electrical problem

[01celicagts21]

i have dim lights while driving, It also drains the battery while the car is off over a period of like 2 days. the altinator has been changed, battery also.my turbo timmer only reads 11volts while the car is running.i cant figure it out i think that something is grounding out. please help. car is a 95 talon tsi awd.also the car will not run with battery disconnected. im not sure if it needs the battery to run or not.

 

[LT1andDSM]

I know 1gs have a alternator fuse. 2gs should havee one under the hood as well check it out.

 

[01celicagts21]

i checked the altenator fuse and it was fine.im wondering if i ot a bad altenator.but i dont think that would cause the battery to die when the car is not running. i cant figure it out?

 

[luv2rallye]

also the car will not run with battery disconnected.

Usually that means your alt is bad but if you had a massive short that would also do that when idling.
To find a short/drain: http://www.dsmtuners.com/forums/showthread.php?t=179481

 

[01celicagts21]

so should my car run when the battery is disconnected?

 

[luv2rallye]

so should my car run when the battery is disconnected?

Yes if your alt is ok and the alt fuse is good.

 

[toybreaker]

I strongly recommened AGAINST disconnecting the battery with the engine running.

It is not a valid test when you weigh benefit to risk.

If you are having an alternator/charging system issue, disconnecting the battery removes the only buffer/protection against overvoltage...The battery provides resistance to rapid voltage change/spikes due to it's sheer size/storage capacity.

It will most definately spike the system voltage as the load of the battery is removed.

A cheapy voltmeter from radio shack will tell the tale much more accurately, and can be used for other tests. You will also learn more about how things work by using how to use a voltmeter. Then when faced with a problem in the future, you will already have a head start on understanding the system, and how it works.

Gtm has written a nice and quick test on how to check charging systems, using inexpensive tools that are readily available. Please check it out.

Back in the days of vibrating point voltage regulators, this test had a little value...

Again, no offense intended, but this test became sketchy when solid state alternators became common place, and every single proffessional tech I know will not do this...ever.

The possibility of fragging the ecu or other sensitive electronics is not worth the risk...and all the electrical rebuilders I know will_ not_ warranty any alternators that have been "tested" like this. It is quite likely that you will damage the diodes and other parts of the voltage regulator with repeated connection'/disconnection of the alternator with the system under load.

My opinion, yours may vary...

 

[steve]

I strongly recommened AGAINST disconnecting the battery with the engine running.

I second this. You stand a good chance of causing damage while your disconnecting the battery to do this "test". Anybody should be able to measure the voltage at the battery with it connected and the car idling to see if the alternator is charging.
If the voltage is above 12.6 and below 14.7 volts the system is likely doing what it should.

Steve

 

[Dasamary]

My car won't run w/o the battery...I had an issue where my alternator bracket had come loose and I wasn't getting good contact. My car would lose power and almost die. My guess is that your alternator isn't correctly charging the battery and supplying enough power.

Was this a sudden problem or had you put any new parts on then the problem occured? If you had installed somthing in the last week it might be the cause; or miswire on that part. I had an old pick-up that blew the alternator; i had a brand new one put on and it only lasted a week...You could have bought a bad alternator...but most likely its the wiring somewhere.

 

[01celicagts21]

i put a remaned altenator in i wonder if thats the low voltage problem. but the batery will die in 2 days when the car has not been run.meaning i didnt drive the car for 2 days and when i got to start it the battery is dead no lights nothing. when i jump it with jumper cables off another vehicle. it shows 13.8 on my volt meter in the car if i unhook the cables the volts drop to 7.8 volts and the car has a hard time running .

 

[01celicagts21]

thanks for the help guys i appreciate it.

 

[luv2rallye]

Toybreaker and Steve are right and have excellent points - thanks guys. It's not worth the risk of blowing the ECU, stereo, etc. (I must have been very tired staying up all night to not mention that.) If you suspect the alt (you wouldn't be the first to get a bad rebuilt), measure the battery voltage as Steve says, or do the GTM alt test, or have it tested at a place that repairs alts & starters who will do a proper and complete job of testing (not an auto store which only does a go/no go voltage test). For a suspected battery drain see my link above.

 

[01celicagts21]

i'll try these test this weekend thanks again guys. if u have any other ideas let me know