Help me diagnose this problem: I can't rev past 3500 RPM intermittently (AK370Z)
 

Hey guys,

So I have been meaning to post this thread about an year and half now. But the issue is SO intermittent, I have been reluctant to do so because when it doesn't happen, I tell myself "the issue has been fixed" ... but it reality it didn't. However, I should say this before I write about the issue first: when the issue doesn't happen, Z runs absolutely 100%. Smooth, fast and actually I think it still feels like it has 15,000 miles! (in reality at 72,xxx). I Autox monthly and once/twice a year HPDE and I have no issue. When this happens, it just happens to randomly. I have Gold prefferred (Bumper to bumper) warranty till 2016 or 120K miles. So I really want this fixed before that expires

Video of the issue: My 370z wont rev past 3500 RPM Intermittently - YouTube




Here's what happens:

Intermittently, my car won't let me rev past 3500 RPM. This started VERY first time (late 2011) after I pulled over on the highway. When I got back into the highway, as I was rowing through gears, it won't let me rev past 3500. Just out of the blue, this issue started. This happens (RANDOMLY) if I accelerate from a stop light or sitting in a traffic jam or whenever. I have no idea when this 3500 rev limiter thing will trigger. It can/has happened 2 minutes into driving the Z, it has happened 2 hours into driving etc. Also, it's VERY VERY random. I can have the rev limit occur on my way to grocery store. Then 2 days can go by and It won't happen, 2 months can go by, it won't happen or heck even 6 months will go by and this will not occur once (I think 6 months was the longest gap). Sometimes it happens twice a day then it may not happen for next 6 months. If this happens, all I have to do is -- Stop the car --> shut the engine off --> open door to reset the car --> I can start the engine and it's fine (for how long, I don't know. It can be 1 hour or 6 months). When it happens, I can still drive the car as long as I row throw the gears and keep it below 3500 RPM. It's when I go PAST 3500, it happens.

I really don't know what's the problem. Has this happen to anyone here? I took the Z for service in past, but they were giving me the :icon08: eyes, thinking I'm crazy. I told the dealer everything but there's NO CODE. They spent hours looking for a code or to replicate the issue -- nope no luck. However they said, if it occurs again, come straight to the dealer. We want to see it. I said,"fine".

Monday 6/18/13 4:20 pm, as I'm going to UPS, this happened again (I think after about 1 month). I went straight to the dealer. Had the tech drive the car and he finally saw what I meant. As I type this, my Z is in the Nissan dealer. All day today they tried replicating the issue first but of course he couldn't get to replicate it as it's VERY random (and even I have no idea what triggers it). Tech called Nissan Tech line and they were confused as well. They (NIssan) first suggested a faulty oil temp sensor which is telling ecu the oil temp is high (but in reality it isn't). I personally think it might be a buggy old ECU as my car is one of the earliest built car. Tech wants to call Nissan tech tomm or try to replicate the issue again so that there's a solution to this (and I told them I really want this fixed as I bought the car before for exact thing). i have done overnight negative battery terminal reset in past and it doesn't fix it. I have tried that.

What do you guys think is the issue? Has this happened to anyone? What should I tell the tech tomm to look specifically? You help, comment, suggestion is highly appreciated. :tup:

Are you UpRev tuned at all in a way you could drive around and do a Data Log to try and see what happens when this happens?

No tuned at all. Bone stock. That did came to mind but I rather want dealer to fix it under warranty as plan A.

Loose connector, bad sensor, or bad computer (more like bad/corrupt update). Check your battery cables make sure they're tight too. I had a similar issue with my old car. I had a red top optima and the side post bolt was stripped. I had random performance issues just like this, changed the post and it was fine. Took 6 dealer trips, 2 alternators, and one trip to something like pepboys to figure it out.

I understand that of course, but it might be time for you to look into a tune... 72k on Stock tune with bolt ons, is pretty far.

Wondering if maybe an o2 sensor or something has been clogged over, and the ECU is holding back to compensate?


Quick google search brought up these threads... one might have promise:

http://www.the370z.com/engine-drivet...all-gears.html

http://www.the370z.com/engine-drivet...pm-help-2.html

Specifically, this post:


http://www.the370z.com/nissan-370z-g...tml#post250296

:ugh2:

Not to be completely off topic, but do you go to the dealership and say, "hey... So, the world's largest 370Z forum... Yeah, the370Z.com, I OWN that bítch, fix my car or I will own you too!"

