Ok well my rpmtach just dies out of the blue. Well in the morning when i take off to school it will do fine but then itdies at any time there really is no giving time. But it really makes me mad. please help me out..

 

If you find out let me know, have 90 Daytona 2.5 turbo
does same thing.
90Shelby

 

Well, the circuit board behind the instrument cluster is notorious for loosing the tach circuit.. Check all the wiring to make sure its good and tight. You can also pull the cluster out CAREFULLY, and without pulling the wires off, take a meter and make sure you are getting a signal to the tach pins. Do a little checking to make sure which one it is (I don't remember). If you're getting a signal but the tach won't work (like mine), there is a break in the printed circuit board (again, like mine). If your not getting a signal, trace the wires back through the circuit to find out where the break or problem is. That's about all you can do. Mine went out about13 years ago, so I just bought an aftermarket tach. And yes, it will go dead at anytime, a loose connection will wiggle until it creates an open, it can also open once the car has warmed up, which makes me think it may be the circuit board (since you said it works and then dies). As the interior of the car warms up, the circuit board has a tendancy to expand a miniscule amount. Since the board will expand more than the printed "wire", it's only a matter of time before the "wire" breaks. Once the car is turned off and the interior (and circuit board) cools down, the board will "shrink" and make the connection again... Until you start the car and the whole thing starts again. Usually worse in the winter when it's colder. Once the weather warms up it may work fine or not at all.

 

Thanks for the info. Mopar rules & GO COLTS!!!!!!!

 

Mine likes to jump around....but it is due to the plug in the drivetrain end....not the cluster. The plug was cracked somehow.

 

My '88 Shelby Z had the same problem, but it was with the speedometer/odometer and a new gear didn't fix it. My tach worked flawlessly thankfully as I had to judge speed based on RPM's in what gear I was in.