Why Did My Z, Keep Revving? Video.

JB1 · 01-31-2010, 06:49 PM

Quote:

Originally Posted by TheWeatherman

But AK was movin' though! Mine does that too just to keep the revs up enough so if you select a lower gear, it doesn't have to rev so dramatically. I'm trying to think... Doesn't it shut itsself off/let the RPM drop if you leave your shifter in the same spot, outside of any gate, without motion after a few seconds? I'm just asking. It's like the car saying, "Okay, no gear selected rev matching? I'm going to leave you idle in neutral." Just a question. Not a fault. My SRM works/(worked

) perfectly everytime!

After reading this thread, I tried the "put the shifter in neutral" while driving, and your right Weatherman, the revs go up as in AK's video but they drop after a few seconds. So it's like SRM is concluding "OK, your not going to continue shifting into a lower gear, no need to keep the revs up" I tried it in 6th, going about 60~70MPH. Shift to neutral and RPM's go up to about 4K RPM, so perfect for a shift to 4th, but too high for a shift to 5th, which is kinda strange I think.

However, non of this explain what happened to The Weathermans car. I sure hope it's not something like what Toyota is dealing with now...

Here's the Toyota problem explained (this is also interesting for all of you who want to know how our electronic throttle pedal works)

UPDATED: Video: In-depth look at Toyota's sticky accelerator — Autoblog

MightyBobo · 01-31-2010, 07:46 PM

Quote:

Originally Posted by JB1

After reading this thread, I tried the "put the shifter in neutral" while driving, and your right Weatherman, the revs go up as in AK's video but they drop after a few seconds. So it's like SRM is concluding "OK, your not going to continue shifting into a lower gear, no need to keep the revs up" I tried it in 6th, going about 60~70MPH. Shift to neutral and RPM's go up to about 4K RPM, so perfect for a shift to 4th, but too high for a shift to 5th, which is kinda strange I think.

As long as the clutch is pressed in, SRM will try to blip the throttle when the shifter is moved around. The 3 "major" positions are 1/2, 3/4, and 5/6 of course. If you shift to neutral, clutch pressed in, and release the shifter to its dead-center position, SRM will automatically blip to the MINIMUM amount for the highest gear in that position. That'd be 4th gear. If you decide to go into 3rd, it will of course, blip higher. Same goes for 1/2....it will rev to 2nd gear as soon as you slide to the left, but if you go into 1st instead, it will go higher.

Purpose for this is because its not going to assume you want to rev to the LOWER gear automatically, more than likely to save gas Im sure. Its obviously fast enough to catch if you decide to go higher, and blip accordingly.

If you dont want SRM mucking with your RPM's when you move the shifter in the positions, just release your clutch...SRM stops blipping at that point.

JB1 · 01-31-2010, 08:09 PM

Quote:

Originally Posted by MightyBobo

The 3 "major" positions are 1/2, 3/4, and 5/6 of course. If you shift to neutral, clutch pressed in, and release the shifter to its dead-center position, SRM will automatically blip to the MINIMUM amount for the highest gear in that position. That'd be 4th gear. If you decide to go into 3rd, it will of course, blip higher. Same goes for 1/2....it will rev to 2nd gear as soon as you slide to the left, but if you go into 1st instead, it will go higher.

OK, that makes sense, thanks for the explanation.

But I did notice that, if you leave the shifter in neutral and you release the clutch, SRM will still hold the RPMs up for a few seconds. Not that is matters though, just an observation.

MightyBobo · 01-31-2010, 11:12 PM

Correct, it holds it for a moment just incase you decide to press the clutch back in and pop it into gear, but it wont wait forever

. After a moment, it just disables, and no more bliping of the throttle.

