Battery drain with ignition off

[bmxr152]

So i fixed my fuel pump fuse problem and replaced the battery with an optima yellow top, but now im having issues with holding a charge. I tested the volts and it seems to to drop from 12.7 volts to 12.0 volts in about an hour. I also scanned the codes and came up with code 15 C which says power interruption to computer memory or EEC keep alive memory test failed.. I bought new terminals also and that didnt help. Forgot to mention if i keep on charger overnight i can start it in the morning fine.

 

[fishwish3]

did you check all your lights for a high paracitic load? for something that you think would be off but is not, i.e. glove box light

 

[geoph1986]

Check your relays in the power distribution box under the hood. These things are notorious for relays staying closed.

 

[bmxr152]

I have a turn signal bulb out if that would cause anything. As far as the relays go, i just replaced the fuel pump relay and the brown one i pulled out while testing voltage and still drops.

 

[shaggymane]

Like fishwish says, check all those *should go off* lights.....under hood light....brake lights too.
Had a bad Voltage reg cause an over night drain.

And when you're doing the test light between the neg battery post and the neg battery cable, pulling fuses till you find the drain, disable your under hood light so it's not drawing power and causing confusion.

 

[bmxr152]

So heres some more numbers, with the car running i get 14.8 volts at the terminals. The factory gauge however looks like around 10-12 or so. So then i turned the truck off and tested each fuse, and the only ones that had voltage were
ignition fuse was slowly creeping up voltage from .2 to 2+ volts.
Electric shift was 4.03 volts
Fuse panel was 12.5 volts
Headlamps 11.38 volts

I dont have any lights on why would there be a voltage through that circuit? Also the electric shift and igntion fuse shouldnt have power with key off should they?

 

[Jethro Tull]

I just went through a similar problem with my '91. It was intermittant. Some days there was no drain, and some mornings I went out to a dead battery. Because it was intermittant it made it very difficult to track down.

The problem turned out to be a sticking EEC relay, @$36.70.

 

[catfisher81]

:are you having starting problems too. I rebuilt my starter when i was having this problem and after i had it rebuilt, i wire brushed the rim of the starter off mounted it back and changed the terminals and cleaned alll the ground wires extra good and this completley fixed my problem. was going dead every day or every other day.
thanks and hope this helps

____________
1991 ford explorer 4x4 4.0 5speed

 

[ramcav92]

@ Jethro- i'm a complete newbie at all things mechanical but i dont find a traditional relay in my 1991 ranger (4cyl) it looks like a huge fuse (green-30amp i think) is that the relay???? I actually hear my fuel pump (i think it is) kick on when the truck is off and it's draining my battery. Done it for years. coincidentally my fuel gauge also quit about the same time this began if i recall.. Anyway, Its more noticeable in the winter (always dead) but in the summertime it usually has enough to crank if i drive it weekly at least. Any help is really appreciated. Clint

 

[Arne13]

You said you replaced the battery, then this started. Have you tried disconnecting the battery overnight and see if it drains. You mite have gotten a bad battery. Arne.

 

[shucker1]

BMXR152,

Voltage drop or a dead battery after several hours could be caused by the alternator "Locking On" even after the engine is shut off.

Quick test, Run the engine for a while. Shut it completely off. Take a metal wrench and touch it to the front pulley of the alternator. If the wrench tries to stick to it the alternator is still magnetized meaning the voltage regulator has failed "On".

I have seen this before.

 

[5spdman]

This may not help you track down the problem, but I was having the same problem with my old 93.

I went the simple (and maybe cheater's) route and installed a battery kill switch...kills literally everything but radio memory. Moved it to my 91 when I got it, just in case.