Lol :icon18:

This may be completely unrelated but this happened to me at the track during my first event and one of the threads on the forum said to disconnect the battery, drain all the power by holding down the brakes, and reconnect and it should be fine. It fixed it for me and it hasn't come back since no matter how hard I drive.

Then again after a year my car only has about 7k miles on it. You might try that to see if it makes your problem go away. Ofcourse, the way you describe it, you may not know if it's fixed for a good 6mos.

The dealer is prolly like:



:bowrofl:

I LIKE IT. :excited:

Check all the sensors and wire connections, and if they all look okay, then maybe have them do an ECU flash?

Hardware is fine judging from you being able to drive normally 99% of the time, so I'd chalk it up to something clogging the sensor (and vibration / rattle re-clogging it), a loose connection somewhere in the wiring harness, or the software has gone weird.

Very hard to diagnose on their behalf with no error code to guide them for starters.

I'm with the thinking it's a technically glitch, And with a simple reset/restart it usually goes away.

I would figure it's something to do with either oil temp sensor telling the ecu go into limp mode or the ecu maybe causing the issue.

Sorry to hear she's spending the night at the dealers, But IF they can replicate it?

They should figure it out. :keepingfingerscrossed:

mine did this too. was an auto 7 speed and would only rev to 5k. had no other issues while driving just when revving would top out at 5k. very strange

When I had that issue we traced it back to a faulty crankshaft position sensor

I had something similar like that happen on my Altima Coupe 3.5 6MT, but when it happened it was a weird stall that I had in a parking lot due to some moron in front of me (and a brain fart on my part). When I stalled, I restarted kinda quickly as traffic started moving again and when I clutched in, the VDC and SLIP lights came on, and I couldn't rev past 2500 rpm (it would bounce fairly violently at that RPM).

I pulled over into the next parking lot, turned off the car, waited 30 secs, started it up and the lights were gone and I never had it happen again until I traded the car (20,000 or so additional miles over a year's time.)

Your issue is peculiar as you have no trouble codes or anything. The crank position sensor is likely not it as it should throw a code.

My instinct say it's something to do with the oil temp sensor as, to my knowledge, it is the only thing that can throw a car into a "limp" mode without throwing a trouble code. A Nissan CONSULTIII tool should be able to pull the information on the temp sensor as I believe it is logged when you ping the 260 degree limit, but will not throw a code.

I would take it in and at least have them look at it. You paid for the warranty.

^ ZBro, that's known as limp mode :p not as random as AK's issue. sounds like you freaked out the ECU after stalling and probably clutching and trying to get back into motion too quickly.

AK370 i think it is because of you're sprint driving, the the temp skyrocket instantly on this engine, i have noticed it on my z. Its when you push it hard and lets say stop n go, not on highway where air is not cooling off the engine constantly it makes soooo much heat at idle and full throttle its horrible, i had to instal a 48row oil cooler in order to avoid this issue. I know that it also might be the sensor or other equip but from exp i think that our engines would make a great oven for the house.

Also i removed my engine cover (not the best idea) but the temps went downnnnnn like 2oo wile racing or sprinting. It stays 220 constantly wile just drifting in parking lots, airports, not streets its effin dangerous.

Mine had all sorts of issues with wiring melting and it did not throw a code, so I'd still encourage Nissan to take a look, especially given the positioning of the sensor.

It would be helpful to have a way to datalog. I know bad MAF readings will cause a similar behavior, but would also expect a code.

Red__Zed, you're not the only one with the bad sensor. A few owners had theirs replaced after experiencing similar issues. Resetting the ECU didn't help as the problem returned after a few miles.

Yes! Finally someone else who is experiencing the same issue!!! I told Nissan that I could not be the only person in the world experiencing this on the 370. I have about 60K miles on my baby now. Mine started doing the 3500rpm thing randomly towards the end of 2012, but then it became a daily occurrence. The difference between your situation and mine though is that I started to hear some rattling noise towards the front of the car. It kind of sounded like trying to get a big diesel truck into first gear. Well anyway, first they said that I was low on engine oil, so they tried replacing the oil. It was good for a few days, but then the issue came back. They then tried re-flashing the ECM, but that didn't help. After that, they tried replacing my throttle body, but that obviously didn't work. Eventually, some valve timing code came up and they told me that my engine was leaking oil internally somehow, so it looks like they had to bust open my engine and replace several O rings (I'm looking at the no charge invoice right now). That seemed to have fixed it, but then the issue resurfaced almost a month ago after about 5 months of no issues. I live about 40 miles away from work...stop-and-go traffic pretty much all the way and the issue tended to happen right before I reached work. This time though, like your situation, no codes were coming up. Nissan was stumped. They ended up replacing my automatic transmission (took about 3 weeks to get my car back), but then the issue came back the very next day, so I made a U-turn and headed back to Nissan. My baby is back in the shop :( I got a call from Nissan last Friday and they told me that they have to bring in a specialist to see what's going on. Hopefully they figure this out because I can see this happening to more people and most likely, it will become a recall situation. I will keep you updated as this nightmare unfolds. Well, at least I got a new tranny and throttle body out of all of this ;)

