Hotter weather does make the issue worse but I've had the delay happen on a morning where it was no warmer than 60 F.

The ONLY time that I don't get this problem is in the first 15min after I start the car. After that, the delay is there every time I hit the gas.

I wonder if the G37 community still has or still has similar issues. All I remember was the complaint about not using the ester oil causing throttle response problems with VVEL.

Although VVEL is neat-o and keeps the torque band flat I wouldn't mind switching to the VQ38HR from the 380RS. I never had throttle response issues with the 350Z other than the transmission killing the fun. Nowadays when I'm in the passenger seat of a 350Z, I'm usually pinned to the seat at low revs... something I miss :(

Can't a good tune add some low end torque to the car's power band? I was under the impression that there is a bit of headroom to make some more torque down low which would be a great asset as the VQ37 is a bit gutless down low.

no, a honda is gutless down low. the z is good down low, but nothing to write home about.

:iagree:

We suffer from the same crap. Accelerate - Pause- Launch.

ive been driving around all morning here in south florida, 90+ degree heat, 210 oil temps, vdc off, and no problems at all. power on demand, as long as the gear and rpm were appropriate. to me, vdc is such a buzz kill with its throttle cutting that ive decided to only turn it on when the temps outside are real low, when it rains, and on the highway.

now i dont know if vdc has anything to do with this problem, as some of you say you have experienced he problem even with vdc off, but it may be that. or it may be operator error, vvel, or some other problem. Until we get a cooperative dealer or tuner to tell us what is going on, we're left with our thumbs up our asses.

I experienced this first hand today since I had the Z to myself... I'd downshift from 7th to 3rd or 4th and punch it as it was shifting into the destination gear, and it would result in a 1 second pause or so before power delivery really kicked in. I don't know if I want to just buy an Osiris tuner and tune out the lag, or if one of the modules would be worth my money.

i personally would rather have a tune than lose the ability to better modulate the throttle, which i would expect from a chip that goes WOT in a shorter pedal press.

agree but how much will it be for a tune 600$+ :icon14:

yep. it would seem that for getting rid of the slight delay and it being worthwhile, you'd either have to have money to burn or a damn good reason, like the z being your competitive track car. neither are probably in the realm of possibility for a lot of us, rendering the need for this gadget or a tune (strictly for this reason) relatively unneeded.

Once again guys, I have an Uprev tune and still have this issue.

Yes, but that could just be that your tuner did not play with the throttle mapping. From what I have been told by popular tuners like SpecialtyZ and Technosquare (along with members who have been tuned) is that effective tuning of the throttle maps can make a big difference.

This coming wednesday, I am getting my Z tuned so I will be letting you know!

Also note how the problem seems to be more noticeable on automatic cars? I bet Nissan just dumbs down the throttle response even more to protect the AT. If I recall correctly, the automatic I drove did the same exact thing

The automatic Z I test drove over a year ago did not have this issue, and the temps were cooler at the time it was being tested. It was the first time testing a 370Z, and my initial impression was that it was eager to rev to past 3k with little throttle tip in. I was sold and ordered the 6MT.

What I would like to see done since I don't have the funds to get the appropriate tools, is to get a data acquisition board of some sort to record the voltages for the gas pedal, ECU outputs, VVEL outputs, stepper motor inputs, and temperatures in different areas including the stepper motor assembly. All of this data would be logged and graphed to observe temperature and the relationship of the signals controlling throttle response.

The gas pedal voltage should be 100% linear from 0-5V.
The ECU throttle output may not have a 1:1 correlation to the gas pedal potentiometer.
The VVEL controller, which I know nothing about, I will assume is a black box with input and output to control the stepper motor.

Somewhere along the lines of capturing this data and graphing it we should see somewhere in the system of gas pedal travel (2nd gear, pressing pedal from position 0 to max) we should be able to graph the delays and compare it to temperature. Obviously something's getting hot and slow. Has anyone felt the stepper motors? That thing is scorching hot. I'd be curious to know where the VVEL "box" is located as well.

[EDIT] Service manual indicates there are terminals for the VVEL Control Shaft Position sensor, so the voltage levels can be measured here. Then there's the VVEL Actuator motor which we can probably log and compare with the sensor values. Just for kicks, we can log the TPS sensor as well.

THIS is EXACTLY what I've been trying to get!

that kind of scan gear is gonna run someone quite a tab, if it is even possible to get. like i said, it is gonna take a cooperative dealer, and that is more scarce than... well something that doesn't exist!

Actually, hardware like USB DMMs to record voltage over time isn't expensive, though the data logging software can be. I believe you can even do logging with some TI calculators with the right kit. The problem might be syncing with an OBD II logger.

My 2009 Auto hasn't exhibited the problem at all, so I can't do any testing.

Last time I was doing data logging with Uprev I noticed there were like 4-5 different VVEL things that you can log/monitor. If this would be useful to anyone, I can find out what things it can log. I can't do any useful logging though since I can't reproduce this problem either.

Exactly. The actual hardware isn't that expensive. However, the software can be. And it's very niche software. Interfacing with OBD is the hard part (for me anyway).

Datalogging software isn't needed as long as the voltages can be recorded over time and stored in a comma delimited text file. I use open source library, ZedGraph, to graph data with several hundred thousands of points. If you guys like, I can write a simple program that uses this library to import individual csv files and plot them as separate graphs or overlays.

