hey, i've got one of those auto meter air/fuel ratio guages(as pictured top right), now the problem lies here!

when i'm driving around the guage "floats" between stoich rich and lean depending on where my accel pedal is, now, when the sterio is cranking, every bass beat makes the guage jump toward the lean side of things.

i was wondering if anyone knew if this was due to the loss of voltage to the motor due to the bass beat or maybe the knock sensor picking up a vibration from the sub causing it to play with the timing making it go lean?

ps it's not a dud battery, (odessy 1200 dry cell) and the voltage guage(bottom left) doesnt drop below 13 volts.(the motor is off but ignition is on, thats why it is saying only 11.5 volts)

any thoughts would be appriciated, thanks

magnetic field ?

where ya tweater / crossover ? its not in the door is it?

crossover ,passive under head unit, active under pass seat
tweeter in dash, six inch in door, baseball bat and mag light under seat grrr!lol

crossover ,passive under head unit, active under pass seat
tweeter in dash, six inch in door, baseball bat and mag light under seat grrr!lol

could be those im not expert maybe you could try disconecting them and see what happens. or move the guage to in front of the steering wheel where the voltage is

but that means no tunes so no voltage drop, everything normal then, only happens at high vol

ok - i dunno why your stoich meter would be reading that on bass beats - but where did you get it from??

I want one as wel.

Manual

its an auto meter one, you can get them from any good hot up / spares / car audio shop, you just hook it up to power and to the 02 sensor on your exhaust manifold or trace it back to the ecu and mount it, looks good and is sort of helpful in trobleshooting matters!

so how is yours connected?? Via ECU or via the o2 sensor??

Manual

I'M LAZY, IT ALOT EASIER to hook up to the o2 sensor than trace the wire all the way back to the ecu!! you just splice it into the existing wire so the ecu can still register the reading, hooking it up to the ecu is neater as mine is in the passenger footwell kickpanel, but as i said above, the o2 sensor is easier!lol ;)

Your subs will suck a lot of amps (as in the electrical unit short for Amperes, not amplifiers; although if it's big enough it may do that too!), so I'm suspecting that whenever a bass beat hits there is a loss in voltage to the gauges causing the dip in the gauge.

(Dingo mate you're an electrical engineer, help me out here! I've got half an idea that has to do with Ohms Law but can't explain it properly. :( )

V=IR, therefore if your amperes drops (I) then with the same resistance (R) your voltage (V) will also drop off hence the drop in gauge reading (since mechanical gauges are simply high resistance heating wires wrapped around a thermostatic strip).

As for why your voltmeter gauge still reads 13 volts may be because the drop is only measurable in millivolts (mV) and your a/f gauge may only use mV to operate.

I'm making a lot of assumptions here but I think I'm somewhat right at least. :? :)

yeah Ray, you've pretty much summed it up the whole V=IR there... good job!

and its applies directly to the problem we have.... after reading the tech tips on autometers website (had to make sure what how the meter got its reading) the problem is the drop in voltage...

the stoich meters send a basic (according to the website) 0-1V reading and displays it in 0.05V sections...

so... as Ray said... when you're sub is cranking, the power to the meter is reduced and you get the bumpy readings....

to fix this problem... you want to condition the power supply to give a constant 5V....... you need a 5v regulator(/low pass filter type) setup.... (basically a capacitor across the 5V input and a inductor inline with it)..... so that it supplies a constant 5V... i will have a play around with some numbers tomorrow (no time tonight, have to work till 10, and then go out :D )

but your local auto sparky / stereo installer should know more about this, and may even have the components (should be very cheap, ie less than $5) to put across it to give a more even power supply.