VP D4-300 boost problem

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GrahamHR

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2009 D4-300, EVC-C.

We used the boat yesterday, last used some 2 weeks previously. On trying to accelerate, the supercharger was cutting in and out and the boat would not go above 16- 17 or so MPH, Engine reaching 2200 or so RPM, disengaging, dropping to 1800 rpm or so, engaging, reaching 2200 rpm, disengaging again etc. Eventually it seemed to clear itself allowing the same top end speed as 2 weeks ago ( 35mph, down on the 35 knots from early season but there's a lot of growth on the drive/ props)., only to reappear later., A turbo boost display showed up in the tacho, clearly indicating boost going up and down as the supercharger engaged/ disengaged.

Singe we've had the boat, as the engine revs rise and drop and the supercharger engages disengages, it's always been very noisy (my daughter asked if we had a whale in the engine compartment !). Is that noise normal ? ( I had V8 petrols before, so this is all new to me ), That noise seems to have become diminished.

Any ideas where to start looking ? ( no error display in the EVC tacho)
 
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The boost shouldn't fall when the compressor cuts out it should continue to rise as the turbo should now be working, and they should overlap seamlessly. It sounds like one of two things, the turbo isn't working or more likely the boost sensor has failed, this usually fails by falsely thinking the air temp is up around 100C, this won't give a fault code but will cut the fuel delivery to protect the engine, less fuel burned less exhaust gas pressure which is what drives the turbo, so you end up with a non turbo charged engine just when you need it most, when the compressor cuts out, the engine revs fall due to the load and the compressor wakes up again as designed to, and you end up with the symptons you have. To be sure you need to connect a Vodia and read engine inlet air temp on the live data page
 
Thanks for the quick response. I'll get the local VP dealer to look at it as you suggest.

What do you think about the noise aspect ? Difficult question I now when you can't hear it! When accelerating it's always been noisy ( not at idle) , and again when the engine revs are dropping after the throttle is reduced. At higher and lower revs the noise is not there, so it must be supercharger related I suppose.
 
I carry a boost sensor as stock, it easier when you have a hunch it's the sensor as 9/10 it usually is because when it fails it doesn't bring up a fault code but as SM says it thinks it's too hot air inlet temp so it backs off the fuel giving the symptoms you have . They really should have fitted two sensors as per the KAD 44/300 73/74/75 engine, at least the boost temp sensor gives a fault code when it fails.
 
Sounds like boost sensor, boost pressure leak or a turbo problem. I've had many boost pressure sensor faults, a few boost pressure leaks and one turbo failure.
Check air inlet temp with Vodia first.
 
GrahamHR said:
Thanks for the quick response. I'll get the local VP dealer to look at it as you suggest.

What do you think about the noise aspect ? Difficult question I now when you can't hear it! When accelerating it's always been noisy ( not at idle) , and again when the engine revs are dropping after the throttle is reduced. At higher and lower revs the noise is not there, so it must be supercharger related I suppose.
Click to expand...

Yes the supercharger does make a distinct wailing sound and is normal, worry when you don't hear it!
 
volvopaul said:
I carry a boost sensor as stock, it easier when you have a hunch it's the sensor as 9/10 it usually is because when it fails it doesn't bring up a fault code but as SM says it thinks it's too hot air inlet temp so it backs off the fuel giving the symptoms you have . They really should have fitted two sensors as per the KAD 44/300 73/74/75 engine, at least the boost temp sensor gives a fault code when it fails.
Click to expand...

The engine only has about 30 hours on it, but is of course about 6-7 years old now . Due to the location, the labour charge for traveling to and from the boat is going to be quite high, even before any diagnostics. I'm tempted to buy one and see if it solves it ( even my wife agrees, unless they are £ many hundreds). Are the part numbers for the D4-300 versions all the same ? I used to do a lot of work on the V8 petrols myself, I've no idea yet where this boost sensor is !

...........and thanks to Spannerman for your comments about the noise. I knew Rootes superchargers used to wail like hell in the 1980s, I wasn't sure about more modern ones !
 
