Georgia Fiero Club Forum

All Things Fiero => Tech Tips, Tech Questions => Topic started by: Donster on April 14, 2020, 07:01:34 am

Title: Best way to find a power drain
Post by: Donster on April 14, 2020, 07:01:34 am

We seem to have a slight power drain on the Fiero. We leave it set over night and the next day the battery doesn't have enough power to start the car. Interior light are bright, trunk pops no problem, head light come on no problem, so I'm assuming it is only a slight drain. Funny thing is, the radio looses all presets. Could the stereo be somewhat the source. What is the best way to find the drain?Help!
Thnx,
\D

PS: The fuel pump is NOT running!

Title: Re: Best way to find a power drain
Post by: GTRS Fiero on April 14, 2020, 07:23:49 am

You can pull fuses, until the source is located.  If you're in a hurry, set your multimeter to amps, and connect it in place of the fuse.  If you see more than a few milliamps, you found a drain.

It could be a short.

Title: Re: Best way to find a power drain
Post by: Donster on April 14, 2020, 07:30:47 am

Thnx

Title: Re: Best way to find a power drain
Post by: GTRS Fiero on April 17, 2020, 07:34:22 pm

Did anything turn up?

Title: Re: Best way to find a power drain
Post by: Donster on April 19, 2020, 10:05:19 am

Have not had a chance to test yet

Title: Re: Best way to find a power drain
Post by: Donster on April 21, 2020, 03:59:29 am

Turns out, it was the battery (just 6 weeks old, by BOSCH). It would charge (14.3 V), but as soon as you try to start the engine, it woulkd drop down to .5 V.New batteryy, all good.
 

Title: Re: Best way to find a power drain
Post by: GTRS Fiero on April 21, 2020, 08:10:52 am

That's about the best outcome you could have.

Title: Re: Best way to find a power drain
Post by: Fierofool on April 21, 2020, 09:31:27 am

Quote from: Donster on April 21, 2020, 03:59:29 am

Turns out, it was the battery (just 6 weeks old, by BOSCH). It would charge (14.3 V), but as soon as you try to start the engine, it woulkd drop down to .5 V.New batteryy, all good.

Yeah, you know they get that German stuff from China, don't you?  :)   Honestly, though, I was just shopping for Bosch fuel injectors for my car and most of them came from China. 

Title: Re: Best way to find a power drain
Post by: Roger on May 10, 2020, 02:18:52 pm

Take a 1 amp fuse.
Put it in a socket where high amps would be drawn (power window; etc.)
Is it blown? Good!
Now solder a 12vdc lamp to the back side of the fuse.
With the car NOT RUNNING and ignition OFF, one-by-one insert this into each fuse socket.
When the lamp glows you've found the circuit that's draining your battery.

Title: Re: Best way to find a power drain
Post by: GTRS Fiero on May 10, 2020, 04:34:45 pm

The smart fuse comes with the light built in.

Title: Re: Best way to find a power drain
Post by: TopNotch on May 10, 2020, 08:24:37 pm

Quote from: GTRS Fiero on May 10, 2020, 04:34:45 pm

The smart fuse comes with the light built in.

But you still have to blow it to see the light, and it's a LED, so it will glow on much lower current, perhaps even a normal drain, such as your radio keep alive drain.

Title: Re: Best way to find a power drain
Post by: GTRS Fiero on May 10, 2020, 08:33:36 pm

No.  It did not blow or glow on the power window circuit.