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Discussion Starter · #1 ·
Ok so this problem just started about 3 weeks ago. I have a stereo system in my car that runs at 600 watt rms. When im driving in my car at 3rd or 4th gear and i punch it and hit higher rpms, All the lights dim in my car, the headlights, interior lights, the fan. Ive had this system in my car for 1.5yrs, and never had a problem like this before. Now im wondering if My alternator could be goin or my battery. The battery is about 2 yrs old, I was debating on buy a yellow top optima battery but the guy at mopac said that if it was my alternator it would still continue to happen. I need advice from you guys.

Thanks
 

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Mine does that too, but I have the car tuned to turn the alternator off at full throttle.
 

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Discussion Starter · #3 ·
i have a tune too, but i didnt ask to get that included. perhaps they could of on accident. Is there anyway i can tell on my xcal2?
 

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mine does it to...i haven't ever really thought it was a problem...all my vehicles I have owned has done it. i could be wrong, but i think that some cars turn off the alternator after a certain RPM to prevent damage to the battery...i think the focus might be one of those
 

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Shot me 3 deer!!!
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sounds like the altrenator to me. you can run an overdrive crank pulley, and that will cause the pulley on the altrenator to spin faster, so its a little less stress on the electrical system at high rpm. but if ur altrenator is going, then you will need a new one and this will not help.
 

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do u run a capacitor with ur system? Try gettin one of those or another alternator (cheapest route id pick). i need to install mine soon before i also start havin problems.
 

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Discussion Starter · #7 ·
No i dont have a capacitor, but like i said. Ive had my system for a year and a half and its just started to do this. So i dont think a capacitor is goin to help. Maybe the cold is getting to my battery. Its been -30 c here since beginning of dec. I think next weekend im gonna splurge for a optima yellow top battery and get ford to look at my car since it is under warranty. I can also get a HO alternator for 270. So if its goin ill just splurge for one of these. But im still open to any suggestions anyone might have to help me with my problem
 

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Sounds like the alternator is going.......the system should work normal even with a weak battery, as long as the alternator is putting out enough current to match the draw.

Test it.....hook up a volt meter to the lighter socket. At WOT with everything going, the volt reading should be around 13.8. If the reading is below 12V, you've got an alternator problem, or the belt is slipping for some reason. Clean off the battery terminals and try again. Sometimes a bad connection can do the same thing.
 

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Before you throw parts at it i suggest you get the battery load tested at a shop and then do an alternator output test. You can kinda do the load test. Unhook your coil pack connector so the car just cranks, you could also disable fuel. either way you dont want the car starting for this. use a volt meter, check your battery before you do this. It should be above 12.45V then crank the engine or have some one do it for you so you can watch the volt meter, it shouldn't drop below like 9.6V. Those voltage numbers are for a true load test which this is not but it should work for you. If after that you are convinced its the alternator, autozone checks them it should put out no more than 14 volts full fielded or at max output but and no more than .5 AC Volts.

Andrew
 
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