2000 GT40PB cuts off after 3 seconds?

[2000AN]

I have had 3 nautiques now I have a 2000 Air Nautique 351, w/gt 40 Pro Boss engine, fuel injected. It will start and run for about 3 seconds but then cuts off like someone pulled the kill switch. It will run fine on ether. I have changed the fuel filter, both relays, distributer cap and roter, low pressure fuel pump and jumped the kill switch. Still does the same thing. Replaced the high pressure fuel pump last year. Fuel filter has 40 psi. Seems like it is the computer. Is there a way to test the computer? Does anyone have any other ideas? Wish I had a Holley. Thanks for any help or ideas. Paul

[AB]

The anti syphon valve on top of the gas tank can cause a fuel supply problem.
There is a check ball in it that can get gummed up and will only trickle fuel into the FCC.
You can take it off and spray brake cleaner or electrical parts cleaner in it to clean. Mine was the one with red tape on it. There are two, I was told the red tape indicates main feed

Is your gas good, i.e. Water I. It?

[2000AN]

Thanks. Yes, gas is good. It actually ran fine at the house last weekend with 1 month old gas and then I put 15 gal. of new gas in it and then it kept cutting off at the dock. I also keep the green stabil in it. I tried to run the boat with the gas cap off in case there was a vapor lock and it did did the same thing. Paul

[DanielC]

Does the engine maintain fuel pressure when it is dieing?
Not after it has died, or before. While it is dieing.

[2000AN]

My pressure gauge goes up to 40psi when the motor starts to run and stays there even after the moter cuts off.

[DanielC]

If the motor is maintaining good fuel pressure, and still dieing, I would start to suspect the ignition system. A quick and dirty way is to smell the exhaust. If there is a strong oder of gas, that kind of points to the ignition system. No smell of gas, put a finger a fuel injector, and see if you can feel a vibration caused by the injector opening and closing.

Just like a engine with a carburettor, and points, compression, ignition, and fuel, and the engine will run. Millions of engines prove that every day. Find what your engine is missing, that it needs to run.

[whataboat]

Does it have the seperate fuse for the ECM ?

[DanielC]

I forgot to add you can download the GT-40 service manual from this site, in the down loads section.

[2000AN]

Problem Fixed. Thanks!

Problem Fixed. Took the boat to Miami Nautiques, unbelieveably great guys, worked on it right on the spot. Went through everything again with their mecnahic and found two issues. My brand new fuel filter had swolen due to the alcohol in the fuel and was too tight in the canister to draw adaquite fuel into the high pressure pump and the low pressure pump was only working intermitently probably due to being overworked trying to push fuel. If you have this problem get the smaller PCM filter. The mechanic said this was a big problem with all types of boats. Thanks, Paul