New Help with my 2003 GTX DI Wont start Cranks well??!

[aaronsanio]

Hey guys,

I just put in a rebuilt engine into my GTX DI, I have done this before with the same ski but looks like I might not have gotten all the parts this time. I am 95% sure all connections are correct. When first fired her up she ran fine for maybe 20-30minutes. Now it cranks, I checked the plugs there fine. Compression is good(well lets hope so it was just rebuilt by SBT). Fuel was just replaced with brand new fuel. Lubed up pistons. She will crank run for a second than die right away. I have the Code reader so I read all the codes. There were some saying unable to read MAS. Although when I do a realtime this with the sensor I can see it changing.... Think the pressure was at 14.8? All seems good to go. Must be a fuel or air issue.. Any ideas????

Thanks!

 

[ski-d00]

I've seen piston failure in 5 minutes on a new SBT DI motor so don't rule it out, check compression. what's your fuel pressure?

 

[Coastiejoe]

Compression test then fuel pump pressure test. 107 psi at idle.

 

[aaronsanio]

I cant do a pressure test as I do not have the equipment. What is the best action to do if not pressure test is available? I live on a island 4 hours from any city. I can order something in if I have to. Fuel rail has to be getting enough pressure as the air pressure piston was just rebuilt.... injectors maybe? Clean em?

 

[ski-d00]

If you're going to do any work on 2 strokes, you will need a compression tester. Even a cheap one is better than none. I put my thumb over the spark plug holes pressing hard and crank it so I've kind of developed a calibrated thumb but I've done that for 30 years. Some say not to do it because it can suck your thumb in but I've never had a problem.

I would check to make sure your air injectors and fuel injectors are working. Your code reader is CanDoo? Not sure if this will do this but I use BUDS which does. Dirty fuel injectors don't do what you're describing and are very reliable.

Did you add oil to the gas for extra lubrication for the rebuilt engine?

 

[Coastiejoe]

I cant do a pressure test as I do not have the equipment. What is the best action to do if not pressure test is available? I live on a island 4 hours from any city. I can order something in if I have to. Fuel rail has to be getting enough pressure as the air pressure piston was just rebuilt.... injectors maybe? Clean em?

You can rent for free a Compression Tester from any local auto parts store. Just because the air pump was rebuilt, it does not mean you are getting the correct fuel pump pressure as it is a combined effort. It takes BOTH the air and fuel pump to get to the correct pressure.

You can also get a fuel pump pressure tester from the local auto parts store.

I see you live on an island, but these two things are CRUCIAL. If you don't do these two tests, nothing else matters. You will be chasing ghosts. It will get to be a VERY expensive guessing game..

 

[aaronsanio]

Got it I will check the compression, I do have a tester. I am pretty sure I tested it not to long ago and it was good. I started to fix it last fall but stopped once winter hit and now working on it again. Ill let you guys know what comes up. There is a Napa down the street. Is this a universal pressure gauge?

Thanks!!

 

[ski-d00]

Did you add oil to the gas for extra lubrication for the rebuilt engine?

This could be your problem.

 

[aaronsanio]

200:1 Always have run this ski like that.

 

[ski-d00]

You should not add oil to the fuel tank of a DI motor. Even though 200 to 1 isn't very much, it can still clog the fuel injectors over time. Some people may disagree with me but I have seen clogged fuel injectors that have ruined a freshly rebuilt motor, although it was added at 32 to 1. Once the fuel injector becomes clogged, it leans out the motor and boom it goes. There is a reason why the DI motor gets such great fuel economy. It relies on the minimum amount of fuel atomized at high pressure. Starve it of either pressure or volume of fuel and bad things happen.

The compression tester gauge is universal. Not sure if NAPA loans tools out free like the discount parts places do. It will probably have a few different tips for different spark plug sizes but should include the size you need.

Also, what oil are you using?

 

[aaronsanio]

The Expensive BRP stuff. $50 a gallon. So I trust your opinion but I want to add something to the DI and oil mixture note. I have met guys that pull the Oil injection system right off these and run them 100:1 with many less issues. But they could have to spend $400 a year on new injectors im not sure...

Ill pull the injectors and run them in some carb cleaner.

Also I have the Compression tester, but I need to get the fuel pressure tester.

Cheers mate!

