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Jimmypooh

Should Fuel Pressure hold after engine is off?

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Jimmypooh

When I read the fuel pressure, it read the normal 58-62 psi when key up and the entire throttle range.  I fixed a high pressure issue a few years back.  However, key off, the pressure drops to 0.  I thought it should hold (at least for a little while).  I'm wondering if I have a leaky injector or bad fuel pump.  I've also always had a funky exhaust smell that I don't smell on other Malibus with the same engine, and some times it takes a while for the engine to fire when cranking.  Thoughts?  Could the high fuel pressure from a few years ago damaged the injectors?  If I remember correctly it was making the gauge spike well over 100.

It's probably time for a cap and rotor replacement.  Any links to the cheapest version?

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REW

Not sure about the fuel pressure but that funky smell means something is not right with the mixture (mine stinks when I get vapor lock).  If you have a leaky injector it will cause the motor to run rich by not metering the fuel properly.  Check out the web site below and see if that my be a rout you want to take.  

 

https://www.rceng.com/Fuel-Injector-Cleaning-P43C0.aspx

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Jimmypooh

Thanks,

I might try cleaning them myself when I get some time,  I'm hoping that will fix my issue.

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23LSVOwner

The boat should hold fuel pressure for quite a while after it is keyed off.

Could be one or more leaky injectors of a fuel pressure regular issue.

If you had fuel pressure that high there is a possibility that it did damage one or more fuel injectors.

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Ndawg12

I've checked fuel pressure on both my boats and a buddies 05vlx.  Every time we shut the boat down the gauge went to zero within a few seconds.  I don't think you have an issue there.  What do your plugs look like?

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Kmfish87

Sounds like a fuel pressure regulator or check valve in the pump. Pressure should start dropping as soon as the pump turns off but it should not be hard/slow to start. As stated above check your plugs for wet or fouled plugs

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Ndawg12

Also mine cranks over a good 8-10 times before it starts on the first start of the day.

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oldjeep

It should hold pressure, sounds like either a leaky injector or bad check valve at the pump.

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Shastasurf

My 1996 efi systems holds pressure.  I've left gauge in for hours and its always pressurized when I remove it

Edited by Shastasurf

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Jimmypooh

Hmmm.... This is as clear as mud to me now.  So my guess is that the pressure should hold.  Is the one way valve built into the fuel pump or is this something that can be replaced outside of the pump itself?  I can't imagine testing the injectors is really that hard to do yourself.  I'll pull all of the plugs to check them, but I don't remember them being fouled the last time I looked at them.

Still, the smell has me a bit baffled.  It's not a raw gas smell, but is pretty strong when sitting on the platform about to jump in.  We make a habit of shutting the engine off if we're going to sit more than 20 seconds because you can start to smell it in the boat.

Does anyone know if the injectors in the monsoon engines are 12 volt?  I would assume so, but don't want to burn one out testing it on a battery.

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23LSVOwner
15 hours ago, Jimmypooh said:

Hmmm.... This is as clear as mud to me now.  So my guess is that the pressure should hold.  Is the one way valve built into the fuel pump or is this something that can be replaced outside of the pump itself?  I can't imagine testing the injectors is really that hard to do yourself.  I'll pull all of the plugs to check them, but I don't remember them being fouled the last time I looked at them.

Still, the smell has me a bit baffled.  It's not a raw gas smell, but is pretty strong when sitting on the platform about to jump in.  We make a habit of shutting the engine off if we're going to sit more than 20 seconds because you can start to smell it in the boat.

Does anyone know if the injectors in the monsoon engines are 12 volt?  I would assume so, but don't want to burn one out testing it on a battery.

The "valve" is a fuel pressure regulator and it is replaceable. I think the part number is 006073 for the newer pumps, not positive on yours. Might want to check with bakesmarine to see for sure.

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Sixball
17 hours ago, Jimmypooh said:

Hmmm.... This is as clear as mud to me now.  So my guess is that the pressure should hold.  Is the one way valve built into the fuel pump or is this something that can be replaced outside of the pump itself?  I can't imagine testing the injectors is really that hard to do yourself.  I'll pull all of the plugs to check them, but I don't remember them being fouled the last time I looked at them.

Still, the smell has me a bit baffled.  It's not a raw gas smell, but is pretty strong when sitting on the platform about to jump in.  We make a habit of shutting the engine off if we're going to sit more than 20 seconds because you can start to smell it in the boat.

Does anyone know if the injectors in the monsoon engines are 12 volt?  I would assume so, but don't want to burn one out testing it on a battery.

If you don't have fuel at pressure and able to alter injection rate I don't think you could do much. Injector test stands are quite involved.  Evin if you hear the injector sound like its working it may not be seating thus leaking. And if you are looking at performance all around you need to be able to look at atomizing.

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Kmfish87

https://www.fuelinjectorconnection.com/

Those guys quoted me $25/injector to test,  clean and rebuild with a 2 day turn around time. As soon as I get a chance to get mine pulled I'll be sending them in.

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Jimmypooh

This is my Fuel pressure regulator:

http://www.bakesonline.com/detail.aspx?ID=1650

I'm pretty sure this does not act as a one way valve for the fuel system.  It's essentially a pressure overflow valve that allows any extra pressure to flow back into the tank.  This is an offshoot of the circuit from the pump to the rail.  The fuel going to the rail does not go through this, only fuel not being used (extra pressure) goes through this.

Is it possible this is the part that is the one way valve that is supposed to keep the pressure in the system/rail?

http://www.bakesonline.com/detail.aspx?ID=2653

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23LSVOwner
29 minutes ago, Jimmypooh said:

This is my Fuel pressure regulator:

http://www.bakesonline.com/detail.aspx?ID=1650

I'm pretty sure this does not act as a one way valve for the fuel system.  It's essentially a pressure overflow valve that allows any extra pressure to flow back into the tank.  This is an offshoot of the circuit from the pump to the rail.  The fuel going to the rail does not go through this, only fuel not being used (extra pressure) goes through this.

Is it possible this is the part that is the one way valve that is supposed to keep the pressure in the system/rail?

http://www.bakesonline.com/detail.aspx?ID=2653

http://www.howstuffinmycarworks.com/Fuel_pressure_regulator.html

I've wrenched on them for years. It regulates the fuel pressure at a certain PSI and passes the excess back to the tank. It holds this pressure for a while after the engine is turned off.

The second link is an antisiphon valve. If the fuel line was to come loose while fuel is flowing it prevents it from siphoning out of the tank.

Edited by 23LSVOwner
additional info

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