Car revving without applying gas?...

ChrisSlicks · 02-21-2012, 06:35 AM

Quote:

Originally Posted by RLM2390

Hey man this happened to me a couple of times. I noticed it happening when its really cold out and when the car hasnt warmed up. Other then that I have no idea on what it could be but I would like to find out why.

This was my experience as well. I tried it with SRM off as well, think it is something to do with the stock tune, went away after an uprev tune.

Nick911sc · 02-21-2012, 07:19 AM

Car was definitely warmed up, it happened 20 minutes through my drive. I'm going to just assume it was a SRM glitch as it's never happened before and it didn't happen again. Unfortunately, you guys have scarred me for life and I won't be able to get into my car without thinking someone or something is in my back hatch waiting to strike when I least suspect it.

ChrisSlicks · 02-21-2012, 08:23 AM

Quote:

Originally Posted by Nick911sc

Car was definitely warmed up, it happened 20 minutes through my drive. I'm going to just assume it was a SRM glitch as it's never happened before and it didn't happen again. Unfortunately, you guys have scarred me for life and I won't be able to get into my car without thinking someone or something is in my back hatch waiting to strike when I least suspect it.

The only time I've seen this happen when warmed up at a stop like this was when there was a problem with the accelerator pedal unit. If the pedal sticks just a hair then it will be sending a higher pedal up voltage than it was originally calibrated for. Re-calibration might fix it short term, but worst case the pedal needs to be replaced. Either way I wouldn't worry about it too much unless it starts reoccurring regularly.

KingZee · 02-21-2012, 12:15 PM

Quote:

Originally Posted by Vince

The whole idea of SRM is to help when downshifting going into a corner, when you are slowing down. It's intended so you don't use the engine to help slow you down. That's what the brakes are for.

Huh? Rev matching while downshifting isn't a new thing. The SRM just uses a computer to assist you in doing so. Down shifting before a turn is used specifically (in racing at least) to assist the brakes in slowing down and allow you to be in the correct gear coming out of the turn at maximum acceleration.

ChrisSlicks · 02-21-2012, 02:16 PM

Quote:

Originally Posted by KingZee

Huh? Rev matching while downshifting isn't a new thing. The SRM just uses a computer to assist you in doing so. Down shifting before a turn is used specifically (in racing at least) to assist the brakes in slowing down and allow you to be in the correct gear coming out of the turn at maximum acceleration.

It has nothing to do with braking really. Yes there is a slight engine brake effect, but the reason that you blip the throttle is to synchronize the gears for a quicker smoother change (racing gearboxes often don't have synchro's). Engine braking happens but it is actually not desirable as it messes up your brake balance. I've taken to downshifting a lot later and at lower RPM than I used to for that reason.

KillerBee370 · 02-21-2012, 02:29 PM

The problem is that cars are run entirely on computers today.

Nick911sc · 02-21-2012, 02:29 PM

Quote:

Originally Posted by KillerBee370

The problem is that cars are run entirely on computers today.

Completely agree... I'm itching to get something old school lol

Jordo! · 02-21-2012, 02:32 PM

Weird. If it happens again you might want to have the accelerator pedal greased or something -- could be sticking.

Nick911sc · 02-21-2012, 02:34 PM

If it were sticking wouldn't it have continued to rev after I took the car out of first into neutral? I never touched the gas pedal between putting it into first from neutral and then back out.

Jordo! · 02-21-2012, 02:48 PM

Quote:

Originally Posted by Nick911sc

If it were sticking wouldn't it have continued to rev after I took the car out of first into neutral? I never touched the gas pedal between putting it into first from neutral and then back out.

Yeah, guess that's not it then.

If it's the SRM logic, there might be a reflash option? haven't heard of anyone else having this problem tho'...

If still under warranty, they'd probably just reflash or replace the ECU if it happens again and couldn't be traced back to something like a faulty TPS sensor.

