2003 Seadoo RXDI fuel system leak

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E

EdwinBland

Member
I have a 2003 RXDI I bought as a project.
The engine was ‘rebuilt’ by PO. I took it apart to inspect it after it failed leak testing…
It’s now back together… no engine leaks…
I put a Quantum Fuel System, HFP 501DI fuel pump in the tank.
It fires up…yea…
However, it idles rough and then dies…
Pressure tests:
~26psi at fuel filter with key installed…
However, the pressure drops off quickly to zero in less than a second. I have sprayed soapy water all around the top of the tank, fuel lines and connections on the fuel rail… but haven’t located any leaks yet.
When it’s running it goes up to ~107psi… fluctuating…
I would think a leak that big would be easily visible or possibly even heard…

I’m looking for some suggestions on common leak locations with the fuel system.

Any recommendations are appreciated.

Im reviewing the manual…
I’m thinking I’ll do the process of elimination…I need a way to block the line coming out of the gas tank… to isolate it to the tank and line only..? Thinking out loud…

Any ways to test the connections under the rail?

TIA,
Edwin
 
Check for air leaks on the compressor and lines to the rave valve. Make sure all your lines are connected properly. 107PSI should be maintained with the engine running. I purchased a testor for both the fuel and air side of the fuel rail. You could have a O-Ring leaking or a bad fuel pressure or air pressure regulator. I had a compressor failure due to a disintergration of the oil line to the compressor. Stick with it.
 
You shouldn't be checking for leaks "outside" of the fuel loop, those would be obvious and very hazardous.

The "leaks" you are talking about would be inside the fuel loop. By fuel loop I mean the high pressure (107 psi) hose from the fuel module, through the fuel/air rail, then the low pressure return hose back to the module.

Not holding the 27 psi (key on post) is most likely the fact that the pump doesn't have a check valve like the OEM. That is not really a problem.

The fluctuating 107 psi when running is a problem and could be the fuel pressure regulator in the fuel rail, but it is much more likely the built in pressure relief valve in the pump. These 500DI pumps (or 501DI) don't have a visible relief valve port on the top of the pump so it must be internal. The smaller HFP 342DI pump has a visible port. I have had a brand new 500DI pump fail with the stuttering performance you mention. When riding with my fuel pressure tester gauge installed I could see the pressure fluctuating down even into the 90 psi range. The 107 psi required for the DI is tough for these pumps, so I believe that small relief valve spring eventually starts to give out a bit. I have had better luck and longer service with the 342DI pump since I epoxy the relief port shut. I have only tried two of the 500DI pumps, one lasted about 10 hours, and the other was DOA as I mentioned, with those symptoms. I would love if the 500DI relief port could be plugged since it looks like the OE and probably is more robust. I have gotten as much as 160 hours out of one of the 342DI pumps.

As etemplet says, these DI are great, when they are running right.
 
Ok… a baby step.
I replaced the compressor input to the fuel rail with an ~80psi source from my shop air compressor…
The system starts and runs… albeit a little rough.
I then took the fuel rail off to inspect the pressure regulators. The air regulator had some particulate in it…I blew that off and reassembled it.
Here’s a video of it starting and running…
I have a leak in my compressor quick connect fitting… I’ll need to replace that before going further.
The ski compressor had a rebuild kit in it and appeared to develop pressure when manually tested during install. Since it builds up to 107psi… I’m thinking this points at the compressor reeds vs regulator. ? I cranked the shop air up to 90 psi and can hear the regulator purging air. Are there some definitive tests for regulator and compressor?
I’d like to directly test the compressor. Any issues with directly putting pressure gauge on it?
 
EdwinBland said:
Ok… a baby step.
I replaced the compressor input to the fuel rail with an ~80psi source from my shop air compressor…
The system starts and runs… albeit a little rough.
I then took the fuel rail off to inspect the pressure regulators. The air regulator had some particulate in it…I blew that off and reassembled it.
Here’s a video of it starting and running…
I have a leak in my compressor quick connect fitting… I’ll need to replace that before going further.
The ski compressor had a rebuild kit in it and appeared to develop pressure when manually tested during install. Since it builds up to 107psi… I’m thinking this points at the compressor reeds vs regulator. ? I cranked the shop air up to 90 psi and can hear the regulator purging air. Are there some definitive tests for regulator and compressor?
I’d like to directly test the compressor. Any issues with directly putting pressure gauge on it?
Click to expand...
Sorry… I didn’t realize I needed the video to be linked… thought I could just paste it in… will post it… when I have Utube account verified.
 
