2001 GTX DI issues

[nickmo12]

When it was winterized in the fall, it ran fine. Unwrapped it, charged battery and tried to start. Cranks and fires but immediately stalls. Runs for literally 2 seconds. Continued that way for 5 or 6 times. The fuel pump is running. Compression is 95 in both cylinders same as last year. I know that's a bit low, but has been that way last 3 seasons without a problem.

 

[DeWet]

Fuel pressure an air pressure? With the fuel rail if the air pressure is low the fuel will low too at the injectors.

Had the same issue and it turned out to be the air compressor that was leaking and not building pressure

 

[POPPS]

There is no way it will run on 95psi…should be around 135…which is why it needs high octane,

 

[Poormanracing]

I used to use compression as a basis of engine health but gauges are different.i do a leak down test instead takes a little longer but get a better idea what's going on.also on skis with rave valves I pull the raves to look into the cyl.put a spark tester on the plugs and first see if you are loosing spark.then you can narrow down a direction to go

 

[DooWacka]

Since you own a DI, you need to have the ability to test fuel pressure. Hearing the fuel pump run is good, but if it doesn't get up to and maintain the high pressure needed, it won't run or stay running. Most DI problems I have had are either fuel pressure or voltage related (Rectifier/Regulator).

As stated your low compression could be due to the gauge you use, or your altitude. I am at 6000 feet elevation, and usually only get 95 to 105 psi compression.

If you still have the OEM fuel pump, and there was much water in your fuel, the pump could have corroded over the winter. The OEM pump is truly amazing (low current draw with great output), but does have metal pump parts that have been known to corrode. As the pump corrodes it draws more current. There are people on this forum that have had good results with cleaning/rejuvenating the OEM pump by running it in a container of toluene.

If you test fuel pressure and perhaps find it low, then you can investigate if it is related to the fuel pump or the air compressor. My experience has been it is much more often the fuel pump.

 

[nickmo12]

Since you own a DI, you need to have the ability to test fuel pressure. Hearing the fuel pump run is good, but if it doesn't get up to and maintain the high pressure needed, it won't run or stay running. Most DI problems I have had are either fuel pressure or voltage related (Rectifier/Regulator).

As stated your low compression could be due to the gauge you use, or your altitude. I am at 6000 feet elevation, and usually only get 95 to 105 psi compression.

If you still have the OEM fuel pump, and there was much water in your fuel, the pump could have corroded over the winter. The OEM pump is truly amazing (low current draw with great output), but does have metal pump parts that have been known to corrode. As the pump corrodes it draws more current. There are people on this forum that have had good results with cleaning/rejuvenating the OEM pump by running it in a container of toluene.

If you test fuel pressure and perhaps find it low, then you can investigate if it is related to the fuel pump or the air compressor. My experience has been it is much more often the fuel pump.

Thanks. Your posts and others are always so helpful. My next step will be to check fuel pressure. I replaced the pump at the beginning of last season with a used OEM from Ebay. I tried 3 different Quantum pumps that wouldn't work. Wouldn't a low voltage issue throw a maintenance light?

 

[DooWacka]

Low voltage should cause a light and display. However, I have had both slightly low and high voltage not show in the display. High voltage, like when a voltage regulator goes out, most often causes the MPEM to misbehave and get squirrely. High current draw and low voltage causes the same erratic MPEM behavior.

Sadly, all my OEM fuel pumps are gone. I have used various Quantum pumps over the years, with pretty good results. None of them are as good as the OEM pump with both current draw and output. I am currently trying their latest, hopefully more robust 500 version, which is the same size and looks a lot like the OEM Seadoo pump. So, I am hopeful of a longer service life.

 

[POPPS]

I have yet to find a aftermarket that works off the trailer.

 

[DooWacka]

I have mostly lately used the HFP-342DI, and am now trying the HFP-500DI which is a larger pump that looks just like the original Airtex built Seadoo pump. If the 342DI is not working for you "off the trailer" then check two things. If the pump "tilts" while riding, the "sliding seal" can leak, so the original plastic support should be modified to hold this pump from flopping side to side inside the module. Secondly, I have found that the over-pressure relief port (small hole on top of pump) can start giving way over time, so I routinely epoxy (JB Weld) the port closed before install. If the sliding seal is damaged then the module won't achieve or maintain the required pressure, and I haven't found a source to replace the seal.

 

[etemplet]

I have mostly lately used the HFP-342DI, and am now trying the HFP-500DI which is a larger pump that looks just like the original Airtex built Seadoo pump. If the 342DI is not working for you "off the trailer" then check two things. If the pump "tilts" while riding, the "sliding seal" can leak, so the original plastic support should be modified to hold this pump from flopping side to side inside the module. Secondly, I have found that the over-pressure relief port (small hole on top of pump) can start giving way over time, so I routinely epoxy (JB Weld) the port closed before install. If the sliding seal is damaged then the module won't achieve or maintain the required pressure, and I haven't found a source to replace the seal.

How long are these pumps lasting after install?

 

[DooWacka]

The current pump recommended and sold by HFF for the DI is the HFP-342DI.
My records show my worst longevity for this pump was 24 hours, and the best (so far) is 84 hours.
I now have two of the hopefully more robust HFP-500DI installed but are both only about 10 hours so far.

Considering previous pumps they sold:
HFP-382 --- one pump had 56 hours, and another had 66 hours
HFP-RTN --- one pump had 61 hours, and another is still running at 144 hours so far.
(the RTN pump does however use about 9 amps so about 50% more power than the 342DI)

The good news is that these pumps are Lifetime Guaranteed by HFF (Quantum), and they have been good at sending replacements.

 

[etemplet]

Strange how difficult it is to duplicate the OEM pump performance and power usage. Scary thing about the 9am is.... will that much power draw down exceed the charging system? Good stuff though as it is difficult to find anyone with real world experience with the aftermarket pumps. Thanks for sharing. I feel pretty good about replacing pumps if needed.

 

[Mwhitlock1984]

There is no way it will run on 95psi…should be around 135…which is why it needs high octane,

02 gtx di - does the compressor hose unscrew or is it held in place with the Allen key attached to fuel rail? Want to test the compressor side. Don't see info in manual how it comes off the rail.