Rough idle on my 2003 gtx di

[baddb1]

It has a rough idle and stalls sometimes. It runs fine at higher speeds and has normal top speed and acceleration. I changed the plugs because one plug was fouled at first start of the season. I added seafoam in the tank and ran a tank through it but it still idles rough and has actually gotten a bit worse. Any ideas? (Rave valves and injectors were cleaned a few years ago)
Thanks for any and all help!! :thumbsup:

 

[- BiRkS_]

Never ever add any additives in the gas tank! on a DI ski that is horrible. Bad for the pump, injectors, everything. Does it sound like its running on one cylinder? Does the maintenance light flash? Check your battery voltage at idle. You may have a failing battery and the charging system can't keep up at idle. Also, when is the last time your fuel filter was changed?

 

[baddb1]

Never ever add any additives in the gas tank! on a DI ski that is horrible. Bad for the pump, injectors, everything. Does it sound like its running on one cylinder? Does the maintenance light flash? Check your battery voltage at idle. You may have a failing battery and the charging system can't keep up at idle. Also, when is the last time your fuel filter was changed?

Ok, I didn't realize that stuff was no good for these engines. :blush:
No, it is running on both cylinders. No maintenance light. No low voltage from battery warning light. I'll verfiy voltage though.

 

[DooWacka]

Is this the DI you put the new non-OE fuel pump into?

If so, what BiRkS says about the battery bears investigation, since the aftermarket pumps draw more current.
Also, if you have the capability, measure the fuel pressure at idle, to see if it is dropping off of 107 psi.
Fuel pressure down in the 90's can cause rough idle, yet when you get the increased power from the MAG at higher speeds the pressure may be 107 psi.

 

[baddb1]

Is this the DI you put the new non-OE fuel pump into?

If so, what BiRkS says about the battery bears investigation, since the aftermarket pumps draw more current.
Also, if you have the capability, measure the fuel pressure at idle, to see if it is dropping off of 107 psi.
Fuel pressure down in the 90's can cause rough idle, yet when you get the increased power from the MAG at higher speeds the pressure may be 107 psi.

Yes, its the same DI w/ non-OE pump. You make a good point, what should the Batt voltage be at idle? 13.8V like a car system?

Unfortunately I have no way to check fuel pressure. If I had the gauge to do it, where do I attach it? I'm wondering if it's cheaper to buy one and do it myself rather than haul to a dealer and pay them?? What do you think?

Thanks - Bill

 

[DooWacka]

Do you have the HFP-342 (Walbro "knockoff") from HighFlow.com? If so, you probably have the pump that uses at least 12+ amps. Therefore it won't be quite as easy checking the voltage as for the car. Since the pump draws so much current, I think it would be rare to see the voltage much above 12.8v even at running speeds. At idle it could measure below 12v, since the battery may not even be charging. That is the problem I have with that pump. On mine (like that), I measured a DISCHARGE of about 1 amp at idle, and charging at about 1.5A while riding. So, I tell people riding it to not have to long of idling periods without mixing in some normal running speeds, in order to keep the battery up.

HighFlow is currently selling a Seadoo replacement pump that draws 9A, which allows charging of about 1A at idle. The magneto and rectifier/regulator only put out about 18A, and that has to be shared with the fuel pump, all the electronics including MPEM, and some left to hopefully charge the battery. Both the pump and the MPEM don't like to be "starved" of power, so they start acting up.

So, that could very well be your problem. Make sure your battery is a good one, and fully charged, and see if the rough idle diminishes.

The fuel pressure tester I built (patterned after the one in the Seadoo shop manual), is shown on post #82 of this thread:
http://www.seadooforum.com/showthread.php?46680-DI-Seadoo-Fuel-Pump/page4
It cost me almost $100 to build, but it is a useful tool, and about the cost of paying a dealership to measure pressure.

 

[baddb1]

Do you have the HFP-342 (Walbro "knockoff") from HighFlow.com? If so, you probably have the pump that uses at least 12+ amps. Therefore it won't be quite as easy checking the voltage as for the car. Since the pump draws so much current, I think it would be rare to see the voltage much above 12.8v even at running speeds. At idle it could measure below 12v, since the battery may not even be charging. That is the problem I have with that pump. On mine (like that), I measured a DISCHARGE of about 1 amp at idle, and charging at about 1.5A while riding. So, I tell people riding it to not have to long of idling periods without mixing in some normal running speeds, in order to keep the battery up.