EdwinBland said:
Ok… a baby step.
I replaced the compressor input to the fuel rail with an ~80psi source from my shop air compressor…
The system starts and runs… albeit a little rough.
I then took the fuel rail off to inspect the pressure regulators. The air regulator had some particulate in it…I blew that off and reassembled it.
Here’s a video of it starting and running…
I have a leak in my compressor quick connect fitting… I’ll need to replace that before going further.
The ski compressor had a rebuild kit in it and appeared to develop pressure when manually tested during install. Since it builds up to 107psi… I’m thinking this points at the compressor reeds vs regulator. ? I cranked the shop air up to 90 psi and can hear the regulator purging air. Are there some definitive tests for regulator and compressor?
I’d like to directly test the compressor. Any issues with directly putting pressure gauge on it?
Click to expand...
The service manual (found on Google) has a procedure for dead head testing the air compressor. It should hit 90 +/- 2 psi during cranking.
 
The service manual (found on Google) has a procedure for dead head testing the air compressor. It should hit 90 +/- 2 psi during cranking.
Click to expand...
However, also note from the service manual, that the test should use an overpressure relief valve to avoid possible damage to the compressor. It would be great to know what pressure this relief valve is set at (Seadoo PN529 035 711). What if the relief pressure is only 92 psi? These type of relief valves are under $20 if you know what pressure, which is a lot cheaper than the price of that Seadoo part number. If you don't have a relief valve I would be very careful and stop cranking after reaching 90 psi.
Here is an example relief valve:
Amazon.com
Here is a cheaper one:
Amazon.com

1700494260164.png
 
Last edited:
Update:
I hooked up the computer to the ski. It's reporting a low battery & a bad temperature sensor... pretty sure temp sensor shouldn't affect running when it's cold. Also pretty sure low battery shouldn't cause low compressor pressures... I'll replace the battery, however.

I then hooked up the fuel rail test adapter to the compressor high pressure outlet... I'm only getting about 25 psi max after about 20 sec of cranking.
I took the compressor top end off... visually it looks OK. It had reportedly been a new compressor rebuild kit by the PO. However, who really knows... I took pics. I had reassembled it... but didn't quantitatively measure pressure before putting back into hull.

I'd like to see a diagram of the compressor to understand what the large hose does that goes to the throttle body. Might it be possible this is a leak source -vs- the compressor itself? Replacing a compressor with the engine in the hull looks like a PITA.

TIA

Edwin
 
DI's can be tricky to diagnose so you really need to go system by system. Start by confirming the air compressor puts out 80+ psi. Then move to fuel pressure. My comments below are from working on my 2000 DI but I think most systems are the same.

The air compressor has an o-ring under the head that can be tricky to position. Check for leaks there. From memory, I think the air feed for the compressor is that hose from the throttle body. The 2 outlet hoses from the head can leak - 1 to the fuel rail and the other to the RAVE solenoid, so check both of those.

Your comments on low battery + aftermarket fuel pump also raise some red flags. Aftermarket fuel pumps are known to draw more amps than the ski can keep up with. That is why so many people say to stick with OEM fuel pumps, though they are crazy expensive.

Lastly, on the codes, are you sure they are current and not from the past rebuild/troubleshooting? The codes on SeaDoo work differently than cars. Try clearing them to see what comes back.
 
I agree with everything WaarrEagle mentioned with only minor additions.

Yes, the compressor input hose coming from the throttle bodies is to get "relatively dry" air to compress.

The early aftermarket fuel pumps to replace the OE could draw 12A+ which is way to much for this system to operate well. The OE pump only draws about 4A so it is truly amazing for achieving 107 psi. The latest aftermarket pumps like the 342DI draw about 6A which at least doesn't starve the MPEM and provides left over for battery charging, and is cheap. When the OE pump starts to fail, it often causes higher current draw, which wrecks havoc with the MPEM, causing it to often spew multitudes of erroneous codes.

BTW - having put well over 1000 hours on my four DI, I have never had a compressor problem. It is almost always voltage/current related usually requiring replacement of the Rectifier/Regulator, or it is fuel pressure related requiring fuel pump or module work.
 
Update: I replaced the compressor with a new one. The key thing was getting the o-ring installed correctly… after that … onto the next thing… I discovered the spark plugs weren’t to spec… ugh.. I got some NGK ZFR4F 11 4043 per the manual.
Replaced the air regulator… and it starts and idles smooth and steady. About 80 psi from compressor… about 107 at the fuel pump.
Tx everyone for your suggestions!
The DI must be smarter than the carb models… it idles at 1500 out of water…. I’ll have to wait for warmer weather to water test it….

I love the sound of the engine… it has a throatier sound than the 951 carb ones I have.
 
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