Datalogging with UpRev is one thing, but we need to acquire signals at the source (I/O control signals and driver output). The ECU and VVEL module output signals to control the throttle and VVEL actuators and each has its own position sensor, but I don't know the system well enough to determine if the control signal output to the actuator goes from A to B in X milliseconds that the actuator is expected to physically change positions from A to B in X milliseconds as well.

In other words, we might have a situation where the control signal expects the actuator to move from point A to B. The actuator does move from point A to B, but there is no mention about how fast it should get there to meet the timing tolerance. It is like playing an FPS game with a wireless keyboard and mouse getting pwned from the 0.5s lag.

But I think the 1-2s lag combined with it happening primarily when warm means it should be possible to narrow it down, just a lot of work.

Good point.
Does anyone have a scrap OBD-II cable they would be willing to mail me? I literally just need the cable to plug into the car. I will be breaking it out into a breadboard, so I preferably do not want it coming from something working. I have an NI 14 bit DAQ that will be perfect for this.

Oh snaps... how many channels? I guess we can start with one side (i.e., left/right actuators and sensors) with common inputs (gas pedal potentiometer, temps, etc.). Definitely create the "cool" logs where the car behaves normally, and "hot" logs where the car starts lagging. I'll try to find some time this week to write a small program using ZedGraph.

8 analog channels, 12 digital I/O channels.

sound like you guys have a good grasp on this. good luck! Im very interested in the results if you can get any!

I've not had time to write the graphing program. Once I know what the log file looks like, then I can write the code to parse the rows and columns of data.

Today ambient temps hovered around 65F for the high. With the engine bay cooler than usual throttle response is the way it should be. I can press the pedal close to 50% in 1st and 2nd and be able to get the car moving immediately with no delay.

Of course, after a longer duration of the drive (15+ min.) the throttle starts lagging and doesn't open up as much as anticipated. I can floor it in 2nd and 3rd. The exhaust gets loud, but the car doesn't seem to accelerate much at all. It's very gradual as if throttle isn't opening up fully.

Then I make a quick stop to get stuff. Get back in and get moving, and throttle response is normal again for several minutes.

I'm not quite sure if Sprint Booster is going to fix this problem especially when I try to floor it and the car barely accelerates, but only when it's cooler.

Heh... I'm pretty sure you guys are annoyed by my bump posts for this thread. I'm wondering if all this lack of response has to do with the current programming of the VVEL actuators. After doing some reading about the VVEL TSB for G37 owners, some owners were complaining that the reprogrammed ECM made the engine unresponsive. So for those who wonder about VVEL software adjustments, it is possible, but at the price of enduring the knocking noise?

Here's a quote and response:
MyG37 - View Single Post - ITB08-028a - Noise from bank 2 VVEL actuator (amended 9/3/08)

From FreshAlloy:

^ Interesting

If this problem were a dinosaur, it'd be a failaciraptor.

Count me in as someone w/ the lagging acceleration problem.

what bothers me more than the lag, is the bucking feel when the car is either cold or accelerating decently from a roll at low rpms in 1st/2nd gear.

Yup! I get that one as well even though the clutch is fully engaged and the pedal is still. It's like throttle movement is somewhat stuck and tries to apply more power to unstick itself. It happened to me over the weekend when I shifted to 3rd and kept steady acceleration close to redline before merging on the freeway. At times this is smooth, and other times it felt "clunky."

Then there are times where I'm in 2nd, steady throttle, the acceleration is a bit slow, car jerks, and it gets quicker as if I applied more throttle even though I didn't.

I'd like to go FI one day, which will void the warranty, but now I'm getting paranoid about VVEL actuator failure. :confused:

Welcome to the suck. I get that same hesitation as well.

This is what I've been suspecting, hence needing to record VVEL position and temperature data. Just been too busy! I'll be gone AGAIN this whole weekend (and not with my car). I think it's the ECU programming telling the VVEL to do something "wrong".

so after 19 pages no one has any idea yet?? ok i guess im in for updates

Same here. I'm bankin on DIGI pullin through on this one. He's the tech guy of the forums.

Haha not really :p Just curious mind with a bit of troubleshooting tendency at heart.

Fall weather is here with much cooler temperatures, so I'm not encountering laggy throttle response as often on my drive to and from work. It is still there, though. Easy test is to punch it in 3rd, and you can feel the car accelerate for a little bit and then it feels like you let off the throttle even though the foot is still planted. Go figure... :rolleyes:

Just get me a simple CSV file for each reading:
xxx,yyy
xxx,yyy
etc.

I finally got to spend some time looking at the service manual last night. I tried to follow the directions to read the values from the VVEL Actuator and sensors. None of the harnesses are very accessible. This is definitely not going to be easy. This is definitely an all day task.

well, i dont have what you guys are talking about. my car simps halls *** in all gears at all times no matter how hot or cold. i did unplug the bosch sensor to completely disable the VDC and Traction control so i have no interferance what so ever with the computer. i personally couldnt stand to drive a car that is acting the way you guys are describing. it sounds like the car is cutting power on you and thats what i use to feel before i disconnected the bosch sensor. well good luck to all of you because this would drive me insane enough to burn the car to the ground.

^ What I do notice about the 370Z is that VDC is a tad aggressive. Even slightly rough engagements will activate it. My 350Z came with TCS so I didn't remember it overreacting on dry pavement. The lagging does feel like VDC/TCS kicking in, but with no SLIP indicator even when it's [supposedly] disabled. O_o

Where is this sensor? Any drawbacks other than the lack of VDC/TCS at times when it is necessary?