 

[ski-d00]

It's not even possible to run a DI without the oil injection system as it would fail right away. For a carb motor, this is no problem and all the racers do it because the fuel/oil mixture goes through the bottom of the motor first which lubricates and cools. With a DI, the only oil lubrication and cooling on the crank is from the oil injection(other than the air itself). When oil is added to the fuel on a DI, it is directly injected into the cylinders and burned right away with very little extra lubrication to the rings as most of the oil is just burned in the combustion and then it smokes more than it should.

Good to know you're using the proper BRP full synthetic oil.

There are some homemade methods to cleaning fuel injectors that do work that involves putting pulsing power to them, check youtube, but they need to have cleaner put through them while activated for proper cleaning. Sitting in cleaner won't do much.

 

[mikidymac]

Please keep in mind that most dealerships do not service the 2 stroke seadoo's any more. This forum is the best source of knowledge for the 2 stroke seadoo's there is these days. And we are telling you do not pre-mix a DI seadoo regardless of what you hear others doing. We are trying to help you and give your ski a long life.

 

[68ragtop]

The Expensive BRP stuff. $50 a gallon. So I trust your opinion but I want to add something to the DI and oil mixture note. I have met guys that pull the Oil injection system right off these and run them 100:1 with many less issues. But they could have to spend $400 a year on new injectors im not sure...

Ill pull the injectors and run them in some carb cleaner.

Also I have the Compression tester, but I need to get the fuel pressure tester.

Cheers mate!

Like Ski-d00 mentioned, oil in the gas on a DI will only burn up expensive oil & do nothing for lubrication.
The mixture is injected into the top of the combustion chamber & is burned up right away & out the exhaust.

The oil (as you might have noticed) is injected directly at the crankshaft rod bearings & works its way though everything from there. Short of adjusting your oil pump rich, or dumping some oil in the bottom of the case halves there is no way to add more oil. Switching to mix & eliminating the injection oil is a gauranteed death sentence to the DI engine.

 

[aaronsanio]

Ok update here guys,

140 PSI on both cylinders so compression is good!

Now today I pulled the injectors and than cleaned them put them back in and got it to idle.

At this time I assume the gas is bad. It had about 1-2 gallons that has been sitting in the tank for over a year. 2 weeks ago I topped up with premium gas.

Today I added Sea foam. Ran it for a while but would die every time I gave it gas...

Some points I could rev the engine and I held it at 5000rpm steady for 1 minute, sounded great just like a 2-stroke should. (This was not consistent, it was difficult for me to get it to a higher rpm, 90% of the time I touch the throttle it would die.

I think there might be a timing issue. This is new to me but I got the engine rebuilt at SBT but I guess the software you need to adjust the timing on it? Is there a way to do this without the TDC tool? Can you slowly change the setting and see if things improve. Currently its sitting at 3.5. This obviously is a big deal.

Let me know your thoughts!

Cheers!

 

[ski-d00]

It sounds like a fouled plug. Even new plugs can foul almost immediately. Put new plugs in and test, don't try to clean the ones in it as it won't fix it. You said it ran good for the first 20-30 minutes and nothing has changed, correct? Make sure to use NGK, not some aftermarket.

I doubt it's timing. Especially if it ran fine before and it idles fine now. Have you checked your air injectors? Your software should do that, BUDS does. Are sure fuel injectors are misting properly?

 

[aaronsanio]

Hey Ski-D00 I replaced the spark plugs, helped a lot. Revs up well now. While I was revving it up when I though everything was good it held at 5000rpm without my even holding the throttle! Pull the safety key and now when I go to put the key back on it burns up the 25 amp fuse! So more problems! Also the idle not smooth at all, well when it was running, now its not. Ill review the owners manual and go through the circuit and see what can be blowing it. I assume it has something todo with the relay that turns the computer on when the dess key puts in place.

Man I love this ski

Thanks for all your help guys!

 

[aaronsanio]

Fuse is the second to last one closest to the fuel tank, After reading the diagram looks like its the main fuse for injectors, ing coils, beeper, start solenoid

 

[aaronsanio]

Wait could be voltage regulator, ill test that, they go bad all the time as I know already! Might have an extra one hanging around!

 

[aaronsanio]

Ok guys I am fairly convinced the Diode in the MPEM is blown.... How can I test this forsure. The 25 amp battery fuse blows over and over again anytime I attach the lanyard on? Thanks for all your help. Third engine in the ski I guess I need a 3rd computer to go with it?

 

[tkarvelis]

Pull all the other fuses on the MPEM except for the one that blows. See if it still blows the 25A fuse. If it does, then the MPEM is bad, if not, find out which one or combination of fuses causes the 25A to blow. It could be a shorted regulator.