Help! Engine Dies during braking!?!

[IronD01GTvert]

My battery had run down from the car sitting the other day, so i hooked up the charger to it. After about a day of charging I removed it. The car started up fine and the voltmeter was registering normal. Took the car out and the stero and such worked fine. As soon as i got to the nearest stoplight the car died as soon as I pushed the brake pedal in. It started right up but both the Speedo and the odometer no longer work. Now everytime I come to a complete stop (traffic light, parking, etc) the car dies. If the ignition is switched off and then the car is started up again the odometer comes back, but only until you brake fully again and then the car dies, along with the odometer.
I checked all the fuses that would pertain to instrument cluster or ABS but none of them are burned out. If anyone has any ideas, please let me know.

 

[MidnightBlk98GT]

Sounds like it's time for a new battery. If the old one died and you have to jump/charge it the life expectancy is only about 2 weeks. The battery not only provides charge to start your car but also it acts like a load. Think of it this way: when a battery dies it's not like it has no charge left (i.e. you could start your car right up when it stalled out on you at a stop light/sign), it does. What really is happening is that the battery is shorting out and when it does that there is no load for your car to run the necessary functions like engine management, speedo, odo, etc. You have to replace the battery anyway because it died but I'd bet that if you took it to someplace like Sears and had them hook it up to their testing machine, they'll tell you that you need a new one. Hope this helps.

Edit:The Monster Cap that you have in there probably isn't helping the situation either...try first without the cap then if all goes well, let it run for a bit to see if you have any further problems before hooking up the stereo.

 

[DropTopPony]

were you crankin the tunes? leave off the radio and hit the highway to see if the alt will charge the battery up. If it won't hold the charge its time for a new one. Do you leave the car sit for long periods without driving? If so invest in an optima yellow top.

 

[B's 96 GT]

This sounds just like the problem I have. I was told to replace the IAC, which I did and it didn't help. I put a new battery in it and that didn't help either. Let me know what fixes it. I want my damn stang to run again.

 

[IronD01GTvert]

I dont believe it to be the battery. I have turned the stereo off while driving, but to no effect. Also when the stereo IS on there is no dimming of the lights or power problems. I am currently runing 2 batteries an optima yellow top in back for my stereo and a duralast up front for the car.

Still stumped

 

[IronD01GTvert]

both batteries are good. ZFront puts out 12.5 amps and rear puts out 12.00 when car is off. when car is on, charging systemp puts out 14.5 amps

 

[sgarlic]

How many amps is your alternator? Seeing as how back when I was in to car stereos people didn't use 2 batteries, I wouldn't know, but the fundamentals of charging systems would say that one alternator at stock amperage probably ain't enough to keep up with 2 batteries.

Edit: And greetings to a fellow Tucsonian. I'll be on the lookout for ya around town once you get it running.. I think have the only black '04 GT coupe in town.. say hi if you see me.

 

[IronD01GTvert]

well i figured it out. After lots of searching here i realized many people have the same problem. Seems that the Speedo Recalculators, used when you want to fix the speedo after a gear swap, when they screw up the car will run like crap. Guess the power wire for my Speedcalc had come loose. After re-attaching it the car runs great!

Garlic, ill look for ya I have the silver 01 gt vert Lic plate ME VS U. Only one in town that looks like it!