Member Since: 15 Apr 2020
Location: Aix-en-Provence
Posts: 46
HPFP or LPFP fault?
I have been having the same problem as many people on the forum with the F, suspension lowering etc while driving. Re-start and it continues perfectly – until the next time which could be 20 secs to 10 mins or the next trip.
Like many people on the Disco forums, I am struggling to understand the intermittent nature of this fault and cannot reconcile this with a failure of the HPFP itself. I could understand failure of the PCV on the pump.
Looking for final flashes of inspiration before I bite the bullet and change my HPFP.
Doesn’t seem to occur until I have traveled about 50 miles – so a temperature element?
Except for once when the fuel level was at ¼ and I went up a steep hill. Then there was no fuel at Schrader valve so I concluded that there could be a fuel gauge fault. Added 10l of diesel and away it went until the next time I travelled more than 50 miles.
Last faults registered are:
P0087 – low fuel pressure
P2290 – injector control pressure too low
P000E – fuel volume control exceeded learning limit
I already changed the LPFP as the pressure at Schrader valve was a bit lower than than recommended in Robbie’s guide.
I also changed:
• the fuel filter for genuine LR one
• the return pipe from the filter to the tank as there is a restrictor in the pipe which sometimes fails and allows the fuel to take an easier path bank to the tank.
With the new pump the pressure and flow are actually a bit lower than with the old pump and the current drawn is just over 2A. So far I can’t find any bad electrical connections to explain the low current draw.
I am going to drop the tank for a 3rd time to check at the pump / tank. My car is LHD so wiring may be different to RHD. I can find a big multi-pin connector on the chassis leg behind the left rear wheel. Only 2 connectors with 2 wires each on the RH side (fuel tank side).
Question 1: Can anyone point me to a connector / likely bad connection?
Question 2: Has anyone aad any experience of a blockage or other problem with the fuel cooler?
I ask because my problems started after I temporarily removed this to improve access to remove starter when I was changing timing belts and oil pump. Also changed fuel filter at this time.
Question 3: Is there any link between the pressure control valve (PCV) which is situated on the HPFP and the LPFP? Does it control the flow from the LPFP in any way?
Question 4: The PCV seems to be available separately on eBay – though I think there may be different types for Euro 3, 4 etc. Has anyone changed it? Success or not?
Question 5: Does anyone have any experience of the volume control valve failing? I think it is built into the housing on the tank where all the pipe and electrical connections connect to the LPFP module in the tank.
Question 6: Does anyone have experience of a new LPFP being faulty?
Question 7: Any good experience with recon HPFPs and recommendations for suppliers? Cheapest genuine new one I can find is over £700. I would hate to change it and still have the problem…
Sorry for the long list of questions. Any suggestions gratefully received.
I will definitely report back on the outcome to add to the general font of knowledge.
Thanks for reading!
27th Sep 2020 9:48 am
Lrsg
Member Since: 10 May 2020
Location: Norway
Posts: 77
P0087 very often means that your HPFP is on its way out. I went through this two months ago, changed HPFP and all is well again. I bought a refurbished pump from this supplier:
https://www.ebay.co.uk/itm/Fuel-Injection-...SwB8Rb3FsT
27th Sep 2020 10:32 am
French Collection
Member Since: 15 Apr 2020
Location: Aix-en-Provence
Posts: 46
Thanks Lrsg!
27th Sep 2020 11:23 am
French Collection
Member Since: 15 Apr 2020
Location: Aix-en-Provence
Posts: 46
I dropped the tank again today. Checked the voltage at the connector to the tank. The most I can find between any pair of contacts is 4V. I presume it should be 12V.
Should I be looking for a bad connection? Or could this voltage be regulated incorrectly by a faulty regulator / sensor somewhere?
27th Sep 2020 3:55 pm
ds23man
Member Since: 19 Jan 2013
Location: Ainum
Posts: 227
The LPFP is not modulated so there should be 12 volt. The only pressure regulation in the LP circuit is the regulator INSIDE the tank. So changing only the pump part itself and/or cleaning the tankfilter will not allways solve your problem.
27th Sep 2020 4:02 pm
discovery3ski
Member Since: 25 Dec 2012
Location: leicester
Posts: 734
Had my HPFP changed a few months ago and it’s never ran better. It gave me all sorts of odd codes and running issues that were intermittent. Also had to do all the LPFP and new tank along with fuel rail as a rodent had eaten into the tank and allowed copious muck into it. Only saving grace was the injectors were all good.
It’s an expensive part but transformed my D3.Discovery 3 tdv6 HSE 2007
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27th Sep 2020 7:43 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4655
Member Since: 15 Apr 2020
Location: Aix-en-Provence
Posts: 46
Thanks alot!
28th Sep 2020 4:10 pm
French Collection
Member Since: 15 Apr 2020
Location: Aix-en-Provence
Posts: 46
Last night I established that the earth (black wire) to the tank pump connector is good.
Rigged up a temporary direct feed from battery positive to the pump and using earth from the plug was able to run the pump. So earth definitely good, pump definitely works.
Seemed to be a good flow out of the pipe, but did not measure it in any way yet.
Next step to find out why I don't have 12V at pump connector.
Pondered overnight and realised that I had not cleared the fault codes.
Cleared those (P0087, P2290, P000E, P0578) and 12V restored at connector - though only for 15s or so at a time which I think is how the pump is programmed to operate.
Still only 4V at the other contacts on the plug for fuel gauge senders. Maybe they run on 4 -5V?
Next step to check the current draw and flow / pressure at tank and potentially put old pump back to rule out a possible fault with the new pump before I put the tank back in.
