What's the main power soruce in a 1995 740 il v8 car? I am currently in the process of repairing my bmw. My Alternator is good, I'm changing the sparks plugs, Going to flush out the gasoline once I fill half a tank, and will be getting a engine flush. The problems I had when my vehicle was running is the powered died. I tested my alternator with positive/ negative method. The Alternator is fine. The vehicle use to have two 12s and a 2500 watt amp. The stero system mainly killed my car a lot. My younger brother always killed my car with the blasting the system. He won't be touching the car anymore! I am having a hard time finding the owners manual of my model of bmw to see where the internal battery is located if it does have one or what the main power source comes from if it doesn't. I also have a back battery which use to power the system. It's only holding around 35% charge and giving out when charging. Will the alternator recharge the battery to 100% if my car starts with fresh gas or will I need to purchase a new back battery?

Get rid of that garbage system.

Then reassess.

You're clearly over stressing the alternator, or shoddy installation is causing a low voltage problem while running.

Low voltage KILLS fuel injection systems. Especially complex ones, like yours.

Buy a multimeter, and return the system to stock.

The battery is under the back seat

Really? Ok I'll look.

Ok thank you. The system is gone!

This post was edited by ugetpkd on Aug 30 2014 03:38pm

A family member helped me replace the battery, change the spark plugs, used treatment in engine and gasoline, and I filled my gas tank half way. We got the car started and test drove the car.. My car isn't accelerating well on the streets 25-35 mph. On the free way my car is picking up speed, and accelerating after about 50 mph. It's taking a lot longer to accelerate up to speed at lower speeds. . literally have to push the gas pedal to get up to speed. He thinks either the transmission has a lot of sludge built up in it and a new transmission filter, new transmission fluids should help, and a transmission flush, and engine flush. What do you guys think? The transmission has no burning smell to it so we highly doubt the transmission is going out. Aside from that, The Check Engine Light is also on. I plan to take to a smog shop at a family members of mine to see if his diagnostics tool can tell us what's wrong with my car, and see if it'll pass smog.

This post was edited by ugetpkd on Sep 5 2014 11:57am