Hi landmaciej,

yes, i can hear the hissing noise when i open the fuel cap after i driving a few kilometers.
Due to its i had opened the cap before and after every ride for testing but the judder was still there sometimes.

Thanks for reply. Still investigating then.

Hi landmaciej,

can you confirm that the juddering + noise appears on one day very often and on the other day not or very seldom?
Or do you have the problem everytime you drive?

Just my tuppence here. I the judder a few times when I also had the vacuum forming in the fuel tank, especially when the tank was getting nearer empty. Since replacing the fuel cap and never having the vacuum I have never had a judder. FL2 TD4 GS 60 reg Facelift - so many issues
2019 DS. Terribly unreliable.
Sold DS for a 2021 Mitsubishi Outlander PHEV. Fingers crossed....
Sold Outlander for a 2014 SD4 SE Tech because I’m mental
Now greatly regret selling the Outlander. MPG of the FL2 is atrocious and so are the fuel bills. Fun though 😎
Couldn’t afford the fuel bills so back to an older Mitsubishi Outlander PHEV. Significantly better than I remembered it to be…

Hi Chuckalicious,

is the New cap identical to the old one or has been something changed by landrover?
Once i asked the LR dealer he said there is no Revision/design of the cap available.

I ran a thread ages ago on it and others who had the same issue and had ordered new caps from Duckworths all got ones with purple plastic inside instead of the brown bit (from memory). When I mentioned it to my dealer they too knew of no such thing.

Replacement cap is genuine LR part. FL2 TD4 GS 60 reg Facelift - so many issues
2019 DS. Terribly unreliable.
Sold DS for a 2021 Mitsubishi Outlander PHEV. Fingers crossed....
Sold Outlander for a 2014 SD4 SE Tech because I’m mental
Now greatly regret selling the Outlander. MPG of the FL2 is atrocious and so are the fuel bills. Fun though 😎
Couldn’t afford the fuel bills so back to an older Mitsubishi Outlander PHEV. Significantly better than I remembered it to be…

Hi Chuckalicious,

thank you for the info. Maybe can the other affected owners check it too.
A new fuel cap would be the easiest solution

Juddering appeared probably when the temp. raised. During winter was absent or rare. I am confused because i think that temp can be important and as i remember other members admit the dependence. On the other hand this pressure in tank. I will try with the cap now. Hesitation on 1st gear/from standing still was present even when it was cold outside but after the engine warmed up. When it was cold gas reaction was immediate and sharp. Now after a long trip from standing still its like a turtle, maybe its the cap..

Or its not about cold/warm but pressure which normalizes after standing with engine off. That makes sense.

Chuckalicious wrote:

I ran a thread ages ago on it and others who had the same issue and had ordered new caps from Duckworths all got ones with purple plastic inside instead of the brown bit (from memory). When I mentioned it to my dealer they too knew of no such thing.

Replacement cap is genuine LR part.

Clarification please. Is this the purple that you are describing? I'd thought this was pink! MY15
I'm reading in interest as our environment would seem ideal for this issue.


 MY15
Tyre Pressure Monitoring System (TPMS)
Surround Camera System
InControl Apps soon to be replaced with CarPlay (WIP)
Meridian Premium Surround Sound
Digital Audio Broadcast
Timed Climate
Cruise ECO Data
Follow Me Home Reverse
Extra Features Menu
Picture In Motion
4x4i screen (WIP)
Digital Broadcast TV
Meridian Rear Media with WIFI
Factory Powered Tailgate
Blind Spot Monitoring (BSM)
Reverse Cross Traffic Alert (RCTA)
Electrochromatic Wing Mirrors (WIP)

Hi all,

this is my fuel cap. I get a lot of vacuum after driving some kilometers.



This video was taken after driving 18km after complete diesel refill. As you can hear this was little vacuum, but after more km i get a lot of vacuum in the tank. Between the tankstop and today i was not able to clearly reproduce the judder. Juddering occured only 2-3 times, but no so hard.
I will take a new video these days.

Hi again,

from a german diesel forum: http://community.dieselschrauber.de/viewto...druck+tank

Unterdruck im Tank, der sich wegen eines defektes / klemmendes Entlüftungsventils langsam während der Fahrt aufbaut.
Daduch kann z.B. an Schlauch-Klemmstellen Luft in die Vorlaufleitung gezogen werden, die bei VP 37-Motoren den Pumpeninnendruck absacken läßt und die Frühverstellung des Spritzbeginns verhindert -> Leistungsverlust. Im MWB 4 kann dann ein Tastverhältnis nahe Null zu beobachten sein, das je nach Luftpolster am Rücklauf-Auslaß der Pumpe auch noch springen kann - ohne daß natürlich ein Defekt an der Pumpe vorliegen muß.
Bei viel angesaugter Luft kann diese auch in den Hochdruckteil gelangen und weiteren Leistungsverlust bzw. Ruckeln verursachen.
Probe: bei wenig Tankinhalt eine Probefahrt ohne Tankdeckel machen. Ist dann die normale Leistung verfügbar, so ist das Problem "Unterdruck im Tank" sicher identifiziert.

Another thread from a german LR forum: http://www.blacklandy.eu/blboard/forum/sho...orruckeln/

I hope you can translate it to your language using google translate etc.

Try to detach parts of the cap and clean it there are instructions on this site. I will try this as soon as my car will be available.

One thing is clear. Because of the construction of the fuel cap, you should NEVER have vacuum in the tank.
If you have vacuum in the tank, this means that one of the valves in the cap is malfunctioning.
And the vacuum will put stress on the lift pump, that is responsible to deliver fuel to the HP pump.

Could you make another log for the fuel rail pressure, but without the fuel cap screwed in?
Maybe that pressure dip will not be present then...

Hi Alex,

at the moment i have to much diesel in the tank to drive without cap
But i have disassembled the cap. Everything is totally clean, no dust etc.
I have tested the valve manually by mouth tastes bad but the valve is working.
It seems that the vacuum which is needed to open the valve is not really high.
But i dont know if it opens early enough. i will check it again after driving a few kilometers.

OBD2 dongle wil be on board...