4.3 MPI random wires

[nichollb]

I just found this little bundle of unused wires under the air filter on my 4.3L.

2 of the 3 are tagged one capped wire says Tach but is not plugged in to any thing and the other marked one is a 5 point that says depth finder it is capped. The third wire the one in my hand is unmarked I have no idea what this could be for.

The RPM gauge on my new to me boat is not accurate it won't go above 3000 and some times just sits at 1000. it however dose have a digital hr meter in the middle of it that works fine. How do I know if this random Tach wire should b plugged into something?

The boat was not installed with a factory depth finder I wired in an after market Faria that works great but I bet had I known that capped harness was back there I could have made the install a lot simpler.

Any one with knowledge of the 2004 - 2005 4.3 MPI wiring that could tell me what I have found?

 

[UncleWillie]

Re: 4.3 MPI random wires

The extra wires are usually for the MerCathode Option that you apparently do not have.

The "Tach" lead with the rubber plug in it is a diagnostic connector for troubleshooting purposes.
It will not be connected to anything except a diagnostic computer at the dealer.
It will measure ~6v DC with the engine running. 0 or 12v is a loss of tach signal.

The digital Hour meter is electrically separate from the tachometer.
Either meter is capable of acting up without affecting the other.