e38 pcm and stock LT1 analog tach
03-25-2010, 11:04 PM
#4
LS1Tech Sponsor
E38 ECM and tachometer Some E38 software sets have the tachometer output wire enabled and others don't. It depends on the vehicle platform. The 2010 Camaro software doesn't but I think the Corvette software does.
If you are using a software set that doesn't have it enabled you just need to change the output type to enable the analog RPM output.
In HPTuners they call the variable "Tach output". Serial output disables the tachometer wire. In EFIlive it is called "Tachometer Type".
Keep in mind you also have to make sure you have a pull-up resistor in the system. I think some LT1 applications had a pull-up resistor in the dash and others didn't. Without a pull-up resistor you won't get an RPM signal that your dash car use.
We do this to put a shift light on the 2010 Camaro SS. With our RPM switch we could just connect to a coil wire but it is cleaner and possibly more reliable to connect to the tachometer output wire in the ECM and make that work like it should.
If you are using a software set that doesn't have it enabled you just need to change the output type to enable the analog RPM output.
In HPTuners they call the variable "Tach output". Serial output disables the tachometer wire. In EFIlive it is called "Tachometer Type".
Keep in mind you also have to make sure you have a pull-up resistor in the system. I think some LT1 applications had a pull-up resistor in the dash and others didn't. Without a pull-up resistor you won't get an RPM signal that your dash car use.
We do this to put a shift light on the 2010 Camaro SS. With our RPM switch we could just connect to a coil wire but it is cleaner and possibly more reliable to connect to the tachometer output wire in the ECM and make that work like it should.
