# 370Z Stutters at 3600+ RPMs



## srmaddox (Apr 9, 2013)

Hello All,

I've been having trouble recently with my 2010 Nissan 370Z Coupe (Base model, 6MT; Just under 20K miles; Fully stock); There's a bit of a backstory here, so I'm posting my diagnostic steps in the order they occurred (steps performed by myself, and reportedly performed by the dealer).

It all started with no Symptoms/Check engine light/codes/etc; had taken the car out to a track and pushed it a bit, just getting acquainted with the handling of the vehicle for the most part. It did not get over about 265F, although here in South Texas with the hot weather we had at the time I did note that the engine oil temp was starting to run up after 30 minutes of hard running (a lot of near or right up to redline). 

Car had no problems, was fine as a daily driver back to the house.

I took it out the next morning, and the moment I hit 3600RPM the engine lurched down to ~2900 RPM and brought the vehicle not quite to a screeching stop; as soon as the RPMs fell, it continued to operate fine, showing the exact same symptom (lurching down to ~2900RPM as soon as I hit 3600).

At this point, I immediately limped her along to my local Nissan dealer below 3600 RPM (where the engine sound and driveability was all perfectly normal to my ear/feel) and left it there. 

They got back to me and reported that they had a code for a malfunctioning Cam Sensor, and I had them replace the Cam Sensor. 

After this, they claimed they could not fix the problem, and suggested that they believed the cam timing was "free floating" due to a sheared pin connecting a cam shaft to a timing sprocket, but they would have to tear down the engine (not covered under powertrain; which was bogus, but that was due to a dispute I had with the initial warranty I was sold and some conflict between that contract (with Ford, ugh) and the nissan Factory warranty)..

Either way, I told them I'd tow it and look at it myself. They removed the new cam sensor and put in the old.

After arriving at the dealership, I noted the car did not even start; It would turn over and detonate, missfire, detonate, misfire, all cylinders with no codes whatsoever. Cam timing totally off. 

So, I towed the car back to my place, started going through the VVEL diagnostics, suspecting one of the VVEL stepper motors might have been seized, and found a dead VVEL relay; Replaced it, the car starts, and now it's back to it's similar symptoms pre-dealer:

(1) Operates fine to 3600, but at 3600RPM, and then starts sputtering; It doesn't lurch to 2900, it just sputters badly and can't get much above 3700 RPM. 

Now it has a Check Engine light and VDC Off light permanently on, but no standard ODB II codes that a sensor can read (i'm assuming a nissan proprietary code that only the Consult III, which I have no access to currently, can read).

I'm suspecting this could have been the initial diagnosis of a bad CAM sensor, since the limited RPM range affected would make sense in this case, but the VVEL relay went bad during the time at the dealer (or due to something they did?)

Alternatively, I suppose its possible upon replacing the Cam Sensor with the old one when I refused to take the new part that did not fix the car, the dealer may have not calibrated it, accounted for why the problem has changed in how severe it is. 

Any thoughts on next troubleshooting steps? I've brought it to a new dealer to simply read the Consult III output and provide it to me, awaiting their response, but don't much trust their opinion so far. 

Cheers,
srmaddox


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## rogoman (Dec 16, 2004)

Possibly a bad MAF causing the system to go into limp mode.


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## srmaddox (Apr 9, 2013)

So the new dealer has no diagnoses yet, reports that they are reading 3 codes;

I was not awake enough to finish getting all of the detail (ugh, I have a wonky overnight shift) but I did catch:

(1) Crankshaf sensor is malfunctioning and CONSULT-III shows its reporting no datra

(2) There are one (14MM0) that is loose and one missing. I have not had any work done to the clutch except a dealer 8 months ago replacing a failed CSC. It was suggested that this could cause that code to fire and the Crankshaft sensor to malfunction, as that sensor is located in the flywheel assembly.

(3) The tech reported that the car is not starting again, with similar symptoms to after the first dealer worked on it. I suggested testing VVEL relay; It appears to be burned out again, suggesting some kind of electrical issue.


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## srmaddox (Apr 9, 2013)

Update:

New dealer has provided additional insight, and has been fairly good about keeping me in the loop, and going above-and-beyond what I had asked them to do so far all within a fairly small Diagnostic fee; I'm slightly encouraged by the fact that they have offered to go a ways further with the diagnostic without charging me more.