A few more suggestions - all are related to upper valve train function.

Below about 3500 the VVEL is at minimum lift, after that it starts stepping up. For it to function correctly there has to be good oil pressure, which on our cars is over 100 psi. Also the crankshaft position sensor must be in perfect sync with the cam position sensor.

It is difficult to test the sensors when the problem is intermittent, but I think it would throw a code. If there was lower than needed oil pressure the ECU wouldn't throw a code because the oil pressure switch is set to 6 psi, basically to detect dry sump or oil pump catastrophic failure. If they are willing to hook up an oil pressure sensor and check the readings through the RPM range that would at least rule that out.

It also looks like you are bouncing off 3500 where as the normal over-temp limp program should soft-limit to 3500. This indicates to me that there is a malfunction at 3500 as opposed to ECU deliberately holding a 3500 limit. Worst case would be a partial blockage in one of the oil passages to the head, would show good oil pressure but almost impossible to diagnose. They would probably replace your engine before they figure that one out :)

I've had this happen once thinking it was limp mode, but the temp gauge didn't seem to indicate that. I stopped, turned off the car, restarted and everything was like nothing happened. It was the same thing...wouldn't let me rev past 3,500 rpm's. I think I may still have the receipt somewhere when I had brought it in to the dealership. I didn't see a code with my OBD II, but they found something with their scanner tool. I don't remember what they said it was, but they reset the ECU and hasn't happened since. This was 3 years ago and I didn't give it much thought.

Ok, so I got my car back last Friday (6/28/13). They ended up replacing my ECM. So far, so good!!! Again, it was happening on a daily basis, so this is a very good sign, but it's probably still too early to tell for sure. I'll check back in about a month. AK370Z, if you want, maybe you should have your dealership check with mine if they want to confirm what was done. Mine is the Buena Park Nissan dealership in Southern California. The invoice says Customer #982413 and the invoice number is 322976. Hope this helps!

Wow what a story, I was waiting for "then they replaced my engine and the next day it came back". :icon17:

First,
thank you guys so much for your replies and helping me diagnose the problem. I appreciate your thoughts, ideas, personal experiences and taking time to dig up older threads with similar issue :tup::tup:.

So, I'll continue my story from post 1.

The VERY next day, Nissan tech drove the Z with the "diagnostic computer" on but he was NOT able to detect any code or replicate the issue (as I have said in the original post it's not easy to replicate the issue). It will happen once and may not happen in 6 months. So tech calls my phone and tells me if I would be willing to take the Z home and if it happens again, bring it back. I absolutely refused! I told him that this is my 2nd time coming here with the same problem. First time, I was told the same thing, "Can't diagnose it. Please come back if it happens again." I told him I am NOT picking up the car until it's fixed.

As I saw Dan, Chris etc mentioned repeatedly about crank positioning sensor:

So I pretty much told the Nissan tech that it could be the crankshaft positioning sensors. I explained to him that there were other Z owners who suffered same/similar issue and by changing those sensors, the issue resolved. I also told him that we gotta start somewhere to fix this issue. This could be our step 1 and we will go from there. He agreed. He told me that he will talk to Nissan to get it approved under warranty and order the parts. Thank God for the Gold Preferred Extended Warranty though(till 120K miles or 2016), I'm not responsible for anything (only a small deductible). So I get a call an hour later where he approved 3 sensors to be changed. If I recall correctly (I will scan the work invoice tomm), he changed 2 crankshaft positioning sensor and a cam sensor?

So took them two days to diagnose and another two days for the parts to arrive. I was Z less for 4 days :(. Finally I got a call that my Z is ready. The tech was nice enough to come outside and show me the sensors he changed and told me if it happens again, bring it right back.

