99 GSX RFI wont idle

[sakosky1]

I bought my gsx a few months ago and just recently got it out on the water.
It started and ran beautifully for 2 outings (3-4 hours of riding). But the 3rd time I took it out, I needed to add a little throttle to start it. Then while riding it would loose power and die (in about 4 seconds). It did that a few times then worked just fine for about 30 minutes. Then I brought it down to idle and it stalled. I started it up a few times and was seeing the tachometer drop into the 700-800 rpm range and it would die. If I added a little throttle and kept the rpms above 1000 it would run just fine. I started it up in my driveway today and it still wont idle on its own. I don't know if the idle speed is out of whack or if this is a sign of something else. I looked at the plugs and they are a little dirty, but shouldn't be the problem. Any ideas?

1999 GSX RFI
compression is good
fresh fuel
half tank of oil

I took a short video of me starting it.
http://www.youtube.com/watch?feature=player_detailpage&v=Tu_WaBif2Ys

 

[Dr Honda]

You say... "Compression is good". But... what is it?


If it's dying while riding... that's not good. That's generally overheating. Or... in the case of an RFI engine... the injectors are going bad.


Have you tried to adjust the idle?

 

[sakosky1]

I bought it used from a boat dealer in Rochester, they said that they checked compression and it was very good. I want to say that he said it was holding 150psi each, but it was a few months ago so I might have that wrong. I haven't made any adjustments yet. It was idling just fine when I first used it, do you think that that's something that could loosen itself? I'll check the idle screw just in case, but it wouldn't seem likely especially with it dying. And come to think of it, the Hi temp warning did come on for a few seconds the last time I took it out, but it went out quickly and didn't come back so I didn't think much of it.

 

[Dr Honda]

Well.... since it ran when you picked it up... but doesn't run now... then you can't say the compression is good.

So... before we can chase a problem... let's get some new compression numbers.

 

[sakosky1]

Tested the compression today, front: 138 rear: 140 (psi).
I noticed a decent amount of oil on the spark plugs.


I've been thinking about the gas. The troubleshooter in the manual says that stalling at idle can be a result of fouled fuel. The ski came with 2/3 tank of fuel. It ran fine on it. The problems didn't present themselves until after I refilled it (87/89 mix 1:1). Do you think it might be related, or just a coincidence?

 

[CReynoldsMIZ]

Those spark plugs are pretty filthy. Start there...

 

[sakosky1]

Changed the spark plugs, sounds a little stronger, but still won't idle

 

[nitr0genics]

What oil is in it do you know?

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[sakosky1]

I don't, I'm going to be using the seadoo synthetic, but still have a half tank of the oil that came with it.

 

[nitr0genics]

If its inferior oil it could be clogging the system up especially if it had xps in and the place where you bought it topped it up with generic 2s oil might be worth asking them because xps will only mix with other xps oil anything else turns to gunk usually

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[sakosky1]

They're closed for the day, ill call them tomorrow and ask.

 

[kicker]

I would go through the fuel system. You could have a weak fuel pump, plugged screens on/under the pump, or your injector could be plugged or just worn out. I just did my RFI, I didnt have a problem, but it is just like a carbed ski, you need to rebuild them once in a while especially when you dont know when it was serviced properly last.

You can do one item at a time to see if it fixes your problem, or just bite the bullet and get it all done so you know it is good.

1) change the 2 airtex screens on the fuel pump module, Advance auto parts has the exact replacements for these.

2) New fuel pump, can get that at Advance Auto as well it is a bosch pump.

3) pull the fuel rail and clean it

4) two new injectors, the cheapest place I could find was five o motor sports, the bosch part number is on the top, it is the same injector as a 5.0 mustang.

I think all the parts for the above was around $200. Let me know if you need the part numbers, i think I have the invoice somewhere.

I dont think this is part of your problem but for what it is worth, take the raves out and give them a cleaning, by the looks of those plugs I would guess the raves are dirty as well.

On another note rfi's have issues with rectifiers, they have different ones, problem is rfi will charge at 4-5 amps -- vs - like 2 amps on a carb ski, extra voltage needed for fuel injection system, a fully charged strong battery is key.

While you have the module out take out the fuel from the tank and clean the bottom of the tank with a clean rag.

 

[sakosky1]

I think I will drain all of the fuel and oil and clean the whole fuel system. Hopefully I don't need to replace the pump or injectors, but i'll definitely replace the filters. Supposed to get some beautiful weather this weekend, would be nice to have it in the water. I'm going to pick up some oil locally because ordering the XPS will take a week or more and I can pick it up next weekend in Connecticut. I've heard that Quicksilver full synthetic is decent, so as long as I don't have to clean it out before adding the xps. I was also thinking of using sta-bil ethanol treatment since there's not a single gas station around here that sells straight gasoline.

At this point, what's really left? It's got decent/good compression and new spark plugs, it will have a clean fuel oil system... I will test the fuel pump and clean the rave valves too. Anything else I should look at while I have it opened up?

 

[nitr0genics]

You will have to drain the entire oil system before adding xps it turns to gunk when mixed with any non xps oil and theres a reason bombadier developed the xps oil for their engines imo not worth risking using any other oil

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[DA080682]

You will have to drain the entire oil system before adding xps it turns to gunk when mixed with any non xps oil and theres a reason bombadier developed the xps oil for their engines imo not worth risking using any other oil

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I have mixed Amsoil Interceptor and XPS 2 with no problems at all in several of my skis.

