Why Did My Z, Keep Revving? Video.

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!

1slow370

actually with mine i have noticed that if i hammer it for a while when i take it out of gear it will hold revs longer than if i cruise on the highway without shifting for hours and mine acts exactly like ak's. I actually have this wierd habit now that when i'm driving around i will push the clutch in and take it out of gear and hold the stick to the right side to get it to drop revs while i coast. Freaked me out the first time i did it in my neon and the revs didn't drop.

MeetJoeAsian

quick question, when your car is coasting in neutral, is your foot on the clutch? I think, if I remember correctly, having your clutch in gives the SRM the signal that you may be engaging a gear, thus causing it to rev up....then again, i could be wrong...I'm at work right now so I can't really try it out, but I think your RPM only goes up when you clutch...

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m4a1mustang

Yeah.. if I pop out of gear and go to neutral with the clutch pedal pressed, SRM will sometimes blip the throttle. But if I just ease out of gear and let off the clutch pedal nothing happens.

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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.

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

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MightyBobo

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.

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JB1

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.

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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.

ChrisSlicks

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

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!

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IcedZ

But why did it only happen to me twice, on two cold days, and never again? If a sensor is bad, it's bad. It shouldn't be weather dependent.

MightyBobo

So I finally watched the video after coming home. Im sticking with a TPS sensor.

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TheWeatherman

Is this common? For all who think I'm engaging the SRM, remember, my car was at 0 MPH. I even get out of the car at near the end of the video, and I'm still getting over 3,000 RPM. Yeah... a faulty TPS would mean your throttle is messed up. You should've seen it when it was doing over 4,500 RPM. I didn't think of taking a video since I was moving floormats and restarting the car at every intersection. It would rev right up after a restart. Bobo, appreciate the input. Spearfish, you're still the man.

Oh, by the way, my clutch didn't like this little incident very much.

m4a1mustang

Could be the TPS. There is a procedure to recalibrate the throttle... I'm sure the service department is going to try that.

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MightyBobo

Its pretty easy if I remember right - look for the service manuals on the website here. Its a matter of mashing the throttle to 100% and then 0% back and forth, but you need to get it into calibration mode...

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