One FINAL PLEA for your Help...Summary of issues

[Singhman]

I have several threads started on some issues with my Murano, but here is a FINAL summary of what I am experiencing (and I think they're all related). I would be very grateful if you guys can help me out, and at least point me into the right direction, because it seems like the Nissan Techs notice the problems when they drive my car, but after hooking it up to the computer, they say "everything's fine", when its not. (and they know it' too). Here is a summary:

I just bought a 2006 Nissan Murano about 2 weeks ago. I am starting to notice a few things after driving it for a while:

- when I am driving at city speeds, and just barely pressing the gas pedal (just enough to maintain speed), I can feel vibration. I can feel it mostly in the gas pedal, but it can be felt it in the cabin too. My wife has felt it while sitting in the passenger seat too.

- It seems that when I slowly accelerate, everythings fine until I hit about 15-20 mph. At this point, at light and steady throttle, the rpms drop to about 1100 and the car starts to ‘struggle’ and vibration is felt. It seems like the power goes down, and the car is sort of struggling a little. If I hit the gas pedal, the vibration goes away, and the car responds powerfully. Also, when this happens the sound of the engine changes. It sounds/feels like a manual transmission car that is being driven in too high of a gear. When I hit the gas the car smoothes out and actually goes pretty good.(good power)

- when the vibration/noise is occurring, I am also getting what sounds like pinging occurring as well. Like I said before, when I hit the gas, or take my foot off of the gas pedal, everything seems to be normal again. It only happens during light throttle, or slow acceleration. 9I'm pretty sure the noise is slight pinging). It sound like crackling sort of.

- HERES A WEIRD THING: this only happens after the car is warmed up. If I park the car for a few hours then drive it, it drives perfect. No vibrations/sounds etc. But, as soon as the car warms up and starts running at lower rpms, the shudder/vibration, and also pinging problems begin.

- the car drives fine at high speeds on the highway

- it seems that when I accelerate from a complete stop slowly, it starts of fine, but after a few seconds the rpms drop down a bit (feels like it upshifted a few gears), and the car starts to vibrate and the engine noise becomes sort of rumbly. Also, when I am sitting in drive at a red light (after car is warmed up), my rpms look like they are at 500.

- I took it to Nissan to get the fuel injectors flushed out, and they did an ECU re-learn. It seems to me like the pinging is happening even more now! Or at the very least, it’s the same as before.

If anyone can help me that would be great. I’ve seen 2 different Nissan techs and they have acknowledged that they do hear/feel the problem and its NOT normal. But after hooking it up to the computer, nothing came up, so they say “run a few tanks of high octane gas and it’ll be ok” (I guess they don't know whats wrong, or how to fix it) Please help…Thanks in advance.

ps- i looked at the a post on another website, and it seems a person had sort of similar problems. He said that one of cylinders wasn't firing and the coil/spark plug was soaked with oil (valve cover didn't have good seal) Could this be the same problem? Am I allowed to post links to other Murano forums?

[Desert Rat]

Pinging can be remedied a couple different ways. To be sure that's what it is, run a tank of 91+ octane through the car and see if the pinging persists. If that clears it up, it was definitely pinging. Cleaning the Mass Airflow Sensor typically helps with this. Just be careful when cleaning it, as the wire in the sensor is fragile, and new ones are expensive. Most parts stores carry aeresol cleaners specifically for this purpose at about $5 a can.

Your other issues sound CVT related. How many miles are on the car? Has the fluid ever been flushed? It may be time for that.

[AZhitman]

I agree, sounds like a MAFS issue.

Any modifications to the car? Service history? Does there appear to be oil getting near the coils? Sometimes a simple visual inspection reveals clues...

[kerrton]

Your vibration issue is due to the nature of the CVT, I own a Rogue and this is a common issue of discussion on our forum, but the concepts are the same. The vibration is by design, caused by the CVT selecting a very high gear ratio in order to provide better fuel economy. It is the equivalent of up-shifting a manual transmission into say 5th gear while driving around town, the vibration would be referred to as "lugging the motor"

The reason why others may not experience this, while your Murano does, is because the CVT and computer (ECU etc..) uses "adaptive logic control". This means that it "observes" your driving style and learns your preferences. If you are very light on the accelerator (i.e. a conservative driver), the computer learns this and in the future it favors fuel economy over power and acceleration. Remember that the gas peddle isn't connecte to anything physical, it doesn't do anything more than provide input to the computer, which in turn decides the appropriate CVT gear ratio and how much throttle to apply. Even though that vibration seems odd, I woudln't worry about any abnormal wear or damage, Nissan engineers ahve designed the engine and CVT to operate within an acceptable range that will not damage components.

I've found with my Rogue that once you understand the cause and realize that it is normal and by design, you quickly get used to the sensation and it is no longer an issue. I'm very picky and meticulous with my vehicles and while can't say I love the way the CVT operates in all situations, this feature no longer bugs me. On days when I don't want to feel this effect, I just apply the throttle a little more liberally, like you said in your example, and the computer choooses a little lower gear ratio, which immediately gets rid of the vibration but fuel economy will suffer somewhat.

These facts are well documented and common to all vehicles with CVT, which is why I can't understand why your Nissan Techs aren't aware of it. This is also why the computer check indicates everything is ok.

Regarding the last part of your post, I'm not sure about the pinging perhaps there is a problem that will become apparent as time passes, but the rpms dropping rapidly is again the way the CVT works. If you've never owned a CVT vehicle before it'll take some getting used to but this is completely normal. The CVT is trying to "upshift" as quick as possible for fuel efficiency but like I said, you should be able to override this by going heavier on the throttle. If the CVT doesn't respond then perhaps there is a problem, you've still got warranty so maybe just give it some time to further develop? Good luck.