Volvo D6-330 won’t rev above 2500

mcanderson

mcanderson

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One of my engines won’t rev above 2500. The other is fine. I have recently disconnected the battery from the engine that won’t rev and have conducted the EVC throttle calibration in case that was the problem, but the issue remains.

I have also changed the primary and secondary fuel filters in case it was a fuel starvation issue.

Turbo boost is normal.

I have 2 hours left on the boat before flying back to the U.K. Any tips greatly accepted.
 
Any fault codes being flashed on the evc panel,or any warning lights on the dash cluster?

Any warning lights are hard to see in bright med sunshine...
 
Are you revving in neutral? You do know that the ecu limits the revs to something really low ( like 2500 rpm,but not sure of the exact number) if you attempt to rev in neutral?
 
mcanderson said:
No at sea. I am aware of the idle limit.
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Thats me mostly out of ideas then, the only other thing i can think of is a stuck turbo,i had a stuck turbo that resulted in the same symptoms as you,but on a d4. But you say that boost is normal so that rules that one out i think.
.
 
Was it ok yesterday? Need to rule out fouling even one cos it’s in a suny position compared to t,other .

Second same theme ( engine mechanical and electrical Ok ) have you eyeballed the props ?

We had same issues all of a sudden - turned out to be that black 2 cm wide builders band that straps bricks up wrapped up between both props in the crevice. Only could see it close up with a snorkel.
Took props off in the water and there was tons out of sight jamming the duo props almost s plastic welded round the two shafts - a b stard to remove btw .
Once removed back to 3000 + rpm - normal service resumes.
 
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When we went out yesterday we only went slowly. The drives have just been serviced (1 month ago) and the props are clean. I will pop my snorkel on and have a look.
 
The plot thickens. Coming back to port I recorded the turbo boost on both engines at the same rpm. The engine that will not go above 2500 has double the boost of the engine which functions perfectly. I haven’t tried high speed since the drives where services. During the service the seals between the shaft and the drive housing was replaced. Am I right I’m thinking that something hasn’t been done right during the drive service?
 
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What are the gaps like between the front and back props? Should be between 3 - 5mm. Could be the bush is spinning in one or both of the props on the side that is getting the revs and transferring all the load to the other engine which can’t achieve the revs.
 
mcanderson said:
One of my engines won’t rev above 2500. The other is fine. I have recently disconnected the battery from the engine that won’t rev and have conducted the EVC throttle calibration in case that was the problem, but the issue remains.

I have also changed the primary and secondary fuel filters in case it was a fuel starvation issue.

Turbo boost is normal.

I have 2 hours left on the boat before flying back to the U.K. Any tips greatly accepted.
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Exactly 2500rpm, or approx 2500rpm?
 
The gaps looked okay and I am now off the boat and waiting for my flight back to LGW. I will need to get a mechanic involved as next time we are on the boat it’s for a 2 week holiday and I don’t want to loose time with a poorly boat.
 
Poor performance with no fault codes & no other problems spotted (fouling etc.) is most likely to be the boost temperature sensor playing up. It gives the ECU a valid but inaccurate temperature figure so it doesn’t inject enough fuel & gives low power.

Easily checked with the Vodia tool by logging ‘inlet manifold temperature’ & comparing the value to the ambient air temp at the time-the Dealer won’t even need to get their tools out to check it!

It could also explain the boost reading being high as it is the same sensor which monitors that so could also be faulty, although I’ve not heard of that as a symptom alongside the temp. side of the sensor playing up before, and as others on here will confirm, it’s a pretty common issue on these engines.

Relatively inexpensive fix if it is this sensor, as it’s about £40-£50 & 1/2 hour labour to access and replace.

However...what does the other engine rev to whilst the other is struggling? You say it’s ok, but if it’s getting towards 3300-3500 then it could be having an easy life & the other engine is doing all the work. If it easily reaches 3300-3500 then I’d suggest slipping props on the ‘good’ engine
 
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The ‘good’ engine will rev to 3300, but with a fuel flow of 60l per hour so it is driving something. Any other tips on diagnosing slipping props?
 
aquatom said:
You know where we’re going with this one Jimmy?
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Well I was thinking about supercharger cut-out - but thinking about it, does the D6-330 even have a supercharger?

Bushed prop sounds favourite based on current info. Vodia tool is the way to go here - load factor will reveal all. Unfortunately for the OP if it is a bushed prop then a lift and new props (= c.£2k all in) is the only way to save his holidays. The fact that it only goes to exactly 2500rpm is strange though.

@mcanderson: when accelerating, do both engines accelerate at exactly the same rate to 2500rpm, or is one leading the other?
 
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