Car revving without applying gas?...
 

Alright guys,

I had a pretty weird experience tonight on my way home from my gf's house. About half way through the drive i was stopped at a light, car in neutral. I had 1 foot on the break and pushed in the clutch and began going into first gear. As soon as I put the car into first gear(clutch still in, foot on the break) The car reved up to like 4500RPM's. It wasn't a blip.. It was a steady climb. I pulled the shifter out of first into neutral and the RPM's dropped back to normal. When I put it back into first it didn't do it again. And for the rest of the drive home it didn't do it either.

Not really sure what to think, has this happened to anyone else? 2009 6MT VDC on and SyncroRev on as well

Nope. Hi Nick! :D

Something similar happened to me once. I was sitting at the end of a parking lot waiting to trun onto the street. Same story -- clutch in, foot on the brake -- and I heard something odd. I looked down and I the engine was climbing from 5,000 RPM up to 6,500. It was doing this slowly. I realized that my foot placement on the brake was very sloppy and I was actually pressing on the accelerator with the side of my foot. No excuse, but I was wearing wingtips at the time.

This or synchrorev malfunction. I'd be worried only if it happens again

Thanks guys, I'm pretty sure my foot wasn't hitting the gas pedal. I slid my foot all the way to the left half of the pedal while it was happening because I assumed that's what was happening. Crossing my fingers that it won't happen again.

Hope everyone's been well since I haven't been around too much!

(Kenchan stole my eggcorns)

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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.

could be throttle position sensor. I had one that acted up intermittenly on a former car. Most of the time it was no problem, was always worse when hot outside.

Cold outside, bad spark plugs, bad coils, or electronic defect. Just from my experiences from the rx8

That has happened to me one time, and a cop was next to me lol.

I think you've encountered the haunted Z ghost .... lol!

I think it is with the synchro rev. Mine is annoying that way revs when I don't want it to. People think I want to race when I am downshifting thing revs for no reason other than to waste gas. I had it off for a while and enjoyed the car a little more. The idea is great, but the program needs modification should not rev match when I am slowing or want to use the clutch to help brake.

Never happened to me but in your case this shit's in your car bro...

http://www.saviodsilva.net/life/g8/ghost.JPG

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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. :)

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.

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.

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.

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

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

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

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.

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.

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.

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

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.

yah, sounds more like a glitch in idle map vs SRM.

at least on MT you can just clutch-in if something goes wrong.

Imagine if I took my foot off the clutch while this was happening? lol

you would immediately clutch-in again i think just from reflex. :D

I'd assume so, if not we'd have another I crashed my Z thread but its all Nissans fault for X reason!

hummm... have you done a idle pedal reset? if not check out my DIY in the DIY section for putting touring pedals on the base Z. i have a sequence there. it's easy to do. :)

will do, thanks for the suggestion.

Looks like Nissan will be the next make with runaway cars...move out of the way Toyota! :p