Engine Loses Spark When Headlights Turn On
- Thread starter fg42lol
- Start date
I'm with DK, check the battery but also check (or have checked) the output from the Alternator. A bad Voltage Regulator (built-into the Alternator) will cause a lot of odd problems. Most auto parts stores will check these items for you for no-charge, they can do it right there in their parking lot.
Kevin
Kevin
Item of note
The car has been sitting in my driveway for two months, and I have just been driving my truck. Went to start it and the battery was dead. My jumper box didn't have enough juice to turn it over but my truck sure did! I ran it for about an hour and then shut it off. Was going to screw with it this morning during day light and she was kuput. The car runs fine with the exception of the lights, and the terminals are corrosion free. Also the battery is less than a year old, so I have trouble believing it's the battery. Would a bad voltage regulator send power to the fan motors? My understanding of auto electrical is elementary at best, so I might as well be pissing in the wind while making assumptions
The car has been sitting in my driveway for two months, and I have just been driving my truck. Went to start it and the battery was dead. My jumper box didn't have enough juice to turn it over but my truck sure did! I ran it for about an hour and then shut it off. Was going to screw with it this morning during day light and she was kuput. The car runs fine with the exception of the lights, and the terminals are corrosion free. Also the battery is less than a year old, so I have trouble believing it's the battery. Would a bad voltage regulator send power to the fan motors? My understanding of auto electrical is elementary at best, so I might as well be pissing in the wind while making assumptions
I'm still thinking battery, especially if it was so dead that a jump box wouldn't get it going again.
Normally a year-old battery wouldn't be suspect but if it was connected it's possible that parasitic losses (clock, radio memory, etc) could have run it down. Could also happen if you're using a lower-quality battery.
I have a couple of cars which sit for a month or so at a time and haven't had any battery problems (yet) but they sit indoors and aren't subject to very harsh temperature extremes. I'm trying to get better at hooking them-up to a Battery Tender.
Kevin
Normally a year-old battery wouldn't be suspect but if it was connected it's possible that parasitic losses (clock, radio memory, etc) could have run it down. Could also happen if you're using a lower-quality battery.
I have a couple of cars which sit for a month or so at a time and haven't had any battery problems (yet) but they sit indoors and aren't subject to very harsh temperature extremes. I'm trying to get better at hooking them-up to a Battery Tender.
Kevin
Fan motors kick on when the temperature gets high enough anytime the vehicle has the ignition on, regardless if the engine is running or not.
My girlfriend's brother managed to destroy an 8-month old battery because he drove the car with a faulty alternator and charged it out of the car every night instead of replacing the alternator. Running batteries completely dead repeatedly is murder on them. When the plates are sulfated, you won't have the amperage to run all of the electronics, so you'll see all sorts of gremlins surface (when the battery was dying on my Matrix my Pioneer kept going to factory settings every time I started the car because the stereo got too starved of juice and lost the keep-alive memory).
Get that tested first. Autozone and O'Reillys will do it for free. If that checks out, I'd start looking at grounds (I've had bad grounds do really bizarre stuff).
My girlfriend's brother managed to destroy an 8-month old battery because he drove the car with a faulty alternator and charged it out of the car every night instead of replacing the alternator. Running batteries completely dead repeatedly is murder on them. When the plates are sulfated, you won't have the amperage to run all of the electronics, so you'll see all sorts of gremlins surface (when the battery was dying on my Matrix my Pioneer kept going to factory settings every time I started the car because the stereo got too starved of juice and lost the keep-alive memory).
Get that tested first. Autozone and O'Reillys will do it for free. If that checks out, I'd start looking at grounds (I've had bad grounds do really bizarre stuff).
Oh, and if you attempt to do this on your own, get a multimeter. You can also check the voltage of the battery with the engine running while a friend throttles to 2500 RPM. Voltage should be 13.8 - 14.4 with all accessories off. Anything outside of that shows issues with the alternator (since sulfated does not affect voltage).