Well last weekend I installed my tach, and it went fairly well. Except lately it seems that at idle to 1/2 throttle, the needle flickers madly . On my way home from work today, I noticed that holding down one of the window buttons made it settle right down and made it very smooth and work like it should (I tapped into the power window fuse).

Any ideas as to what could be causing this?

Thanks

Lucas

 

Sounds like a bad ground to me. Could be a main ground from the battery to body or the one you used for the gauge.

 

Try moving the probe a little. It's very location sensitive.

 

Thanks guys.

I'm going to relocate the ground, since I just tapped into my boost/pyro grounds for the tach. Probably not the smartest, I know but its a learning process right? . I'll also move the probe around and see how that affects it. I remember that getting the clamp to sit nice and square on the alternator was a bit of a fight. Maybe it went crooked and moved the probe at the same time?

 

Update:

I moved the probe around so that it was closer to the alternator. Much better, a lot less flickering at idle and its a lot more responsive to throttle input. It still flickers a bit at idle, again if I hold down a window switch it settles down, so my ground could still be iffy. Overall, much better!

 

The gauge works by picking up electrical pulses, so that's why it is affected by headlights and power windows and the running engine.

Mine only flickers at idle with the headlights or breaklights off; otherwise it works flawlessly.

I think that the problem would be more related to a funny placement on the alternator than a bad ground, although I'm sure both could be causes.