Tachometer issues

[tompumped]

I just bought a cluster to take the tach out of it. I replaced mine and for 150 miles it worked fine. Now once again it's stuck at a given rpm, but sometimes it will read the rpm.

When I got the car the tach was off, it would indicate that the car was redlining at 8k so I took the tach out of a cluster I had. That tach lasted 15 thousand miles. Now i'm back to square one.

Even when I shut the car off the tach doesn't drop down to zero. I'm thinking whatever the issue I just burned out another tach.

I don't think I can read the tach signal with a voltmeter but i'm going to research. I guess i'll start by checking continuity for the wires feeding the tach over the weekend hopefully and report back. I don't know what could be causing this issue, and maybe I threw out two good tachs. I guess too much resistance in the wiring could cause them to go bad.

 

[rubydist]

are you having any other gauge issues? or only with the tach?

because a bad ground can cause all kinds of issues... but would affect other gauges too.

you will need a scope or some other type of device that can read frequency of a signal to be able to look at the signal you are getting to the tach.

 

[tompumped]

Only the tach is acting up. I figured id need a scope. Im going to check all the wires for continuity and I guess resistance. Im not sure what values I should expect to see for resistance.

I was going to buy a scope eventually. Its a good thing to have.

 

[AREA 91]

I have seen the tach read higher then it should on a couple of different SHO's. This happened when the throttle stuck and the needle was bouncing off the peg.
I have also seen the needle on the other side of the tach before.

 

[tompumped]

Two out of the three clusters I have didn't have pegs on the high side of the gauge, but the one I just bought did. I removed it to fit the reverse glow gauge face. I know the gauge face wasn't interfering before i'm going to have to make sure it's not now.

I'll post back after I check it out. I don't have any tools right now.

 

[Anonymous]

mines did the samething in my 91 ,the rpm tach was underneath the peg then eventually somehow went back to normal

 

[tompumped]

The needle was bent I forgot to update the thread. I probably bent it installing the gauge faces. Im betting the one I replaced was good but when I got the car the issue was different. This time the needle would get stuck and if I smacked the dash it would fall.

I bent it down towards the floor and it works fine.

 

[Anonymous]

now Im having a big issue with the tachometer in my 95 ATX , my rpm tach is not working nor the gas gauge and the temp only thing working is the speedometer

 

[intimdatr]

The speedometer is the only 100% mechanical thing in the cluster sounds like your are having electrical issues.