My Z has been "acting up" lately. It started several weeks ago but, now is happening more frequently. Basically, it takes a while to crank. Almost sounds like the starter but, not sure. Here's why: Sometimes it fires up just fine & sometimes it struggles to crank. The starter is engaging but doesn't seem to have the juice to turn over. I then thought maybe it is the battery (which is about 1 year old. NAPA/Exide Battery) so, I had it checked & it "appears " to be ok. On 2 different occasions the car started to crank & then "WHAM" nothing. Total electrical lockdown. No power, no nothing! I had to disconnect/reconnect the battery cables to correct this. Also, when it struggles to crank, & finally does, I sometimes get a weird whistling noise that sounds as if it is coming from the exhaust. I can simply turn the car off & usually it will crank right up & the noise goes away..? The cranking issue seems to happen after the car has been sitting for a while..i.e. overnight, all day at work, etc. My Z is a 2002 w/ 55K miles. I feel like it is the battery but, wanted some opinions from some of you smarter guys. Local Auto Zone has checked battery, starter, & alternator & all tested good...Thanks in advance for any advice!

P.S. Volt meter is reading 13-14 volts.

 

Have you inspected the battery cables and connections for corrosion?

 

Yes. They are clean as a whistle.

Is it possible that the battery could have a bad cell or is losing its "charge" & once the car is cranked & runs for a while the battery "recharges", hence the "Test OK" from Auto Zone? Once the car runs for a while recranking doesn't seem to be an issue. If the car sits for a while and/or overnight in cool, dry garage or all day at work in VERY HOT ALABAMA SUMMER SUNSHINE is when I am having problems.

Thanks

 

Have you checked to see if some small electrical load is draining the battery while its sits for a long time?

 

First.. Whistles are not clean at all.

If the battery had a bad cell in it they would have noticed that in the test pretty quick. I have My 80$ battery charger which tests them as well for a number of things, and it is always accurate. I would check all of the connections for the electrical to make sure they are actually making good contact. Only other thing I could think of is the Alt is going bad

 

How to know..? I turn radar dector,AC/Heat, Radio, etc. OFF b4 I get out of the car. I have a "power option delete" package (1SC I think) so, no power mirriors/windows/cruise/etc.

Could it be ignition, spark plug related..?

 

If you have a volt meter and set it for 12vdc and then unhook your battery on the positive side. then put the probe from the battery terminal to the battery cable, you should get a reading of how much electricity you are drawing, I think. I could be wrong. But if I am, I am still really close.

There will be a slight drain all the time, from the ecu and bcm. Other things that can drain your battery are a bad alternator, bad starter selenoid, a short to ground on an interior wire. (those are always the biggest PITA to deal with). Is the battery to the point of it being dead when you go to start it and you need to charge it up.. or is it intermitent?

 

Intermitent. But happening more often now...getting worse

 

take your alt out and go have it tested to make sure it is good. Could be that something in it is starting to fail is is not charging properly.