P38 non return valve?

jimmacD · Jan 4, 2016

Hi All, I have a fully functioning 2.5 DSE which has a slight cold start delay after being left for a few days. Done away with hot start black box after frying it whilst on trickle charge? Changed leak offs and dumped the underpower (local factor recommended) battery and all seems good.
My question is: I have an 8mm non return valve to fit between FIP and filter but nervous about cutting the fuel line as it will probably not be flexible enough to accept the valve plus the connections on FIP and filter seem far larger than 8mm. Do I buy 8mm fuel line and hope it is flexible enough to go on FIP etc.. or find a genuine LR line? Don't want to start hacking and be left stranded!

wammers · Jan 4, 2016

Fit NRV to black plastic pipe before filter NOT in clear pipe from filter to injection pump. You will need two 2.5" lengths of 8 mm bore 15 mm O/D rubber fuel pipe and four 13 to15 mm fuel pipe clips. Do not use oversize Jubilee clips they will crush the plastic pipe.

jimmacD · Jan 4, 2016

Thanks Wammers for your reply

jimmacD · Jan 4, 2016

Just had a quick look at RR and someone has already fitted a NRV near the bulk head, doh! I might change it as I have bought a replacement. I still have a small air bubble in the fuel line after filter? I have done all the standard fixes other than replace the filter o rings.

plumbfisher · Jan 4, 2016

Not being cheeky, a genuine question... what is the point of the NRV ? Does it help a failing in tank lift pump ? If the FIP takes over after start up why isn't there just a NRV in the fuel line anyway (and no lift pump)?

wammers · Jan 4, 2016

jimmacD said:
Just had a quick look at RR and someone has already fitted a NRV near the bulk head, doh! I might change it as I have bought a replacement. I still have a small air bubble in the fuel line after filter? I have done all the standard fixes other than replace the filter o rings.

If lift pump is working only thing O'rings on filter can do is leak fuel out. If lift pump is duff injection pump can suck air in through them. Bleed the air out.

wammers · Jan 4, 2016

plumbfisher said:
Not being cheeky, a genuine question... what is the point of the NRV ? Does it help a failing in tank lift pump ? If the FIP takes over after start up why isn't there just a NRV in the fuel line anyway (and no lift pump)?

Genuine lift pumps have an NRV in them to stop fuel flowing back into the tank. In certain circumstances this could happen. After market lift pumps even good ones do not have an NRV in them. So some fit an NRV inline. The injection pump does not take over from the lift pump, The lift pump runs at all times when the engine is running, the fuel supplied by the lift pump is pressurised by the injection pump to give an internal pressure, that pressure is used to control timing and aid flow of fuel into the injection chamber. Fuel is constantly bled off via a small overflow opening and returned to the tank via the spill off line. Internal fuel pressure is controlled by a valve, when internal pressure gets to high the valve opens and fuel is returned to the inlet side of the internal pressure pump.

plumbfisher · Jan 4, 2016

Thanks Wammers. As ever, helping my understanding of just how these things work!

jimmacD · Jan 4, 2016

NRV is just to reduce fuel drop when vehicle is left for a few days. A lot of Manufacturers fit them as standard. In the ideal world we replace or repair stuff when needed and all carried out by our local Dealer as we look on while slurping a frothy Hoccamoccachocolatelate slumped in a leather armchair and dreaming of our 2016 delivery, hmm, Green or Red? As a pre loved LR Owner I am normally skint and only get a full tank of fuel on my Birthday, as, like many on here I have more interests and projects than my wallet can handle.
The NRV probably falls into temp fix category until FIP gets rebuild, retiming or I win the lottery and buy a new one! I haven't yet met an enthusiast who isn't into Bikes, Italian sports cars, things that go bang and welding something to something else.... Kings of mend and make do!
My Wife loves Land Rovers, she drives a Subaru... I couldn't cope with having two projects

P38 non return valve?

jimmacD

Well-Known Member

wammers

No longer with us, RIP

jimmacD

Well-Known Member

jimmacD

Well-Known Member

plumbfisher

Active Member

wammers

No longer with us, RIP

wammers

No longer with us, RIP

plumbfisher

Active Member

jimmacD

Well-Known Member

Similar threads