Hi everybody,

Haven't found a specific thread on this issue anywhere and I can't get any resolution from the dealership, so I thought I'd ask it here. I got a 2010 G37xS sedan over a year ago (used) and ever since have had trouble starting it. If it's left for 3-4 days (worse in the winter) it often will crank once and then dashboard lights flicker and it dies. Trying to start it again just results in lights flickering and clicking sounds; brake pedal also becomes stiffer with each try. It seems as if the battery dies after only a few days, although a new OEM battery from the dealership, and them diagnosing no abnormal loads on the battery haven't fixed anything. Using a NOCO Genuis5 battery charger, I can basically prevent the issue by plugging the battery in for about an hour before starting the car after a few days. These chargers have a battery level monitor though, and when plugged in, it immediately reads that the car's battery is almost fully charged, yet it still needs to be plugged in for ~an hour before the car will actually start.

Anybody have any clue what this issue may be? Summary is: no excessive power draws/loads on a new battery (according to dealership), car wont start after a few days, using battery charger it seems like the battery needs to be "topped-off" before it will start even though the charger reads >75% charge.

Thanks so much

 

Have you tried the alternator?

 

Alternator seems to be fine. As long as I'm driving it every day or every other day, I don't usually have an issue

 

How did they go about checking the power draws or excessive load on battery? They should come back and check after the vehicle has been turned off after a couple of hrs. I have seen bad alternators work just fine while the vehicle is on,then start drawing power after being turned off do to it going bad. not saying that is what it is but could be a possibility

 

Starter draw and alternator output passed tests. Ignition-off draw was 0.06 amps after 15 mins, so ok. I'm guessing they didn't leave it for a few hours before doing the ignition-off draws though

 

60 mA draw should be ok. (at this rate it would take about a month to drain the battery)

Make sure the battery, alternator and starter connections are corrosion free.

I would set up the ammeter meter to "max peak" and leave it connected for a few days. This will verify if a module is waking up and drawing current.
Also measure the battery voltage a few hours after turning off the engine, then measure it every day.

You can also remove some fuses in the IPDM/ER and see if the draw stops.

 

Older 2010 G37X owner with similar problem and blue ribbon certified mechanic for Son - we found the Starter Solenoid might be dying, test amp draw on starting if drops below 10v to say around 6 or 4 and fails to turn over starter may need to be replaced. Before ordering and taking out the part check the leads to it aren't corroded and may need to just be cleaned. Rockauto.com for cheapest parts - recommend the BBB rebuilds.

 

I recently had a weird cranking issues on VHR swap. It would accept charge for 2 minutes and then "Full Charge" but would give dead battery signs.
Added a big ground and still, charged up the battery a bit more + jumper + battery tender was the only way I could get crank.

Ended up being a positive battery post that had remnants of the melted black plastic cover of the battery cable terminal preventing full contact.

The cranking system is not that complicated but the VHR is extremely dependent on it and proper voltages. I've had an engine not start due to it going down to 9.5v, at this voltage I noticed that the throttles would not turn on. (lets you know a bit more about voltage necessities)

I would start with a fresh Positive battery terminal. I would also start with a fresh upgraded Negative battery cable (this can be a bit tricky to achieve). Since I have the tools, I would check total resistance of the starter cable, though these power cables are stout units made by Sumitomo, they are susceptible to corrosion from the battery.
Starting with these fresh components, charge your battery to 100% and leave it in the car disconnected and monitor voltage drop. Once you eliminate the battery has not deteriorated from the constant cranks and drains you can move onto the car.
If the problem still persists, the your issue is an amperage draw when the vehicle is off. If you have the tools to check the draw go ahead, there are a few TSBs about amperage draw killing batteries.

In 08-09 there was a TSB that pointed that the EVAP vent valve was the fault of this draw, though it doesn't talk about it affecting newer years, it's possible that I is.

 

I will like to remove my starter on G37X, 2012 , can any one provide any advice to the best way to remove the starter, i check youtube but I got very little info. Thanks guys.