tacometer goes crazy at high speeds

[LeroyBrown]

at regular speeds it is regular once in a while it will jump around but on the highway it jumps around.. what do i need to fix? is it hard? iv never taken apart a dashboard

[dblanehopr]

It depends on what's causing it. There's a chance it could be a loose connection because the tach is electrically operated. I don't want to go too much futher into it because I've never looked at the wiring diagram for what controls the tach. I think it's ran off the transmission because I don't remember anything on the engine that would control that. But I'm not sure. I've never looked into it so far.

Now I'm curious. lol

[Piper]

1 check your ecu connection. if you have moved or taken off your ecu or someone else has, when you hit bumps, it will jar it and lose connection.

2 if you have taken off your cluster or maybe someone else has, your pins on the back of it are very touchy and easy to break/bend. make sure all clips are on and correctly touching contact pads.

3 if those all fail at fixing, try replacing it with a buddys cluster and see how it works for a week or two.

[LeroyBrown]

its not the ecu it did it when i had the ka24de now it does it with srdub ecu to

[leonelrr]

MAYBE BAD SPEED SENSOR?

[romerider153]

speed sensor has nothing to do with the tach the tach is controled by the cam position sensor on an sr that info is sent to the ecu and then sends it to the tach i would look for a wiringproblem thats what it sounds like my guess is some were between the tach and the interior plug that connects to the engine harness.

[dblanehopr]

thinking it's where the cluster attaches to the harness? question is: does the rpm jump up and down randomly or up to the right rpm and then down to a random lower rpm? ..as if the connection on the tach is fading then coming back.?

[LeroyBrown]

up and down rapidly

[dblanehopr]

no, i mean is it going up to the correct rpm of the engine and then down and then back up to the correct rpm?or is it just randomly going up and down rapidly with no consideration to the engine rpm?

[LeroyBrown]

lower speeds it will be normal but when i drive on the high way it goes all over the place...now it doesnt work at all..