Landrover Disco2 TD5 CPS strange peak

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Landrover Disco2 TD5 CPS strange peak

Postby Valhalla » Sun Nov 09, 2014 10:47 pm

Has anyone got any good waveform of the Landrover TD5 diesel "Storm" gen2 engine crankshaft sensor? I have attached a waveform of CPS versus 2 injector currents (for timing reference) which has what looks like a TDC single tooth with high amplitude, once per engine revolution. I have never had to look at the CPS like this before, so cannot say if the high pulse is normal or a symptom of the inbalance that this engine displays.
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Land Rover_Discovery_2003_Diesel_CPS_vs_2injs_single_wave.psdata
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Re: Landrover Disco2 TD5 CPS strange peak

Postby Fat Freddy » Wed Nov 12, 2014 7:13 am

Hi

That looks the same as the capture I have. The same peak in the same location. Internet is screwed so can't upload file. :? .

I'll upload once sorted for future reference.

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Re: Landrover Disco2 TD5 CPS strange peak

Postby Valhalla » Thu Nov 13, 2014 11:34 pm

Thanks for that FF. TBH, I couldn't work-out how any fault could cause the peak to appear as it is, but I'm still intrigued as to the mechanical layout of the tooth that creates that peak, given that its width is the same as the remaining teeth.

I have another possibility to measure a late TD5 with another customer, so I might see if I can borrow his car for an hour.....
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Re: Landrover Disco2 TD5 CPS strange peak

Postby Fat Freddy » Fri Nov 14, 2014 7:17 am

IIRC it's not actually teeth. It's drilling/holes in the flywheel (Would that mean technically the image should be the other way up? - rhetorical thought). So that extra tall 'spike' could be caused by the size/depth of the drilling. A bit like a bent tooth.

Here we go.
http://www.landyzone.co.uk/lz/attachmen ... wheel1.jpg


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Re: Landrover Disco2 TD5 CPS strange peak

Postby tode » Fri Nov 14, 2014 9:24 pm

If the flywheel has holes as a reference signal should be overturned, but it depends on how you connect the leads, as with any inductive sensor when connected to "reverse" the shape is reversed, I think that if the connecting wire pickup also change the signal remains consistent with the presence of the holes.
I would try to remove the sensor and look into how it's done .... out of curiosity.
:D
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Re: Landrover Disco2 TD5 CPS strange peak

Postby Valhalla » Fri Nov 14, 2014 11:38 pm

Thanks for all your responses on this. I had completely overlooked the chance that holes rather than teeth were present. I think that its more likely that the "TDC" hole is in-fact a mechanical pin engagement for locking the flywheel at the timing point for the cam-drive system. It probably doesn't matter that the height is a little taller than the others, as the timing will measure just fine at a nominal voltage threshold.

I'll have to use a tame Defender to measure this, as the Disco2 has the flywheel buried back under the bulkhead. I should have one coming into the workshop on Wednesday next week, so if I'm quick with the "proper" work........ :wink:
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Re: Landrover Disco2 TD5 CPS strange peak

Postby Fat Freddy » Sat Nov 22, 2014 11:56 pm

Hi Val

Tried uploading file today, unfortunately to big. Over 12Mb. But you can see the peak in this image.
TD5.jpg


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Re: Landrover Disco2 TD5 CPS strange peak

Postby Valhalla » Sun Nov 23, 2014 12:23 am

Thanks for that FF. Yep, it's clear that the CPS trace you have has an identical high peak. So I'm not worried about that now!

For information, this vehicle has been quite a case. In each measure, it has been an exercise in eliminating issues that could be causing the problem, until I finally produced my summary report to the customer, which is that the engine is fine from a combustion point of view, but shakes like a leaf from a mechanical imbalance. As I don't have the NVH kit, or have worked-out if it would have helped here, then I have had to go through the whole case from the combustion side;
a) Exhaust manifold temps (within 3degs celcius of each other, static and dynamic)
b) Cylinder balancer additive components (no significant reading) in the ECU
c) Relative compressions (OK)
d) Injector voltage/load comparisons, cyl to cyl (within tolerance, and all switching OK)
e) Engine speed roughness (speed is smooth)
f) Exhaust pressure pulsing (even across all cylinders, permitting some exhaust system resonances)

So the customer has been told to remove the transmission and look for a broken clutch cover plate, DMF, or similar.
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