2002 GTX DI - Won't Run Over Idle Speed

[NautiqueJeff]

2001 GTX DI - Won't Run Over Idle Speed

2001 GTX DI -- It starts up and idles great. When you first start it and accelerate, it will run above idle for a minute or two, but will never rev above about 30%. After a couple of minutes, it gets very difficult to keep it running at all above idle. It just stalls when you give it gas. It will run seemingly all day at idle speed though.

If you shut it down and let it sit for a minute or two, it will fire right back up and accelerate to about 20% before stalling out again. If you start it and let it idle, it will continue to run.

Very rarely, if you give it full throttle, it will slowly accelerate, occasionally popping briefly into normal running for a few seconds (hard acceleration, good speed), but only for a few seconds, and I have only been able to get it to do this maybe two or three times during my 30-minute test run yesterday.

I just replaced the fuel pump and sock filters with the proper unit from High Flow. The old pump was very rusty and the filters were completely falling apart. I also drained and cleaned the tank and added fresh gas. I was really hoping this would fix the issue. It did not.

I also replaced the voltage regulator.

I did not replace the inline filter.

It is running exactly the same as it did before I replaced the fuel pump, sock filters and regulator.

Any suggestions on what to check next?

 

[Coastiejoe]

First, I assume this is being done out of water. If so, is it on the hose?

Even if so, it should not be run for more than maybe 30 seconds. Even that is too long. The hose does not cool the engine, it flushes the engine. The water runs in reverse.

Second, without an in-line fuel pressure gage you can not really diagnose this ski. Poor voltage will make a pump run at a lesser pressure. At idle it take 107 PSI for example.

 

[Dr Honda]

Coastejoe is right.

1) You can't guess with a Di ski. So replacing parts randomly is useless.

2) Check the fuel pressure.
3) Check the air pressure.
4) Check the voltage.
5) Check the compression.

6) Other than the compression... you have to do it ON THE WATER ! (on the hose is useless, since it won't load the engine)


With the above... it's common for the reeds to crack, or get weak. So, I would suggest popping the reed blocks off, and getting a close look at them.

 

[jhjesse]

As an Owner of 3 DI's, I recommend the compression test first.
If compression test is good rig up a pressure gauge and check fuel pressure. (See owners manual)
Should be 80psi fuel and 27psi air added together equals 107psi total. Chances are good the hi flow fuel pump is defective. Several members have had to return hi flow pumps that would not work properly. They are really good about taking it back and replacing it with a good one.
Also connect the gauge to the compressor and make sure it is pumping 27psi.
If you have not already changed the canister fuel filter, I highly recommend doing that as well.
I would check the voltage and make sure your rectifier is working properly.
If the problem is still not solved then remove the throttle body along with the intake ports and have a look at the reeds.
Good luck.

 

[NautiqueJeff]

My testing has, of course, been done on the water, not on the trailer.

 

[tkarvelis]

Check the plugs. Are they a nice chocolate brown color? This will point you to fuel or something else.

What is you DC voltage measured on the battery when running? Idle? When you try to give it throttle?

Your compression should be 120 to 140. Anything below 120 and running is questionable.

The injectors could be dirty. There is a place on Long Island NY (South Bay Fuel Injectors) that will clean them. I have not used them, but I was going to on an 02, but other issues prevented this.

 

[Coastiejoe]

As an owner of a DI ski, you will learn that the DI requires some very specific tests and knowledge. When they are running correctly, they are fantastic. When they are not, they can be a nightmare.

Like most engines, compression is very important. But with a DI ski, fuel pressure is also critical. The pressure is created both by the fuel pump and an air pump. These need to be tested separately as well as combined. Wire quality and connections are very important on the DI as any loss of amperage or voltage can seriously affect fuel pressure.

In the end, this ski is somewhat special. You will need quality fuel pump pressure testing tools and you will likely need a Candoo Pro as well. None of these are cheap items, but they are nearly required for the DI ski's.

Good luck with it, let us know if we can help.

 

[NautiqueJeff]

Thanks for the suggestions, everyone. I am going to do a compression check in a few minutes and I'll report back. I don't have the tools for the fuel pressure and air pressure tests, but I will buy them if needed. Any recommendations on specific tools that work well to test those on this ski?

 

[NautiqueJeff]

Ok, I did the compression test.

115 on both -- It is about 50 degrees out and the battery is moderately charged but not fresh off the charger.

Not great numbers, but is that low enough to make it run like it is?

Also, it had some weird Bosch plugs in it with no numbers on them. I replaced those with new ZFR4F-11 plugs.

It starts easily and idles and revs fine on the trailer.

 

[Coastiejoe]

115 is low. Could run ok on the trailer but probably not in the water under a load.

You NEED a good battery and I strongly recommend using a different compression tester as well. We see many models read low.

I would get the battery charged and redo the test using two different gauges.

 

[NautiqueJeff]

Sounds good. I'll get the battery on the charger right now.

 

[NautiqueJeff]

Well, I have some good news, I think.

After reading some additional threads on 951 DI compression, I found that I should have been holding the throttle wide open. According to [MENTION=57696]68ragtop[/MENTION] this stops the air and fuel injectors and will allow for a correct compression reading.

I did that, and this time I got 131 and 135. Much better!

 

[tkarvelis]

Yes. Throttle clamped open. It will disconnect the injectors. It will beep a different pattern letting you know you are in that mode.

 

[Coastiejoe]

Correct about the throttle.

Should be a cold engine, throttle pegged, good battery. And yes, the throttle being pegged is suppose to stop spark and and injection. That said,, you should always ground out the spark plug wires just in case.

