Parasitic Draw On Battery When Parked.

jivepepper · Jul 31, 2017

I have a 3 month old battery, and when I went to start my car yesterday, the battery was completely dead. It would barely flash the anti theft light. It was only a few nights ago, since I drove it. It ran fine, had bright lights, and the voltage gauge was reading normal.

I charged the battery, and disconnected the ground. Then I put my multi meter between the ground cable and the negative post of the battery. With the key off its reading almost 12 volt. 11.49 ish. I pulled every fuse and relay one at a time and seen no difference in the reading. I even disconnected the relays to my electric water pump and the 40 amp back to my BAP and FPDM. I also disconnected the charge cable at the alternator

I have no idea where the draw is coming from? Possibly the main power cable to the starter or an internal short? Kinda lost on what to test next?

As always any ideas will be appreciated.

Neuron · Aug 1, 2017

Do you have the Mach System?

jivepepper · Aug 1, 2017

Yes, but it doesn't have the back amp rack and speakers installed and I never run the radio.

imp · Aug 1, 2017

@jivepepper
Which car? Year? Think about what equipment remains "on", or ready, even when key is out of ignition. Air bag system, has big capacitors kept charged for instant use: bad one?

Courtesy lighting: trunk, underhood, glove box, places where juice could be going?

If you can access wiring diagrams, look at all fuses marked "always hot", and see what things they feed. Certain ones, like ignition switch, rule out. Just my thoughts.,...imp

jivepepper · Aug 1, 2017

Well I went and tried to measure the amp draw and wasn't getting a reading. The multi meter has 2 fuses one is a 200 Ma/250 volt and the is 10A/250V. The 200 Ma is blown and I'm having trouble. Finding one. The closest I can find is 250 Ma/250V .

imp · Aug 1, 2017

jivepepper said:
Well I went and tried to measure the amp draw and wasn't getting a reading. The multi meter has 2 fuses one is a 200 Ma/250 volt and the is 10A/250V. The 200 Ma is blown and I'm having trouble. Finding one. The closest I can find is 250 Ma/250V .

@jivepepper
Going right direction, IMO. Remove a fuse, insert ammeter probes in it's connections, if current is being carried by the fuse, ammeter will show it.

Don't compromise your multimeter by putting in a larger than recommended fuse! imp

jivepepper · Aug 2, 2017

imp said:
@jivepepper
Going right direction, IMO. Remove a fuse, insert ammeter probes in it's connections, if current is being carried by the fuse, ammeter will show it.

Don't compromise your multimeter by putting in a larger than recommended fuse! imp

Well I think I might have choice but to use the 250 Ma. I have literally have went to every parts and hardware store in my area. The local radio shack has closed down and the nearest one 70 miles away. It's 25% larger in amp rating but at the same time and only 50 more Ma..

Neuron · Aug 2, 2017

jivepepper said:
Yes, but it doesn't have the back amp rack and speakers installed and I never run the radio.

When you turn the key on the amps are energized whether the radio is on or not and have seen where the key does not shut them off any longer. Probably not it but I would unhook all the power going to the Mach System especially if you are not using it. Sounds a lot like an alternator too, has it been tested?

jivepepper · Aug 3, 2017

Neuron said:
When you turn the key on the amps are energized whether the radio is on or not and have seen where the key does not shut them off any longer. Probably not it but I would unhook all the power going to the Mach System especially if you are not using it. Sounds a lot like an alternator too, has it been tested?

I took the amps out years ago

imp · Aug 4, 2017

Amps to this old fart mean only one thing: Amperes of current flow. Amplifiers, AMPS, I studied years & years ago, and decided then that AUDIO just wasn't my thing. imp

Rusty67 · Aug 5, 2017

Try unplugging the GEM, it should be under the dash on the drives side above the kick panel.

Real time recon · Aug 5, 2017

Don't know if this helps.I just replaced a cheap-o battery that lasted 9 Years.I think/believe its due to a in-line battery kill switch on the car.

imp · Aug 5, 2017

Real time recon said:
Don't know if this helps.I just replaced a cheap-o battery that lasted 9 Years.I think/believe its due to a in-line battery kill switch on the car.

@Real time recon
Supposedly the PCM must re-learn strategies each timer the batt. is disconnected. I've never really noticed much, though. Wouldn't bother a carburetor in the least bit! imp

Real time recon · Aug 5, 2017

Dont know imp.But removing the key kills everything .If nothing else its a good anti theft gizmo

Rusty67 · Aug 5, 2017

The ECU does need to relearn everything when it looses power. It does a bunch of system self tests at certain intervals. I've been able to pass all self tests in less that 30 miles before. It will get more efficient as time goes on up to a point as well.

imp · Aug 5, 2017

Real time recon said:
Dont know imp.But removing the key kills everything .If nothing else its a good anti theft gizmo

@Real time recon
True, that! The Passive Anti-Theft System, ("PATS"), going into the 2000s became insane, as far as I'm concerned. The "chip key" can become a miserable PITA under certain conditions. Before that, in the '90s, Ford did crazy things like disable injectors, but the engine would still crank. What an asinine thing to do. Guy's using the wrong key unknowingly, engine won't fire, he immediately thinks of everything that could be wrong, except the damned key!

In the back of my mind, I keep thinking, a creep with the right tools, can steal ANY car, almost ANYWHERE, by dragging it up onto a flatbed and driving away with it, no matter the degree of complexity built into the "PATS" scheme. imp

Real time recon · Aug 5, 2017

imp said:
@Real time recon
True, that! The Passive Anti-Theft System, ("PATS"), going into the 2000s became insane, as far as I'm concerned. The "chip key" can become a miserable PITA under certain conditions. Before that, in the '90s, Ford did crazy things like disable injectors, but the engine would still crank. What an asinine thing to do. Guy's using the wrong key unknowingly, engine won't fire, he immediately thinks of everything that could be wrong, except the damned key!

In the back of my mind, I keep thinking, a creep with the right tools, can steal ANY car, almost ANYWHERE, by dragging it up onto a flatbed and driving away with it, no matter the degree of complexity built into the "PATS" scheme. imp

They will have to run REAL fast.Like 2,000 FPS

Parasitic Draw On Battery When Parked.

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