Unexplained Limp Mode

spearfish25

The story about losing power during an on-ramp turn and then having to restart the car is fuel starvation during a sweeping righthand turn. This is an issue with any model year 370Z.

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FromG2Z

Interesting... so only apparent/evident when tank is 1/4 full or so during said turn?

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Econ

correct

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ChrisSlicks

Unless it is on a race track with race tires, in which case it will happen with 3/4 tank or more. On typical street tires 1/4 tank is the typical threshold.

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cossie1600

yeah fuel starve

juld0zer

ChrisSlicks, i'm struggling to cure my random limp mode problem.

Mine hasn't limited me to 3500rpm but instead the revs while in gear just take forever to climb, as in the car accelerates extremely slowly. Throttle position seems limited to 15 degrees.

My brake switches are fine and adjusted per the manual. Conditions were cool and it's definitely not VDC. No dtc or CEL.

Both cam and crank sensors fail the resistance tests from the manual. Pin 3 seems dead. Car starts and runs fine until the random limo kicks in. Idle is smooth with the occasional sag to 500rpm

shfeddy

My 09 just started doing this too. However it just got tuned on the dyno and I feel the tune might be the issue. Ill be doing 55-65mph and go to pass some one with moderate acceleration, hit maybe 75 mph and it sometimes goes into limp mode. I cant rev past 2-2.5K rpm. Ill turn off my car, wait 10 sec, restart and be fine. This has happened twice now and its starting to annoy me.

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Justice97

Would a dirty throttle body have anything to do with this?

I know mine was giving me minor rpm issues and drops till I cleaned them. It has been a couple of weeks and she is still running like a champ.

Maybe it is sticking?

juld0zer

throttle bodies are often first to blame. whether it be due to sticky flap mechanisms or throttle position sensors which chuck a wonky reading.

i cant remember who it was on here that suggested out of sync throttle bodies as the issue. i've datalogged my throttle bodies and they're about as perfectly in sync as you can get them.

shfeddy - you have a supercharger kit so that adds another variable. but i think a fair few folks with tunes have experienced the random loss of accelerator response. this makes me think there might be one cell in their tuned throttle maps which the ecu doesnt like. hitting that cell would take a certain combination of inputs so it's hard to replicate. i'm still standing by my throttle tune - it's the same map that's been posted up on these forums and most folks have been troublefree so i'm ruling that out for now

P's_Z

This ^^^

Read page 4 from the thread i started, and an update in another thread that you will also find in page 4. Dealer cleaned throttle bodies and recalibrated them. Same issue happened to a friend of mine from this forum. Neither of us has had the problem since then

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IAmTheStig

I don't understand this; the VQ37VHR opens the throttle bodies all the way at very low accelerator pedal positions and uses the VVEL system to manipulate engine throttle control. Therefore, above idle speeds, I don't see how cleaning the throttle bodies would fix this issue.

This video should explain what I am talking about: http://youtu.be/6i1rBkP8dYs

Sorrovv

I'm a noob here but I have this to offer:

I've only seen this once in my 2011 370z - I lost the back end and spun 540 degrees into the other lane to face the way I came from. When the car stopped spinning there was still serious reverse momentum and I left the car in gear for a split second. When I drove off I hit limiter at 3500 in any gear so I pulled over and let it cool for 5 minutes. I cranked her up and drove her hard the rest of the day with no issues.

I guessed it had somehow sensed that I had overheated the clutch and never thought of it again. I've never seen it since.

cfran22

I just experienced this yesterday. After pulling onto a highway, my 09 Z started to hit the rev limiter @3500 MPH. I just drove it below 3500 until I stopped at a restaurant. After leaving the restaurant, it was like noting happened. I guessed it may be software related, so I hit up the Forum, looking for answers and came across this post. I guess no one has found anything definitive as yet so I guess we just keep on having fun in our Z

FLUJOKE

My 2014 just did this last night.....vdc was on in Auto, fresh cold start just driving normal, nothing crazy but when i tried to accelerate i wasn't getting any power. I had to turn it off twice to get her to behave right.....WTF is going on with my car. HELP!!!!!

Silo

Apparently there are at least TWO types of unexplained limp modes, characterized by

a. high idle and limited power (throttles not opening fully)
b. rev limiter at 3500rpm

Common to both is that there is no CEL and no DTC, and they "reset" by restarting the car. I have also heard for instance a. that although no CEL/DTC is shown, doing a DTC clear/reset (with any kind of OBD tool) while car still idles high will reset the limp mode and car will operate normally again. Kind of a "phantom DTC" so to say.

Are all of you that experienced one or the other issue running flashed ECUs? Please specify which reflash and limp behaviour you had.