Volvo Penta 5.7 Fuel Starvation Under Load

[iboatsman]

Hello all. Can anyone share some thoughts please as yall have more experiance than I. I came across this and have a simular situation. Problem started with fuel starvation under load with my 5,7 volvo penta. Approched it by installing new fuel pump. Started ran on trailer great. 5 times at the ramp and she died under load. after two pumps I moved on to replacing cap rotor plugs and wires as it was due. Now it will not start at all. sputters after sitting and cold then will not start, fuel in the oil. Changed the oil. Man the guys at auto parts store got mad as hell when I pumped the gassy oil in ther tank! I didnt know better,,,, Where is the best way to depose of the gassy oil? Anyway.. Pressure at the rail is 55 and holds. (meaning no open injectors?) I changed the fuel regulator then changed it back to original after cleaning it. No differance. Any thought or suggestions? Thanks

 

[ESGWheel]

Please start at the beginning with a more compete story. Example: new to you boat? Year and serial no. of engine? Has it ever run properly? What maintenance has been done and did that precipitate the issue? Please be as informative as you can.

Fuel pressure holding is a good sign but the fuel in the oil is not. Need to contract your local hazardous waster company to determine how to dispose of fuel contaminated oil. Running under no load is not an indication all is good.

After you tell your story you will be asked to do things like compression tests and other troubleshooting techniques. So please highlight if you are comfortable with that and have the tools (sounds like you are given you have a fuel pressure gauge and have swapped out pumps). Knowing this helps me know how detailed I need to get in my responses. Thanks.

 

[Lou C]

Fuel in the oil from trying to start it suggests that the ignition system isn't firing. Have you checked for spark when cranking? I'd do that first.
Always rule out:
Mechanical problems--check for water in cylinders, crank engine with plugs out and ignition disabled (very important, don't want spark with fuel vapors coming out of spark plug holes), if so you need to go thru your exhaust system and if good, air pressure test the cooling system, maybe do a compression test as well....
Next,
Go over the whole ignition system make sure you have a good strong spark, get a commercially available spark tester
Then turn to the fuel system.
And there based on some experiences I have had, the first thing I'd do is run the boat on a remote tank, because then you know it's not the boat fuel system, which can cause trouble with fuel starvation (crud in the bottom of the tank, clogged pick up screen, seized anti siphon valve). Just had this on mine. Should have done this FIRST, before rebuilding the carb!

 

[Lou C]

Should have done this FIRST!

Before doing this!

 

[iboatsman]

Thanks so much for your support.
So the boat is a 2006 fourwinns vista 248. Engine was replaced and upgraded one year ago. It's under 50 hours. 5.7 vortec marine engine. Ran excellent. Not used much. I am mechanically inclined with tools.
I've preformed compression test. 120 to 150psi. Coil is firing good. New plugs wires and cap. Pressure on rail high pressure is 55 holding. 10 to 5 low pressure. I use an external fuel tank with primer bulb clear hose.
It previously started with no throttle advance great
Then it's started fine on trailer. Put it in at ramp and after driving it of trailer it wined like fuel starvation sputtering and died. Great another fuel pump. (Replaced more than a few over 8 years).
Carter new fuel assembly. Same thing.
Bought another.... worse....
Now it turns and fires sputtering a second and will not start with no signs of starting till a few days go by. Then the same fire sputtering then just turns will not start.
I've tried ether starting fluid. Nothing.
Engine turns great with no plugs.
Coil AND plugs are fireing.....
I haven't touched the distributor. I can't imagine the timing being off....
Fuel fire oxygen....
Anything have missed?

.

 

[iboatsman]

5.7 gxi fuel injected.

 

[iboatsman]

And I replaced the fuel regulator. Nothing. So I cleaned the old one and reinstalled it...
Thanks Sirs for the input.

 

[ESGWheel]

You are hitting on the major points. I use “compression, fuel, spark” vs. “fuel fire oxygen”. Reason is that compression is a major ingredient for a running engine and if you have compression, it generally means the basic mechanical of the engine is good. The fuel part implies the O2.

