Excessive fuel pressure revisited
in 912 / 914 Technical Questions
12 years ago
Hello all.
What would cause indicated fuel pressure to remain constantly at red line high after 450 hours steady at middle range ? The indication is correct, I have verified it with another gage, and there is other evidence that the engine is now running rich - exhaust soot deposits are blackening the belly of my ship and the exhaust outlet has a heavy buildup of newish black carbon on the inner walls. I verified that the fuel return is not blocked. The fuel pressure is highest at idle and drops one needle width at 5000 rpm. When the fuel pressure began to register high, fuel also began dripping from one of the carbs at engine shutdown with a heavy fuel smell in the cockpit during flight. The leaking carb and fuel smell stopped after replacing the float valve - the stronger spring inside probably shuts off the flow better. But the fuel pressure remains a concern and now the last possible component is the fuel pump which was replaced by the factory during a 500 hour check 45 hours ago. Anyone had a fuel pump go bad with high pressure? Any other ideas? Thanks, mike.
What would cause indicated fuel pressure to remain constantly at red line high after 450 hours steady at middle range ? The indication is correct, I have verified it with another gage, and there is other evidence that the engine is now running rich - exhaust soot deposits are blackening the belly of my ship and the exhaust outlet has a heavy buildup of newish black carbon on the inner walls. I verified that the fuel return is not blocked. The fuel pressure is highest at idle and drops one needle width at 5000 rpm. When the fuel pressure began to register high, fuel also began dripping from one of the carbs at engine shutdown with a heavy fuel smell in the cockpit during flight. The leaking carb and fuel smell stopped after replacing the float valve - the stronger spring inside probably shuts off the flow better. But the fuel pressure remains a concern and now the last possible component is the fuel pump which was replaced by the factory during a 500 hour check 45 hours ago. Anyone had a fuel pump go bad with high pressure? Any other ideas? Thanks, mike.
