Hello,
I have here a 2012 Nissan Juke /1.6 gasoline /MR16DDT with an abnormal noise and loss of power.
No faults stored in ECU,so I tried to find the source of noise.
and the loss of power.
In the stall test only 2230 rpm was recorded(compared to 2500-300 what is specified) so the loss of power of engine was confirmed.
Then I recorded the "noise" using some MEMS accelerometers placed on engine and CVT.
-as you can see the engine noise is bigger in the first stage of acceleration than the CVT noise...in the end the timing chain cover was identified as the source of noise.
The oil level in engine and CVT was checked,oil pressure was checked and was found ok(no drop of oil pressure when noise appear)
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In the last capture both OCV was disconnected,so I don't know if the reference for MR16DDT can be used to tell something about the chain elongation(before OCV disconnection I checked the supply
Hello Victor and thank you for the post and captures.
I will feedback on your NVH question in the other post topic20941.html?&view=unread#unread
Looking at captures 009 and 0011 with stable engine speeds in both captures, I can see very little difference in the cam crank correlation
Capture 009 below has 3.56° at my point of measurement (850 rpm)
Victor 009
Capture 0011 has 4.31°at my point of measurement (1290 rpm)
Victor 0011
I like the use of the accelerometers to locate the area of concern, which is invaluable information in itself.
Forgive me here as I am not sure if the vehicle is now rectified, but are we looking to conclusively diagnose a worn timing chain?
Listening to the audio recording it does sound like a continual scraping/contact noise from a rotating component with the occasional “contact” or foul condition with an adjacent component (I hope that makes sense)
With regards to correlation issues using cam and crank sensors, do we have a cam sensor for inlet and exhaust? If so could we add the additional Cam sensor and try Cam Crank correlation with OCV’s disconnected……
1. From cold at fast idle
2. When hot at idle
3. Finally the tricky capture, Cam Crank Correlation when hot during the transmission from idle to WOT and again during overrun as the throttle is released.
If we can get point 4 in one capture we can look at the effects of chain whip/flex etc. under these load conditions.
Hello Steve and thank you for your support,
Until now only some measurements was performed,without any repair.
Today I made some new captures with both (inlet and exhaust)OCVs disconnected:
- at fast idle(the engine temperature was 26-28*C,the engine speed was 1380-1420 RPM).
Here the difference in the cam crank correlation is 4,3*
-after WOT with the throttle released the difference in the cam crank correlation is 7.2*
Also the engine compression wasn't good(minimum must be 12 Bar,standard must be 15 Bar) and the measured and corrected values was:11.5,10.5,10.5,11.5 and the valve clearance wasn't good at cyl 1 and 4
(the exhaust valve must open at 25* BBDC and the intake valve must open at 7*ATDC).
Best regards,
Victor
Just to clarify, we have advanced exhaust valve timing due to reduced or no valve clearance?
Was this vehicle running with a gas (LPG) conversion?
I ask because I have had a number of engines where the exhaust valve seat depletes rapidly where the vehicle covers many Miles/Km's per year without any precautions taken to save the valve seat.
Regarding the timing chain, we have an alleged shift in correlation by approx. 3 degrees, could we recheck image 2 in your post above as I believe our 720 degree marker is incorrect?
It would be interesting to see how the correlation changes during the WOT and over-run conditions.
Hello Steve and thank you for your support,
No the car not have LPG supply,only gasoline/direct injection .
Yes,on cyl 1 and 4 the exhaust valve opening is advanced with 12-15* compared to cyl 2 and 3(and technical specs of the engine).
Image 2 wasn't good,here is a new one