Just for drill, do you have a grounding kit installed with a new negative battery lead? The reason I ask is that there is a current sensor on the stock negative battery lead. If the sensor outputs nothing then the ic regulator defaults to a certain output voltage. I am not sure entirely what effect that has but a new negative battery lead or a second one will essentially bypass this sensor on 07 and up sedans (and possibly the coupe).

 

So this week, I noticed that the trunk sometimes did not open from the key fob. I didn't think much of it though. They yesterday, I run some errands and while out, the "press clutch" is flashing when I try to start the car even though I am pressing the clutch. I just did Intgr8r's clutch mod recently so I double checked the clutch switch is firmly in place. After a while, I start the car somehow. Then today, I am out shopping. I notice when trying to get in, the doors do not unlock from the keyfob. I use the key and then notice the keyfob is not recognized, nor will the car start with the fob in the socket. The start button does nothing. I get out and the doors do not lock when pressed. I see an officemax so went and got a CR 2032, maybe thinking the keyfob battery is out. I come back find the car stereo is on and the car is in ACC mode--must have turned on while I was at officemax. The windows and doors switches work but the keyfob is not recognized as being in the car. I put the keyfob in the socket again, and again, the "press clutch" is lit up even though I'm already on the clutch. After a time, the car starts somehow and the check engine light is on. I get back home. I check the code: some fuel sensor overvoltage and then check the battery: 12.1V and only 75% capacity despite a 20 minute drive home. I buy a new battery at Samsclub and all is well again.

Bottom line: some strange stuff happens when your battery is weak but not quite dead.

Just FYI, this OE battery was not even a year and a half old. The dealer replaced my original battery at 9 months old because I had problems with leaving the car for a week and having a dead battery. Unfortunately the same thing happened with the replacement. The dealer checked things out and said the power draw is normal, so I went with a trickle charger for when I plan to leave the car sitting for more than a few days.

 

If you have any further problems check another item right off - your steering wheel lock.

I have an 08 XS which is of course auto. In my case I have had a few no starts and the car ended up in the dealers hand for over 16 days related to this issue. It did toss some codes. Brake pedal switch, steering lock, starter relay, etc. The IPDM was replaced the first time, it failed the next day. Typically it would start after awhile of playing with it. After about a month it happened again, this time the flat bed came and picked it up. Took almost two weeks to get it back with the BCM replaced as well as various other things addressed. It failed twice the next day but with one exception has been ok since then. On that one exception I may have caused it. However on that one exception I remembered what one tech told me and that was to get out of the car and start over from scratch based on a previous experience he had.

Well that worked and the car has been good since then. Now one common item even without the code generated was the steering was not locked. This is part of the start logic.

Another item since you were also messing with the key fob. Another tech told me that you want to be sure that you do not press multiple buttons at the same time as there is a combination that will lock you out of operating the car and this was seen with a user with it in his pocket.

Hope the battery fixes it but if not then I would pay very close attention to everything. I actually had the car start a second or so after releasing the brake pedal and the start button on a no start, I was leaving the car.

 

Had a battery failure at 2 years (5,000 miles) without warning. The dealership checked for any charging/discharging issues and fitted a replacement OEM battery, with a prorated cost to me.

Six months later, same thing happened, checked again at the dealership, no faults reported.

I need to know that the engine will start every time, so am looking at getting rid of the OEM battery. I use Odyssey batteries on my other cars, does anyone happen to know which model would be best for my G35 and if there are any other things to watch out for (fitment problems etc.).

Many thanks

 

Any modifications such as a grounding kit with a new negative battery lead?

 

No, same as it came out of the factory... thanks for your reply.

Probably, the OEM battery is junk, which is why I am looking for a better alternative. The difference between an exceptional car and something that has been made to look exceptional, is this sort of attention to detail, such as trim falling off or rattles that could be prevented.

This is a highly competitive market segment, Infiniti does not need to get a bad reputation over something preventable and relatively minor. Incidentally, the dealership provided a loaner, the 2009 G37 sedan. I can not properly explain why, but the 2009 does not feel as plush as my 2007, is noisier and just has a feel of being very ordinary.

This is the second time I have been loaned a 2009 and the previous one had a very ugly noise coming from the engine. Is it possible that Infiniti are trying to cut back on quality.?

Pinnacle Infiniti in Phoenix have definitely lost any quality they might once have had, I am not going back there. It goes against my principles to support bad service or products.

 

I agree on the issue of reliability, so far my car with just over 15k has been far less reliable than my other ride with just over 150k. The speakers will make the doors buzz, as well as a couple of other issues. The dealer had it in for a problem for over 16 days but had less than 8 hours charged to the job. Three times it has suffered damage by the dealer (which they fixed). It seems to be ok now but then it was before it totally died last time.

In any case the reason I brought up the issue with the 'new negative battery lead' is that the OEM lead passes through a current sensor on 07 and up which is part of your charging circuit. If you bypass this by adding or replacing a negative battery lead chances are your system is now running at a default setting and not watching the battery as designed.

