monty2003

Also, acceleration is not applied to wheels. Torque is applied to wheels and if the torque is greater than any friction in the drivetrain opposing that torque (including brakes), the car will accelerate.

In the OPs case, the car is NOT accelerating as he is not moving when experiencing the high idle.

mathnerd88

iTrader: (1)

True. I guess I accidentally forgot that heat is only generated by kinetic friction, or when the surfaces move and that the frictional force is doing work.

mathnerd88

iTrader: (1)

He is not accelerating because the torque (which is considered force in the rotational world) is counteracted by the frictional force.

Thus, the forces cancel each other out- when the force of the torque is higher, the frictional force is also matched, so frictional force is greater. This cancellation is what causes no acceleration, and thus, no net force.

Plus, torque can be converted to translational force of the wheel. You can think of a wheel is a finite point that has a force applied to it horizontally parallel to the road, not as a rotating object.

Basikk_

iTrader: (1)

So no response/update from the OP yet?

moomax

Hey guys, appreciate the replies! Just wanted to add a few comments here:

1.) The car was completely stopped when it was still trying to push forward. It wasn't a super strong push but it was definitely more than what would happen if you just let your foot of the brake with an automatic transmission.

2.) The problem "fixed" itself after I powered the car off then back on again.

3.) I didn't analyze the situation too too long as I was in the middle of a slow but still traveled road.. however, I did pause long enough to check that:
a.) my foot was NOT on the gas
b.) the tachometer was hovering higher than it normally would.
c.) as I slowly lifted my foot off the brakes, the car started to pull forward more than it normally would

This is the first time this issue ever happened and I've been driving the car straight for 2 years now with 34k miles on it so I do have a pretty good feeling for how the car behaves normally. The only somewhat recent change I had done to it was a brake fluid flush at 30k and the transmission was reprogrammed by the dealer to fix the shifting delay issue somewhere in the 20s.

I'm due for another oil change soon so perhaps I should just bring it in early and have them look at it... Just wish it was reproducible or I had some way to show the issue happened. Maybe i'll get lucky and something logged in the computer?

dirtymaf

I just had this happen to me yesterday, though it's not the first time. I was driving very low speed, less than 5 mph and pulling into a parking space. I was putting my foot on the brake as I began to pull in and nothing happened. Then I hit the brakes hard, still felt like it wasn't responding, then tried to throw it in neutral but by then it was too late and I hit the bumper of the car in front of me. I left him a note to contact me, fortunately the damage wasn't bad, but I'm very concerned about this now.

I tried to find other instances of this happening in the G, but reports look pretty sparse and have a feeling the dealer will blow me off.

The last time it happened I specifically remember I was coming to a stop light and it felt like the car was taking off on me. I threw it neutral to stop and noticed the RPM was above 1500. When this accident occurred I didn't have time to look at the RPM, I had less then 2 seconds to react when it started.

I don't think it's possible I was also hitting the gas, I have an x auto and I have to get my foot into a pretty awkward position to be hitting both pedals. I'm not sure what my options are here, but I no longer trust the car to stop properly.

rpm&my_G35

^ The way you explained your event/situation, in the first paragraph, it sounds more like you have a braking problem.
If you hit the brakes hard, even if the engine is revving at 2-3k RPM, the car should stop.
Good luck with the dealer diagnosis.

mathnerd88

iTrader: (1)

Yes, sounds like you have a braking problem. You should get it checked out. Brakes are supposed to overpower the car's engine, and I know that the computer system is supposed to cut out the throttle when the brakes are applied.

Remember the Toyota acceleration problem?

Nissan touts it as the "brake throttle override system," which was standard in every Nissan vehicle since 2005. I don't believe the car will lurch forward when the brakes are applied.
http://www.thecarconnection.com/news...tandard/page-3

That's why I think this incident is completely isolated. The OP would have been fine as long as his feet were on the brakes. Even if the car wanted to lurch forward, the brakes are much more powerful and would keep the vehicle stopped.

johnycanuck13

Newbie here. The identical situation happened to my wife this past week. Stopped in stop and go traffic in our 2012 G37X, and the car moved forward while she pressed harder and harder on the brake. Moomax, dirtymaf, did you ever get a resolution to or a definitive identification of the problem? I had the car towed to an independent garage and had all the codes scanned but it didn't show anything. Thanks in advance for your help.

Paceship

Same thing happened to me.
Here's my post from a few days ago


Has anyone experienced a sudden engine surge while in gear? Here's what happened to my G37x.
After driving nearly 5 miles, I stopped at a grocery store. After just 5 minutes, I was leaving the lot exit and had to stop and back up a little to let a car go by. After putting the transmission back to drive (my foot still on the brake), the engine suddenly raced and although my foot was pressing hard on the brake the rear wheels started turning fast trying to push the car forward. I quickly put the car in neutral and the engine continued at high RPMs for a couple of seconds before returning to a neutral idle.
I tried duplicating the situation to no avail.
I called the infiniti service dept., but they said they never heard of such an incident. It's not a floor mat issue with the accelerator.
Scary time I would not like repeated. If I did not have my foot on the brake I would have lurched out into the street

KCM

If you search "Accident due to throttle surge while braking", you would have found my post in 2010 regarding the same issue. I still owned the vehicle. The problem that I experienced had not happened again. However, I still believed I did not cause the accident as others had speculated. I speculated that while my car was "inspected" by the Infiniti representative, they might have reprogrammed my car. I stopped posting as I was frustrated with other people accusing me causing the accident, i.e. I stepped on the gas causing the car to move forward. I can tell you I have been a driver for over 30 years, including a Datsun Stanza and a Nissan Maxima. If I had stepped on the gas and brake at the same time, I knew. I tried doing that with the Infiniti hoping to duplicate the accident, as stated in my post, I had to do so deliberately that it was virtually impossible that I would have moved the car that much without realizing the error. At the end of the day, I was not trying to tell others that I did not cause the accident. All I was trying to do with my original post was to see if other people had similar problems and perhaps warned others about it.

johnycanuck13

Paceship, KCM, thank you for the replies. My wife and I both thought about driver error immediately but she's never had an at-fault accident and this is our second G--we had a 2003 g35--and neither one of us had any experience of stepping on the brake and accelerator at the same time. I searched the NHTSA site and found a few similar instances. I plan to assemble a file and send to Infiniti Canada. Ultimately, if we can't be sure the car is safe, we'll have to sell it and move on.