Nissan Micra K11 1.3 weird behavior

Hi guys,

I've got a very tricky and nasty problem that hopefully will be solved with your help.

The car: Micra K11 '99
The engine: 1.3
The gears: NCVT

The problem is that when the car is properly warmed and I try to slow down from any speed when the speedometer approaches the 25~20 km/h the engine over revs at about 2500 rpm. The effect is just like when shifting down manual gearbox and releasing the clutch very quickly so that the engine suddenly raises the revs. The car even slides tires occasionally while slowing down, which can be pretty dangerous if it is wet. It does not matter how fast you are driving. It does it every time after it is warm enough.

Several weeks ago I've changed the whole ignition module and after that it was calibrated with stroboscope. The reason for that was ignition problems while speeding up (I am wandering if this might be the cause of all the problems).

I've also checked a day ago the CVT brushes, cleaned the throttle body very carefully with carburetor spray (without re-soldering the PCB - it seemed too invasive procedure) and cleaned the idle speed control motor without any actual change in the behavior.

One of my guesses was the electrical system. I've checked the alternator today (call it 6th sense) and the readings were less than 14 volts when idling with headlights. After I turned on the AC and started to play with the electrical windows, the readings get below 12.75 volts. Is that normal or my alternator is heading towards the trash can? I know that the clutch is electrical and I was wandering if during slowdown because of the consumption of the brake hydraulics maybe it runs out of power and eventually slip.

My second guess was that when the car warms up properly the MAF sensor is not reading correctly and while leaving the car without any air by releasing the throttle pedal and pushing the brakes, the only thing that operates is the idle speed control motor, which I believe is controlled by the MAF itself and some other engine temperature readings (correct me if I am wrong).

Before I get very boring (I might have already crossed that border) I want to ask for an expert opinion so please advise. This is my wife's car, but I've kind'a started to enjoy it quite a lot and it would be a shame to let her go (not the wife).

P.S. I know that I am starting a second thread, but the original one was with the assumption that there was a problem with the CVT and clearly it is not like this so I decided to get a fresh summary.
 
OP
OP
onassin
has it got a second throttlebody quadrant fitted ? (for the kickdown)
I am not sure what is that, but if you are talking about this thingie on the picture then yes, it has it.

High_Quality_Throttle_Body_Assembly_for_Nissan.jpg


If it is not what you mean, please describe how it looks like.
 
OP
OP
onassin
I had no idea what this thing is until that moment. I also do not know how it should be adjusted. Should I loosen or tighten it up?
Maybe if you tell me how can this relate to the stopping issues I can figure out myself how to tweak it.
This cable is pulling in the exactly opposite direction of the throttle cable, which made me wander what it is used for.
 
Last edited:
OP
OP
onassin
Not much - the problem stays the same if not getting worse.

I have done additionally the following things:
- re-soldering the TB
- changed the IACV
- I've played with the second TB quadrant - no change at all
- unplug every single sensor and spraying with contact spray (even the pedals)

Now, when the car is being driven long enough, I am able to drive it in Ds without pressing the gas pedal at 1500-1700 rpm. It just stays in some kind of balance and it can do it very long time. After I apply the brake and the car goes to 2200 rpm, it stops and then you need to press the gas pedal to continue driving. Obviously the clutch stays on for some reason. Just worthy mentioning - the weather right now is really hot (it goes over 30 degree Celsius)!

In some Russian website I read that when the powder from the clutch fells off the place where it should reside (I have no idea of how this is mechanically realized), it can lead to malfunctions such as bad disengagement or random engagement of the magnetic plates. But this repair can be costly and I need to confirm it 100% before going further. Again - the gear lever is working smooth and does not stick.

I just need to answer the question: is it the clutch that sticks and the engine is compensating the load (IACV don't let the car to wend out by increasing the revs) or the clutch stays on because there is a problem with the engine rpm?

P.S. Can anyone tell me where I can order clutch powder? If it is cheap enough I can most probably try change it myself.
 
OP
OP
onassin
I hope that you are wrong.
According to what I've read the clutch is not that complex. Basically it consists of two flywheels (if I might call them so), a bearing and some "magical" magnetic powder.
Pretty much what you have to do is to polish the plates/flywheels, replace the bearing and the powder.
At the moment I am not able to find the powder myself - maybe I have to go to the official dealer, but I am sure that it will be costly there.
 
OP
OP
onassin
OK ... a little update.

The problem should be now solved. I finally discovered a service that possesses the mysterious knowledge of the CVT. It actually turn out that it is semi-official Subaru service.
Here comes the funny facts: the N-CVT gearbox is actually made by a Japan company other than Nissan (Fuji if I remember correctly) and the patent for the continuous variable transmission is being owned by Subaru.

According to their words the problem was well known. While braking the gearbox tries to downshift a bit in order to help. Due to worn hydraulic part instead of downshifting a bit, the gearbox downshifts a lot. They had actually disassembled the gearbox, cleaned the hydraulics, polished some worn/scratched part and changed the oil.

Right now the car feels OK to drive. It still downshift during braking, but it does it now very gently and according to the head of the mechanics there - totally "within the program" of the gearbox "brain" (i.e. within the norm).
The price of the repair was less than 100 EUR, which surprised me. Let's hope that it will last.
 
Hello onassin. Great reply, thanks for that.
Interesting to hear how the box works.
That's a very reasonable price for that repair...where you to buddy (?)
 
Top