No matter how you feel about grounding kits I think this is one lead that should not be replaced and I have noticed a lot of complaints about batteries, etc. by those with grounding kits installed on these late model cars. Once started the car runs on the alternator so the only main thing the negative battery lead does is charge the battery and provide whatever capacitance, resistance, influence the battery may provide. I measures this at a maximum of 5 amps shortly after the car is started and I believe this was the battery charging after a start. It then drops to less than 2 amps which is where my meter stops being accurate. The positive leads during this time may have a current flow as much as 41 amps. In other words the stock lead is plenty for the use. Since you are running off the alternator the ground reference for the car is actually the alternator not the battery.

This is not to state that the OEM battery is not a piece of junk, just that I have noticed many with problems having the same common modification. I don't think they realize the existance of the current sensor on the newer models.

 

Good point on the grounding kits. It could fool the current sensor connected to battery negative terminal into thinking the power draw is low and lower the alternator voltage. When the battery is fully charged, the alternator puts out 12.9V. When needing charging, it is around 14.3V.

I don't have any grounding kit on my car. The two OEM batteries just could not hold charge long, especially in winter. Ultimate, the battery discharges cut their lives short i think. Hopefully this aftermarket battery solves the problem.

 

Mine has made it through its first year so hope that holds up. If it doesn't then maybe it is one of those non-essential part that helps keep the price of the car low enough. In some case what is OEM in the car from the factory is not really the same as OEM at the dealer, but then with two going bad on you I would go with something else. One brand battery I have been buying for years without every having an issue is Interstate. I have had these for up to 10 years without failure. Typically I have gotten rid of the car long before the battery became an issue.

 

So... Anyone know what series battery fits our sedans?

 

My battery was replaced after about 2 years ownership (about 40,xxx miles).

 

I just had to replace my battery after 2.5 years.

 

Does a grounding kit have any effect on the life of the battery? I order from black betty, will I be dissapointed I dont have any stereo mods or such. The reason I'm getting it is mostly for looks in the engine bay and hopefully a smoother 2nd and 3rd shift.

 

First off I am not a fan of grounding kits on cars period as long as the factory grounds are intact. Clean up your grounds, do the ECM reset and many have reported the same so called benefits. Also if the design has stacked grounds (example - ring connectors greater than 2 high) the center connector can easily be at a different potential than the other two due to the resistance between connectors (and only gets worst as it ages). The top and bottom connector may be at the same potential due to contact with the block and bottom of the head of a bolt (which has its own resistance) but the center connector now relies on a low resistance of the other two connectors. Non cold welded connectors which are the norm will add their own resistance to the project.

So to me if one designs a grounding kit do it correctly, avoid circular currents by not placing in conjuction with stock grounds at different potentials (or using techniques which can lead to it (ie stacked grounds), use wire gauge for signal purposes and not looks, do not use ring connectors, use grounding blocks instead of stacking grounds, connectors if used should be cold welded (ie. Cadweld) etc. If you must use ring connectors use cold welded ring connectors and connect them to a grounding ring, not stacking on a bolt.

Since the 'G' uses balanced sensor inputs then no benefit for sensors should be shown since the sensor itself is not directly grounded. A typical balanced sensor has a positive and a negative (note not grounded) lead and possibly is surrounded by a 'drain' line which is typically grounded on one end only. This is to prevent noise injection by the drain line which could occur if grounded on both ends.

Now back to your grounding kit and charging the battery. On 07s and up the negative battery lead has a current sensor which tells the alternator what voltage to put out based on battery condition. If the output of the current sensor is not seen for any reason then the alternator will fall back to a default value based on the characteristics of the alternator IC.

So if you added a negative battery lead to the mix chances are you just bypassed this current sensor and either took it completely out of the picture or reduced its output by a ratio of the new wire size resistance versus the stock size. Assuming both were of the same size and the battery had a draw of 5 amps the current sensor would only see half of this since the current flow then is split between the new and old cables.

This new cable should not be necessary since the car runs off the alternator and the ground reference is the alternator ground, not the battery which is simply a load. The only possible benefit of the larger ground cable would be for the capacitive, resistive, and inductive characteristics of the battery (assuming the stock ground is in good condition). The jury is still out in my mind about a possible benefit of a fast discharge capacitor added to the circuit as provided by some grounding kits. The battery is not designed as a fast discharge capacitor and its capacitive benefits would not be the same.

On my car the alternator voltage typically follows this pattern. With all loads without headlights. After starting 14 volts slowing dropping over the next couple of minutes to about 13 volts. With headlights on it will drop to about 12.6 - 12.8 and then slowly creep up to about 13 volts. These are the values which are from the OBD read outs which I have compared against my fairly good quality DMM.

I have a hard time stating that your battery will suffer but my guess is that at least initially in the sequence of events it will be 'affected' since it will not be seen correctly. If I remember correct the alternator ic adjust voltages in .5 volt increments so with it out of the picture once 'may' be able to assume (maybe incorrectl) that the battery could be left in a condition other than desired.

I don't fully have a grasp on the statement in the FSM aluded to above which is 'based on the characteristics of the ic'. This could mean that the alternator is simply following system load excluding the battery sensor. Also note there could be a slight mileage change as well based on the statement about the purpose of the charging scheme.

 

You really know your stuff from the sounds of it. Very sufficient, Thank you for you time to evaluate my question.