IcedZ · 01-31-2010, 11:34 PM

Weatherman, let me know what you find out. Mine did the same thing twice. Once per day two days in a row. Mine held at about 2k RPM though, definitely not 3500+. I live in central Florida, so it's not NEAR as cold as you were. I also am over 99% sure it is not SRM. I wiggled the stick in neutral and in and out of gears and let off the clutch in neutral... it was still revving. Both times that this happened it was after a 10+ mile drive on the intersate going about 80. So everything was up to normal operating temperature. Both mornings were cold, but not the coldest that we had. It was definitely bizarre. I cannot get it to repeat anymore now (I'm thinking because it's warmer outside).

Pharmacist · 02-03-2010, 09:41 AM

Quote:

Originally Posted by spearfish25

Keep us posted on the resolution.

I find this issue a bit disturbing 1) with the Toyota recall ongoing and 2) with the fact that my wife would not be well suited to dealing with this issue if she's behind the wheel. If the revs climbed like that on her, I'd guess she'd end up in another guy's bumper or in a ditch. You guys with 7ATs should be a bit concerned too. It's a no brainer going to neutral or clutching if the revs go bonkers in the 6MT. You'll have to have some quick thinking if it does it to you in the 7AT.

why not just pop the 7at into neutral? that's the thing that also puzzles me about all those out of control toyotas with stuck throttles. even if its automatic, it should still have a neutral position.

MightyBobo · 02-03-2010, 09:48 AM

Quote:

Originally Posted by Pharmacist

why not just pop the 7at into neutral? that's the thing that also puzzles me about all those out of control toyotas with stuck throttles. even if its automatic, it should still have a neutral position.

And you have just proven why Darwinism exists...

I have asked myself this EVERY time I heard about people dying due to a "stuck" throttle...

m4a1mustang · 02-03-2010, 09:54 AM

Well most people don't know a thing about cars... in a panic situation they just stand on the brakes.

Zsteve · 02-03-2010, 10:14 AM

Quote:

Originally Posted by m4a1mustang

Well most people don't know a thing about cars... in a panic situation they just stand on the brakes.

True dat, unless you are used to being in bad situations, when you are in one you wont think like you do when you are watching it or hearing about it, you just do what seems natural and slam on the brakes. Its like making good decisions in any situation, you have to have been there and done that before.

Ever come across those people that can answer every question of a game show while sitting on the couch? Get them at the studio and they freeze up.

ChrisSlicks · 02-03-2010, 10:24 AM

Quote:

Originally Posted by m4a1mustang

Well most people don't know a thing about cars... in a panic situation they just stand on the brakes.

Yes, they stand on the brakes, which of course promptly overheat and stop working thanks to their low noise, low dust organic formulation. Actually it's because they don't hit them hard enough, you need to stomp them hard, probably with both feet if you are a girl or a girly man. Of course the other obvious alternative is to shift to neutral or even shut of the ignition (although that's probably the last thing you want to do in a panic situation).

Here's an except from C & D this month. Surprisingly they could stop the cars only a few feet longer than in the regular braking test.

Quote:

Hit the Brakes

Certainly the most natural reaction to a stuck-throttle emergency is to stomp on the brake pedal, possibly with both feet. And despite dramatic horsepower increases since C/D’s 1987 unintended-acceleration test of an Audi 5000, brakes by and large can still overpower and rein in an engine roaring under full throttle. With the Camry’s throttle pinned while going 70 mph, the brakes easily overcame all 268 horsepower straining against them and stopped the car in 190 feet—that’s a foot shorter than the performance of a Ford Taurus without any gas-pedal problems and just 16 feet longer than with the Camry’s throttle closed. From 100 mph, the stopping-distance differential was 88 feet—noticeable to be sure, but the car still slowed enthusiastically enough to impart a feeling of confidence. We also tried one go-for-broke run at 120 mph, and, even then, the car quickly decelerated to about 10 mph before the brakes got excessively hot and the car refused to decelerate any further. So even in the most extreme case, it should be possible to get a car’s speed down to a point where a resulting accident should be a low-speed and relatively minor event.

Full article:
How To Deal With Unintended Acceleration - Tech Dept.

