Also thinking about this as the diesel fuel acts as a lubricant would u then start to get metal fragmanets because the lubricant isn’t there

its just a thought and the more knowledgeable members here will know, hopefully won’t require the replacements of the HPFP, LPFP and injectors

also heard about adding a small quantity of 2 x stroke, of course don’t know how true that is ??
 
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Another thought @pete980 , with it not starting I wonder if it’s worth doing a full canbus test

can talk u through it if ur unsure , was just an idea seeing u can’t pull live data seeing the engine won’t start
 
gstuart said:
Another thought @pete980 , with it not starting I wonder if it’s worth doing a full canbus test

can talk u through it if ur unsure , was just an idea seeing u can’t pull live data seeing the engine won’t start
Click to expand...
@gstuart i agree a canbus check would be worthwhile im going to get stuck into it again when this weather clears (my wetsuit is drying out lol)
It does run but barely on about 550 rpm only for a few seconds then dies i will try and get some data out of it if the physical checks don’t confirm the pressure loss at the pump
 
gstuart said:
just seen that it will run on easy start so at least that cuts out sensors etc , so indeed i would have thought it would be down to the delivery / supply side

when u changed the filter do u remember what make it was plse as I’ve heard cheap ones can cause issues

wonder if its worth connecting a tyre valve onto the fuel shrieder valve , ign on and allowing fuel to pump through into a bucket to ensure 100% only diesel is now coming through , maybe changing the filter with a genuine one just in case it still has some petrol inside the filter

just a thought
Click to expand...
Done this with the centre of the shrader valve removed into a milk carton so i could see the delivery through the pipe into the carton no bubbles and a good flow cycling the ignition
 
pete980 said:
@gstuart i agree a canbus check would be worthwhile im going to get stuck into it again when this weather clears (my wetsuit is drying out lol)
It does run but barely on about 550 rpm only for a few seconds then dies i will try and get some data out of it if the physical checks don’t confirm the pressure loss at the pump
Click to expand...

no probs and indeed worth a shot , wrote out a test sheet for u , plus plse double check the MAF sensor is plugged in

great u put a hose on the test point and allowed it to run into a container , indeed after should see 7psi or 0.5 bar

wonder if it worth running it for a good few minutes to ensure there isn’t a air pocket along the line

if it does just run see if u can get the , pump , injectors live data , fuel rail sensors , etc, we can then compare in what they should be

hope it helps

Canbus testimg


With both battery leads disconnected from the battery posts


Multimeter set to ohms, ( TP Is just short for test probe from ur multimeter )


TP to pin 6 other TP to pin 14, read ohms


TP to pin 3 other TP to pin 11, read ohms


Reconnect battery, ign off, meter set to Vdc


TP to pin 6 other TP pin 4 Read Vdc


TP to pin 6 other TP to pin 5 Read Vdc


TP to pin 14 other TP to pin 4 Read Vdc


TP to pin 14 other TP to pin 5 Read Vdc


TP to pin 6 other TP to pin 14 read Vac


OBD2 pins


Pin 16 battery positive

Pin 1

Pin 2 - PWM positive

Pin 3 - medium canbus (high side )

Pin 4 - chassis ground

Pin 5 - signal ground

Pin 6 - high canbus (high side )

Pin 7 - K line

Pin 8 - transmission module

Pin 9 - ABS module

Pin 10 - PWM Negative

Pin 11 - medium canbus (low side )

Pin 12 - restraint control module
 
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IMG_5692.jpeg
 
Thanks again
especially for the test sheet gstuart
I will work my way thru it
“wonder if it worth running it for a good few minutes to ensure there isn’t a air pocket along the line”
It did run with a bit of easy start help but didnt have my diagnostic plugged in at the time school boy error
the wife was in it and i was too focused on the engine and squirting go juice in it to try and pull any air lock thru if there was one
I will give it another bash to read live data
I will let you no how i get on
 
pete980 said:
Thanks again
especially for the test sheet gstuart
I will work my way thru it
“wonder if it worth running it for a good few minutes to ensure there isn’t a air pocket along the line”
It did run with a bit of easy start help but didnt have my diagnostic plugged in at the time school boy error
the wife was in it and i was too focused on the engine and squirting go juice in it to try and pull any air lock thru if there was one
I will give it another bash to read live data
I will let you no how i get on
Click to expand...
Hi Gstuart
A bit of an update had a break in the weather
So i managed to get some wrench time in
IMG_5479.jpeg

