Hi all,
Have year 2000 454 MPI 385hp horizon motors with MEFI-3 (s/n OL390900)
twin engine installation. Last two weeks have been losing the rest of my hair trying to weed out cause of an rpm reduction problem that doesnt set codes.
Have searched through your threads and see many others with same symptoms, most of whom find a solution in fuel, sensors, or discrete switches like the oil pressure switch. or a bad ECM.
Cut to the chase... Have done all those things followed procedure in the factory manual for no codes non -scan testing, and swapped most suspect sensor parts (MAP, ECT, IAT, TPS, OP switch) with new parts or trial parts of other motor. New cap, rotor, module, wires. new fuel filters, full fuel pressure 43 pounds constant, compression is even.
Someitmes the problem goes away tempoirarily with a cool down overnight. . and we think we solved it but it came back and seems permanent now.\But running it under load for a while it runs up ok then cuts down to 2500 max like half power.sound like RPM reduction mode, but the factory manual states that thi MEFI-3 does not have RPM reduction for this motor.
Have not yet done injectors, becasue they are inaccessible without a time consuming disassembly of the manifold.but since everything else seems to have been eliminated, we now suspect them or a short in the harness somewhere affected by temp. WHen the problem is there 4 cylinders go down.
Question is: if ONE injector is internally shorted out will it make THREE others go down?
Have year 2000 454 MPI 385hp horizon motors with MEFI-3 (s/n OL390900)
twin engine installation. Last two weeks have been losing the rest of my hair trying to weed out cause of an rpm reduction problem that doesnt set codes.
Have searched through your threads and see many others with same symptoms, most of whom find a solution in fuel, sensors, or discrete switches like the oil pressure switch. or a bad ECM.
Cut to the chase... Have done all those things followed procedure in the factory manual for no codes non -scan testing, and swapped most suspect sensor parts (MAP, ECT, IAT, TPS, OP switch) with new parts or trial parts of other motor. New cap, rotor, module, wires. new fuel filters, full fuel pressure 43 pounds constant, compression is even.
Someitmes the problem goes away tempoirarily with a cool down overnight. . and we think we solved it but it came back and seems permanent now.\But running it under load for a while it runs up ok then cuts down to 2500 max like half power.sound like RPM reduction mode, but the factory manual states that thi MEFI-3 does not have RPM reduction for this motor.
Have not yet done injectors, becasue they are inaccessible without a time consuming disassembly of the manifold.but since everything else seems to have been eliminated, we now suspect them or a short in the harness somewhere affected by temp. WHen the problem is there 4 cylinders go down.
Question is: if ONE injector is internally shorted out will it make THREE others go down?
..Ive been tinkering again to much..