Something is clearly amiss and if you are squirting starting fluid down the throat and confident you do have spark, then I am going to connect the fuel in the oil dots with this dynamic and suggest it is being flooded. And flooded to the point of drowning out the spark.
My suggestions are:

• Pull the plugs and look for wetness. Post pics of them as well.
• Unplug the fuel assembly to preclude it from operating or pull fuse or relay.
• Let it ‘dry out’ for a day or so with plugs out, even crank it over a few times to help.
• Now reinstall dry, clean, good plugs and with fuel pump still disconnected try to start it with that squirt of starting fluid. Be cautious of the starting fluid as I am sure you know.
  • If does not fire off on the starter fluid then while you think you are getting spark, you are not.
  • If you get it to fire off, reconnect the fuel pump and see if does not fire off (do not use starting fluid) and if not pull plugs again and check for wetness.

Note: Fire off = it runs but stalls due to running out of starter fluid.

 

[Lou C]

Did you run it on the remote tank when you had problems or was that on the boat tank? If on the boat tank did you check the anti siphon valve and pick up tube, the valve can get stuck or fouled with crud from the bottom of the tank, and the pick up tube can have a screen that can be blocked by crud also. Gas tank vent is open?

 

[iboatsman]

Did you run it on the remote tank when you had problems or was that on the boat tank? If on the boat tank did you check the anti siphon valve and pick up tube, the valve can get stuck or fouled with crud from the bottom of the tank, and the pick up tube can have a screen that can be blocked by crud also. Gas tank vent is open?

Thanks. Yes remote tank was used.

 

[iboatsman]

You are hitting on the major points. I use “compression, fuel, spark” vs. “fuel fire oxygen”. Reason is that compression is a major ingredient for a running engine and if you have compression, it generally means the basic mechanical of the engine is good. The fuel part implies the O2.

Something is clearly amiss and if you are squirting starting fluid down the throat and confident you do have spark, then I am going to connect the fuel in the oil dots with this dynamic and suggest it is being flooded. And flooded to the point of drowning out the spark.
My suggestions are:

• Pull the plugs and look for wetness. Post pics of them as well.
• Unplug the fuel assembly to preclude it from operating or pull fuse or relay.
• Let it ‘dry out’ for a day or so with plugs out, even crank it over a few times to help.
• Now reinstall dry, clean, good plugs and with fuel pump still disconnected try to start it with that squirt of starting fluid. Be cautious of the starting fluid as I am sure you know.
  • If does not fire off on the starter fluid then while you think you are getting spark, you are not.
  • If you get it to fire off, reconnect the fuel pump and see if does not fire off (do not use starting fluid) and if not pull plugs again and check for wetness.

Note: Fire off = it runs but stalls due to running out of starter fluid.

That makes sense! Deduce the equation down to the essentials. Brilliant.
I'll update when done. Thanks!

 

[iboatsman]

It fired off! Connecting remote tank with fresh fuel...

 

[iboatsman]

Water attached. Started with remote fuel tank. Sputtering back firing. Removed remote fuel line AND disconnected power to pumps, started again Sputtering back firing. Removed plugs...
Attaching pics...
Back firing concerning.....

 

[iboatsman]

Changed oil. Brand new. Was at safe level... high now. Smells like fuel in oil...

 

[ESGWheel]

Was working late tonight so this is not a fully digested reply.

From you posts I understand it fired off on the starter fluid (with no fuel pump as per above) so hooked up pump and while it fired off a bit it sputters a lot, etc. and worse your oil level is overfull and smell like gas. Again.

Given this is a GXi and thus a MPI engine, something is amiss with the fuel delivery > its extremely excessive to give you that “overfill” of the oil. Other than thru the injectors and subsequently past the rings I cannot think of another way for this engine to get fuel in the crankcase.

Going to need some help from the community on this one.

@Lou C and @Scott Danforth any ideas? Thanks.

 

[Lou C]

Well this is a tough one but I think more investigation is needed. Everything points to the fuel mix being way too rich, between the fuel in the oil and dark center electrode insulators on the spark plugs. However, we don't know if the injectors are over-fueling due to wear, dirt or if the computer is commanding them to do so because of a fault like the cold start enrichment system staying engaged too long. Don't these port injection systems vary the time the injectors stay open based on engine running conditions? Via pulse width modulation? With a vehicle I think looking at fuel trims would be a clue where in this case the computer is adding fuel for some reason.
Now in the old days of carbs we'd be looking at how long the choke stays closed or if there are clogged air bleeds in the carb, or the throttle blades are too far open at idle speed and are bringing in the off idle fuel system too early. Now in the modern tech era we have to have scanners that give us the data, or else we are just guessing.
Can a scanner for these fuel systems read fuel trims? Then you'd know what the computer is doing, and then could figure out why and what's wrong and how to correct it....