Jimmy Buoy
Well-Known Member
- Dec 3, 2008
- 2,469
- Boat Info
- 2003 Cobalt 293
- Engines
- Twin Volvo-Penta 5.0 270hp & DuoProps
I've been living with this issue since owning the boat for the last year now and would like to nail down the cause. Starting the engines cold (not run for 24hrs or more), both have the same symptom. Turning the ignition key on, the system has one long beep while the fuel pump runs and pressurizes up the fuel rail then stops - NORMAL. Turning the key further engages the starter motor and the engine starts up like any normal engine and idles at about 700rpm but after 5 seconds or so begins to slow down and stall out at about 450rpm. Turning the key to engage the starter 5-10 seconds later and the engine once again starts normally but this time remains running without further issues. The weird thing is that BOTH engines do the same thing! Double start feature??
These engines are new long blocks with 70hrs on both and run well other than the cold start issue. Ignition Cap/Rotor have recently been replaced without any change. I've put a fuel pressure gauge on the Schrader valve and both engines have 44lbs of pressure while the pump cycles and once the pump stops sit at 38lbs. Once the engines are started pressure remains at 38lbs and can fluctuate between 36-39lbs with throttle input changes (nominal). Even with the cold engine stalling pressure at the Schrader valve held at 38lbs.
I do have a Rinda Code Reader and with the ignition on and engine off, the following info displays for the Stb Engine...
Coolant Temp 62F, Manifold Pres 14.2psi, Barometric Press 14.3psi, Manifold Air Temp 66F, TPS V#1 Volts 0.55 vdc, TPS#1 Position 0.1 %, Battery Volts 14.3 vdc, Sensor Power 5.03 vdc
After starting the Stb engine twice (as usual) the readings change as follows...
Engine Speed 725 rpm, Coolant temp 84F, Manifold Pres 7.0psi, Barometric Pres 14.9psi, Manifold Air Temp 66F, Throttle Pct 0.0%, Block Pressure 4.9psi, Battery Volts 14.4vdc
Did the same test with the Port Engine with similar results.
The Port Engine's IAC had been replaced during the summer (had a spare on board) resulting in no change with this strange cold start behaviour.
Any ideas or help would be appreciated. All comments are welcome even if you don't consider yourself an expert!
These engines are new long blocks with 70hrs on both and run well other than the cold start issue. Ignition Cap/Rotor have recently been replaced without any change. I've put a fuel pressure gauge on the Schrader valve and both engines have 44lbs of pressure while the pump cycles and once the pump stops sit at 38lbs. Once the engines are started pressure remains at 38lbs and can fluctuate between 36-39lbs with throttle input changes (nominal). Even with the cold engine stalling pressure at the Schrader valve held at 38lbs.
I do have a Rinda Code Reader and with the ignition on and engine off, the following info displays for the Stb Engine...
Coolant Temp 62F, Manifold Pres 14.2psi, Barometric Press 14.3psi, Manifold Air Temp 66F, TPS V#1 Volts 0.55 vdc, TPS#1 Position 0.1 %, Battery Volts 14.3 vdc, Sensor Power 5.03 vdc
After starting the Stb engine twice (as usual) the readings change as follows...
Engine Speed 725 rpm, Coolant temp 84F, Manifold Pres 7.0psi, Barometric Pres 14.9psi, Manifold Air Temp 66F, Throttle Pct 0.0%, Block Pressure 4.9psi, Battery Volts 14.4vdc
Did the same test with the Port Engine with similar results.
The Port Engine's IAC had been replaced during the summer (had a spare on board) resulting in no change with this strange cold start behaviour.
Any ideas or help would be appreciated. All comments are welcome even if you don't consider yourself an expert!