Volvo Penta D4 Fault

[GTR]

Hi All, I am new to this forum. I have a pair of VP D4s (500hrs) on my Sealine F37 from 2007. The starboard engine works fine, but the port engine sounds an alarm at over 2,200 RPM and goes into limp mode. By this I mean that on WOT it wanders between 2,000 and 2,500 RPM and holds the starboard engine to a max of 3,000RPM.
I have had two VP engineers who say the fault is the MPROP.
So the MPROP was replaced. No benefit. Then a new fuel pump (with MPROP), new water separator and prime pump, pressure limiting valve and pressure sensor (either end of the common rail), another MPROP. Leak off test normal. Run on alternative fuel supply from Jerry can, swapped ACU with other engine. No change to problem. Racor prefilters clean.
The VP chap has been in touch with Volvo who have not come up with any ideas. They do not know what to do now.
I should be very grateful if anyone has some advice. Thanks.

 

[julians]

If its sounding and alarm and going into limp mode, there must also be an error code with it. What's the error code?

 

[volvopaul]

Hi All, I am new to this forum. I have a pair of VP D4s (500hrs) on my Sealine F37 from 2007. The starboard engine works fine, but the port engine sounds an alarm at over 2,200 RPM and goes into limp mode. By this I mean that on WOT it wanders between 2,000 and 2,500 RPM and holds the starboard engine to a max of 3,000RPM.
I have had two VP engineers who say the fault is the MPROP.
So the MPROP was replaced. No benefit. Then a new fuel pump (with MPROP), new water separator and prime pump, pressure limiting valve and pressure sensor (either end of the common rail), another MPROP. Leak off test normal. Run on alternative fuel supply from Jerry can, swapped ACU with other engine. No change to problem. Racor prefilters clean.
The VP chap has been in touch with Volvo who have not come up with any ideas. They do not know what to do now.
I should be very grateful if anyone has some advice. Thanks.

Sounds like they didn't know what they were doing from the start .
That's the trouble when engineers go throwing parts at engines because that's what the fault code says and I'm betting it was an M Prop fault which 99.9% of the time it's a fuel supply problem whereby air enters and not fuel or simply lack of fuel then the pump tries to reach rail pressure but it can't because you cannot compress air but not a liquid . In turn the m prop valve is bouncing off its seat because it cannot maintain a steady pressure.
Now as you also have a Sealine did they or have you ever run this engine off the other tank ? Try that you might find the fault goes in which case it's a blockage in the stack pipe in the tank , in my years I've unblocked stack pipes of debris especially on Sealines than any other boat . This is through careless build when they drilled the tanks or put too much sealant on to fittings and inspection hatches .
Over the years Volvo always told us it's more likely it's a boat builders issue than an engine issue , of which they were right .
Sounds like you have been a victim of the fit new parts brigade because the engineers have little experience other than listening to a lap top . Most of the time a modern diesel engine needs fuel , air and a stable battery voltage to run correctly and that's it .
I'd be looking at the fuel supply for sure , is your boat on my patch ? Central south coast .

 

[volvopaul]

Edit , I see you have run it off a can but did you use a new piece of hose from the racor to the tank ? I've seen silkaflex inside a racor housing before blocking the inlet port , also run the engine and check if the primer bulb is being sucked down , if it does it's definitely a supply issue .

 

[GTR]

Thanks for your quick replies. It gives the same fault both when I run off the (other) starboard fuel supply, and when we ran it off a jerry can we used new fuel pipe and 'clean' diesel straight to the water separator, not through the prefilter. Same result. Primer bulb does not get sucked in. I can't give the fault code as my VP dials just say 'Caution, see user manual'. The Vodia chap says its MPROP issue.
I'm at Craobh Haven, West Coast Scotland.
Sucking air seems a likely cause. As the fault occurred with the jerry can of diesel direct to water separator, I'm assuming the fault is downstream from there. Its a new priming bulb/water separator so I thought next thing might be to replace the fuel line (Part no 3582998), from the water separator to the fuel pump. I guess after the fuel pump and through the fuel cooler is at high pressure so no risk of air entry. Does that make sense?
I did clean all the fuel line and blew them through with air. I could not remove the stack pipe but blew it through with air.
Thanks again for all your advice.

 

[volvopaul]

The fuel cooler is low pressure it's on the return to tank from bleed off rail .
It could be the crimp fitting from the engine filter to the common rail pump still sucking air , swap the lines from the other engine .
Have you changed the rail sensor pressure switch ?
If it's not sucking the primer bulb it's got fuel to it but the suction is made from the CP pump , you say it's a new one ?

 

[GTR]

Ah, did not realise cooler was on the return side, thanks.
Good plan, I can swap the line from the other engine.
The rail sensor and pressure limiting valve (one at each end of the rail) are both new. The fuel pump is new too.

 

[GTR]

Update..... On the thought that air is being drawn in to the fuel line somewhere I replaced the fuel hose between the water separator/primer pump with a new one and am still getting an alarm when I hit 2200RPM (entering limp mode).
Previously we had put a new fuel hose into a jerry can of clean fuel attached to the priming pump to see if my boat fuel lines were restricted or allowing air, but same alarm and restriction of RPM to 2,200.
Previously replaced Racor filter, water separator, priming pump and water sensor unit, fuel rail sensor, fuel rail pressure limiting valve, fuel pump and MRPROP. Swapping ECU with other engine did not have any effect.
I am again at a loss as to what to do now. Any further advice gratefully received. Thank you, Graham.

 

[Irish Rover]

As a tech numpty I wouldn't dare to offer an opinion but I'll relate my experience with a D4 from around 12 years ago. From recollection the symptoms were similar and the local mechanic was insistent it was a fuel problem. Nothing he did worked, and I eventually got an out of town Volvo guy to come. He diagnosed a faulty oil pressure sensor, replaced it, and that was the end of the problem.

 

[jrudge]

I am not sure how you can run off a Jerry can. The fuel flow will be vast as most is returned.

I only did it once on a Williams jet rib and it ran for about 30 seconds before all the fuel had gone. On a bigger engine you would not even get close to that time.

Replacing fuel hoses temporarily with clear pipes lets you see air. We did this once on a generator.

 

[Seastoke]

I hope u saved all the parts u replaced

 

[GTR]

Yes, we put the return back to the jerry can. Only used about 5 litres doing a quick out and back test.