GrahamHR said:
The engine only has about 30 hours on it, but is of course about 6-7 years old now . Due to the location, the labour charge for traveling to and from the boat is going to be quite high, even before any diagnostics. I'm tempted to buy one and see if it solves it ( even my wife agrees, unless they are £ many hundreds). Are the part numbers for the D4-300 versions all the same ? I used to do a lot of work on the V8 petrols myself, I've no idea yet where this boost sensor is !

...........and thanks to Spannerman for your comments about the noise. I knew Rootes superchargers used to wail like hell in the 1980s, I wasn't sure about more modern ones !
Click to expand...

The IAT sensor is a really common component, same part number covers many VP engines. It is a really easy diy job to change over - will only take you 5 minutes, literally.

Item 4/5 in this diagram:

27960.jpg
 
Take off the black top cover held on with torx screws, then the sensor is on the top of the inlet manifold just inboard of the oil filters, held on with a 10mm head bolt.
 
volvopaul said:
I carry a boost sensor as stock, it easier when you have a hunch it's the sensor as 9/10 it usually is because when it fails it doesn't bring up a fault code but as SM says it thinks it's too hot air inlet temp so it backs off the fuel giving the symptoms you have . They really should have fitted two sensors as per the KAD 44/300 73/74/75 engine, at least the boost temp sensor gives a fault code when it fails.
Click to expand...

This was exactly the problem I had that Paul fixed many moons ago. Seem to remember it was the "best value" i.e. cheapest fix ever on the boat. Hope it's the same issue for you.
 
Thanks to everyone who has helped; it'll be a few weeks before I'm down at the boat again, I'll let you know how I get on. ( I always wanteed to take off that black cover to see what's underneath!)
 
GrahamHR said:
Thanks to everyone who has helped; it'll be a few weeks before I'm down at the boat again, I'll let you know how I get on. ( I always wanteed to take off that black cover to see what's underneath!)
Click to expand...

Well, I fitted a replacement VP MAP boost/ temperature sensor. and tested the boat. Problem solved. Thanks to everyone for their help. The VP sensor I bought has a Bosch part number on it, could be interesting to find if there's a £20 automotive equivalent to the £60 VP one !
 
Hello! I had the same problem with twin D4 260. After being back in the water after general maintenance, when i tried to accelarate the one engine couldn't go more than 2000 rpm and looking on EVC the turbo of one engine was rising normaly and the second was rising on 90-100 and then "0". So the boat wan unable to run normally. Do you believe that the boost/ temperature sensor failed? Or the turbo has a problem? No faults, no smoke.
Thanks.
 
jimmy_the_builder said:
The IAT sensor is a really common component, same part number covers many VP engines. It is a really easy diy job to change over - will only take you 5 minutes, literally.

Item 4/5 in this diagram:

27960.jpg
Click to expand...
Can you please send me the diagram showing the exact location of the boost sensor on the D4-300? I’ve a super tight space in the engine room and while I was able to remove the cover I’m having to use a telescoping mirror to see into the void behind the filters…very difficult.
 
Beasterdamas said:
Can you please send me the diagram showing the exact location of the boost sensor on the D4-300? I’ve a super tight space in the engine room and while I was able to remove the cover I’m having to use a telescoping mirror to see into the void behind the filters…very difficult.
Click to expand...
Under the black cover top of engine .
Remove cover , as you are looking from front of engine it’s on the right , has a single bolt to locate it , take off plug and prise the sensor equally up otherwise you may break it . Lube the o ring on the new sensor before fitting
 
Thanks - changed out the sensor but still have problems…port engine accelerated to 2500 rpm (noting about 5 psi on the turbo pressure gauge) and then it dropped off to where I could not get the engine to run above 1700rpm. Could it be the fuel filters? Bought the boat in April and put about 70 hrs on the engines since then…all filter were supposed to have been changed out.
 
olgaP said:
My turbo had a tiny trush (very difficult to see) and after cleaning it was fine!
Click to expand...
What is a “trust” and how do I find it. After one more sea trial - following replacement of all fuel filters and the boost pressure sensor I noted an oil drip line on the turbo-charger… . Also, while I can get 1700rpm on the engine its registering 0 turbo pressure. See pictures
 
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