Volvo D6-370 Not Getting Enough Boost Pressure

[Midnightsun]

Got an issue and it seems like Volvo diesel techs are impossible to find.

I think I self inflicted this however it may very well be something else going on. I explained my problem to a Volvo tech and he said my turbo is probably sooted up so just go out there and floor it for at least 10 minutes which I did and sadly it changed nothing. Apparently running low rpm for extended times on Volvo diesels, causes the turbo to get full of soot and the turbo does not spin freely.

Have not put her on step this year and went to do so last week. My Starboard engine is not producing the proper power as it will not go over 2550 rpm. The port engine manages just 3050. When full power is available from both, I can attain 3650 rpm on both easy. Since the weak engine is not helping the good engine I can see it is not coming up to rated RPM as it simply does not have the power to do so without help of the starboard engine.

Turbo when running WOT is giving me 200kpa on the port however only 110-120kpa on the starboard so definitely a turbo boost issue happening not allowing the engine to produce the rated power.

Both engines fire up instantaneously and purr like kittens and run great at hull speed. My Starboard engine has been giving off a little smell/smoke (black) since the beginning of last year+ so something is not perfect on that side and may have been a warning something needs attention.

Now I do know quite a bit when it comes to mechanics but diesels are like Chinese to me along with Turbos. One of my friends is a Diesel specialist and he is pointing me to a probable waste gate issue which could be stuck partially open not allowing enough exhaust pressure to spin up the Turbo to its rated rpm.

Anyone have any info or suggestions that could possibly help me out until I find a Volvo Diesel tech? I am leaving on vacation on the boat tomorrow so timing of this sucks then again I do like to travel hull speed any way so not the end of the world being our plans were to stay in about a 100km radius from home port.

[km1125]

Well, regarding the comment " Apparently running low rpm for extended times on Volvo diesels, causes the turbo to get full of soot...", that is common to EVERY turbocharged diesel out there, not unique to Volvo. Diesels ALWAYS like to run under a nice load, so you need to make that part of your repertoire to keep them healthy! You don't always have to do it, but work a little "up at speed" cruise into your routine. A friend of mine didn't like to cruise fast due to fuel costs (and his wife wasn't really comfortable going fast), but after they cruised around for a while at slow speed, he would put it up on plane for about 10 minutes heading back to the marina. That helped "blow things out" on a regular basis.

You friend could well be pointing you in the right direction with the wastegate issue. I'm not sure on that particular motor, but on others I'm familiar with you could manually operate the wastegate and compare both the engine wastegates to see if they operate smoothly and with the same degree of movement.

And the black smoke is a sign that the engine is being starved for AIR. That could be because the turbo isn't spinning up like it should, or there could be other things, like air filters. When was the last time you cleaned or replaced the air filters??

[Midnightsun]

Believe me I am anal on filters, all filters get changed every fall without exception. Air filters, oil filters, fuel filters, crankcase ventilation filters and if I missed one I surely changed it. Odd thing is I always put her up on plane occasionally however this year for some reason it had not happened yet and was rather surprised with the results, freaked me out actually as these engines are rock solid and always have performed flawlessly. I will triple check the filter/intake cavity for whatever but every time I change them they still look almost like new.

[bud37]

Does your friend think the waste gate can get itself back to normal operation range with some use or will it need a mechanical cleaning ?

Have a good trip.....

[Midnightsun]

bud37,

He has not seen it yet as he also is out floating on vacation. When I say he is a diesel specialist he specializes in Volkswagen, Audi and Porsche so there may be some nuances that set marine apart. Diagnosis was over the phone only. Will be leaving tomorrow morning and may have a marine diesel tech waiting for me in Clayton NY. Friday morning. Not that it needs to be fixed right now, just is nice to not have this in the back of my head if they can diagnose the problem.

[pepmyster]

Yup, I agree with the waste gates or the turbo not spinning freely. Black smoke, definitely starving for air. When I did a small stint at a truck center, (really didn't like that), every time we saw black, headed right to the air filter. Not saying it's that but a great place to start. We know how you take care of your machines, just go and double check all that you have done on the maintance side of things. Good luck!!!!

[Midnightsun]

FIXED!!!

Back a couple of weeks. My oil pressure sensor was reading a little low so I decided to swap out for a new one to see if it was the sensor. New one gave me a --- reading on my EVC so i figured I would put back the old one. Oddly enough it also gave me a --- reading. I cancelled the error that came up and just continued on as normal as i knew there was oil pressure. I did order another new sender and this morning at anchor decided to put that one in place. When ignition was turned on I now got 0 oil pressure so I knew the sensor was operational. We pulled anchor about an hour ago and sure enough oil pressure reading were coming up like they should. Decided to gun it to see if that changed anything, it sure did. Back to normal operation, time for a shot or 2 of Tequila.

Bottom line is the oil pressure sensor not reading caused some kind of reduced power output from the computer.

[bud37]

Good to see....I have always said when odd things happen, go back to the last thing you just did and recheck.

Odd in this case,.... if the engine was in a fail safe strategy with the low oil pressure readings and so it seems by the restricting of engine power you experienced.....you would think it would inform the operator as to the reason for restricting performance with an audible/visual alarm. In the case of zero pressure readings while engine on, I would think engine shut down may take place to limit damage.

In any case you had a longish run there and all ok now.

[Midnightsun]

Source of the post if the engine was in a fail safe strategy with the low oil pressure readings and so it seems by the restricting of engine power you experienced.....you would think it would inform the operator as to the reason for restricting performance with an audible/visual alarm.

This threw me off also. If there is zero pressure from a defective sensor you would think they would not allow the engine to run at all. Making 2/3 HP with reduced boost seems a little odd.

[bud37]

Source of the post Making 2/3 HP with reduced boost seems a little odd.

Actually that part makes sense based on your low oil pressure readings.....gone into a sort of limp mode. Maybe see if you can get Volvo to expand on their ECU parameters to see what drives engine safety and limp mode etc.

It may be possible it is programmed for a marine installation and there needs to be minimal power for safety.

Have a good holiday now>>>>>