Z does not accelerate

nomodsjk

I had this same problem and it turned out to be a throttle positioning sensor was faulty. Unfortunately Nissan doesn't just sell the sensors you have to buy the whole throttle body which is 835 $each! I had to find a used one on eBay for 210 $. Good luck to you sir

7speed

Did this cause occasional jerky acceleration? I felt some hesitation/judder when I was accelerating today.

So at lunch I tried it out, I just took off normally in first (this is all under like 10mph) As I was rolling all of a sudden it felt like I pushed the clutch and jumped off it. (Because car stopped accelerating then accelerated, the tires did a quick chirp and vdc flashed)

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09 370z 6spd traded 1/12/15 for 15 Challenger RT 6spd

P's_Z

But i assume it is covered under warranty if ones warranty has not expired, right?

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Zeta

7speed

Nvm , pulled a coil pack and have oil on it.

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09 370z 6spd traded 1/12/15 for 15 Challenger RT 6spd

P's_Z

This happened for the 2nd time now. So p!ssed!!! Cant believe a 2013 40k car(in PR) with only 10K is having issues already. Going to the stealership this week to see what BS they come up with. Sorry everyone, just blowing off some steam, im just really frickin p!ssed

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juld0zer

2 switches near the brake pedal. disconnect the left one, then fit a jumper across the connector on the harness side (jumper the male connector, not the switch which you have now disabled)

nb: disconnect battery as it's very easy to accidentally short something while fitting the jumper.

jumper can be a big staple, wire or whatever. tape it up to insulate after

P's_Z

Sorry in advance for the question im about to do, but: how would this help and what possible risks am i looking at? Sorry, but never heard of doing this before.

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juld0zer

have a read of my thread, esp the last page: HELP! Severe acceleration lag

the switch on the left is mainly used to kill the cruise control when you brake. the switch on the right is for the stop lights so dont worry, your brake lights will still work as they should.

the left switch is also used to tell the ECU when you are braking (don't ask me why Nissan chose to use two switches...) and in a bid to prevent a runaway Toyota situation, the ecu will not let the throttle plates open more than 15 degrees (until you pass 4000rpm) if it detects the brake pedal is pressed. Think of your garden hose when it gets a kink, then you unkink it... wet tshirt due to sudden increase in water flow etc.
I've actually discovered thru a lot of experiments that if your foot is on the brake pedal, the ecu will not let you accelerate faster/open the throttle plates further than its position at the moment you pressed the brake pedal. until you eventually pass approx 4000rpm.

So, if your brake pedal switch is not adjusted correctly or faulty and the ecu is misled to believe your foot is on the brake pedal, grandma's going to leave you at the lights while you're swearing and cursing.

This particular switch on the left is a normally open switch so when you press the pedal, the switch is NOT depressed and therefore circuit is open. The one on the right is normally closed.
So the jumper trick fools the ecu to always think the brake pedal is NOT pressed, by simulating a closed circuit - as if the brake pedal was at rest (which means the switch is depressed).

Eventually, the lag issue will appear again. I think it's because the ecu's failsafe is to assume the driver has to press the brake pedal at least once in X minutes of operation or Y distance has been travelled. I havent triggered it often enough to notice a pattern but both times when the issue reappeared with the jumper in place, it was after driving in heavy stop/start traffic.

hope that helps see what the dealer says/does and then try my get-you-home trick if they cannot solve it

juld0zer

only risk i can see is if you use the cruise control - it wont know when you are braking so you might be fighting the cruise.

simple way to avoid this is to refrain from using cruise control, or if you must then remember to turn off the cruise when you brake/coast

Zoren 370

Can you post a picture of this switch next to the brake pedal? Thanks

juld0zer

sorry folks, either the LHD models have the sensors arranged differently or my memory has failed me.

i cant upload pics via this damn iphone but i'll point you to this thread: I have a serious engine problem

there are two pics in it. the switch i am talking about is the skinny black one which is on the RHS of the first pic. the chunky one is for the brake lights. dont disturb that one

juld0zer

ok so i just went outside to check my car. my memory didn't fail me.

RHD models will have the cruise control brake switch on the left, stop lamp switch on the right.
LHD models will have it the other way around.

either way, it is the black skinny one you're after.

P's_Z

Thanks for taking the time to post and explain juld0zer. I will go to the dealer first but im anticipating a lot of BS+they will not solve the problem. Ill throw them a bone and try to explain the possible causes to this issue from what ive gather on what everyone has said and see if that helps. If not, guess ill have to follow your advice or live with this problem. Kind of bummed right now, and a bit disappointed with nissan

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juld0zer

the brake switch could be the solution but keep your mind open to other possibilities as i know of a few other possible causes/solutions.

for me, i'm 95% sure it's brake switch related as i can induce the problem by simulating a depressed pedal.

keep us updated!

Kabestro

Hey P's Z, looks like you're not the only one, I've had this problem for quite some time. I thought it was the tune I had being too aggressive or dirty MAF sensors. Last thing I did was get an etune from uprev and changed to 93 octane gas. I haven't had the problem since. But it always happened to me in the mornings when I first started the car. Shut it off, turn it on again and it would go away. Let us know what the stealership says.

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Stillen Gen 3 CAI / Fast Intentions HFC and CBE 12" Res. (#730) / Swift Springs / 20mm H&R Spacers / Clutch Helper Spring / UpRev Tune 322whp.