 

[nitr0genics]

I have mixed Amsoil Interceptor and XPS 2 with no problems at all in several of my skis.

i guess there are a few that will mix n i suppose its all personal preference, but from what i understand the XPS oil was developed to withstand the higher temperatures the rotax engines run due to their design, surely theres a reason why XPS was developed other than to keep you using the extortionately highly priced OE oil?

 

[kicker]

Look at the screens when you get them out, chances are if they are gummed up real bad, your injectors and fuel rail will not be in the best of shape either.

Change the oil filter while you have the tank drained. You will have to bleed the lines at the pump to get the air out of them. It sounds like your anxious to get out on the water, but on the "to do" list you should change the 15 yr old 3/32 lines going form the pump to the injectors.

Good luck, hopefully it is just some plugged screens. Let us know how it goes.

 

[goatcheese]

Nice write ups kicker! Not much info on the rfi around. Fantastic fourm, one of the best I am a member of.

 

[sakosky1]

Thanks, I'll be getting into it tomorrow, hopefully I'll back on the water this weekend.

 

[sakosky1]

So i finally got around to the fuel system today. I only had enough time to take the fuel pump out. I replaced both of the flters on it and they were quite filthy (I will post some pictures tomorrow) at 130 hours I'm not surprised. But then I looked at the fuel... It is green... gasoline is usually a clear liquid with a golden green color, but this is opaque yellow-green.


(You can barely make out the specs of dirt on the bottom)

So I think that is the problem. I originally didnt think about it much, but since I bought the gsx, I've only refilled it once, and the problems didn't start until after the refill. Sufficient to say that I will never buy gasoline from that station again. If all goes well, I'll have that horrible excuse of fuel out of my doo tomorrow. Found a place nearby with straight 91 gas.

Hopefully the rail and injectors aren't too bad off, but I'm sure that fresh fuel, new filters, and a clean tank will make a big difference.

 

[sakosky1]

So i cleaned out the old fuel and refilled with 91 octane non-ethanol fuel. It seemed want to idle, it would hold 800-900 rpm for up to 30 seconds before quitting. Checked the fuel pressure to be 54 psi, not too bad. I figured that the injectors might be a little dirty, so I added some seafoam to it and decided to take it out and see if it would clean up. I took it out yesterday, and besides the idling problem it worked well for about an hour. It was responsive, powerful, and got up into the mid 50s easily. But after about an hour of riding, it died, lost power and stalled while going about 30mph. I tried to start it a handful of time, but it wouldn’t start, didn't sound like there was any combustion. Luckily my sister was on our 96 sp (that thing always works), I had a hose pincher with me and pinched off the cooling intake hose. We towed it at idle speed for about 20 minutes, but the sun was going down and we were still 6 or 7 miles from the boat launch. So I tried starting it again, the first couple of tries it sounded like it would start and die instantly (as if it only had a few drops of gas and ran out), I think the tachometer only showed it hitting ~500rpm. Then I tried starting it at the same time quickly fluttering the throttle 0-50%, it caught and ran rough for 5-10 seconds then was running like nothing happened. We jetted directly back to the launch. About 1/4 mile to the no-wake zone, it started bogging down, only holding ~4500 rpm, We got to the no-wake zone and I went down to ~20% throttle and it died. We were close enough to the launch that we towed it the rest of the way.

This morning I tried starting it, took several tries to get it to start (Had 3/4 tank of fuel, but while starting it sounded like it was out of gas). It started and still wouldn't hold an idle. Yesterday it would try to idle for a few seconds before stalling; today it was stalling right away. I was able to rev it to 7000 rpm, but didn't hold it there because it was out of the water.

So with clean fuel filters, decent fuel pressure, and new spark plugs, I'm worried that the problem is with the injectors or the engine management computer. Bummer as today was gorgeous.

In a further twist, I decided to start it again later today and it took several tries for the key to be recognized (double beep). Then when i pressed the start buttom the digital display went blank and nothing happened. I tried several times after that, most of the times I inserted the key, it wasn't recognized, once it started, and the other few times it would go blank. To me, this points to the computer... I really hope it isnt...

 

[- BiRkS_]

Well 54 psi is half of what it should be! it needs to be 107 psi. These skis run very high fuel pressure. So i would check your fuel pressure again, what it sounds like is the pump is starting to seize up. Runs great, then slowly seizing=drop in fuel pressure, then it locked up, cooled down, went to working again, then started to lock up again. I would start there for sure. Next thing to consider are the air injectors/system.

 

[sakosky1]

the shop manual says 56-60

I know the Direct Injection models use the high preasure, but don't the rfi models only need 56-60

 

[- BiRkS_]

maybe i'm thinking of the DI? Kicker seems to know these best. Either way, you are below. So you have a restriction somewhere, or your pump cannot maintain pressure when under load. You want to keep that gauge connected and ride it. When it acts up, watch the gauge. If it drops off, then you know for sure it is failing.

 

[kicker]

It is very possible that when you don't get the beeps when you insert the lanyard it could just be your buzzer, it is common that they don't work on that age of ski. I don't think it is your computer because typically they don't work intermittently, which from what you describe it seems to be doing, it is either fried or not. My best guess for that is your DESS post or key is faulty or dirty.

As far as how it runs, I am with Birks on that, be sure you are getting proper pressure while it is running, if that checks out then you have to go through your fuel rail and injectors. Without knowing that your injectors and fuel pump are working properly you could be chasing your tail all summer.

BTW, don't use Seafoam in a 2 stroke, you are compromising your lubrication system.