Heat Soak problem

[Grant_West]

I have been having this problem for what sems like FOREVER. This is what happens.
While under Idle my boat (02 Air with PCM 351) dies. The dash temp gauge reads 140. It dies like some one hit the stop button. If you try to re-start it it will turn over and just die. The only thing that will make it re start if lifting the engine cover. Its like a breath of fresh air to the motor allow's it to start up. Dont know why but this works everytime

Some other things its doing. So after it dies and I lift the lid and it either cools down or gets fresh Air you can hear the fuel pump cycle. Only after you hear the fuel pump cycle with it re start. This usually take's between 5 and 30 seconds after you lift the engine cover. The fuel pump cycles and then it fires right up.

I have replaced the Relays at the back of the motor.
I have replaced the starter solonoid.
I have taken apart and cleaned out the Flame arrestor and the Idle circut sencer on the throttle body.
I have replace the Main computer on the back of the motor.
I tryed disconecting the neutral switch on the transmission.

I even installed some computer fans on the back of the Computer thinking that the computer was getting hot and causeing the boat to die. Im at a total loss. Any help would be great.

Thanks in advance I have been chasing this problem forever.

[Grant_West]

Also I forgot to say I replaced the Fuel pump also. Its about 2 years old.

[Laptom]

RE: Heat Soak problem

Is there nowhere a lose contact or a faulty wire? When you lift up the engine cover it will though the faulty/lose wire and get it going again? Probably not, otherwise you already found that one.

When the engine stops (immidiatly what I understood), does the high presure fuel pump still turns? I understood you're pretty handy, so this should be easy to check, and if the fuel pump gets its 12V at that moment?! Put a light or a multimeter on your dash and continue to check it until it fails. Otherwise hot wire the fuel pump (both) and see if the problem arises again, if not, trace back from here. Some wires, the fuelpump relais, relais connections and last part; the ECU...

Tom

[Grant_West]

I could try the light on the fuel pump to see whats going on. Also someone talked about a fuel pressure gauge mouted on top of the fuel filter.

Here is the orginal thread I started back in 05 looking 4 the problem
http://www.planetnautique.com/index....ht=motor+quits

[AuMDLST]

Is it possible to still have vapor lock with non carb motors?

[DanielC]

If you have seen any of my other posts about GT-40 problems, You will know what I am going to tell you next.
Download the GT-40 service manual from this site. It has a very good diagnostic section.
The manual is free, except for your time to download it. Parts are expensive, and you could spend lots of money and time buying a part, changing it, taking the boat out, making another guess, changing another part, ETC.
If you suspect a relay is bad, you can jump where terminal 30, and terminal 87 on the relay socket are. That will bybass the relay. do not run the baot like this. Your fuel pumps will be on all the time if you do, and will not shut off when you want them to. Jump for testing purposes only.

[DanielC]

The GT-40 engine with the FCC is very hard, if not impossible, to vapor lock. Fuel is constantly circulated through the FCC by the low pressure fuel pump, and the high pressure side will not allow a vapor to form.
Get a fuel pressure gauge, and check the fuel pressure. The computer has no feedback on the air to fuel ratio, and it just assumes the fuel pressure is correct.

[Grant_West]

Dan: If I was to get a fuel pressure gauge that would mount onto the shrader valve of the FCC it would show pressure when everything is working correctly and when the motor die's it would show no pressure?

The thing that makes me think its a electric problem is how sudden it stops and then starts. If you were to starve or shut of the fuel it would stumble before it started or stopped Correct????

This stop's like the key is being switched off

[DanielC]

There is a schrader valve on the right side bank, near the front of the engine, on my 1997 Ski, I do not have the schrader valve on the FCC.
If you have both, I would use the schrader valve closest to the fuel rail, or injectors.
There should be only liquid fuel in the fuel rail. There is no pressure tank, so if the high pressure fuel pump quits working, the fuel pressure will drop very quickly, and this sudden drop will mimic an ignition loss.
Of course you could have an ignition loss. too. That is why you have to know what the fuel pressure is when the driveability problems occur.

[Laketexoma]

I had a problem with the touch pad on my 00 SAN. Grant it sounds link like mine did. It would die and then when you pushed the start button it would crank but not start. After a few minutes it would start and run fine. Have you checked out the pad yet? Or have you check out the kill switch to make sure its not craping out on you. (just a thought)

later
Shawn

[DanielC]

Do this:
http://planetnautique.com/index.php?...;p=88224#88224
And this:
http://planetnautique.com/index.php?...;p=88222#88222
Let us know the results.

[Grant_West]

Dan: Where do you think I might be able to find a Fuel pressure gauge?
Ill get the Spark tester.

[DanielC]

Auto parts store. Tell them you are using it on a Ford fuel injection, so you get the right fittings.

[Grant_West]

Ok Ill get the stuff 2marrow: Thanks 4 your help so far.

[Grant_West]

I bought a Fuel pressure gauge from PeP Boy's I have a solid 35 to 40 Lbs of fuel pressure all the time My pressure is constant when the boat dies the pressure still stays up where its suposed to be. I pop the engine lid and went to the back and started moving wires around and I could make the fuel pump turn on and off by moving wires around I tryed to plug and un plug everything I could get my hands on but not one wire seems to do the trick. All the wires are tied together so pulling on one wire pulls other connections its very hard to trace down the source. Because the on and off problem on happess after the boat dies. Example if the boat is running fine you cant just turn it off and start moving things around and make the problem happen