Factory Tach Way off

[ecna]

My factory tach seems way off. I have not hooked up an aftermarket to give you exact numbers and I have not driven the car hard since I just got it so I can't say how far it's off at higher rpm. It shows about 4000 rpm when I would say it should be about 2-2500. I do have another dash and can swap it if you think it's the problem. What else could be causign it to read so inaccurately?

Thanks,
Eric.

 

[QUIP'6']

My factory tach seems way off. I have not hooked up an aftermarket to give you exact numbers and I have not driven the car hard since I just got it so I can't say how far it's off at higher rpm. It shows about 4000 rpm when I would say it should be about 2-2500. I do have another dash and can swap it if you think it's the problem. What else could be causign it to read so inaccurately?

Thanks,
Eric.

AGE they were never accurate i think they were there just to let you know something was going on . the same goes with the boost gauge

 

[SLOW_85]

Check out:
https://www.casperselectronics.com/...creen=PROD&Product_Code=103070&Category_Code=

 

[t3intercooled]

Mine actually reads 1000-1200 when it is really idleing around 800. Scanmaster helps out with that giving the correct rpm.

 

[GNVenom]

Here is some interesting reading. You want to know WHY the tach goes out of calibration?
Read up:

Tach Boost Article

-John