Hey folks,

I've got everything hooked up but cant seem to get a good tach signal. TPS is fine. Here is what I have done:

1. Located white wire at the PCM (pin 10), and crimped in with the white tach signal wire from my MSD window switch using a T-connector. I ran this up to near the battery (my Wideband commander and MSD switch are located on top of a batter cover).

2. tapped into the MSD tach signal wire with another connector, and used the orange wire on the WB commander, which should be the tach signal wire.

3. Started car, fired up the wideband software, and no RPM value.

4. I then cut the WB commander orange wire and tried tapping the 3 white wires under the passenger side of the dash - nothing.

5. I then put male/female disconnects onto the orange wire which I cut and then reconnected, and noticed an intermittent tach signal. I would ONLY get signal at the instant when I touch the connectors together, or when I pulled them apart. When fully connected, no signal.

6. I have tried changing the multiplier and the sensitivity in the software - no luck.


I havent tested the window switch yet, could this be interfering? Maybe this weak signal will prevent the MSD switch's operation too - or maybe it is the cause. I am getting the intermittent signal, so I am pretty sure I tapped the correct wire off the PCM - maybe the tap itself was bad? the tach in the car still works just fine so the wire didnt sever.

I don't think the ground is bad cuz the TPS value is read just fine.

My best guess at this time is the tap wire running down to the PCM is suffering interference since it is based on frequency and not voltage? It is running straight down to the PCM, next to the battery and near the positive battery terminal...

Thanks in advance for the help!