99 Air Nauti Engine Problem?

[NautiBrophy]

Alright so ran my 99 air nautique this weekend and ran great for a while. Then went to puts around the lake and it died. Wouldn't start up for about 20-30 mins. Then ran fine again. Did it again. Then Saturday it was a little hotter outside and ran fine. It sat for a while. Ran it hard and it died at high RPM's. Sat for 20-30 mins and started up again. Did this again also. Engine is the PCM GT-40 351 EFI 5.8 L.

Ran a computer scan on it first time it said 22 122 22 and that was after pulling a bunch of wires (Pulled the connection to the MAP sensor and trying to start it). Cleared the codes. Ran it until it died and ran the code scanner again and came back w/ nothing.

I've read on a forum about bad MAP sensor issues. So I picked one up and I picked up a fuel pressure tester.

Checked the fuel pressure right away. Turned the key on the on position (not starting). No fuel pressure. Again... nothing. Started it up and it jumped up to about 32. Shut it down and turned the key to the on position (not starting) and fuel pressure rose to about 39. Ran it until it died and then checked the fuel pressure. No fuel pressure. Waited about 20-30 minutes and then fuel pressure came back started up and ran.

Unplugged the connection to the low pressure fuel pump and it started. Unplugged the connection to the high pressure fuel pump and it didn't start.

I didn't change out the MAP sensor because I figured it wasn't the problem but I may be wrong.

My question is could the MAP sensor be tripping this? Or would it be some fuel pump relay? Or the high pressure fuel pump? Low pressure fuel pump causing issues for the high? Or???? Anyone else have to deal w/ this? Any feedback is appreciated. I'm worried that this could be a re-occuring problem if I don't fix it correctly the first time. Thank you for your time.

[NautiBrophy]

Also anyone in the Milwaukee / Grafton WI area know of any decent mechanics?

[AB]

I have a 99SN GT40. Pretty much doing the same thing. I replaced the killswitch and low pressure fuel pump last year and ran great the rest of the year.
This year I was checking gauges with a short high speed run, the engine just shut down like someone turned the key off. Another forum recommended replacing the fuel anti syphon valve, which I did. Ran fine the next time out. Tonight, it stopped running while pulling me but didn't shut off, just went to idle and then ran great for 2 other skiers.
I shut it off and wouldn't fire up. Just caught a little and died. Pulled up on trailer and now wondering what te heck?

What are you finding out?

[DanielC]

This is how to check the fuel pressure on a GT-40
http://planetnautique.com/vb3/showth...=Fuel+Pressure

Note the jumper wire into the test port. This commands the computer to turn the fuel pumps on. by testing this way, you check the entire electrical to the fuel pumps, the relays, and the operation of the fuel pumps.
The low pressure pump should put out about 5 to 6 PSI, and have good flow
The high pressure pump should be 39 PSI, plus or minus 3 psi.

This post gives some general information about the relay connections.
http://planetnautique.com/vb3/showth...=Fuel+Pressure

For testing purposes only, either relay can be replaced with an automotive relay that has the same pin connection locations. You can also just jump pin 30 to pin 87, and not need the relay.

[NautiBrophy]

hey

I am just looking into what different forums are saying so far. Everything points to the low pressure fuel pump but the thing that doesn't point to that is it acts up in the heat. Which could be electrical that is shutting down the fuel pumpes. AB I'm almost tempted to just replace everything from the relays to the low and high fuel pump. I'm not happy to hear you are having the same problem and this is my first boat that I bought that's having this problem. Should have gone w/ Malibu : X

AB have you taken it to a mechanic or dealership? Does your boat start up after 20-30 minutes of sitting like nothing happened? Do you see it act up more when it's hotter outside?

Daniel thanks for the info I replied to your relay post. I've read "That being said, the ECM does not store engine fault codes for anything other than the secondary ignition stuff, which basically means the sensors like knock, MAP, temp etc. These all give feedback to the engine that the computer uses to create the ideal fuel/air mix. The primary stuff like fuel pressure and ignition timing and components is not captured". Is that true? If my relay is faulty the computer won't pick up on it? I ran the scanner and nothing came up after I cleared the codes and tested it when it failed again.

Like I said I'm worried this is electrical and it's sending a signal to the fuel pumps to shut down for whatever reason which could be very hard to find the issue and be very costly. Thanks for your replies and hope to keep this discussion going.

