clears up the problem do not purchase anything other than an OEM regulator/rectifier.
 
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Water Crafts
02 GTX DI, 04 GTX supercharged
#7
Thanks for all the replies! I put a new (aftermarket) fuel pump in yesterday, pressures are exactly the same as the SeaDoo pump, 25 when lanyard put on and 105 when running. I don't know how accurate my pressure gage is though. Finally downloaded the manual and these numbers are within specs so I'm keeping the seadoo pump as a backup. The guy that was helping me is the guy I bought these skis from, he has the Candoo system, no warnings or codes present. The last code was low voltage. We noticed that the voltage was 13.4 while running, didn't change with throttle and every once and a while this would drop to below 10 for just a second or less. We were running on a hose so we didn't run very long but my battery was pretty low by the time we finished. We took resistance readings on the stator, all were at .8 ohms. He had a spare used regulator, put that in and it charged the same. Seemed like it started at 12.1 v and slowly climbed up to 13.4. Any ideas?? Also found out that this ski has 36 hours on a total engine rebuild, all new internals, injectors, air pump, coils, regulator plus more I'm sure. Thanks.
 

mikidymac

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Location
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Water Crafts
2003 GTI
2001 XP
1997 GSX
1996 XP
1996 HX
1996 SPX
01' Superjet
#8
Good luck with that aftermarket pump, you have been warned multiple times but I wish you the best of luck. Also seeing 10 volts the ski will not run. The computer will shut down on a DI ski at that low of voltage.
 
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Water Crafts
02 GTX DI, 04 GTX supercharged
#9
Thanks for the reply mikidymac. I know you and others warned me but I just couldn't spend $800 on something I wasn't 100% sure was the problem to begin with. If this aftermarket one fails, I'll definitely buy a factory pump. I rode it yesterday, started out horrible, maint. light on and beeping. I beached it and found one of the connections to the spare regulator had come loose, plugged that back in and no luck, started getting the low volt alarm and serious misfire. Plugged the other regulator back in and within a couple of minutes the beeping stopped and the alarm went away. No misfire and the ski ran extremely well the rest of the day. Maybe, just maybe I've got it right. My battery voltage when I got home was 12.5, put it on my trickle charger and it was charged within a couple of hours. Thanks again everyone.
 

mikidymac

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Location
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Water Crafts
2003 GTI
2001 XP
1997 GSX
1996 XP
1996 HX
1996 SPX
01' Superjet
#10
I do know the aftermarket regulators are iffy on a DI ski. They have to have perfect voltage or do all kinds of crazy things. OSD Seadoo sells a modified 4-TEC one for the DI skis I think.
 

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