In point (3) in my last post, I'm noting here that it was actually the service representative that gave me this information, which was not entirely accurate. 

Current information:
(a) VVEL Relay is still functioning
(b) Car will start, but "sounds like crap," runs/idles rough now
(c) The Consult-III is showing "Many different codes relating to the cam sensors, crankshaft sensor, and other timing issues." There are also additional codes being thrown, according to the technician quite a few and no real consistency other than the Crankshaft/Cam sensor codes. I'll be asking for a complete list of codes scanned when I go speak with the technician.
(d) The tech has suggested the following, somewhat generic possibilities:
(1) At some point the flywheel and crankshaft sensor were installed incorrectly, leading to a cascade of timing problems;
(2) "Otherwise, I believe we had a timing issue in this engine; we'll have to take it down to the valves and tune/adjust the timing as needed."

I'm somewhat wary of this last generic statement that is could be a "timing issue" - What would cause said timing issue, etc?


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## FriendlyNismoTech (Oct 28, 2012)

There is no valve adjustment on these engines. If you want my opinion you burned up a VVEL actuator motor. This cause the engine to run in limp mode and will cause improper timing codes, the engine runs like crap, misfires and lacks a lot of power. And reporting the warranty not covering the repairs being bogus is well in fact not bogus. You took the car to a track, if you read your warranty paperwork this voids the powertrain warranty. It qualifies as excessive abuse. But I was not at the dealer that originally serviced your car so I don't know why they denied the claim. However, if the actuator is burned up the whole assembly needs to be replaced, and when it is replaced it will need to be initialized via consult III+


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## srmaddox (Apr 9, 2013)

Fixed the car up two days ago. 

I found the following, but I'm trying to narrow it down to a cause. 

The car ran in limp mode before bringing it to the dealer; when it came back, it didn't run at all. 

Replacing the VVEL relay restored it to running in limp mode. 

After getting another dealer to give me the sensor readout for the Crankshaft sensor, it was clear that the flywheel was at that time off - by 2. During hard driving, the engine still had some hiccups and missfires. 

I towed the car home, re-installed the flywheel properly and the car runs fine. 

With some additional work disassembling the engine, I found that the timing chain was a bit loose, so I replaced that. Engine purrs like a kitten now, after replacing the VVEL relay, reinstalling the flywheel, and replacing the timing chain. 

What I can't understand is how the flywheel got installed wrong. With the crankshaft sensor off due to this, it wouldn't run at all - and it quit running only after the first dealer.

Best I can figure, I turned it in with a bad VVEL relay , and they put it back together wrong, after not finding the dead VVEL relay. 

I have no idea what would have stretched out the timing chain. It was visibly larger than the replacement part, with signs of wear/bending across several links. That engine is a fairly durable engine all the way around, the timing chain isn't under-engineered by any means - so I'm having a hard time believing hard driving would have lead to that. 

That being said, I also can't find much causality between the VVEL relay or incorrectly installed flywheel and the timing chain. I suppose the issue with the timing chain could have been a longer standing issue, something that could have progressed after the chain was initially weakened, and not really notice; with the VVEL relay failing being the cause of initial symptoms, and negligence by the first dealer resulting in the misinstalled flywheel. I can't imagine how else the flywheel could've wound up as it did. 

As an aside, the issue with the warranty was that they didn't want to cover it under power train - and the non-factory warranty they sold me I had cancelled to replace (within 30 days) with another non-ford warranty... As ford had informed me of a number of issues with their dealer-offered warranty and my car, as well as the excessive price.


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## FriendlyNismoTech (Oct 28, 2012)

I must have missed where you stated you had taken the flywheel off. Yes if they are not installed correctly they will run like shit if at all.


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## imanzare (May 21, 2016)

*2008 g37 journey sport 5 A/T same problem*



FriendlyNismoTech said:


> I must have missed where you stated you had taken the flywheel off. Yes if they are not installed correctly they will run like shit if at all.


i know this thread is very old, but i have 2008 g37 coupe 5 speed A/T.....vvel bank 2 driver side is knocking and it was after hard driving my car started knocking, then turned off. i changed the cam sensors....from the codes p0340, p0345.......and the engine was able to run again.....but its not reliable to make it even to the store a block away......the engine can't go past 4k theres the similar problem this gentleman had but he has a 6 speed manual mated to his vq37vhr.....so i have an automatic with a transfer case....what could be the problem you suppose?


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