390Express
Regular Contributor
I know full-well that these sensors exist for a reason, and I know full-well that the OP sending unit is different than the OP switch...
That said, I'm trouble shooting an issue where the engine runs great up to 1900, revs past 1900 fine at idle (no pops backfires, etc.) but will not: 1) sustain an RPM above 1900 at idle (not 2000, not 2100, nothing, 1900 is the magic number, perfect to that point, **** after 1900), and 2) will not go above 1900 while under power.
I have a hard time believing that it's fuel system related, but acknowledge that it could be. I have changed all fuel filters and checked the anti siphon valve - all fine. The engine runs the exact same under a load (which requires more fuel) as it does at idle - perfect to 1900, falls on its face after 1900. Has good fuel pressure through 1900, which may indicate that it's not sensor related (if memory serves, the "safety" cuts power/pressure to the fuel pump), but the pressure is ultimately controlled by a mechanical/spring loaded diaphragm on the TBI.
To the best of my knowledge, there are only two safety switches on the boat - the knock sensor and OP switch. To rule those out, I would like to bypass each, temporarily, one at a time.
Does disconnecting the switch bypass the switch for each, or do they need to be grounded, or otherwise lied to?
That said, I'm trouble shooting an issue where the engine runs great up to 1900, revs past 1900 fine at idle (no pops backfires, etc.) but will not: 1) sustain an RPM above 1900 at idle (not 2000, not 2100, nothing, 1900 is the magic number, perfect to that point, **** after 1900), and 2) will not go above 1900 while under power.
I have a hard time believing that it's fuel system related, but acknowledge that it could be. I have changed all fuel filters and checked the anti siphon valve - all fine. The engine runs the exact same under a load (which requires more fuel) as it does at idle - perfect to 1900, falls on its face after 1900. Has good fuel pressure through 1900, which may indicate that it's not sensor related (if memory serves, the "safety" cuts power/pressure to the fuel pump), but the pressure is ultimately controlled by a mechanical/spring loaded diaphragm on the TBI.
To the best of my knowledge, there are only two safety switches on the boat - the knock sensor and OP switch. To rule those out, I would like to bypass each, temporarily, one at a time.
Does disconnecting the switch bypass the switch for each, or do they need to be grounded, or otherwise lied to?