720 Tach off how do I recalibrate??

[85 720 king cab 4x2]

I just put in a tachometer stock. I don’t know I guess from an ST I got it off eBay. Anyhow, I have 85 720 2 Wheel Dr. deluxe. Someone said it was plug and play. I put a whole new instrument Harness in the other day I’ve been having a big-time problem with all kinds of electrical but anyhow someone said it would be plug and play and Shernoff it was plug and play works great when I  put it in. It works great but it’s off by 10 or 15 because the needle is All the way down by X 1000 doesn’t how can I zero it out how can I get it up to where it starts at  zero any help would be great I appreciate it. P.S. The speedometer is on the money.perfect right where it was before I started! Although I am very stoked, attack is working, but it’s just really off! Thanks for any help you can give me!

[datzenmike]

Off 10 or 15 what???

 

Is there a peg the needle rests against?Is it on the wrong side?

 

[85 720 king cab 4x2]

I am sorry the Needle is all the way down where the 1000 is off the aprox distance from 1-2 I’m the 1000 rpm’s 

[85 720 king cab 4x2]

If I knew how to print a picture I could show you the Neil would be more like at 7 o’clock even more towards the 6:00 mark if u know what I am saying?

[Crashtd420]

How are you verifying the inaccuracy?

Or this just a visual thing?

[datzenmike]

What does it read when idling? or does it read????

[85 720 king cab 4x2]

way below 1000 like I said it’s down by th very bottom @ a 7:00 when Idling moves up closer to you by two and then you know it should be about 3 1/2 the shift so like I said I’m stoked it’s working it’s just offIdling moves up closer to you by two and then you know it should be about 3 1/2 the shift so like I said I’m stoked it’s working it’s just off

[85 720 king cab 4x2]

Hey any kinda of help u can give me is well appreciateated. Sorry I haven’t been around to get back to the floor but I’ve been busy putting in finally play vintage Kenwood stereo KDC-Z919 & my Spectrum analyzer X-707 . Since I’ve put in the New Instrument harness I’ve been able to hook up the radio the correct way still trying to figure out the dimmer switch she doesn’t seem to be working with the dash lights right yet hopefully I can figure that out as well?? it’s been quite the electrical nightmare! But finally coming around I can still get my hand inside there I wonder if I could unplug the tack and then to plug it back in do you think maybe that would help I guess I couldn’t hurt to plant now I don’t wanna touch anything once I got it running I was so amazing to put plug and play I thought for sure I had to go find the resistor or something?…

[85 720 king cab 4x2]

Oh yeah sorry I didn’t go back as far everything is all just visual !

[Thomas Perkins]

I took my speedometer out awhile back and changed it to one that has a clock in it but put the speedometer mileage part back in this one.My tack spun around.So I spun it back to zero and when I started it and ran it and turn key off.The dial would stop at 1000 rpm's.So I spun the dial clockwise to zero,then counter back to zero in front of the peg and that corrected it.It would show that it was idling lower but it did correct itself to the setting I use.

Edited March 31, 2023 by Thomas Perkins

[Stoffregen Motorsports]

Down at 7:00 sounds less like calibration and more like a broken or bent piece inside the gauge.

 

Have you had the gauge cover off and looked inside yet?

[85 720 king cab 4x2]

No I bought it some guy form eBay said it was in great shape and I working order! I am bummed I should of know better!, like I said it works but the needle doesn’t start to register till it’s time to shift Its so low! I get it up,to 1000 rpm’s when I shift so u can imagine how far down it is! It’s definitely something I’ve always wanted a Tach and I wouldn’t settle for something added I tried a little one down where the water and oil temp gauges are but waited till I had enough $$ to buy the original one I am assuming out of a 720 ST It was wrapped in a box like a little piece of treasure foam square with a circle in it in the tag inside of it it was totally cool I’m just bummed out it doesn’t work like it should maybe I did something wrong I don’t know that’s what I was trying to find out all I did was Gruden and plug it in when I change the harness oh my instruments it was the same one that I took out I can’t find a fire of a Nissan side is brand new old stock look exactly like mine the same numbers of mine from a deluxe 720 it had bucket seats just not a ST if I knew how to post pictures and you should’ve seen it when I got it into what it looks like now two different trucks, Hey I’m getting off the beaten path here to talk about Tachometers is not my truck! Sorry but if anybody else may know what I did wrong or if maybe it’s just busted and I spent almost 100 bucks on it!

[Stoffregen Motorsports]

If you have another tach, compare them side by side. I've repaired broken gauges by simply comparing one to another, spotting the issue and bending things around on the inside.

 

Some tachs have a tiny little adjuster screw in them for calibration. Below is a pic of an early 4Runner tach showing the adjuster.

 

 

[None_zero]

Despite my rank on this site I'm no expert, however it may just be that the needle is spun back on the spindle it sits on and if you rotate it with your finger all the way counterclockwise as far as it will go and then continue turning it past the point where it stops the same distance it is below zero when off that may solve the issue for you

[Stoffregen Motorsports]

Rank shmank.

 

Quite possible.

[None_zero]

9 hours ago, Stoffregen Motorsports said:

Rank shmank.

 

Quite possible.

I just meant I wouldn't want anyone to mistake me for a person with an expert level opinion is all I meant. However I did have the same problem with my tach and I fixed it like that.

Edited April 3, 2023 by None_zero