Ok I read that the alternator case is grounded through the engine block. I have a 2000 watt stereo in the car and I've been upgrading the charging system wiring. I figured that I'll upgrade the engine to battery negative wire, but I read that I should ground one of the alternator brackets to the firewall. Has anyone heard the same thing, or actually done this?

98 SLE

No, can't say I have heard anyone doing this. But, it wouldn't hurt anything.

Ok I'll give it a shot and see how it works. Also does anyone know how many engine grounds there are and their locations?

98 SLE

i think the reason is that the case needs to have a good ground, and sometime people dont realize, the brackets might be painted or loose and not have a good electrical connection to the engine. if i was going to do anything it would be to the alt case.

Main negative cable from the battery to front side of engine and from the negative side of the battery is a short smaller gauge wire to the body.
PCM sensor ground that connects multiple sensors, back side of engine.

You could get a ground strap and connect it to one of the bolts at the alternator and feed a junction block.

Thanks for the help guys. I was planning on connecting the ground cable to the bracket that bolts to the top rear of the alternator.And then run the ground to the firewall under the maxifuse panel. Our do you guys have a better place in mind for me to ground it?

doesnt really matter just put some dielectric grease or something so it doesnt get corroded

Use one of the mounting bolts at the top of your strut tower.

Ok I grounded the case using one of the top bolts that screw through the case into one of the mounts from the lower intake. And I grounded it to a brace directly behind the strut tower that the Fenner bolts to.Immediately I noticed that when I started the car the voltage gauge in the dash stopped fluctuating when the bass hits hard. And I can hear the spark plugs firing louder which I hope that means their firing with a stronger spark. Thanks for the help guys!

good to hear it was worth the effort