Nissan X-Trail Non-start Timing Chain?

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Nissan X-Trail Non-start Timing Chain?

Postby TasSparky » Tue Apr 11, 2017 11:40 pm

Hi team,

I have a 2006 Nissan X-Trail QR25DE here which is a non-starter. It came into our workshop with a cam sensor fault. The customer replaced both cam and crank sensors with the same result. The vehicle also had a starter motor fault which was repaired first. I connected our scan tool and checked the codes. A cam sensor fault code was present. I cleared the codes and re-checked. The vehicle still will not fire and there are now no fault codes present. If I disconnect either the cam or crank sensor the engine will fire, which made me think of a timing issue, as I know these Nissan's have problems with stretched timing chains. When cranking it will try and fire on the first attempt only then gives up. When scoping the coil and injectors, the signal is there on the first attempt but then there is no signal after that.
The customer also stated that the vehicle had a head gasket done a week prior to this problem starting.
I have attached a waveform showing cam vs crank. Any help on this would be greatly appreciated.
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Nissan X Trail cam vs crank.psdata
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Re: Nissan X-Trail Non-start Timing Chain?

Postby PicoKev » Wed Apr 12, 2017 11:22 am

TasSparky,

First off welcome to the Pico Forum.

The Waveform library is your friend especially in this instance. :D

You have a forum user name and login so you can access the WFL for free at any time provided you have your scope connected to the PC you are using to access the library.

You will find the WFL listed in the file menu of the Picoscope software (subject to the above) click on the link and input your forum details and use the search criteria on the left hand edge.

Nissan + Xtrail + QR25DE will filter down from the current 3,083 waveforms to 3! One of which is a CMP/CKP Known Good from a highly respected forum member.

You can download the file from the WFL and duly analyse the data and make your diagnosis at leisure. 8)

Keep us posted on your conclusion.

Kev.
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Pico reply.PNG
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Re: Nissan X-Trail Non-start Timing Chain?

Postby TasSparky » Thu Apr 13, 2017 7:00 am

Hi Kev,

I see on the waveform you have provided that both the sensors are 5 volt hall effect sensors where mine is 12 volts. Is that the difference between diesel and petrol engines?
Or is that my problem?

Cheers!
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Re: Nissan X-Trail Non-start Timing Chain?

Postby speck » Thu Apr 13, 2017 11:21 am

The wave form Kev provided is not the
right one.
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20130527-0001.psdata
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Re: Nissan X-Trail Non-start Timing Chain?

Postby STC » Thu Apr 13, 2017 8:33 pm

Hi Tas

I have just measured that as retarded some 16 degrees of crank rotation. In that case, if your camshaft has about 45 teeth, then it is exactly a tooth out. I am trying to establish if this timing or a stretched chain.

Would you post the number of teeth on either the Cam or the Crank and another capture from Start > Idle >WOT - Over run back to Idle > Switch Off. 10 - 15 Seconds across the screen, So all on one. Just to see if it is consistently out or establish drift.

Thanks
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Re: Nissan X-Trail Non-start Timing Chain?

Postby TasSparky » Mon Apr 17, 2017 10:25 pm

Hi STC,

I will try this tomorrow and report back. The vehicle will not start, so Im unable to show you exactly what you are after.
I'm also unsure of the number of teeth. If there is any other capture you would like?

Cheers,
Jared
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Re: Nissan X-Trail Non-start Timing Chain?

Postby STC » Thu Apr 20, 2017 10:20 pm

The vehicle will not start, so I am unable to show you exactly what you are after.


Sorry I must have missed that in your post. And being a chain it is not going to be easy to count the teeth on the sprocket. And of course the Known Good Waveform.

If you do end up stripping it to replace the chain, please post the number of teeth on the Cam or Crank Sprocket.
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Re: Nissan X-Trail Non-start Timing Chain?

Postby Fat Freddy » Wed Apr 26, 2017 6:24 am

I'm sure you will have this wrapped by now. Anyway my two cents from observations, of Nissan cam/crank captures,.

Most of these 1,3,4,2 cam teeth configurations seem to have the 1st cam tooth towards the left edge of the 180* crank window.

Often a physical look at the tensioner if possible will be a give away - check specs.

The other thing I noticed but did not really have a chance to confirm if it is true across the board. Is excessive chain slack on cold start. The cam seems to 'roll over' on the peaks of the lobes. I'm assuming it's taking up the excess chain slack and momentarily stopping with a tooth in front of the sensor. Before being turned again by the crank. I assume this slack is created by the of ratchet on the tensioner and before oil pressure is built up to remove the excess slack.
It is no wonder it logs a Cam sensor fault. The N16 in the image below would start after a long extended crank, log a cam sensor code but would occasionally cut out. Replacement of the chain and tensioner moved the cam signal left in the crank window and virtually removed this Cam tooth 'stretch'.

Chain stretch.jpg


I did read another explanation on iatn that put the problem to a 'nick' on the cam shaft. So after replacing the cams and the chain the problem was gone. :shock:
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Re: Nissan X-Trail Non-start Timing Chain?

Postby TasSparky » Thu Apr 27, 2017 1:58 am

Hi guys,

Sorry I have been away for a couple of weeks. Thanks for your input. I'm pretty sure its a timing/chain issue but the customers mechanic who replaced the head gasket says it wont be. If the timing is out, will this cut the injection and/or the spark? If I disconnect the crank sensor it starts everytime. Cheers.
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Re: Nissan X-Trail Non-start Timing Chain?

Postby TasSparky » Fri Apr 28, 2017 12:04 am

Its got me thinking as this will start everytime with the crank sensor disconnected, but as soon as I reconnect it, it will not start. The crank sensor is also not going to 0 volts. There is about a 250mV drop. I guess the main question is, if the timing is out will this cut spark? Its like it has jumped a tooth maybe?
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