I will not keep you in suspense, it was fuel pressure.
Early in this saga, I did check fuel pressure and injector leak down. Everything looked fine (55psi and no measurable leak down).
I am either senile, stupid or this somehow snuck by me.
Being a rather recent widower, I would rather be out on the water than working on the boat now. I took an old friend down just to enjoy a cruise. We stopped for lunch, and upon restarting the boat, starboard (high fuel consumption engine) would not start. It sputtered to life, then quit. We returned to the marina on the port engine, pondering the issue the multi hour trip back.
Back at the marina discovered the fuel rail would only rise to about 10psi, so pretty much knew the low pressure pump was alive and high pressure pump was not running.
Connector on high pressure pump was overheated and deformed. Repaired well enough to get electrical connection and fired engine up. Fuel pressure climbed to over 120PSI. Gauge was pinned. (So - this forced the ECM to open the IAC to sustain idle, dropping engine vacuum causing an increase in injector pulse width due to simple use of vacuum/pulse width look up table - which is my best guess).
Replaced regulator, and fuel pressure is correct now. Engine fuel consumption is correct. Vacuum is correct (15" idle, >18" 1000 Rpm and up). Injector pulse width is correct.
Screen on old regulator is not clogged - so probably just an internal failure???
I am left with a slight miss, and engine does not want to climb out to max RPM.
I am hoping my plugs are fouled from overly rich operation. Next step is to change out plugs - first had to source a very thin walled 5/8" spark plug socket. Last time I changed plugs i had the manifolds off so did not encounter the clearance issue. My current manifolds are GLM, so that might be part of the clearance issue..........
Early in this saga, I did check fuel pressure and injector leak down. Everything looked fine (55psi and no measurable leak down).
I am either senile, stupid or this somehow snuck by me.
Being a rather recent widower, I would rather be out on the water than working on the boat now. I took an old friend down just to enjoy a cruise. We stopped for lunch, and upon restarting the boat, starboard (high fuel consumption engine) would not start. It sputtered to life, then quit. We returned to the marina on the port engine, pondering the issue the multi hour trip back.
Back at the marina discovered the fuel rail would only rise to about 10psi, so pretty much knew the low pressure pump was alive and high pressure pump was not running.
Connector on high pressure pump was overheated and deformed. Repaired well enough to get electrical connection and fired engine up. Fuel pressure climbed to over 120PSI. Gauge was pinned. (So - this forced the ECM to open the IAC to sustain idle, dropping engine vacuum causing an increase in injector pulse width due to simple use of vacuum/pulse width look up table - which is my best guess).
Replaced regulator, and fuel pressure is correct now. Engine fuel consumption is correct. Vacuum is correct (15" idle, >18" 1000 Rpm and up). Injector pulse width is correct.
Screen on old regulator is not clogged - so probably just an internal failure???
I am left with a slight miss, and engine does not want to climb out to max RPM.
I am hoping my plugs are fouled from overly rich operation. Next step is to change out plugs - first had to source a very thin walled 5/8" spark plug socket. Last time I changed plugs i had the manifolds off so did not encounter the clearance issue. My current manifolds are GLM, so that might be part of the clearance issue..........