Just had a new clutch and flywheel installed. Tachometer is going nuts...spiking from 3K-5K back to 3K all within one second. I haven't heard of the tach. units going bad at all. Maybe it's a connection on top of the tranny? Anyone wanna guess?

 

Check the connection behind the dash. They usually rust out, and the wires sometimes do not recieve signals. Thats the usual response I got from when I SEARCHED. I havent had a tach since I bought my car two years ago. Also, my tach "dances" to my music, It fun to watch sometimes.

ALI

 

There's an often quoted problem that the FD's tach suffers from bad internal solder joints. I successfully repaired mine and documented in a DIY repair procedure. It’s in pdf format and the file is about 700K because of all the pictures.

Send me a PM or e-mail if you'd like a copy.

 

Mine had the same symptoms. Found a used dash and all the problems went away. Very well could have been solder joints, but I had an electrical engineer look at the thing and he said it was probably one of the chipsets gone bad in the tach signal decoder.

Mine was erratic and intermittant, sounds like the same thing you have going on.

Sorry

 

If it is not the connections you would probably want to replace the speedo, it holds all control over the cluster.

 

How much is that gonna cost me? Thanks for all the replys guys. Looks like one more thing to fix.

 

Well it costed me $433.99 but they installed it for me. I felt ripped off becuase I later took off the gauge cluster to replace it. Half of that price was labor. Do it yourself. It will save you some $

 

I thought I was spending a lot doing an autometer conversion at about, um, $300?

Yea, taking the gauge cluster out took exactly four minutes.

 

Yeah do it yourself, its not hard. You can find a used cluster for cheap on the forums. Probably around 200. Before you do so try to use a friends and make sure thats the problem. It sounds like a connection problem if someone was playing with the tranny and then it stopped working.

 

my tach needle stays at 9k and beyond sometimes. i have the PDF that junkie sent me but I havnt had the time to work on it yet. let alone pull it out of the dash. just get used to it somehow...

 

mines still like that but I am not driving it because my motor isn't finished yet.

 

My tach used to not work either. I heard its a pretty common issue. I just replaced mine actually.