Vapor Lock again

[dalt1]

I have acquired a fuel pressure test gauge to use this weekend. I will hook it up to the Schraeder valve that is located on the port side front of engine on the fuel rail on the 06 VLX. Yes I finally found it. Hope to get a positive diagnosis this weekend.

[Boatman]

Thanks Pete I will do that, Also plan on putting on new distributor cap and rotor on since it has over 700 hrs on it. Wondering if maybe heat is affecting it? Any one have a part # for them?

For what it's worth, I would only try one fix at a time. Otherwise you won't know which one was the fix (assuming success).

[Pistol Pete]

Dalt,

You're gonna need to know what the pressure should be.

I don't have the book with me but, I think it should be around 37 psi.

Here's where the schrader is on my 2000 Monsoon. Yours should be attached to the fuel lines or rail somewhere similar. The valve just looks like a tire stem.

Edited June 3, 2011 by Pistol Pete

[shawndoggy]

Dalt,

You're gonna need to know what the pressure should be.

I don't have the book with me but, I think it should be around 37 psi.

I'm pretty sure it's closer to 60 on the 06+ boats.

[Pistol Pete]

Oh yeah,

They went to high pressure at some point.

Good call, Shawn.

[Lzy0k0]

Dalt1 my boat was much older but same symptoms I was going to install something similar to this set-up on my boat, but then I sold it. I installed a fuel gage on my fuel rail and mine was losing fuel pressure. Once the boat sat after a run.

http://www.skidim.com/prodinfo.asp?number=49-5137

[dalt1]

Dalt,

You're gonna need to know what the pressure should be.

I don't have the book with me but, I think it should be around 37 psi.

Here's where the schrader is on my 2000 Monsoon. Yours should be attached to the fuel lines or rail somewhere similar. The valve just looks like a tire stem.

The book calls for min 60psi. My valve is on the port side front of engine. I finally located it. I also pulled the cap and rotor today and it was corroded bad. Cleaned it all up and reassemble it. Will see what happens tomorrow.

Thanks for all the suggestions. I am determined to figure this out.

[Pistol Pete]

Wow,

That's funny that vapor lock is such a prevalent problem that SkiDim sells a "vapor lock pump kit"

I'm gonna have to kiss the gas station fuel pump next time I gas up.

[Pistol Pete]

The book calls for min 60psi. My valve is on the port side front of engine. I finally located it. I also pulled the cap and rotor today and it was corroded bad. Cleaned it all up and reassemble it. Will see what happens tomorrow.

Thanks for all the suggestions. I am determined to figure this out.

Good luck.

[Pistol Pete]

BTW,

Corroded cap and rotor would give you different problems, FWIW

[shawndoggy]

Wow,

That's funny that vapor lock is such a prevalent problem that SkiDim sells a "vapor lock pump kit"

I'm gonna have to kiss the gas station fuel pump next time I gas up.

it's an indmar part/kit (which is really a low pressure carter fuel pump and a harness that tee's in with the factory high pressure fuel pump). From what I remember in trying to get to the bottom of my issue last year, they came out with this kit because the first year that they put the cat motors in supras they all had chronic vapor lock problems.

Edited June 4, 2011 by shawndoggy

[Pistol Pete]

they put the cat motors in supras they all had chronic vapor lock problems.

** light bulb goes on in Pistol Pete's small brain **

Ah Ha,

I bet peeps who have cats have more vapor lock problems then us guys w/o. That would be the number one source for higher than usual engine bay temps. Now, I gotta kiss my 2000 Monsoon too!

[dalt1]

Today's saga. Hooked up fuel pressure gauge and keyed pump without turning over engine. Fired 65 PSI and settled at 50 ish. held pressure and slowly leaked down to about 40 in 30 mins. Got to lake and fired rigt up but see pressures as low as 30 to 40 psi in first 30 mins. Boat ran fine. Finally showed values of 60 to 70 PSi and made 3 foilin runs. All good. Stop to tie up with friends and while idling, pressures fall below 30 PSI and boat dies. (now engine compartment is hot) Sets for over 1.5 or 2 hours and cools. Relieved fuel rail through pressure gauge relief valve, still won't run. Pulled fuel line loose at top of pump, starts but coughs and spits. Got it out of cove by feathering throttle then pressure finally fired up to 70 psi. ran back to dock about 20 minutes away and no problems. I jumped off boat to get trailer and while idling Dies again. Pressure @ 10 PSI.