HighFlow is currently selling a Seadoo replacement pump that draws 9A, which allows charging of about 1A at idle. The magneto and rectifier/regulator only put out about 18A, and that has to be shared with the fuel pump, all the electronics including MPEM, and some left to hopefully charge the battery. Both the pump and the MPEM don't like to be "starved" of power, so they start acting up.

So, that could very well be your problem. Make sure your battery is a good one, and fully charged, and see if the rough idle diminishes.

The fuel pressure tester I built (patterned after the one in the Seadoo shop manual), is shown on post #82 of this thread:
http://www.seadooforum.com/showthread.php?46680-DI-Seadoo-Fuel-Pump/page4
It cost me almost $100 to build, but it is a useful tool, and about the cost of paying a dealership to measure pressure.

Thanks for the info!!
Yes, I have the highflow pump that I got on Ebay. You commented on the other thread stating that it looked like I had the lower amp pump, due to the white top on it..? I hope I do! http://www.seadooforum.com/showthread.php?54790-2002-GTX-DI-Fuel-pumps

Either way, I will verify the battery voltage.

 

[DooWacka]

Yes, if it is the white top it is the 9A pump that does charge at idle.
I also have two DIs with the 9A pump, and I'm looking forward to putting some serious hours on them this July.

 

[baddb1]

Interesting development,, first, I checked the battery seemed a little low, so I tried a different battery I had, but the rough idle was still there. So I took apart the fuel rail and noticed this white gunky (kinda greasy)substance on one side. (see picture) It appears to be coming from the left side where the air pump is? IS the air pump getting water in it or what is happening here? Any ideas?? I'm not sure how the air pump system works w/ the fuel injection.

Thanks...

 

[- BiRkS_]

Looks like you had a mixture of oil and water at some point in there. Clean it out with shop towels, blow it out with compressed air, and re-install. That goey mess could have been clogging up an air injector=bad idle.

 

[baddb1]

I spoke w/ seadoo mechanic briefly and he said it could be the air solenoid valve and that was a common fail item. Anyone else have it fail??? I'm just going clean out everything and see how it goes...

 

[DooWacka]

That is the air pressure regulator that looks "gooey". I'm not sure how it would get water in there, and from where. The only solenoid I believe is the one that gives pressurized air to the RAVEs. I am not sure how water would get into either air circuit. If water made it into the crankcase, then was compressed by the air compressor, is the only water connection I can guess.

The compressor supplies air to the rail, which is regulated to 80 psi for the Direct Injectors. The injectors you see on the top of the rail you have removed is for the fuel injection. The fuel injectors inject into the top of the Direct Injectors (mounted in the head; between the rail and the head), that then provide the high pressure air to further atomize the fuel droplets, while injecting the mix into the cylinders for combustion.

When I have heard of air solenoid failure, it only affects the RAVE valve opening, so you lose top end performance. I have never heard of water entering this way.

 

[baddb1]

That is the air pressure regulator that looks "gooey". I'm not sure how it would get water in there, and from where. The only solenoid I believe is the one that gives pressurized air to the RAVEs. I am not sure how water would get into either air circuit. If water made it into the crankcase, then was compressed by the air compressor, is the only water connection I can guess.

The compressor supplies air to the rail, which is regulated to 80 psi for the Direct Injectors. The injectors you see on the top of the rail you have removed is for the fuel injection. The fuel injectors inject into the top of the Direct Injectors (mounted in the head; between the rail and the head), that then provide the high pressure air to further atomize the fuel droplets, while injecting the mix into the cylinders for combustion.

When I have heard of air solenoid failure, it only affects the RAVE valve opening, so you lose top end performance. I have never heard of water entering this way.

OK thanks for the explanation. I followed where the lines went and I see what you mean. Since the compressor also feeds the RAVEs, maybe somehow some oil blows or drains back into the compressor if the air solenoid valve was bad...? Seems unlikely though...

Maybe the water entered through the air inlet hose going to the compressor? Also, I see a water cooling line go in near the compressor so I hope there isn't a leak there!!

I cleaned everything out good and blew it out good,, so we'll see how it runs tomorrow or Thursday.

 

[baddb1]

Got the GTX running today and she seems to run really well now! Now I just hope it doesn't gunk up again!