11-07-2017 08:04 AM
As both Engines are exhibiting the same issue then this should discount any component failures as such.
As there is no exhaust smoke it sounds like the engines are getting stuck where FRC (Fuel Ratio Control) Limit due to available boost pressure is not allowing the engines to recieve additional fuel required to accelerate any higher. Assuming the engines used to achieve full rpm (2300 rpm) and propellor and hull demands have not changed then this is most likely issue
provided your fuel density is good and both engines have good fuel pressure. There is an FRC Offset selectable parameter in the engines ECM that provides 3 different settings which is used to trim or strike a balance between exhaust smoke and acceleration. Could this parameter have been changed? There has also been several software updates eg boost sensor calibration changed from manual to automatic calibration etc. Try latest software. Take boat for a run with ET (service tool) and monitor fuel positions if Actual fuel = FRC Limit under problem condition then this confirms the problem. You could place a small resistor in the boost sensor signal wire which will then give a boost sensor reading higher than actual boost and it turn give the engines more fuel under acceleration.
05-21-2017 04:45 AM
I've just joined the forum in the hope of receiving some comments and suggestions about an intermittent issue I am experiencing on my boat.
The vessel seems to get stuck / wont accelerate past 1500 rpm, it feels like the turbo's just arent kicking in and then the engines are limited to this speed.
Boat is a 2000 48 Riviera fitted with twin 3196 660hp Caterpillars, engine have had scheduled services their entire life and most recently less than 20 hrs ago, clean hull, 1/4 tank in fuel and otherwise all is normal load.
Top speed previously was 28 knots at around 2,200 rpm, now cant do more than 1500rpm and just 14 knots.
There is no smoke,
Air cleaners have been replaced
Fuel filters replaced
Port engine Turbo has been removed cleaned and rebuilt,
Port engine aftercooler was removed and cleaned.
The issue was originally identified by the Cat technician as being the Sensors for the Turbo Part #169-3725 which they replaced with new model part #218-3840.
After replacing the sensors the vessel pushed past 1500rpm and reached max 2100rpm without issue, upon our next cruise though the issue returned.
Removing, cleaning and or changing sensors seems have a result and the boat performs well however the issue is intermittant and then returns. We've tried swapping sensors from other boats and also from the Fuel system Part #161-9930 however the problem is still not 100% resolved.
Please any idea, suggestions very much welcomed.