highflight2k2
Contributing Member
"This is a problem I've ha
"This is a problem I've had since I bought the boat. Some of you may remember my problem. It's with my starboard engine. I'll try to summarize.
I've been using ScannerPro to monitor engines. I know they will never be exactly the same, but I've seen notable differences between port and starboard. I've attach two side by side comparisons. The first is WOT where the starboard engine didn't spool up. The second, it did. Notice the GPH differences. Also, why is the IAC so different?
Symptoms:
- Engine, at times, won't go above ~3300 RPMs
- When RPMs do come up to normal speed, they may stay for duration of trip or may not...it's not consistent. When RPMs do come up, it still requires more throttle to sync RPMs and shows 5 or 6 GPH more than port engine.
- When the problem occurs, if I back the throttle back to where it naturally runs at ~3200 RPMs and match RPM with port engine, starboard engine requires more throttle and shows higher GPH on computer.
- Oil pressure gauge seems to have a "tick" but pressure is fine. Pressure doesn't fluxuate...its more like when you tap a gauge and the needle shakes. But it is constant.
- Engine runs fine (but still requires more throttle than port) at all RPMs below the ~3300 RPMs
- Engine RPMs were not right at delivery but was assumed to be related to steaming (which they fixed so they bailed on me with poorly running engine).
History:
- Dealer: Exhaust manifolds replaced to fix coolant leak into exhaust
- Dealer: Heads re-manufactured
- Dealer: Fuel pressure regulator changed
- Dealer: 3 injectors replaced (damaged during head work)
- Dealer: Cap, rotor, wires, and plugs replaced (and gapped)
- Dealer: Computer swapped with port engine with no change to either engine
- Dealer: TPS swapped with port engine with no change to either engine
- Dealer: MAP replaced
- Me: Fuel pressure on rail is fine (equal to port engine) at all RPMs
- Me: Timing verified in base timing mode to be 8 degrees BTDC
- Me: Throttle position verified by side by side comparison with port engine
- Me: Swapped oil pressure sensor
- Me: Not a fuel quality problem verified by running off of a portable tank with fresh fuel
- Me: Coil swapped with port engine with initially RPMs coming up but problem returned later
- Me: Flame arrestors cleaned
- Me: Transmission fluid verified. No audible difference. No vibrations.
- Me: Voltage seems ok. The meter shoots up when RPMs come up.
- Me: Oil changed and checked. No foaming or discoloration.
- My Marina: Props computer calibrated and reconditioned
Thoughts and Questions:
- The only thing at this point that I take note of is the variability of the problem and the oil pressure gauge having a "tick".
- The variability doesn't seem to have any relationship to anything like temperature or humidity.
- Can fuel injectors be ruled out since it does at times spool up (even though when it does spool up, GPH is notably different)
- Does this scream electrical? If so, how do you track it down? What electrical problem would account for the variability and the GPH difference when it does spool up? When it does spool up, RPMs are smooth.
- The engine does spool up at times so does that rule out mechanical?
- Every sensor has been either replaced or swapped
- I know the IAC shouldn't have anything to do with it...but why in my attached examples were they different?
I very much appreciate you taking the time to read all this and sharing your thoughts.
Take care.
Jon
"
"This is a problem I've had since I bought the boat. Some of you may remember my problem. It's with my starboard engine. I'll try to summarize.
I've been using ScannerPro to monitor engines. I know they will never be exactly the same, but I've seen notable differences between port and starboard. I've attach two side by side comparisons. The first is WOT where the starboard engine didn't spool up. The second, it did. Notice the GPH differences. Also, why is the IAC so different?
Symptoms:
- Engine, at times, won't go above ~3300 RPMs
- When RPMs do come up to normal speed, they may stay for duration of trip or may not...it's not consistent. When RPMs do come up, it still requires more throttle to sync RPMs and shows 5 or 6 GPH more than port engine.
- When the problem occurs, if I back the throttle back to where it naturally runs at ~3200 RPMs and match RPM with port engine, starboard engine requires more throttle and shows higher GPH on computer.
- Oil pressure gauge seems to have a "tick" but pressure is fine. Pressure doesn't fluxuate...its more like when you tap a gauge and the needle shakes. But it is constant.
- Engine runs fine (but still requires more throttle than port) at all RPMs below the ~3300 RPMs
- Engine RPMs were not right at delivery but was assumed to be related to steaming (which they fixed so they bailed on me with poorly running engine).
History:
- Dealer: Exhaust manifolds replaced to fix coolant leak into exhaust
- Dealer: Heads re-manufactured
- Dealer: Fuel pressure regulator changed
- Dealer: 3 injectors replaced (damaged during head work)
- Dealer: Cap, rotor, wires, and plugs replaced (and gapped)
- Dealer: Computer swapped with port engine with no change to either engine
- Dealer: TPS swapped with port engine with no change to either engine
- Dealer: MAP replaced
- Me: Fuel pressure on rail is fine (equal to port engine) at all RPMs
- Me: Timing verified in base timing mode to be 8 degrees BTDC
- Me: Throttle position verified by side by side comparison with port engine
- Me: Swapped oil pressure sensor
- Me: Not a fuel quality problem verified by running off of a portable tank with fresh fuel
- Me: Coil swapped with port engine with initially RPMs coming up but problem returned later
- Me: Flame arrestors cleaned
- Me: Transmission fluid verified. No audible difference. No vibrations.
- Me: Voltage seems ok. The meter shoots up when RPMs come up.
- Me: Oil changed and checked. No foaming or discoloration.
- My Marina: Props computer calibrated and reconditioned
Thoughts and Questions:
- The only thing at this point that I take note of is the variability of the problem and the oil pressure gauge having a "tick".
- The variability doesn't seem to have any relationship to anything like temperature or humidity.
- Can fuel injectors be ruled out since it does at times spool up (even though when it does spool up, GPH is notably different)
- Does this scream electrical? If so, how do you track it down? What electrical problem would account for the variability and the GPH difference when it does spool up? When it does spool up, RPMs are smooth.
- The engine does spool up at times so does that rule out mechanical?
- Every sensor has been either replaced or swapped
- I know the IAC shouldn't have anything to do with it...but why in my attached examples were they different?
I very much appreciate you taking the time to read all this and sharing your thoughts.
Take care.
Jon