Okay on my 1990 CRX-Si (D16a)My tach ticks erratically (sometimes at 0-1 while acctually at 3-4)(usually at highway speed) and does so randomly, then kicks back to normal.) What all does the tach run off of? Electronic of the Crank Speed sensor? If so what all should I look at, I've never delt with tachs before because none of my other cars had one. Could this be electrical, or is there a manual linkage somewhere in there (like the speedometer runs off the lil gear in the tranny)

Appreciate any help thanks all.

 

I have no experience with your year but it should run off the ignitor/ignition module like my car. I'd be Fing shocked if it didn't.

It could be the connection needs cleaned and tightened, I don't know what color the wire is on your car, but if you clean all 4 than you know you got it. If that doesn't help than it might be possible that your coil or ignitor is going bad.

Oh, also check the grounds in the engine compartment to make sure clean/tight.

 

could be the mechanical vss or the cable is loose. if those are fine then it could be the gauge itself.

 

You realize he's talking about the tach, not the speedometer right?

 

My guess would be a gound is bad somewhere. First thing I'd do is check all the ground wires you can find in the engine comparment and look underneath the engine compartment, too, and see if there are any down there.

 

Loose wire or ignitor.

 

mine does that same thing did any of these fix yours?