200,000 miles on my Jeep. Whenever I let it sit for a week or two without cranking, it really hesitates to crank up. If I'm driving it every day it cranks right up. The issue only happens after its sat a while. Stock Alternator checked good at AutoZone as well as the brand new battery. The guy at Autozone said it is likely a short somewhere drawing power. Anyone have any ideas how to try and track down the culprit?

 

Yes. Stop listening to the guy at Autozone.

Now, does it crank for a while at normal cranking speed, then start?

Or, does it crank over slower than normal with the starter?

 

I know...I felt dumb even typing out what he said, but I figured it would give us somewhere to start. If its been sitting for a couple days it cranks slowly and makes an almost whine before starting up. Usually cranks right up quickly otherwise.

 

Slow cranking speed after a few days, right?

Anything on with the ignition off that shouldn't be? Interior lights etc?

 

OP,


Look at the voltmeter on the instrument cluster after the Jeeps sits for an extended time.


Turn the key to ON/RUN (before cranking the engine). It should show around 12 volts. Turn on the head lights for a few seconds and see what the voltmeter reads. It should stay around 12 volts.


When cranking the engine, the volts should not drop below 9 volts.


You may want to consider removing the Ignition Off Draw (IOD) fuse from the PDC if you are going to let the Jeep sit for extended periods of time. The IOD fuse location is shown on the lid of the PDC.

 

Try unhooking the battery before you let it sit next time. then hook the battery back up and see if it cranks normal or slow. If slow it's the battery. You could also do a volt meter test to see what the battery is at before you start it and also watch it as someone cranks the motor. See what happens to the voltage under a load.

Max

 

Or read post #5.

 

I normally just disconnect the negative battery cable if letting the vehicle sit for a few days. The Autozone isn't entirely wrong. He probably meant to say parasitic drain. There are lots of videos on the subject but basically it goes like this:
1. Charge battery to full. Use a deep charge.
2. Remove surface charge by turning lights on for a few minutes. Battery should read 12.4 - 12.6 volts.
3. Disconnect trunk light, door light, dome lights, etc (although you can still do with door light on but it will take a little longer). You want to turn off everything that still operates when car is off.
4. Connect meter in series to the battery not parallel. That is, disconnect a battery terminal and place meter leads from terminal to cable.
5. Meter should read something depending on amount of drain. I believe its anything over .4 volts is a parasitic drain.
6. Go through each fuse individually both in engine and cab. Remove one fuse then check meter. If the drain still remains, plug it back in and move to next. If voltage drops considerably then you've found the drain.

 

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