So,, you are back to a potential fuel pressure issue. You need to get a gauge and get it in line and see what numbers you are getting. As noted above, with the DI engine, Fuel Pressure is very important.. You can not assume you have good pressure just because you have a new pump. In fact, most aftermarket replacement pumps are BARELY good shortly after being installed. They simply can not provide both the pressure and volume needed.

I am assuming you bought an aftermarket pump, yes?

 

[NautiqueJeff]

Yes, aftermarket pump, but from what I understand, these guys have a pretty good reputation. This is the one i bought. Thoughts?

http://www.highflowfuel.com/i-90518...on-seadoo-sea-doo-gtx-di-rx-di-2000-2003.html

 

[Coastiejoe]

Yes, aftermarket pump, but from what I understand, these guys have a pretty good reputation. This is the one i bought. Thoughts?

http://www.highflowfuel.com/i-90518...on-seadoo-sea-doo-gtx-di-rx-di-2000-2003.html

I am not able to give you any info on the company you bought from. All I can say is that, I would bet 75% of those that install aftermarket pumps come here with issues. And in most cases,,, it is the pump.

 

[tkarvelis]

There is a subject on the fuel pumps and how to make the gauge. I have built one for my gtx, and purchased the material off Amazon, but you should be able to get it all from an auto parts store.

 

[NautiqueJeff]

Ok, got the fuel pressure gauge and other parts needed to make it work on this ski ordered. Should have them soon.

Also ordered a replacement inline filter.

How can I test the air pressure?

 

[wolfie]

I was wondering how you made out with the problem ??

 

[NautiqueJeff]

Got the fuel pressure gauge installed today and tested it on the trailer. Haven't gotten it to the water yet.

I'm getting about 150 PSI at idle, which is confusing me. Why is it so high? The gauge is mounted in place of the external filter right now.

Here's a video of the gauge showing the readings.

[video]https://youtu.be/rYsA0TMEMPk[/video]

Here's where the sensor is mounted.



Giving it a couple of small revs just totally pegs the gauge.

 

[NautiqueJeff]

Anyone have any idea why the fuel pressure is so high? Am I checking it in the correct location?

 

[jhjesse]

Still have the aftermarket fuel pump installed? Possibly a bad gauge? At any rate sounds like a water test is next. Let us know how it turns out.
I am also curious as to how much voltage you are drawing with that fuel pump?

 

[68ragtop]

First I would put the gage on a shop compressor air line to see if your gage is accurate. gages can vary a lot over 100 psi. IF the gage is good. The other possibility is the return fuel line from the fuel rail, or the air rail is pinched or not flowing well, the regulator in the rails are what keeps fuel pressure between 27-107 (depending on the air pressure side) once they hit the right pressure the regulators start to open & returns the excess fuel flow (and pressure) to the tank, & air out of the back of the hull, keeping the pressures steady.

If either one gets blocked & your fuel pressure will rise. If your air line was restricted, I would expect to see a rise in fuel pressure with a rise in engine RPM's It should rise a couple lbs in a normal working system, but not much.

If you really have 150 PSI, I would suspect one of these things:
restriction in the fuel supply line (between the gage tee & rail), restriction in the fuel return line (from the rail to the tank), restriction in the air rail vent line (air rail to the back of the hull) or the regulators themselves could possibly have a problem. The regulated air pressure sits around 80 when idling. If the air line that exits the rail is blocked, this could drive the air pressure past 80, & this will drive your fuel pressure higher as well.

On a side note, I dead head tested an oem fuel pump a couple years ago & those things are crazy strong. They can produce near 200 PSI in a blink if not regulated. Thats a crazy powerful pump! scared me when I saw the needle climb so high, so quick. That made me understand why BRP uses such a high pressure hose on these things.

But, check the gage, hopefully that's all it is

 

[NautiqueJeff]

Thanks for the suggestions, everyone. I tried to find someone with another gauge that I could try today, but wasn't successful. I did get out on the water for a test today though.

When I first put it in the water, it seemed to be running better. It was still not smooth like it should be, but it would at least plane off and run pretty fast. I removed the external fuel filter in order to install the fuel pressure gauge, so I was initially thinking that that filter must have been clogged and causing at least some of my issues. After riding for a couple of minutes, it started doing the same things again though -- immediately bogging down when I give it any throttle, and refusing to run above idle very well. I did have two brief periods of clarity where it took off with full power, nice and smooth, up to full throttle for a few seconds. Both times, after a few seconds, the fuel pressure took a nose-dive and the engine stalled. It would always start right back up though with the pressure reading just under 150 PSI and idle fine but not accelerate well if at all.

I did have the fuel pressure gauge hooked up the entire time I was out though, and I noticed that the fuel pressure was reading 130-150 when it was running, either at idle, running roughly at speed, or during the brief periods where it ran well, but when it would really stumble badly, the fuel pressure always dropped rapidly.

I am not sure how accurate my gauge is. It is new, but that doesn't mean anything. I'll keep trying to find another one to borrow.

I'll check for restrictions in the lines as mentioned above. Could severely clogged injectors cause the pressure to be so high? I assume not, since the return line to the tank should allow the fuel to just flow there, but I thought I would ask anyway.

Also, I finally broke down and ordered a CanDooPro today. Maybe that will help me figure out the issue.

 

[NautiqueJeff]

Got the CanDooPro in the mail today.

According to the CanDooPro manual, there should be a six pin connector coming off of my MPEM that is used for diagnostics. Mine does not have this connector. I looked all around and never found it. Anyone know where this connector might be on a 2001 GTX DI?


Here's where it is supposed to be, according to the manual:

Here's the same area on my ski. As you can see, there is no connector.