Have to get to the day job now!
29th Sep 2020 6:52 am
French Collection
Member Since: 15 Apr 2020
Location: Aix-en-Provence
Posts: 46
Update
After doing a lot of checking and creating problems for myself along the way I established that:
Electrical connections to the LPFP were good and that apparent problems were due to the tank being on angle so I could connect the pipes but still have access to the electrical connector.
There are no connections in the wheel arches for the 2008 Disco. There is a single loom that runs all the way from a connector in the front left corner of the engine bay just in front of the Webasto auxiliary heater and down the LH side of the chassis on top of the main rail anf then across to the pump just forward of the rear axle. The routing might be on the other side on RHD, mine is a left hooker.
That my 'new' Allparts pump was drawing only 2A whether connected / powered through the connector on the car or when powered direct form a separate fully charged 12V battery. Conclusion: if there is a fault it is not due to car wiring.
I concluded that it didn't make sense to change the HPFP while I still had doubts about the LPFP. So I ordered a new genuine LR complete LPFP module from Rimmers.
Fitted that and took the car for a test run today. Complete 100km this morning with no fault.
Previously the most I have managed since the saga started was around 70km. I am bearing in mind that the previous runs when I had a fault at 70km were several weeks ago when it was significantly warmer here.
On the advice of Profesr G I purchased a GAP IID diagnostic tool. Not cheap but impressive with Bluetooth connection to mobile phone for data display and recording.
I used this to do a reset on the lift pump (which I assume is the LPFP). No idea what this reset does, but GAP manual says it should be done when pump is changed.
I also used this to log some data during today's test.
The graphs of the rail pressure, pressure control valve and volume control valve readings all follow each
other closely and vary according to engine speed and load.
Voltage is mostly at around 14.3V but with quite a few spikes where is drops to 14.1V - not sure why that is, could be because I had the heated seat on. I will keep an eye as I have seen posts where alternators were causing the sort of symptoms I have had.
Volume control from about 21 to close to 40%.
Pressure control valve from about 12 to 27% except when there was a jump in rail pressure and engine speed.
I have no idea if these values are in the right range?
So, sitting tight for now and waiting for a warmer day to do another test. In the meantime, I will use it for my daily commute of around 50km each way.
Planning to drive it to Brussels (about 1000km) mid-November.....Bentley 8
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25th Oct 2020 6:06 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4655
Sounds like you're over the hump. yµ (idµ - eAµ) ψ=mψ
25th Oct 2020 6:11 pm
French Collection
Member Since: 15 Apr 2020
Location: Aix-en-Provence
Posts: 46
Hello Everyone,
In spite of a week commuting to work without any issues, the Disco fault returned over the weekend - when, of course, I was towing a trailer with another Land Rover on it.
Same as before, warning message on dash, loss of power, suspension lowering etc. This time, however, I had my IID tool plugged in and logging data and can see that for each fault incident the pressure contrl valve reading spikes.
Click image to enlarge
Hope you can see the turquoise line in the graph. The light green just below the turquoise is the fuel rail pressure and normally these two lines are pretty parallel.
As far as I have understood from other posts, the pressure control valve is built into the HPFP and this is often the component of the pump that fails.
So I guess this is conformation that my HPFP needs to be changed? Any thoughts anyone?
Thanks for reading!Bentley 8
Rolls Royce Silver Shadow
Triumph Stag
Volkswagen Karmann Ghia Razor Edge
Jaguar XJC
Jaguar E-type
Jaguar XK8
Land Rover Discovery 4
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4th Nov 2020 7:48 am
French Collection
Member Since: 15 Apr 2020
Location: Aix-en-Provence
Posts: 46
I decided to change the HPFP.
I couldn't find anything online about how to do it so I posted my procedure here:
https://www.disco3.co.uk/forum/guide-chang...91857.htmlBentley 8
Rolls Royce Silver Shadow
Triumph Stag
Volkswagen Karmann Ghia Razor Edge
Jaguar XJC
Jaguar E-type
Jaguar XK8
Land Rover Discovery 4
Mercedes E350
Ford Granada 2.8 Ghia X
Ford Granada 2.8i Ghia X
15th Nov 2020 6:12 pm
villib
Member Since: 29 Dec 2020
Location: Hafnarfjörður
Posts: 1
@French Collection
I'm having a very similar issue you had except it getting worse, every few minutes after the car gets warm. Have similar ODB readings as you do. Did it solve the problem to switch the HPFP?
PS:Thanks a lot for the step by step guide how to replace the HPFP, it will become very helpful.
5th Jan 2021 7:15 pm
French Collection
Member Since: 15 Apr 2020
Location: Aix-en-Provence
Posts: 46
Hello Villib
It appears to have solved the problem. The new pump was fitted early November and I have not had any recurrence.
Note however that most of my trips since fitting the new pump have been only 50km, with 1 trip of 70km. Nevertheless, I am reasonably confident.
I have some other problems in the meantime, related to cold starting when ambient temperatures are below 4 deg. I think I need to replace the glow plugs.
I bought my new pump from Maltings in the UK, who had the best price I could find. Note that there is another post on the forum about the pump replacement which I did not find before changing mine. I think that post may explain better how to remove the oil separator.Bentley 8
Rolls Royce Silver Shadow
Triumph Stag
Volkswagen Karmann Ghia Razor Edge
Jaguar XJC
Jaguar E-type
Jaguar XK8
Land Rover Discovery 4
Mercedes E350
Ford Granada 2.8 Ghia X
Ford Granada 2.8i Ghia X
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