Help me find the short..PLEASE. car wont start.

Milenko

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Nov 5, 2001

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Boston, MA

Jun 19, 2004

#1

• Jun 19, 2004

• #1

Had to get it towed home today. Heres the problem:

Open the car door, everything looks normal. Put the key in the ignition and turn it to the first click...everything dims, nothing works, car won't start.

Even when the key is turned to accessory..when i step on the brake...brakes dont light, everything cuts out.

What the HELL is wrong, wheres the short?

 

N

n0v8or

10 Year Member

Aug 23, 2003

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Rhode Island

Jun 19, 2004

#2

• Jun 19, 2004

• #2

Sounds more like a bad battery connection or defective cell in the battery.

 

N

n0v8or

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Jun 19, 2004

#3

• Jun 19, 2004

• #3

The above assumes your charging system is OK (the battery measured more than 12.6V with everything off). If your battery is discharged, my first suspect would be the rectifier diodes in the alternator.

 

Milenko

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Jun 19, 2004

#4

• Jun 19, 2004

• #4

n0v8or said:

The above assumes your charging system is OK (the battery measured more than 12.6V with everything off). If your battery is discharged, my first suspect would be the rectifier diodes in the alternator.

Click to expand...

Guess I'll toss it on the charger and see what the outcome is.

If the interior light is on, and I step on the brake, nothing works. How could that be?

 

Dark Knight GT

I can't get it up......ok that didn't sound right.

May 26, 2003

3,653

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56

Ozark, Missouri

Jun 19, 2004

#5

• Jun 19, 2004

• #5

It doesn't take much power to power an interior light. However, it does take more power to power the brakes and rear brake lights. You're probably just low on power. The battery is probably dying or dead and has just a enough power to power the interior light. That would be my guess.

 

Milenko

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Jun 19, 2004

#6

• Jun 19, 2004

• #6

Wouldn't the brake lights at least come on very dimly or something?

 

trinity_gt

10 Year Member

Jan 31, 2003

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Jun 19, 2004

#7

• Jun 19, 2004

• #7

Milenko said:

Wouldn't the brake lights at least come on very dimly or something?

Click to expand...

I tend to agree with Dark Knight. If the battery has an internal fault such that its internal resistance is comparatively high or a bad connection, it can manifest itself exactly as you see.

A lighbulb requires only an amp or two. Assume you've got an internal fault giving an effective resistance of just 1-ohm. If you draw two amps out of the battery to drive a bulb, the output voltage will only drop from an open-circuit value of, say, 12V to 10V (Vd=I*R). You won't really notice the effect on the bulb...

Now try to draw a couple of hundred amps to turn the starter motor. Attempting to draw a few hundred amps through one ohm results, theoretically, in a few hundred volts drop across that resistor. Of course, what happens is that the output voltage of the battery drops as the load increases to the point where it reaches nearly zero volts; the load isn't getting 200 amps of course since there isn't the required voltage to drive it. When the output voltage of the battery drops, the lights all dim as well since they aren't getting current either.

Check the connections at the battery. Most likely the battery itself has gone goofy on you.

 

Milenko

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Jun 19, 2004

#8

• Jun 19, 2004

• #8

Thanks guys.

Took the battery to auto zone, they said theyd charge it and give it back. tried charging it, wouldn't hold a charge. Replaced the battery, all is well.

Appreciated.

 

Milenko

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Nov 5, 2001

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Boston, MA

Jun 20, 2004

#9

• Jun 20, 2004

• #9

Another problem.

The new battery worked for a day, tried to start the car this morning, 100% dead.

What the hell is going on..?

 

trinity_gt

10 Year Member

Jan 31, 2003

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Jun 20, 2004

#10

• Jun 20, 2004

• #10

Milenko said:

Another problem.

The new battery worked for a day, tried to start the car this morning, 100% dead.

What the hell is going on..?

Click to expand...

It sounds like a fairly large "quiescent" (i.e. current drawn when the ignition is "off") current draw going on. Assuming that this new battery doesn't have any internal faults (unlikely) and you haven't left any large power consumers on (e.g. headlights )then the next likely suspect would be the alternator, specifically the rectifier bridge. If a diode is shorted it will drain the battery fairly quickly. You might try, before parking the car for the night, disconnecting the alternator. Before trying to start it the next day, re-connect the alternator, then try it. If the battery is fine it's likely that the drain path is through the alt.

 

Milenko

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Jun 20, 2004

#11

• Jun 20, 2004

• #11

Anybody else have any other suggestions?

What could be causing this short?

I need my car fixed today, so I need as many suggestions as possible.

 

Milenko

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Nov 5, 2001

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Boston, MA

Jun 20, 2004

#12

• Jun 20, 2004

• #12

New Results:

I had the car on the charger for awhile. I went outside, opened the door, put the key in, the chime was ringing, the interior light was on.

I turned the key forward, the idiot lights lit up, everything seemed normal, fuel pump made the starting noise.

I tried to start it, and nothing. It was like the starter wire was disconnected. Everything stayed lit though.

I took the key out and tried it again. The starter clicked once, and then everything went completely dead. Even the interior light wouldn't light. It's sitting on the charger now.

 

Milenko

Skid Mark Layer...only not fro

Founding Member

Nov 5, 2001

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Boston, MA

Jun 20, 2004

#13

• Jun 20, 2004

• #13

New results again:

I think that there was a short in the drivers side kick panel. I moved the wire harness around and all of a sudden everything lit up and the door chime was ringing.

I tried to start the car, and the starter won't even click now. No response when I turn the key.

It's like the starter isn't even plugged in...odd..

 

Milenko

Skid Mark Layer...only not fro

Founding Member

Nov 5, 2001

462

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19

Boston, MA

Jun 20, 2004

#14

• Jun 20, 2004

• #14

I think it's fixed.

I cleaned and sanded\filed every wire under the hood in the fuse box, put it all back together, recharged the battery and everything seems to work okay now.

 

N

n0v8or

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Aug 23, 2003

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Jun 20, 2004

#15

• Jun 20, 2004

• #15

If it's a bad alternator diode; the problem will be back in the morning.

 

Dan_Soprano

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May 7, 2003

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Jun 20, 2004

#16

• Jun 20, 2004

• #16

take the alternator out of the system then, I.E. pull the plug off the voltage regulator and the chrage wire off. let it sit then try to start it. that should help in the trouble shooting.

 

Milenko

Skid Mark Layer...only not fro

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Nov 5, 2001

462

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19

Boston, MA

Jun 20, 2004

#17

• Jun 20, 2004

• #17

Just got back from the movies, car sat for 2 hours, started up without a problem. We'll see if it's okay in the morning.

 

BullittStangV8

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Oct 5, 2002

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NJ

Jun 20, 2004

#18

• Jun 20, 2004

• #18

Hope you fixed it. Reminds me of when i installed my shift light, and didnt reconnect the computer tight enough..the car wouldnt even crank. i was scared as hell that i ruined the car...
Mike

 

Milenko

Skid Mark Layer...only not fro

Founding Member

Nov 5, 2001

462

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19

Boston, MA

Jun 21, 2004

#19

• Jun 21, 2004

• #19

Car started up fine this morning for work, thank God. Thanks for your help guys.