TheWeatherman · 02-03-2010, 10:56 AM

Hey ChrisSlicks, thanks for posting that C&D article. I see that Nissan/Infiniti has that throttle cut feature. For some reason, mine didn't do that. It was pulling faster with my foot on the brake. Here's the catch, I didn't slam on the brake, I just hit it light/moderate. (I was getting close to an exit on a 55MPH highway. I just hit the clutch and coasted down the ramp after I could feel the car pulling on me. It was speeding up over 60MPH with no cruise and no foot on the gas.) I wonder if there's a threshold of cutting the throttle. As I came to my first stop, I was revving over 4,500 RPM without any let-off on the RPM. Of course I knew to just hit the clutch and let the car do it's thing. It didn't feel very nice trying to have a decent start and burning the clutch though. I'm pretty sure if I would've popped it, the wheels would've slipped a bit... That's how much throttle was being applied to the car as I was taking off. She was on a mission, and that mission was to keep on revving. I still haven't heard a peep on what happened. Your C&D article makes this even more bizarre. I'm still positive it wasn't my floormats because when I got to my first "revved" stop, I pulled my floormats away from the pedal. I really just thought it was my mistake. 4,500 RPM is really up there. I started taking a video after I restarted the car twice. That was about 8 minutes after the 4,500 RPM events. Just trying to put it all in perspective for you.

ChrisSlicks · 02-03-2010, 12:13 PM

With the throttle cut feature on the Infiniti and our Nissans, you do have to press the brake reasonably firmly. With the brake pressed the throttle input is cut back (but not cut completely) if the throttle input is moderate to high. If the throttle input is light then it will let you press both pedals at the same time and wont interfere.

As it doesn't take a lot of throttle input to rev to 4500 rpm unloaded (out of gear) I'm guessing that the throttle input signal wasn't high enough to warrant a throttle cut. Even with a throttle cut you would feel the car pull on you a little as you braked but it would be easy to overcome by braking firmly.

Would be interesting to see what voltage the APPS (accelerator pedal position sensor) is sending out in the misbehaving case. From that you could determine if it was a bad sensor or if the ECU needs to recalibrate a new up-pedal voltage. Bad sensors are rare because they do send out 2 redundant signals. It could be that the dealer screwed up the calibration by disconnecting the harness when you took it in for something else. I'll check if the car sends out throttle position or voltage as and available data point on the OBDII/CAN.

TheWeatherman · 02-04-2010, 04:35 PM

Okay, here's the latest update, and hopefully the final one. First, Nissan sent down their Quality Control Engineer to look at the vehicle. He was happy because he was able to duplicate the randomly revving engine. After taking it out, taking vids, pictures and logging all information into his computer, he said he was sure of the problem. Any guesses?

From his analysis, he's went with malfuntioning clutch and neutral position sensors for the.... Synchro Rev Match. There ya go! Those both were replaced, and so far, wallah! No more problems with the revving engine.

I would like to thank the Quality Control Engineer, Nissan Corporate, Nissan Japan, and Russ Darrow Nissan for the prompt and excellent service. Everyone explained everything to me to a tee. They also completely detailed my car since I only take it out when it's completely dry, and they had it out in the salt. That was an extra touch that really made me happy.

Wrap-up... No stuck throttle, a problem that was fully logged and closely reviewed in Japan's engineering headquarters. Should this ever happen to any of you, it seems to be one or both of those sensors. It's great to have both the 2009 Infiniti FX35 and 2009 370Z back in perfect running order.

To not tarnish Nissan's name and to take down my accusation of a stuck throttle, I'm going to take down that YouTube video if I can figure out how. It's great to see this forum work in such a constructive way. By everyone's input, it made the problem interesting.

Feel free to add anything if you'd wish.

