Member Since: 07 Jan 2016
Location: Darmstadt
Posts: 3
Is your fuel pump still working? Or did your fault come back? Thanks for your response.
Christian from LRTime.
28th Jun 2021 12:55 pm
French Collection
Member Since: 15 Apr 2020
Location: Aix-en-Provence
Posts: 46
Yes, have not had any problems since changing the HPFP. Tanking down the A71 from Cherbourg to Aix-en-Provence in it as I write (wife driving, I think she likes it now!) after a few weeks in Donegal in the north west of Ireland.Bentley 8
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28th Jun 2021 4:26 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4679
What happened to Co. Monaghan? yµ (idµ - eAµ) ψ=mψ
28th Jun 2021 6:05 pm
missesthi
Member Since: 28 Mar 2015
Location: Alps
Posts: 13
I like to share some thoughts/findings with those of you also batteling with the 'F, suspension lowering, performance drop while driving issue', that was eventually solved with a new hpfp.
The fault in my case was linked to a specific set of circumstances
- started intermittently in summer 2020, stopped in autumn 2020 and happend again only in summer 2021
- the fault would occure only on warm / hot days (>25°C)
- it would only happen, when the car was driven for more then 30min, then parked for 1 to 2 hours. When starting the car thereafter, the fault appeared after approx 8min driving.
- after ingition cycling, the car would run for the next 8min, before the fault would come again.
- if this 8min driving - ignition cycling etc. was repeated for 2 to 3 times, the car would eventualy run the rest of the journey without any issue.
- the fault never happend, when the car was parked for the night (>half a day)
- and the fault never happend, when the car was just parked for some minutes
Out of this, my conclusion is, that for a used/worn hpfp:
- if both diesel and pump have the same temperature (either both cold or both hot), there is no problem
- but if you have hot diesel and a warm(not hot) pump, there is an issue.
Maybe the low viscosity diesel combined with some akward thermal expansion in a worn, warm/cold hpfp could be the rootcause
At first, I was under the impression that the fault is due to a sudden drop of the fuel pressure.
Therefore I monitored the common rail fuel pressure with my iiDtool and checked lpfp pressure with an analog gage (as suggested in Robbie's guide, but with a long hose, so that the gage could be placed on the dashboard while driving - please note: there is good reason, not to bring a fuel line in the car interior - so think twice, before you try to do something similar)
At the very moment the fault occured, neither the common-rail fuel pressure nor the low pressure fuel system showed any sudden drop.
So the 8min leadtime to the fault rather seems to be the time of the diagnostics, before the fault is lighted up.
Finally, once the car was driving stable after several of the above described ignition cyclings, the pressure of the hpfp was roughly 20% higher then when the fault occured (comparing the same driving maneouvre), while the pressure of the lpfp did not change.
After the exchange of the hpfp, the car was running now for several month without the fault. What I have to add, is that there was no real 'hot' day this summer in Switzerland, once I changed the hpfp. So I guess, next summer will be the final proof.
Finally, thanks to all who added so many great posts and guides on the matter!
7th Nov 2021 8:06 pm
Gastón did castelnuovo
Member Since: 15 Apr 2022
Location: Argentina
Posts: 15
Hi guys, how are you. Some years later having exactly the same problem as French Collection. Have replaced LPFP and filter but problem still happens, usually after 3 hour+ of driving, could be much more than that. Last one happened after 500km or so. When the fault occurs, it's impossible to get rid of it. I have the GAP tool and cleared faults, disconnected the battery, but the F and lowered suspension still there, had to make 130km and F mode, at 60km/h and lowered, and worst, with wife and two kids!
Day after D3 started normally, no faults, no lights on dashboard, did some 40 km or sso and everything is fine. This thing is blowing my mind.
Did the HPFP replace solved it? Anybody think it could be anything else?
Thanks a lot! Gastón from Argentina
15th Apr 2022 3:04 pm
Gastón did castelnuovo
Member Since: 15 Apr 2022
Location: Argentina
Posts: 15
HPFP
Click image to enlarge
Click image to enlarge
Click image to enlarge
Well, after the fault happpened again, had to make some km on F (not lowered this time since i´ve removed N°26 fuse), left my D3 and continue the trip on a friends car.
YEsterday my D3 arrived on a bed truck , started like nothing hapened, everything works fine, acceleration is great, performance, etc. but dont have confidence nor wife aproval to make a new trip before knowing and fixing the issue.
As LPFP have been replaced, next move is HPFP, sadly in Argentina is impossible to get one under 3k and waiting for, at least, a month. Been thinking of fixing this one in a specialized placed and getting a new one on june when wife will be in UK
Does anybody knows and can tell me where to get a new one and "cheap" HPFP there?
Here are some screenshots of IID Tool when las fault happened
Click image to enlarge
20th Apr 2022 12:41 pm
Gastón did castelnuovo
Member Since: 15 Apr 2022
Location: Argentina
Posts: 15
Got my new HPFP. Made about 800km and everything works as it should. Next weekend going a trio again. Hope that $3.000 job worth
10th Jun 2022 4:28 am
missesthi
Member Since: 28 Mar 2015
Location: Alps
Posts: 13
This is just a short update to confirm, that the HPFP replacement has fixed the issue.
The car has been running fine for nearly 1 year now with the new HPFP, even during the hot days this month, where the issue usually occured previously.
23rd Jul 2022 8:11 pm
Flatlander
Member Since: 20 Jul 2015
Location: Here
Posts: 575
I'm looking at a 2007 D3 manual with P0087 DTC - suspension lowers but initially has 'HDC Fault', it's only occurred since service (by me), it's had a fuel filter change, which has been replaced again, both genuine parts. No other DTC's, SAS has been calibrated and tyre pressures re-checked..
My question is, has anyone else experienced this with a HPFP issue - without any other DTC's? the LPFP was changed for a genuine item 2 years ago due to noise and occasional P2290 which was caused by a restricted primary filter and has been fault-free ever since.
The HDC fault and subsequent suspension lowering only occurs when 'giving it some beans', i'm wondering if the fuel temperature sensor is giving incorrect readings as that can really throw a spanner in the works...
23rd Jul 2022 11:15 pm
sol_stevo
Member Since: 17 Jul 2021
Location: The Empire
Posts: 174
discovery3ski wrote:
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.
Do you remember a rough price of the replacement job? And how did they do it? Drop gearbox, body off?
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, started like nothing hapened, everything works fine, acceleration is great, performance, etc. but dont have confidence nor wife aproval to make a new trip before knowing and fixing the issue.
