Engine, Drivetrain & Forced-Induction
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Problem with high idle/RPM spikes

Old Apr 11, 2021 | 01:41 PM
  #16  
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Yes, technically the TSB applies to AT vehicles, but the fact that these idle issues are occurring points to the ECU being suspect. I really doubt there is much of a difference between AT and MT ECU's...

You will likely have to argue with the dealership to have them reflash the ECU whether this TSB applies or not. Mine didn't want to at first- even though the TSB applied to my car, but after I refused them replacing a million and one different parts (at my cost), doing the research and finding this TSB, they finally agreed to reflash (at Infiniti's cost).

As the slogan goes... "Knowledge is Power."
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Old Apr 15, 2021 | 05:30 PM
  #17  
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Couple of updates. First, the voltage drop I previously mentioned when this issue occurs was a coincidence. Having recorded more and more normal drives / issue drives, none of the sensors actually change. The voltage drop that time was just from battery charge completing. Really every sensor is the same before and after, if you didn't look at throttle/rpm you wouldn't think anything had gone wrong with the car.

Second, WOT / redline through a few gears is definitely the most consistent way to reproduce the problem and get the car into this bad 'mode'. Again - turning car off / back on always clears the issue.

Third, my mechanic is still totally at a loss other than thinking this is an ECU program issue, and I tend to agree with him (and you guys). However I returned to the Infiniti dealership again today and got zero help. I showed up with the car acting normally, drove around for a while recording all sensors until the issue happened, showed them the recording, and then took their 'master mechanic' on a drive while the issue was occurring. He said it's not really a problem(?) even when I turned the car off/on for him and showed the revs suddenly acting normal again, idling normally, engine no longer revving up by itself when my foot is off the gas. How is that not a problem? Then he gave some bull**** about the clutch probably going bad and confusing the engine ???????. I argued a bit that it doesn't make sense, but then just left.

Also at my previous visit to Infiniti, I thought they had only reset the learning of my ECU but when I asked about it again today, they checked their notes and said it was in fact a full re-flash from their software. So if there was an update or some program issue it should have already been fixed a couple weeks ago. But still I consistently have this problem.

Really not sure what to do now, I wanted to keep this car for at least a couple more years, maybe longer, but I absolutely don't want to deal with this for the next 5 years and all the time be cycling the car off and on.
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Old Apr 15, 2021 | 06:00 PM
  #18  
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Unhappy

Originally Posted by Satchel
Also at my previous visit to Infiniti, I thought they had only reset the learning of my ECU but when I asked about it again today, they checked their notes and said it was in fact a full re-flash from their software. So if there was an update or some program issue it should have already been fixed a couple weeks ago. But still I consistently have this problem.
It is a moot point, but what does your receipt/invoice say they did? Do you have it in writing that they reflashed the ECU or just their "verbal" word?

Is their a independent mechanic in your area thare specializes in Nissan? Your symptoms are nearly identical to what I had- only difference is 5AT v. 6MT. It has to be a ECU issue.

I pulled my receipt showing the reflash and that the dealer did it on their dime:


​​​​​​
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Old Apr 15, 2021 | 06:11 PM
  #19  
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True, yea I'll do some research and see if there's a Nissan expert around me who isn't the Infiniti dealership.


To me this is ambiguous. So today they verbally told me that meant a flash:

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Old Apr 15, 2021 | 06:18 PM
  #20  
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They lied. RESET is NOT the same thing as a REFLASH. I would find a reputable indy shop that specializes in Nissan or, worst case scenario, find another dealer.

Poor idiots. Can't even spell. Its fusible, not fusable.

Last edited by ILM-NC G37S; Apr 15, 2021 at 06:28 PM.
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Old Apr 15, 2021 | 06:43 PM
  #21  
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Lol.

If anyone can recommend a (far west) Chicagoland shop like this, let me know...
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Old Apr 15, 2021 | 07:43 PM
  #22  
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I think your ECU ID is JK75B... and if that is accurate, there is an update: JK78C
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Old Apr 15, 2021 | 07:55 PM
  #23  
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Thank you for this info. Man I'm going to be pissed if that's the fix. Happy but pissed, like who the f*ck is supposed to know the ECU needs updates if not Infiniti themselves? They are clowning. I'm still looking for another place to take the car.
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Old Apr 16, 2021 | 04:25 AM
  #24  
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I have a 2011 and recently started to experience the RPM issue. During cold starts the car would idle fine at 550-650RPM and after doing a few stops it would still idle fine. But, once it is really warmed up it would constantly fluctuate from 750-900RPM. Also, when coming to a stop it feel like the car is lunging forward, and I have to really get on the brakes. I also thought it could be an electrical issue, and I had the same results where my battery voltage would start at 14.1-13.8V, then drop to 12.6-12.8V. After checking everything over and over, I realized that my test pipe gasket had a leak from the side and the bolts have backed off a bit. After tightening it the car has been idling perfectly fine. Drove for a good amount and it would idle fine. I just ordered some new gaskets and will replace it for a permanent fix. Might be the same case, but just wanted to throw that out there. Also the exhaust leak was so minimal that I could not even hear that it was leaking until I sprayed some soapy water around the contact areas and noticed bubbling.
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Old Apr 23, 2021 | 01:51 PM
  #25  
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I've come to believe that the JK78C update is from ITB08-028b. It describes "a slight ticking / tapping / knocking noise coming from the Bank 2 (driver side) VVEL actuator." The tapping noise (which I can't even hear apart from the rest of the engine) is supposedly caused by the ECM losing track of VVEL state after hard driving, essentially in an unhandled scenario where the ECM can't bring the VVEL back to the correct range but also doesn't think any codes should be thrown. So all these crazy symptoms, high idle, random revving, surging/lagging come as a result of the confused engine state. Of course turning the car off/on was fixing this since it forced the ECM to find everything again and reset for car startup.

Anyway I finally have the update so should be smooth sailing from here



Last edited by Satchel; Apr 23, 2021 at 02:19 PM.
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