??? Will the fuel rail show pressure at the test gauge if it is vapor locked?

After relieving pressure at schraeder valve, wouldn't that eliminate vapor lock?

I am leaning toward bad pump after heating up?

[woody]

** light bulb goes on in Pistol Pete's small brain **

Ah Ha,

I bet peeps who have cats have more vapor lock problems then us guys w/o. That would be the number one source for higher than usual engine bay temps. Now, I gotta kiss my 2000 Monsoon too!

Didn't Malibu start putting cats on in '06? My '05 doesn't have cats and I have luckiely never had this issue. I don't buy corn gas either.

[Bawshogg]

Sounds like a possible retriction on the inlet side, or a bad pump to me. 07 was the first year for the ETX cat motors. Monsoon got it first I think.

Edited June 5, 2011 by Bawshogg

[dalt1]

Didn't Malibu start putting cats on in '06? My '05 doesn't have cats and I have luckiely never had this issue. I don't buy corn gas either.

07 got cats and pumps went inside the fuel tank.

[Pistol Pete]

Will the fuel rail show pressure at the test gauge if it is vapor locked?

That's good question. I was wondering that myself. I don't know what a fuel pressure guage would read if the fuel is boiling and there is vapor in there. I guess what I'd do next is put an ammeter in-line with the fuel pump. This will tell you if the pump is drawing constant amperage or not.

[Baddog]

I put a towel on top of the fuel pump and the lines immediately running out of the pump. Then I pour a cold bottle of water on the towel, usually going again in about 10-15 minutes, 45 minutes is way too long!!

Sooo, Ndawg, your idea sounds like you are into water boarding your poor innocent boat.

[Baddog]

I feel your pain dude. Same issue with my 05 Monsoon. Fix for me is I turn on the blower if I plan to sit still for more than about 15 minutes to keep cool air running through the engine box. Also, a cold damp towel wrapped around the fuel pump always works. Not sure I'd recommend dumping cold water on the pump though.

Do you always fuel up at the same gas station?

Have you guys thought about insulating the fuel lines and the pump? I bought some cheap pipe insulation at Lowes and it I haven't had any more vapor lock issues. The lines are easy, the pump is a bit harder to insulate.

[Baddog]

Would a leaking injector cause the drop in fuel pressure and make it seem like vapor lock but not be?

[Pistol Pete]

Would a leaking injector cause the drop in fuel pressure and make it seem like vapor lock but not be?

A leaking injector (or, a couple) would give a scenario after warm start where the engine would be flooded. It would give some of the same conditions but, would not explain the super low fuel pressure when the engine was running or, barely running.

[shawndoggy]

Dalt1 what's the latest?

[dalt1]

Dalt1 what's the latest?

:rockon: :clap: :partytime: Got out Saturday. Started and ran perfect all day 95 degrees and hot out. Did not open hatches or leave the blower running to try to help cool it down after stopping. Can you tell I am HAPPY!

To recap, I put in a new fuel pump, new fuel regulator, new fuel lines from tank to pump, new spark plugs and wires, full tank of non ethanol 93 octane fuel.

I don't know which of these elements fixed the problem but it is gone after 2 years of fighting it. I will have to go back to ethanol laced fuel as that is all I can get in some areas. If the problem returns, I will then add the second low pressure fuel pump in line before the regular pump. Hope not to have to do that.

Thanks for all the replies and suggestions.

[Lzy0k0]

That's awesome dalt. I am glad to hear that fixed the problem. Hopefully it won't come back ever!!!. It was good talking to you again. Next time I'm in TN I will give you a shout.

[dalt1]

Update after 2 tanks of fuel. Had to go back to 10% ethanol fuel. Still running Premium 93 Octane. So far not one problem. So nice to not have to open hatches and leave blowers running to try to cool engine compartment. I still don't know if it was the fuel pump, regulator, debris in the screens or combination. So what I suspected as vapor lock for 2 years may have in fact been something else.

One other thing I noticed during the repairs was that the fuel hose that comes directly off the tank then goes to the filter was not real tight at the tank fitting. I now have that one double clamped as I wonder if it didn't let air get sucked into the fuel system after things got heated up?