tachometer reading 250rpm low

[EstoMax]

Hi Techs,

so i swapped out my odometer last weekend, and after doing that, my tach started reading low by 250rpm. I plugged in my laptop (i have a daughterboard on the ecu) and double checked, and at idle im around 700 instead of 950 (which is what my idle is set to and shows on the computer), and if i rev up then the tach revs follow it but the tach is 250rpm behind. What in the world could cause this?!?!

cheers for inputMarko

[Q45tech]

The tach like the speedometer is nothing but an inexpensive D' Arvonsal 0-5 volt meter.http://www.engineersedge.com/i...t.htm

[EstoMax]

thanks, but i think a replacement tach unit is not cheap . i did drop my gauge cluster on the ground when i was working on it,(not hard, but it broke the clock adjusting rod which probably cushioned the fall). I think what i'm gonna do is just pull out the needle and move it by 250rpm.

Marko

[EstoMax]

damn. i think i just broke the thing. i was trying to remove the needle and it started coming up with the pole, now the tach is very choppy. no smoothness.

is the motor a standard part number i can solder/replace? or no? how much is just a new tach unit? lol

i am using a 97-98 240sx gauge cluster btw.

Marko