Today I'm on 13th day since the Z was fixed. Car has been running 100% and smooth. Granted I have put a bottle of Redline SI-1 Complete Fuel System Cleaner a week before but car has been revving and idling much smoother. I have done an Autox session with 5 runs, drove the Z to up to 140 MPH to test, drove aggressively and even brought the oil temp to 240 :driving: and I have NOT been able to replicate the issue. If those sensors were the culprit, then I'm super happy. I suffered on and off for last 1.5 years with the issue. I'll def keep you guys posted :tup: . Again, thanks for your post(s).



yeah I think I read somewhere that heat causes some of these sensor to go bad. So, 3 sensors were changed and the issue has yet to come back. Keeping my fingers crossed

Chris, thanks for digging up the posts man! I really appreciate it. I totally forgot about those threads.
Honestly, I really don't have any bolt on expect HKS exhaust. I took off Stillen G3 because I want the Z tuned by Akuma motorsports to bring back the lost low end tq due to G3. I may do the tune and put the G3 back once I can make sure this issue has gone

hahaha this post made my day! I wish man! This dealer came a long way though and I am happy to see that (after owner change). When I had my 350Z in 2006-2007, I'd rate this dealer 5/10. It was horrible. Now, they are actually a good 8.5/10 which is a lot of improvement. But nope, they have no idea who I am lol

I did that many times. I did that almost every time I had the issue but no luck :(. You were lucky it never came back.


If the sensors do not do the trick, step 2 would be ecu. I'll keep pushing for a new ecu. thanks


Thanks Trips. They couldn't replicate it :(. I just went by the suggestions of the members and got those sensors changed. Now, I'm just driving the living he** out of the Z so that I can replicate the issue lol. So far I haven't been able to :tup:


I think the issue you had, I experienced similar in 2009. As saber said, I think the Ecu just freaked out and it was fine afterward. I agree with the faulty oil temp sensor. That would be the next thing to change if it happens again.



yeah in my case, my car wasn't hot at all. One time this happened only 1 minute driving the car which means oil aren't even hot yet. That's what makes this so confusing.


Holy sh(t man! that's crazy! wow man, you dealt with a much bigger issue. I'm glad it's finally sorted out. If the issue comes back, I will most certainly ask you a for a copy to present to my dealer. I really appreciate you willing to help me by providing the work order. I initially thought my issue was a case of buggy ECU too.



Lucky you! In these modern cars, there are so many da*n sensors, if one doesn't work properly, engine management goes into protective mode. Well, I'm glad your issue was fixed.

Awesome AK, looks like you got it sorted!

:tup: :tup:

yep it was most likely the crankshaft sensor.
It happened to me on my 350z (around 60K miles).
Car would completely shut off while driving. Got it diagnosis and
the code came up, luckily autozone had the part i needed for $70 and 30 mins of labor
vs the nissan dealership charging me $400.

Glad it was fixed and covered! Good to know if we encounter this.

Hmmm... Sound like they know exactly who you are.:rofl2: That's why their service bumped from 5/10 to 8.5/10 suddenly. Maybe they are on this forum spying everything.:bowrofl:

In any case, it's good to hear AK! Hope the problem is fixed permanently!:tup:

Some folks would have invoked the lemon law by now, but if the car's modded, then them buying it back, what does that get you? They won't pay for the mods, guess you can take them all off?
I admire you all for sticking with it, good luck!

Happy 4th!

I'm pretty ignorant about sensor locations, but there was discussion about making a small heat shield. Think it's possible to silver or gold wrap the sensor body?

lol it's nature's way of telling you to buy a vette

*Ducks flying objects*

You could be misfiring and the Z is in failsafe.
Happened to me

I was actually hoping for that ;)

the have the same problem occur after i washed my car. the rpms woudlnt go past 3500 it shuts it down .. what can be the problem?

i have the same problem^^how do i fix it?

Check post #25
http://www.the370z.com/2391530-post25.html

What dealer did you go to? I am experiencing the same issue. I took my car to MeadowLands Nissan and they told me to drive the car another 7500 miles before they can properly diagnose the problem. My car is threw 3 codes P0451, P0300, P0340

7500 miles?! would take me a year wtf

That is what I said. I told to the guy 7500 is a looooonggggg time. He doubled checked with the tech and there was some miscommunication it is 1k miles I have to drive for.

I have the same problem after uprev tune

The problem was repeated more than once, and if it became a problem i switch the car off and changed the map and turn on the car and the problem will end.

http://i59.tinypic.com/t0ooxg.jpg

Is it possible to be the cause of the problem within the image ??