Tach Problems - Help Needed!

[Skilz10179]

My tach is acting crazy, it works correctly maybe 10% of the time but the other 90% of the time its jumping around like crazy or just sitting at 8,000 rpm. It will also sit at 8,000 rpm while the engine is not running most of the time.

Anyone have any ideas of what the problem is or what i should start checking first to solve the problem?

BTW, the car is a 98 240SX SE manual.

[Skilz10179]

Seriously, no one?

[Steady_One_S13]

Check wiring from the sensor to the dash. Check for breaks.It'd prolly be a good time to check the vss. The fsm has a how to checkwith an ohm meter.Or just maybe the tachometer is going bad.

[1990-240sxsr20det]

ok.. i had the same problem on a truck i used to have. The rpm's would bounce all over. the number 1 cylinder(tach gets its read from) had a wire disconnected. Check it. Hopefully thats it. good luck

[Skilz10179]

Thanks guys! At least now i have a place to start.