Kburke

this is weird i turn on my window defroster and the car starts to shake a lot more then usual same if the fog lights are turned on then off you can hear a drop in noise from the engine it actually gets lower could it be the Battery ? or something more scary. p.s. i think its my alternator belt is starting to squeel but it doesnt do it all the time just reandomly i live in VA so i was told it could just be from the moisture just want to make sure thats what the majority of people think. i have got my timing belt replaced and tightend so i think it might be my alternator belt so im sure it cant be that if any other thoughts let me know

drift a 944

Watch your battery voltage when you turn on those things. If it drops below 12 and your car starts shaking you might need a new voltage regulator. Try installing a spare one to see if your problem is fixed.

Van

Along with whatever is broken, you may need engine mounts.

V2Rocket

mine used to do that whenever, with the headlights on, the fans switched on. the lights would dim for a fraction of a second and the RPM would drop.

i made a wiring harness and hooked it to the alternator and it no longer happens.

Kburke

actually its funny you bring that up i have started to watch at my volt meter it usually stays around 12V but now its right in the middle of 12 and 14? i cant remember. my oil gauge reads high i was told its the gorund a buddy of mine actually showed me where it was i actually havnt gotten to it yet where is the voltage regualter located.

Van

When charging (i.e. motor running) it should be about 13.5 to 14 volts. Less than that means your alternator isn't charging. You could always check your gauge with a multi-meter on the battery...

The voltage regulator is bolted onto the back of the alternator and also holds the brushes. They do die and they're not too expensive.

I did a thread on rebuilding an alternator about a year ago - do a search and you'll find it.

xsboost90

well since the defrost may be ran by the a/c pump- that could be the issue- does your a/c work?

Spidey944

Anytime your vehicle is under a high load, i.e. a/c, defrost (runs compressor), headlights on, stereo, etc. the load stresses the alternator more, as well as slows engine speed a little which the ISV should make up for. But the increased load will also increase any issues with worn mounts etc. This is just another instance where having bigger guage wiring and clean grounds will make a difference.

It's hard to determine if your voltage regulator is working properly until you check the output with a meter, but I would agree that motor mounts may be in order, as well as some better gound/power cables assuming the regulator checks out.

Kburke

I will look into that to the other person my Ac works sort of. it blows just not cold. it need new freeon

gtroth

--probably a good idea to start cleaning grounds if you haven't already. Heavy loads through dirty grounds equals high currents through electrically resistive connections. In other words, your grounds can actually be at slightly different voltages, which can play tricks on signals measured by the gauges and DME.