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Portland68 · 11-17-2021, 05:28 PM

The factory tach I installed in my 72 K1500 seems to be working great up to 2000 RPMs and after that it isn't responsive - wondering if it is a bad unit?

Yes I am running HEI but it is reading idle correctly as well as light throttle, but it pegs out right around 2k whether I am going 70 on the freeway or trying to go 0-30 in a hurry.

I dug up an old thread about running a dedicated ground wire to the stud on the back but though this was a special case because it is sort of working. Thoughts?

11-17-2021, 05:28 PM	#1
Portland68 Registered User Join Date: Apr 2017 Location: Portland, Oregon Posts: 184	What is wrong with my tach? The factory tach I installed in my 72 K1500 seems to be working great up to 2000 RPMs and after that it isn't responsive - wondering if it is a bad unit? Yes I am running HEI but it is reading idle correctly as well as light throttle, but it pegs out right around 2k whether I am going 70 on the freeway or trying to go 0-30 in a hurry. I dug up an old thread about running a dedicated ground wire to the stud on the back but though this was a special case because it is sort of working. Thoughts?