ChrisSlicks · 02-04-2010, 05:02 PM

Great news! Still don't see how it could be the sensors they mentioned given that it would do it from a standstill, maybe they're trying to avoid a Toyota like recall?

m4a1mustang · 02-04-2010, 10:59 PM

Quote:

Originally Posted by TheWeatherman

Okay, here's the latest update, and hopefully the final one. First, Nissan sent down their Quality Control Engineer to look at the vehicle. He was happy because he was able to duplicate the randomly revving engine. After taking it out, taking vids, pictures and logging all information into his computer, he said he was sure of the problem. Any guesses?

From his analysis, he's went with malfuntioning clutch and neutral position sensors for the.... Synchro Rev Match. There ya go! Those both were replaced, and so far, wallah! No more problems with the revving engine.

I would like to thank the Quality Control Engineer, Nissan Corporate, Nissan Japan, and Russ Darrow Nissan for the prompt and excellent service. Everyone explained everything to me to a tee. They also completely detailed my car since I only take it out when it's completely dry, and they had it out in the salt. That was an extra touch that really made me happy.

Wrap-up... No stuck throttle, a problem that was fully logged and closely reviewed in Japan's engineering headquarters. Should this ever happen to any of you, it seems to be one or both of those sensors. It's great to have both the 2009 Infiniti FX35 and 2009 370Z back in perfect running order.

To not tarnish Nissan's name and to take down my accusation of a stuck throttle, I'm going to take down that YouTube video if I can figure out how. It's great to see this forum work in such a constructive way. By everyone's input, it made the problem interesting.

Feel free to add anything if you'd wish.

Wow, thought for sure we had ruled it out but whaddyaknow! Glad it was all sorted out and your service experience was a pleasant one!

01-31-2010, 11:12 PM	#79 (permalink)
MightyBobo A True Z Fanatic Join Date: Feb 2009 Location: Las Vegas, NV Posts: 8,465 Drives: No cars; only bikes Rep Power: 52	Correct, it holds it for a moment just incase you decide to press the clutch back in and pop it into gear, but it wont wait forever . After a moment, it just disables, and no more bliping of the throttle. __________________ I don't own a car anymore.

02-03-2010, 09:54 AM	#83 (permalink)
m4a1mustang A True Z Fanatic Join Date: Feb 2009 Location: Northern VA Posts: 55,385 Drives: on two wheels Rep Power: 6962	Well most people don't know a thing about cars... in a panic situation they just stand on the brakes. __________________ - Steve Zs & Coffee - Saturdays at 10AM in Fairfax, VA and Columbia, MD (Click the banner!) LIKE us on Facebook!

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01-31-2010, 11:34 PM	#80 (permalink)
IcedZ Base Member Join Date: Feb 2009 Location: Gainesville, FL Posts: 194 Drives: 09 370 Yellow, 6MT Rep Power: 16	Weatherman, let me know what you find out. Mine did the same thing twice. Once per day two days in a row. Mine held at about 2k RPM though, definitely not 3500+. I live in central Florida, so it's not NEAR as cold as you were. I also am over 99% sure it is not SRM. I wiggled the stick in neutral and in and out of gears and let off the clutch in neutral... it was still revving. Both times that this happened it was after a 10+ mile drive on the intersate going about 80. So everything was up to normal operating temperature. Both mornings were cold, but not the coldest that we had. It was definitely bizarre. I cannot get it to repeat anymore now (I'm thinking because it's warmer outside).

