3L mechanical pump and Tach. Error. (1 Viewer)

[Houser]

Last month I replaced the injection pump on my 2lte with 3L mechanical pump and also upgraded to 1kzt injectors. The engine now starts and runs better than ever. Drives very smooth and quiet and has lots more low end and mid range diesel like grunt.
So far the only down sides were an annoying check engine lite and the Tach. Was reading lower than normal rpms. About 800 low at 85kmh. I was able the fix the check engine lite by reinstalling some of the sensors from the old injection pump on the now unused wiring harness. I was also able
To correct the Tach. Error by replacing a correction resistor on the tachometer circuit board.

 

[Houser]

The resistor on the circuit board is labled RT. And is 35k ohms. I started off by soldering in an extra 4K resistor to see what effect it had. It increased the rpm reading by 100rpms @ 85kmh. I reeded 800 more rpms. So I did some math and decided the the target resistance should be around 67k.
I didn't want to keep taking the cluster apart to swap resistors so i replaced the existing resistors with a wire pigtail which allowed me to swap resistors on the wire rather than the circuit board.
Anyway, short story long, I cobbled together
Resistors till I found a combination that gave me 66.2k. Soldered them on the wire pigtail and now my Tach seem to be just about dead nut on.

 

[Houser]

This is the actual final conglomeration of resistors and how I covered them.