OK, first let me apologize if this has been covered. I have searched and searched and keep finding things for the 90-92, but I have an 87 firebird. Anyway..... My 87 firebird originally came with a 2.8 v-6, now it has a 350. The factory tach does work, just reads higher than it should, which I assume is because of the extra 2 cyl. Now I am sure this can be corrected with the right amount of resistors, and I do have the tach apart right now. I just don't know which resistor you need to change and by how much. Thanks for any advice!!!!

 

Oddly enough I just covered this : https://www.thirdgen.org/forums/elec...-89-tachs.html

The first one was a V6 tach that I converted over for a V8, but the second repair method in post #17 of replacing the feedback resistor (using 192 kOhms instead of the 256 kOhms for the V6) will also work.

 

Hey thanks for the response demented. But I think the circuit board in my 87 firebird's tach is a little different. yours looks like it is about the sise of the tack face. Mine is just a little guy about 2 1/2 inches long by about 1 inch wide with 3 metal tabs with screw holes to help hold it to the instrument cluster.

 

Anyone???

 

Theyre all the same circuit, but with different PCBs. If you post a pic, I can point out what needs to change.