Tested the physical fuel pressure at the rail and it goes off the scale
Also managed to get some brief data from diagnostics attached
Now i can see i have pressure but still wont bloody run
IMG_5477.jpeg
IMG_5476.jpeg
IMG_5473.jpeg
IMG_5475.jpeg
IMG_5468.jpeg
IMG_5470.jpeg
IMG_5469.jpeg
IMG_5474.jpeg
 
I am no expert by any means. so please tell me to go away if I am totally wrong.
Is the 2.7 a common rail?
Are those pressure readings of the HP common rail? If so then your gauge should have blown up.
Did you try a bit of easy start while doing the test.

What I am saying is the pressure is too low (don’t know the 2.7 ) but if it’s too low the injectors will not fire or if they do will be very poor.

I maybe totally off the mark and need to look at docs on other device later.

J
 
marjon said:
I am no expert by any means. so please tell me to go away if I am totally wrong.
Is the 2.7 a common rail?
Are those pressure readings of the HP common rail? If so then your gauge should have blown up.
Did you try a bit of easy start while doing the test.

What I am saying is the pressure is too low (don’t know the 2.7 ) but if it’s too low the injectors will not fire or if they do will be very poor.

I maybe totally off the mark and need to look at docs on other device later.

J
Click to expand...
You could be right there, I don't know much about petrol common rail but a quick Google suggests between 50 and 350 bar so that's 700psi to 4,900psi.
 
Datatek said:
You could be right there, I don't know much about petrol common rail but a quick Google suggests between 50 and 350 bar so that's 700psi to 4,900psi.
Click to expand...
It’s Diesel. But yes high pressures needed for diesel too

J
 
Bloody hell, should read 7 psi or 0.5 bar

must confess never seen it that high at idle , , wonder if the gauge is faulty as don’t know how the low pressure fuel pump can produce those high figures

what does the gauge do when u slightly press the accelerator pedal plse

also wonder if the pressure regulating valve is faulty ?

plus have u tested the amperage of the fuel pump plse as per Robbie’s guide, if no joy might be an idea to post on the D3 forum to find out why those figures are so high

DISCO3.CO.UK - View topic - Robbie's Guide To The Low Pressure Fuel System

Community site dedicated to Discovery 3, 4 LR3 and LR4 Owners and Enthusiasts. Totally free to join - message boards, galleries, wiki, off road events, social meetings.
www.disco3.co.uk www.disco3.co.uk
 
Last edited:
gstuart said:
Bloody hell, should read 7 psi or 0.5 bar

must confess never seen it that high at idle , , wonder if the gauge is faulty as don’t know how the low pressure fuel pump can produce those high figures

what does the gauge do when u slightly press the accelerator pedal plse
Click to expand...
I thought he was looking at the rail pressure.
 
That test point at the back of the engine is for the LPFP readings , which indeed should be 7 psi or 0,5 bar at idle

if the gauge fluctuates when the accelerator pedal is pressed indicated either a blocked filter or LPFP is failing

also seen where cheap fuel filters can cause issues but that will normally show very low pressure

would be tempted to clear all the codes after noting them and see what comes back

would then look at the live data for MAP, MAF, LPFP and HPFP to see what they are at idle
 
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Hi guys thanks for the input
I made a line up from the rail in between the injectors to physically see the pressure of the hpfp while cranking and yes the needle bounced all the way to the stop !
Checked the live data and the readings were as per the images
Datatek said:
I thought he was looking at the rail pressure.
Click to expand...
hi yeah the gauge nearly did blow its top
I wanted to see physically if there was any pressure from the HPFP while cranking
As it was still throwing a low pressure fuel error
I was trying to confirm the 13162hg
i was seeing on the live data was actually there daft i no but just wanted the confirmation
 
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