Was wondering how accurate the RPM data is coming from a TunerPro datalog? My tach is useless, it reads 3k at idle.

Reason I ask is I'm only registering a max of 5750 RPM before the trans shifts at WOT (Auto, in Drive). I'm running a MSD-6AL with a 6200 chip and according to Comp Cams, my combo should pull strong to 6k.

Last Dyno my rev limiter kicked in and killed the run at 5850, and now I'm only reaching 5750 as indicated in TunerPro.

Can I pull the resistor chip and have a friend watch the laptop RPM? I'd like to figure out if my combo is the limiting factor or a faulty MSD box/chip?

Any recommendations?

 

As long as the conversion equation is correct the ECM's RPM data is accurate.

I would do away with the MSD rev limiter and use the one in the ECM.

There is a sticky at the top of the Electronics board here on how to fix the tachometer.

RBob.

 

Got the instructions and resistors already to fix the tach, it's on the to-do list.

Didn't know there was a rev limiter in the ECM...are you saying to program it in to the .bin? Like dropping SA from the tables? Or is there a Table/field I've missed?

You also say to do away with the MSD Rev Limiter; by that, do you mean to just pull the 6200 RPM chip and run it with no chip installed? Wasn't sure if that was OK to do or not. THX!

 

These are from one of the $8D XDF files floating around:

Fuel Cut Off Engine Speed
Fuel Resume Engine Speed

Just be sure to set them high enough that they shouldn't be hit unless there is a loss of traction or drive-line breakage.

If pulling the chip out of the MSD box disables that rev-limiter, that is what I would do.

RBob.