02-03-2010, 10:56 AM	#86 (permalink)
TheWeatherman Enthusiast Member Join Date: Mar 2009 Location: Milwaukee, WI Posts: 265 Drives: 2009 370Z 6MTw/Sport Rep Power: 16	Hey ChrisSlicks, thanks for posting that C&D article. I see that Nissan/Infiniti has that throttle cut feature. For some reason, mine didn't do that. It was pulling faster with my foot on the brake. Here's the catch, I didn't slam on the brake, I just hit it light/moderate. (I was getting close to an exit on a 55MPH highway. I just hit the clutch and coasted down the ramp after I could feel the car pulling on me. It was speeding up over 60MPH with no cruise and no foot on the gas.) I wonder if there's a threshold of cutting the throttle. As I came to my first stop, I was revving over 4,500 RPM without any let-off on the RPM. Of course I knew to just hit the clutch and let the car do it's thing. It didn't feel very nice trying to have a decent start and burning the clutch though. I'm pretty sure if I would've popped it, the wheels would've slipped a bit... That's how much throttle was being applied to the car as I was taking off. She was on a mission, and that mission was to keep on revving. I still haven't heard a peep on what happened. Your C&D article makes this even more bizarre. I'm still positive it wasn't my floormats because when I got to my first "revved" stop, I pulled my floormats away from the pedal. I really just thought it was my mistake. 4,500 RPM is really up there. I started taking a video after I restarted the car twice. That was about 8 minutes after the 4,500 RPM events. Just trying to put it all in perspective for you.

02-03-2010, 12:13 PM	#87 (permalink)
ChrisSlicks A True Z Fanatic Join Date: Mar 2009 Location: North East Posts: 6,203 Drives: 09 370Z Sport M6 Rep Power: 653	With the throttle cut feature on the Infiniti and our Nissans, you do have to press the brake reasonably firmly. With the brake pressed the throttle input is cut back (but not cut completely) if the throttle input is moderate to high. If the throttle input is light then it will let you press both pedals at the same time and wont interfere. As it doesn't take a lot of throttle input to rev to 4500 rpm unloaded (out of gear) I'm guessing that the throttle input signal wasn't high enough to warrant a throttle cut. Even with a throttle cut you would feel the car pull on you a little as you braked but it would be easy to overcome by braking firmly. Would be interesting to see what voltage the APPS (accelerator pedal position sensor) is sending out in the misbehaving case. From that you could determine if it was a bad sensor or if the ECU needs to recalibrate a new up-pedal voltage. Bad sensors are rare because they do send out 2 redundant signals. It could be that the dealer screwed up the calibration by disconnecting the harness when you took it in for something else. I'll check if the car sends out throttle position or voltage as and available data point on the OBDII/CAN.

02-04-2010, 04:35 PM	#88 (permalink)
TheWeatherman Enthusiast Member Join Date: Mar 2009 Location: Milwaukee, WI Posts: 265 Drives: 2009 370Z 6MTw/Sport Rep Power: 16	Okay, here's the latest update, and hopefully the final one. First, Nissan sent down their Quality Control Engineer to look at the vehicle. He was happy because he was able to duplicate the randomly revving engine. After taking it out, taking vids, pictures and logging all information into his computer, he said he was sure of the problem. Any guesses? From his analysis, he's went with malfuntioning clutch and neutral position sensors for the.... Synchro Rev Match. There ya go! Those both were replaced, and so far, wallah! No more problems with the revving engine. I would like to thank the Quality Control Engineer, Nissan Corporate, Nissan Japan, and Russ Darrow Nissan for the prompt and excellent service. Everyone explained everything to me to a tee. They also completely detailed my car since I only take it out when it's completely dry, and they had it out in the salt. That was an extra touch that really made me happy. Wrap-up... No stuck throttle, a problem that was fully logged and closely reviewed in Japan's engineering headquarters. Should this ever happen to any of you, it seems to be one or both of those sensors. It's great to have both the 2009 Infiniti FX35 and 2009 370Z back in perfect running order. To not tarnish Nissan's name and to take down my accusation of a stuck throttle, I'm going to take down that YouTube video if I can figure out how. It's great to see this forum work in such a constructive way. By everyone's input, it made the problem interesting. Feel free to add anything if you'd wish.

02-04-2010, 05:02 PM	#89 (permalink)
ChrisSlicks A True Z Fanatic Join Date: Mar 2009 Location: North East Posts: 6,203 Drives: 09 370Z Sport M6 Rep Power: 653	Great news! Still don't see how it could be the sensors they mentioned given that it would do it from a standstill, maybe they're trying to avoid a Toyota like recall?