Alternator? Or something else?
Thread Starter
|
Senior User
Joined: Dec 2002
Posts: 439
Likes: 0
From: Temecula
Alternator? Or something else?
Whenever I come to a light or let it drop to idle when im driving I lose voltage, the volts drop down, but after a second or two they go right back up, whats happening? Not a big deal, but headlights dim when it happens, along with everything else, not too good with my amp for my subs! Any ideas would help!
-Ryan
-Ryan
Lead Driver
Joined: Jul 2003
Posts: 7,406
Likes: 52
From: Wheatland, Mo
Check both your alternator and battery. The alternator only puts out what the battery needs. So if your battery is going bad and dumping more power than what it should, then the alternator has to work harder to re-charge, thus showing lower volts at low idle. You can have em both checked at a local parts store. They usually do em for free. If those both check out then it could be the voltage regulator. But if it is attached to your alternator, then just replace that and you have already taken care of two of three items.
Junior User
Joined: Dec 2003
Posts: 65
Likes: 0
This could be caused by a short in the wiring to some component. How low does the voltage drop? Does this happen with the headlights off? But check the alternator and battery first. Once I had a loose alternator belt cause this problem. When the engine was idling the belt had enough slack to slip.
Senior User
Joined: Dec 2002
Posts: 288
Likes: 0
From: New Jersey
My truck does the samething. My alternator and battery are new. It only reallly does it when I have the lights, heater, and al the other stuff on. I think the alternator does put out enough to really run everything at idle in gear. Once I step on the gas or put it in park or neutral and the RPMs go up, everything goes back to normal. As soon as it warms up. I am going to do the g3 conversion
Thread Starter
|
Senior User
Joined: Dec 2002
Posts: 439
Likes: 0
From: Temecula
The amp is small, it isn't enough to put that much stress on the electrical system, I can play it for a half an hour wihtout the engine running and no voltage loss at all. The battery is brand new, so it couldn't be the battery. The voltage doesn't drop that much, but everything dims when it happens, and what is that conversion?? Might try that, because I figure on moving to a bigger amp.
Trending Topics
Posting Guru
Joined: Sep 2002
Posts: 2,195
Likes: 1
From: San Antonio, Texas
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
Logistics Pro
Joined: Nov 2003
Posts: 4,371
Likes: 7
From: PA
i have the same problem with my 1987 bronco i was driving down the road the one day and all of a sudden my stereo stopped and my windsheild wipers went really slow like 1/3 of the normal speed on low then i went to pull into a turkey hill and it didnt start i got it towed home and got a new battery and had my alternator tested they said it was fine well now it works but when i first start it up everyday i cant put on the heat because the voltage meter is way down below the half way mark
Fleet Mechanic
Joined: Aug 2002
Posts: 1,568
Likes: 33
From: Swansea SC
amperage
Try after getting your alternator checked, cleaning all connections---i mean all Grounds included .Rust and bad conn.on a electrical connection can do all of what your saying robbing amperage n voltage.Cold weather we run a whole lot more things, heaters windshield wiper radio,etc .U notice even with good connections things dim in time(age) .I took the time to clean all engine grounds even add one ---(parallel)and clean the connections and add parallel grounds through out my whole system. i was running a big cb ,10 mm radio with every thing dimming when keying the mic. After the clean and addition to grounds -even hooking the cb up off my battery made a big difference .The older our trucks get rust is apparent and connections get weak.Our truck uses the frame and points throughout the body as grounds.Hope this helps TR
Junior User
Joined: Dec 2003
Posts: 65
Likes: 0
For crazed87bronco. I saw your idling problem on another thread.
If it goes down to 600rpm, then low voltage might be expected. The two problems may be tied together. If the truck idles good for the first couple of minutes maybe something that is activated by the computer after 2 minutes may be the cause? Maybe a short in a wire going to a component that's supposed to activate?
My bronco idles really high when I start it cold for 5-10 sec. Then it goes to normal idle. Is this what you're talking about? How long have you had the idling problem?
If it goes down to 600rpm, then low voltage might be expected. The two problems may be tied together. If the truck idles good for the first couple of minutes maybe something that is activated by the computer after 2 minutes may be the cause? Maybe a short in a wire going to a component that's supposed to activate?
My bronco idles really high when I start it cold for 5-10 sec. Then it goes to normal idle. Is this what you're talking about? How long have you had the idling problem?
Last edited by 88bronk; Jan 18, 2004 at 12:01 PM.
Logistics Pro
Joined: Nov 2003
Posts: 4,371
Likes: 7
From: PA
mine idles high to when i start it up then it gos to about 600 then it rises to about 1200 or so then it drops back down it keps doing this it dont stop and do a solid idle it just go's up and down up and dopwn its been doing this since i got it but just the past month or so my battery gos way down once in a while
Thread Starter
|
Senior User
Joined: Dec 2002
Posts: 439
Likes: 0
From: Temecula
Yeah, on mine the idle is low when the voltage drops, at around 550 or 600, if the idle drops down this low it is obviously going to cause the alternator to spin slower leading to less power, so is this the problem? Do I need to just adjust my idle, or is something else causing it to idle low?
Junior User
Joined: Dec 2003
Posts: 65
Likes: 0
Crazed. I read where the exhaust temp takes about 2 minutes to heat up to 600 deg. and then the O2 sensor starts its input. That may be one problem. I still think 600 rpm is too low. Did you clean the air bypass valve yet. ( from your other post)? Before you start spending on parts buy a manual to see how to check the parts or have a diagnostic test ran on it.