Member Since: 05 Feb 2006
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Yeah the Pico premium for putting a battery and transducer in a box for £600 is rather sobering, especially if you need 2 or 3 of them. Far better to stick 5v DC into a regular £10 transducer and call it quits. When working on a car it's not like you are short of places to grab DC power from!
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 23 Oct 2011
Location: Isle of Skye
Posts: 124
brightyuk wrote:
Valhalla Thanks your help.
Would you expect the trace to read higher or be smoother?
I thought the pressure regulator was attached to the low pressure fuel pump which has been replaced. I have also changed the fuel filter.
I have a new relay so will fit that and re-scope and get some live data using the IID of the rail pressure sensor or pressure delay.
I will post further.
I think that the overall pressure level of the trace you have is OK, certainly within production tolerances of the 0.5BAR that you would hope to see. The SVDO commonrail system is not as fussy as some for supply pressure, it's more fussy about return restrictions, etc.
The odd think is the dip in pressure under WOT (which I assume is at standstill, and is a free acceleration in Neutral?). If the LP system is struggling to keep up here, then it will definitely be struggling on the road under higher engine loads. I would not expect to see the pressure dropping down as low as 2psi or thereabouts.
The fuel filter head has some complications that might be worth a second look; firstly, it incorporates the mechanism that decides which way the fuel is directed on the return from the engine. The bi-metallic valve might well give you different results from cold-fuel condition to hot-fuel condition (after a hard run) and that might point to a problem (if there is one) in the filter head or LP pipework.
The other problem is damage to the connectors that push onto the filter, displaced seals, and mixed-up pipework that doesn't tally from port-to-port (pipework on the wrong stubs). If there is any doubt about the fuel delivery to the engine, then a good start is the filter head for a pressure measurement or two. Unfortunately, I have no easily accessible data for spill-return line pressures at this stage - I'll have a look over the weekend, or maybe re-measure some data off a good car.
Sorry about tardy responses - I'm a bit useless that way!
26th Feb 2016 12:22 am
brightyuk
Member Since: 11 Apr 2013
Location: Bedworth
Posts: 394
Valhalla,
Thank you for your assistance any response is better than now response :thumbs:, It gives me things to look at. Any traces I am doing I am uploading to the Picoscope wave library.
Yes this was at stand still with a cold engine
On the original trace the pipe work on the fuel filter was around the wrong way. Has been fitted correctly now and a new filter fitted.
I will disconnect the lines and see if any seals are dislodged, and give the lines a blow out and see it the helps.
Will post later with new waves and see if any difference.
Member Since: 11 Apr 2013
Location: Bedworth
Posts: 394
Thanks Rob,
Will do. Before running any length of time going to strip the bottom of the engine, to check the crank as sounds a bit rattly. ( Maybe a new thread)Vehicles
2016 D4 Landmark Indus Silver
2005 D3 HSE Silver
Detent Circlip 'How to Guide'
26th Feb 2016 9:28 am
Robbie
Member Since: 05 Feb 2006
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EeekLand Rover - Turning Drivers into Mechanics Since 1948
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
Robbie wrote:
Yeah the Pico premium for putting a battery and transducer in a box for £600 is rather sobering, especially if you need 2 or 3 of them. Far better to stick 5v DC into a regular £10 transducer and call it quits. When working on a car it's not like you are short of places to grab DC power from!
Made a box of tricks to cover a few pressure transducers to cover various ranges. Not my finest work but beats the heck out of a £600 tool:
Click image to enlarge
Click image to enlarge
Click image to enlarge
12v from the battery to red plus a suitable ground to black and the yellow connector off to a scope or meter.
Job done.
Land Rover - Turning Drivers into Mechanics Since 1948
Hello brightyuk,
What kind of current sensor are you using for the picoscope?
Thanks, junds
22nd Dec 2016 5:55 am
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
Brighty was using the Picoscope branded transducer. They are a quality item with a good range but the price is eye watering, hence my preference for a homemade bit of kit. Indeed, I would wager that almost anyone who can use a scope has the skills to put together their own version.
Land Rover - Turning Drivers into Mechanics Since 1948
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