RPM tach not working

[devon.818]

ok the other day i had the car in nutruel, reving the engine to around 1500 after she warmed up. then the rpm tach decided it didn't want to work, i tapped the plastic thinking it was just "stuck" at 0. nope nothing.

any ideas? im hoping its the gauge in the cluster, not a sensor or something...

[CHIF8008]

hit the dash *seriously

[87-325ic]

check the si board and or a fuse


or hit the dash harder..

what else stopped working?

[devon.818]

gonna hit the dash when i find my keys again... :/
nothing that i noticed(yet). MPG meter still goes up and down.

[Zinno_e30]

Smack the side of the dash.. my tach stops working once in a while as well.

[devon.818]

yeah i hit the damn thing all over, nothing!
the mpg gauge moved around a bit.

ideas?

[e30rapidic]

SI board needs replacing. What do you service intervals lights look like?

[devon.818]

i need oil change and service...its on yellow, red goes on and off.(dash)

the ones by my sunroof-check brake light stays on even after reset.

my speedo works just fine...think that would be soon to go?
thanks.

[matias88e30]

just get a used rpms gauge.. done

[KirkerBezerker]

just get a used rpms gauge.. done

This isn't a sure fix. I just replaced my whole cluster and my tach/eco still don't work. Could be dead si batteries.

[nando]

the gauges themselves rarely break - they are just stepper motors. there aren't really any moving parts.

si batteries are likely dead.

there also is no "tach sensor". The tach get's it's signal from the ECU.

[izickc]

i've replaced my cluster for the third time and tach and mpg still aren't working.....what else could it be??

[jlevie]

i've replaced my cluster for the third time and tach and mpg still aren't working.....what else could it be??

The clusters you've tried could have bad SI board batteries or a bad SI board. the tachometer and econometer depend on the SI board.

The batteries in the SI board depend on unswitched power from the ignition to prevent them from discharging. If a cluster has been out of a car a running car for a while, the odds are that the batteries will be dead unless the cluster was opened and the jumper moved. That jumper would have to have been moved back before the cluster was installed.

[e30construction]

oh man did i have this problem..i replaced my batteries and tach motor..ended up being a fuse..nobody here has said fuse so i would def check there check fuse 21 10 are the 2 main ones but 12 also runs the speedo and what not they are all 7.5a..i would go ahead and just change them..a good indication if the si board batts are dead would be to see if your led lights up when you turn the car on..let me know if that was it

[jgilber0]

Reviving this old thread with gratitude.

LOL just smacked my dash and BANG! the tach is working again.

That irritating feeling when something stops working on your e30, replaced by the elation of an easy fix.

I love R3V. Thanks!