Tach not reading right?

[dcrolin]

Hello all...I have a 91 CRX SI MT completely stock w/75k miles...My problem is that I think my tach is not working right, but I'm curious to see what you all think? At first I approached this problem thinking it was an idle issue, so I replaced the EACV, Fuel filter, Plugs, Wires, Dizzy, PCV, and all new vacuum hoses. My issue is that the tach needle reads 0...on the peg...at idle...after it warms up to temp...about 5 min. Now I'm thinking it is just the tach...b/c at highway speeds 70-75 mph and I push the clutch in, the needle reads 0...on the peg...So, any ideas out there left for me to try. Oh yeah, idle is adjusted right and timing is dead on. I'm going to swap tachs next and see if that fixes it, but I'm not sure. Any help would be awesome. Thanks

[turtlecrxsi]

Sounds like you have a really nice car. If you tap the tach with your finger does it straighten out? Mine does, especially if it's cold and I gun it... it gets stuck. Just swap the gauge cluster (plug and play) from another 90-91 (88-89 doesn't plug in). If your car is running right, it's probably just a stubborn gauge.

[dcrolin]

Thanks for the response turtle, it doesn't help if I tap the tach I already tried that. I just got a '90 gauge off ebay, but I wanted to know for when I swap them, can I just replace the tach itself....take off the tach from the new cluster and put it on my old one, or do I HAVE TO replace the entire cluster...I'm curious b/c my car only has 75k on it and I would hate to put 147k cluster on... Thanks.

[turtlecrxsi]

It's easier to just swap clusters. What you can do is remove your stock odometer and put it in the new cluster. GTA did this. He's a moderator. Maybe you can PM him and see if he can walk you through it.

[FrodoGT]

You can take the tach out just as easily as the odo..prolly easier, your already taking the whole cluster apart (there isnt much in there anyway), I swapped a cluster on my friends 88 mazda b2200 for one with a tach, and we took the odo apart and rolled it back by hand..took us about 30 mins (after we got the thing away from his grandfather..) because his truck only had 29k original miles on it, and the new cluster read like 174.

[dcrolin]

Thanks for all the responses...problem is solved. I replaced the tach only...it was quite simple since the cluster was out anyways...there were just three screws and the tach is out. Anyways...that seemed to be the problem cause now when my rex is warmed up, the tach reads slightly under 1K rpm's where before it was at 0. Thanks again for the help.