10k ohm resistor mod for 79-83 tachometers

[swilson]

In my research I found a lot of posts for people with 79-83 trucks asking for this info, but never found the info.

I solved it tonight. Though I haven't verified the reading against the ECM, the gauge was showing 1100 RPM idle after a cold start.  Seems about right to me.

You'll want to solder the 10k ohm resistor in parallel with the one I circled in the 2nd photo.  It's easiest to install it on the back side since there's more room to work.

I can also confirm the 10k mod works with the 2TR-FE [emoji106]

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[sirdeuce]

Since you had the thing out, you shoud've replace the electrolytic caps, if any, as well. Might consider replacing diodes too.

[swilson]

I couldn't get good access to the circuit board. Wasn't sure how to disassemble it and definitely didn't want to break it!

Anyone know how to get the needle off without causing damage?

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[sirdeuce]

Anyone know how to get the needle off without causing damage?

Hammer!

Actually, skould be able to pull it off with your fingers. If it takes more effort than that, a couple of screwdrivers to pry it off, like removing a pulley. To protect the tach face? A couple layers of paper towels between the driver tips and the face of the tach.

[bpwilliams]

I am VERY happy to report this worked in my 1982 Toyota Pickup with a 1996 Toyota Tacoma 3RZ engine. I also verified it against my OBD II reader and it appears to be spot on up to 3000 rpm anyway.  I just placed the 10k resistor as @swilson indicated and connected the ECU tach wire to the gauge cluster tach wire. I removed the whole cluster from the dash to get at the circuit board. Once out, you just remove some screws in the back and the tach with circuit board drops out.

Thanks, bro!

[Ku_Guy]

Hey guys my tach board is different! No resistor matching yours... do you have any insight?