Re: Volvo RPM issue
We dealt with a check engine error message last season that was related to the turbo boost pressure, so I did spend some time reading up on the function of the Variable Geometry turbo (VGT) that is installed on the D3-110IC.
The VGT basically adjusts the physical size of the inlet of the turbo based on the amount of exhaust pressure available to produce the maximum consistent boost, so that there is wider range of power available and to minimize the peaky boost that some turbos produce. If you do not get the proper boost pressure from the turbo, the engine will not reach maximum RPMs. Since the turbo was just rebuilt and assuming the work was done correctly, and the fact that you are not getting a check engine error, you should be seeing boost pressures that match the RPMS.
On ours the Boost VS RPM is as follows:
RPM Boost (kpa)
This is in gear and not at idle. How much boost pressure are you seeing at these RPMs?
Mohammad and Aty
AMEL 54 #099
From: main@AmelYachtOwners.groups.io <main@AmelYachtOwners.groups.io> On Behalf Of Doug Smith via groups.io
Sent: Friday, October 29, 2021 7:44 PM
Subject: [AmelYachtOwners] Volvo RPM issue
Question for the group.
I have seen many messages from a few of you with the Volvo D3-110, where you have worked on or around the turbo. I have read through most that I could find and spoken to a couple of you to try to figure out our issue.
I have a Volvo D3-110-I C, and it has around 2000 hours on it. I purchased it 24 months ago, and on survey it would run up to 3000 RPM’s. After running it on a longer passage, of 5 days, at 1500 RPM, I haven’t been able to get up to 3000 RPM’s again. When moving the throttle forward, the engine will climb to about 1500-1600 and slowly over the course of 2-3 seconds continue climbing up to 2070. No more. At the dock and in neutral, it will easily climb to 3000, without hesitancy and the engine is responsive to the throttle appropriately. I lubricated the external turbo actuator, but it didn’t change the hesitancy or the top RPM and it moves freely.
Next, I did the seasonal haulout, and the bottom was cleaned and the prop was shiny again. All blades of the autoprop were free to rotate.
The first day back in the water, I could get to 3000, and I figured my problem was solved. But literally the next week, I was unable to get back to 3000. Same exact sense at the throttle, and same top RPM of 2070.
So I had the turbo rebuilt. In speaking with Mark McGovern, he was confident that a good cleaning would likely be needed after the prolonged running at 1500. Rebuilding a turbo, seemed too precise a job, so I had it professionally done, and the guy who did it felt there was some carbon build up, and after replacing the internal bearings, assured me this one would run like new. After reinstalling it, no change. At all. 2070. Same hesitancy at the throttle.
So then I came across those threads speaking of the Turbo boost pressure sensor, Bosch 31355463. Certainly, that must be it. No change after installing it.
The engine starts easily, runs at a good temperature, and seems to perform well at the lower RPM’s. 1500 is the sweet spot. Runs fine up to 1800-1900. The transmission has a new filter and new fluid. The
C-drive Wear bushing, seals and fluid have all been recently changed. I double checked the tightness of the exhaust manifold, and the mixing elbow is clear.
Thank you for any of your thoughts on this.
S/V Aventura, Amel 54-113
White Point Marina, Kinsale VA USA