[xlair]

sent you a PM

[AB]

I talked with SkiDim and the guy on the phone seemed very knowledgeable. He said that there are 2 relays in the rear of the engine labeled Hella that cause a lot of problems. One controls the fuel pump and one the computer, so you can't pull one to plug in to the other. They are $12 so I have one coming. With shippig and ASWA discount it is less than $20, so worth a shot.

He also said there can be a red wire coming off the positive cable on the battery that has a 50 Amp fuse in it. This has caused a lot of problems, and at some point, not used by PCM. I am going to check this when I get home tonight. If you have one, you can check it for a blown fuse or corroded terminals. He said you can cut the wire and stuff it back into the 60 Amp breaker (red button) on the back of the motor. Just put a fastener on it to match and plug it into the "protected" side of the breaker. This is the opposite terminal from the one that goes to the starter relay.

He also said he has seen loose wires on the back of the igntion switches cause problems, so I am going to check those tonight as well.

Stay tuned!

Please post any other ideas or findings - I need to get my boat back to being reliable again!!


Thanks

[NautiBrophy]

AB

AB

I am very intrigued to hear how this helps you. If you could take pictures of what you did I would greatly appreciate that as well. There are so many relays and wires I don't know if I would be able to pick them out. Thank you for the information and calling SkiDim. Fingers crossed this will help you.

[AB]

Nauti,

My boat has run like a champ until problem last year, which seems like I didn't fix. Only change oil and change plugs every other season (probably didn't need to).

What is bizarre is that it runs great then just craps out and won't start. When it is running, the wakes are awesome and the motor runs real strong. No Malibu for me!

A fuel issue would probably cause rough idle and performance, unless it is no fuel at all due to some electrical problem. It would be great if I lived on the lake and could try something and take it out, but I don't and have to wait for all this junky weather to pass as well.

[AB]

I don't have the extra red wire on the positive terminal.
All wires on the back of ignition are tight.
Turning on ignition I don't hear the fuel pump priming.
I do hear a click from the relay area on the back of the engine. They are both supposed to click.
No one was around to work ignition and for me to feel the relays to see if they both are clicking.

[eseybold]

its the relays

........I had same problem this year - chased my tail and spent a lot of money changing fuel pumps and all the sensors and chasing fuel lines etc etc ...............then I spent 20 bucks and changed the 2 relays in the back - fixed the problem immediately

[NautiBrophy]

Thanks

And you haven't had a problem since?

[eseybold]

no problems since

runs like a champ and starts like a champ - we use it everyday at our ski club.

[AB]

The relay came in from Skidim. I must say that this company continues to deliver outstanding support and service.

As the boat sits in the garage with engine box up, when I turn the ignition on, I did not hear the fuel pump priming (only the Perfect Pass system). I replaced the fuel pump relay and tried ignition again. Viola! The pump turned on. I fired it up and turned it off.

The part is Item # R130011 Fuel Relay 12V 4RD. Cost $12.72 before AWSA 10% discount. Maybe there is a Planet
Natutique discount?

There are 2 relays, the other one controls the ECA, which could cause other problems.

The way to tell which is which, is by looking at the wires going into the relay (which is the half that is bolted to the bracket that holds them). Both relays have several wires going into them, but the fuel pump relay has a green/yellow wire and blue/orange wire. My fuel relay was the relay farthest away from the motor, as they are side by side, and looks like unless there is a technical spec to mount one in a specific location, they could be mounted in either location.

If weather cooperates, I plan to run it this weekend.

I also did some testing on my kill switch. When I pull this, not even the Perfect Pass system loads up, so it is not a kill switch problem.

I believe this relay was starting to go bad last year, and I probably didn't need a fuel pump, kill switch, and an anti-siphon valve. I now have a low pressure pump and anti syphon valve for spares. I pitched the kill switch.

Good luck!

[NautiBrophy]

My brother and dad did some diagnostics looking at the relays and unplugging them. Undoing the fuel lines to the low and high fuel pump and I guess they came to the conclusion that it's the low pressure fuel pump.

What they did was before it failed they unplugged the line from the low to the high and key on engine off and got about 1/4 cup of gas into the container they had for it. Then ran it until it failed and did the same thing and no gas would come from the low pressure fuel pump to the high.

I don't understand why this would only happen when the fuel pump is hot but hopefully it fixes it.