Hello, My 93 Prelude si. I watched at the tachometer when engine on as idle. I used the timing light was about 800 rpm but tachometer under dash is about 400 rpm. And bit revved up to 2,600 rpm by timing light but tachometer was 2,200 rpm. I think what wrong with tachometer . How to adjustment on the tachometer?
Thank you from Robert F.

 

if you remove the gauge cluster from the console it's kinda a bitch but self explanatory once you begin - start by removing the tweeter covers and the plastic strip that runs on the underside of the top of the dash - and the rest should be self explanatory - the gauge cluster is most likely plugged in by 3 connectors - one for speedo one for taco, and one for SRS if you have that - and then on the bottom of it there are 5 screws remove those and you'll see two circuit boards one is for your speedo - the other your taco! they both have adjustment "pots" on them - i've never played with them myself (; but i've seen them there and i imagine that is how you will solve your prob. - but i would be damn sure your timing light (? - mine doesn't tell me rpm - just flashes heh) is correct before i f'd with it.

i was just in my dash today, changing my old imperial si gauge for a jdm 4ws vtec metric one... it was a bitch because everything was for RHD, so didn't fit exactly up, so i basically just changed the facing for now - i still have to figure out a way to get the metric circuit board to fit so that my klicks roll in the correct incroment. but i think it's going to mean elongating the ribbon connector so i can mount it elsewhere because it certainly didn't just plug into the LHD spot. I considered a canadian replacement for LHD - but then the vtec light wouldn't function so i'd be back to square one... so i gotta jerry rig this jdm one to work (;