RPM Guage Movement

[iver729 10+ year member]

I noticed this a few days ago and want to know if you have any thoughts on it. When I sit in idle at a stop light or something, my RPM guage will flutter up or down when the low bass notes hit. I have all stock wiring, battery and alt. But I'm not pushing a lot of power (600w). Is it an electrical problem or something else?

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[mlstrass 5,000+ posts]

Depends upon if the electrical is taking a hit and the alt is drawing more power to kick out more juice, so the needles just dips up/down a little....

Or does the needle just bounce from the bass shaking the car as it's not a mechanically driven tach.

 

[iver729 10+ year member]

I don't think it's mechanically related, makes me wonder if my alt. is dieing. It's 100A and should take 600w with ease. I'm installing a profile ap1000 amp next week to power some new comps and I don't want to worry about my alt.

 

[mokedaddy 5,000+ posts]

Doing the big 3 should help and depending on the age of your factory battery you may want to go ahead and upgrade that as well.

 

[J31Rob 5,000+ posts]

May just be your idle.. fluttering up & down.

My girl has that problem w/her car. Unsteady idle..