Nick911sc · 02-21-2012, 02:51 PM

I avoid Nissan dealerships like the plague (any dealership for that matter).. So I'll just keep driving and see if it happens again.

Jordo! · 02-21-2012, 03:05 PM

Quote:

Originally Posted by Nick911sc

I avoid Nissan dealerships like the plague (any dealership for that matter).. So I'll just keep driving and see if it happens again.

Fair enough. Only worth it if something needed to be replaced under warranty anyway.

Any pending CEL/MIL/SES codes? A faulty TPS sensor would probably trip that. If you don't have a scanner, I think autozone does that for free still.

Nick911sc · 02-21-2012, 03:12 PM

Nope never had any codes thrown on my car. My tires needed air since being in the garage and the cold weather, but I filled them to the proper pressure and the light turned off.

AlphaSnacks · 02-21-2012, 03:41 PM

Odd glitch. I'm sure it was just a SRM oddity.

ChrisSlicks · 02-21-2012, 04:06 PM

Quote:

Originally Posted by Nick911sc

If it were sticking wouldn't it have continued to rev after I took the car out of first into neutral? I never touched the gas pedal between putting it into first from neutral and then back out.

Good point. The weird thing is that SRM is only activated in the gate area so it shouldn't have been trying to rev while in gear - especially not while stopped. SRM target RPM is a function of gear ratio gate position times speed, so if speed is zero it shouldn't be doing anything.

02-21-2012, 02:32 PM	#23 (permalink)
Jordo! A True Z Fanatic Join Date: May 2010 Location: nirvana Posts: 6,394 Drives: 2023 NATM Rep Power: 418	Weird. If it happens again you might want to have the accelerator pedal greased or something -- could be sticking. __________________ Enjoy it. Destroy it.

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02-21-2012, 07:19 AM	#17 (permalink)
Nick911sc A True Z Fanatic Join Date: Feb 2009 Location: Long Island, New York Posts: 1,698 Drives: 2010 Nissan GT-R Rep Power: 20	Car was definitely warmed up, it happened 20 minutes through my drive. I'm going to just assume it was a SRM glitch as it's never happened before and it didn't happen again. Unfortunately, you guys have scarred me for life and I won't be able to get into my car without thinking someone or something is in my back hatch waiting to strike when I least suspect it.

02-21-2012, 02:29 PM	#21 (permalink)
KillerBee370 A True Z Fanatic Join Date: Mar 2009 Location: So Cal baby! Age: 51 Posts: 5,964 Drives: with passion Rep Power: 321	The problem is that cars are run entirely on computers today.

02-21-2012, 02:34 PM	#24 (permalink)
Nick911sc A True Z Fanatic Join Date: Feb 2009 Location: Long Island, New York Posts: 1,698 Drives: 2010 Nissan GT-R Rep Power: 20	If it were sticking wouldn't it have continued to rev after I took the car out of first into neutral? I never touched the gas pedal between putting it into first from neutral and then back out.

02-21-2012, 02:51 PM	#26 (permalink)
Nick911sc A True Z Fanatic Join Date: Feb 2009 Location: Long Island, New York Posts: 1,698 Drives: 2010 Nissan GT-R Rep Power: 20	I avoid Nissan dealerships like the plague (any dealership for that matter).. So I'll just keep driving and see if it happens again.

02-21-2012, 03:12 PM	#28 (permalink)
Nick911sc A True Z Fanatic Join Date: Feb 2009 Location: Long Island, New York Posts: 1,698 Drives: 2010 Nissan GT-R Rep Power: 20	Nope never had any codes thrown on my car. My tires needed air since being in the garage and the cold weather, but I filled them to the proper pressure and the light turned off.

02-21-2012, 03:41 PM	#29 (permalink)
AlphaSnacks A True Z Fanatic Join Date: Jan 2010 Location: Windermere, FL Posts: 1,618 Drives: '13 XKR-S, '10 370Z Rep Power: 18	Odd glitch. I'm sure it was just a SRM oddity.