I'm having a problem with my 96 GT. I started it yesterday and when I turn on the park lights the engine runs rough and then stalls. Same thing happens when I put my foot on the brake pedal. The signal lights blink fast and my break lights go dim. I cleaned all the grounds I could find and that didn't work. The only thing that seems to work is when I leave the battery disconnected for about an hour and then everything works fine for a bit. Any idea what it could be?
Electrical problem stalls engine
- Thread starter Kevman74
- Start date
ttocs
Post Whore
sounds like you have a battery going bad and possibly an alternator. Take the battery out and drop it off at autozone and leave it with them for a few hours. Have them put it on the charger, then wait a couple of hours after it finishes and then test it. I say to wait because I have seen batteries that come off the charger that tests good but with nothing hooked up to them they start to drop voltage over time. If the battery tests good then have them test your alt
cobrajeff96
Well-Known Member
Make sure the car has at least 14 volts when at idle. You'll at least know if the alternator is putting out.
It's not uncommon to have a significant voltage drop even if everything is working as it should, such as when you put a lot of load through the electrical system (stomping on brakes while A/C is on full blast with stereo blasting and operating window switches simultaneously... all while at idle speed.
But if there's no significant voltage drop as in such a scenario but the system is still giving you problems, that's usually an indicator of a failing alternator because it's a 12 volt system and everything in the car needs at least that in order to work well. Ideally, it's a little hotter at anywhere between 13.5 and 14.5 volts as with alternator output.
It's not uncommon to have a significant voltage drop even if everything is working as it should, such as when you put a lot of load through the electrical system (stomping on brakes while A/C is on full blast with stereo blasting and operating window switches simultaneously... all while at idle speed.
But if there's no significant voltage drop as in such a scenario but the system is still giving you problems, that's usually an indicator of a failing alternator because it's a 12 volt system and everything in the car needs at least that in order to work well. Ideally, it's a little hotter at anywhere between 13.5 and 14.5 volts as with alternator output.
ttocs
Post Whore
if your alt is going bad it could be killing the batteries.
So I took the battery to Napa to have it tested. They tell me the battery is good. They were good enough to give me a new battery to try. I've put the new battery in and it worked fine for a bit and then I have the same issues with it stalling when I turn on the park lights or put my foot on the brake. Alt is charging at 14.4v.
cobrajeff96
Well-Known Member
That's weird. So if you were to only turn on the parking lights, no foot on brake, the engine will die?
ttocs
Post Whore
not running under drive pullies are ya?
But if I unhook the battery for a bit and I hope it back up I can start the car and everything works fine for A few minutes then it goes haywire again
cobrajeff96
Well-Known Member
I couldn't think of another culprit. Wiring could be a factor as well.
Dubsport
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Hood light?
cobrajeff96
Well-Known Member
Either hood light or the brake master cylinder level sensor.
ttocs
Post Whore
I had a problem with my cruise control a while back that I could not understand but for some reason with the module plugged in, the brake lights would only see 9.5 volts. With it disconnected they see full power. It is easy enough to disconnect to test to see if that could be causing a strange problem like this.
cobrajeff96
Well-Known Member
Ever since I Coyote swapped, the CC module has been removed. I'm actually kind of curious to see what would happen if I installed it again.
weendoggy
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I can tell you I left my CC in with cable in the fender well. Actuating the switch does nothing and it doesn't interfere with the cars operation. This is AFTER my swap. I am going to play around with it this winter, I have an idea!
