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Riccarton



Member Since: 10 Aug 2015
Location: Gods' Own Country
Posts: 280

Scotland 2012 Defender 90 Puma 2.2 HT Zambezi Silver
Help Please - Puma 2.2 tdci Fuel Pressure Regulator Replacem
Can anyone tell me if I need to recalibrate the ECU if I replace the Fuel Pressure Regulator (VCV?) ?

I'm having ongoing problems that are getting worse and the BAS RRC gives me a P0194 fault code stating either an error with the Fuel Pressure Sensor or the wiring to it. I've replaced the sensor and done all the checks on the wiring but still to no avail.

I am now noticing that when under load (codes reset) the car feels like it's surging. My fault only comes on when I stop for junctions / lights / etc and never whilst actually travelling once I've got going.

I'm now praying it the Pressure Regulator that's causing the issue - does anyone know how stable the fuel pressure should be at tick-over? Mine jumps around like a crazy thing and only stabilises once revs are applied.

Many thanks Thumbs Up
Post #537916 6th Jun 2016 1:58pm
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Caterham



Member Since: 06 Nov 2008
Location: Birmingham
Posts: 6264

England 2011 Defender 110 Puma 2.4 XS CSW Stornoway Grey
to the bet of my knowledge the rev should be about 800 +/- 20rpm on tick over once at temp.

could an egr passing also cause the erratic idle?
Post #537927 6th Jun 2016 2:41pm
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Riccarton



Member Since: 10 Aug 2015
Location: Gods' Own Country
Posts: 280

Scotland 2012 Defender 90 Puma 2.2 HT Zambezi Silver
Ah - no - you misunderstand me. I wasn't clear enough.

My tick-over is stable - it's the fuel pressure that's erratic at tick-over. I believe it should be about 200bar but not sure whether that is a stable 200 or one with peaks and troughs!!??!!
Post #537928 6th Jun 2016 2:44pm
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Caterham



Member Since: 06 Nov 2008
Location: Birmingham
Posts: 6264

England 2011 Defender 110 Puma 2.4 XS CSW Stornoway Grey
I believe the pressure etc is erratic. as the VCV opens / closes but hopefully someone can confirm?
Post #537930 6th Jun 2016 2:46pm
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Riccarton



Member Since: 10 Aug 2015
Location: Gods' Own Country
Posts: 280

Scotland 2012 Defender 90 Puma 2.2 HT Zambezi Silver
Update - apparently it's now called the Fuel Vapour Valve (FVV) - Part No: LR079825.

Anybody know the symptoms if this part fails?
Post #537933 6th Jun 2016 3:22pm
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xpertoftheseas



Member Since: 05 Jan 2016
Location: Salisbury, Wilts
Posts: 164

United Kingdom 2014 Defender 110 Puma 2.2 XS CSW Aintree Green
Can you clarify what you mean by "Surging"? At no load, in neutral on idle, is the idle smooth and constant rpm, or rough and varying rpm?

When under constant load (pulling in 3rd gear, with foot on throttle in a constant position), is the car acceleration constant?

The fuel rail pressure will be constant at non-changing RPM, as the rail is designed to absorb the pressure changes when fuel is taken from the rail. The pressure in the rail is controlled by the ECM and is varied by the HP fuel pump dependent on engine load and RPM. You state that the FRP sensor has been replaced? Just for clarity this is the sensor that is at the end of the HP rail, correct? I only ask as I thought this sensor could not be changed with changing the entire HP rail.

I have some pictures but right now the site will not let me upload due to a fault. If you can advise on the above we can take it from there. My 10th Land Rover, but my first Defender.
Post #538297 7th Jun 2016 8:48pm
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Caterham



Member Since: 06 Nov 2008
Location: Birmingham
Posts: 6264

England 2011 Defender 110 Puma 2.4 XS CSW Stornoway Grey
I don't think the frp sensor has been replaced. There is mention of replacing the vvc which I believe is on the back of the pump.?
Post #538352 7th Jun 2016 10:24pm
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xpertoftheseas



Member Since: 05 Jan 2016
Location: Salisbury, Wilts
Posts: 164

United Kingdom 2014 Defender 110 Puma 2.2 XS CSW Aintree Green
In this case, where the sensor has not been replaced, then this should be the first item to look at.

Idle Pressure - 220-250Bar
Driving Speeds - 1300-1600Bar

However, fast fluctuations outside of these pressures at fixed loads/no load in rail pressure can be caused by several things - failing injectors (slow open/close, leak back valves passing etc), failing HP pump (would cause lethargic response and lower powers, most definitely triggering different fault codes), passing pressure relief valve etc.

The fuel rail pressure sensor is key to ensuring the correct fuel pressures for varying loads and demands on the engine and for emissions control.



From the Workshop Manual....

The FRP sensor is located in the end of the fuel rail. The sensor measures the pressure of the fuel in the fuel rail. This input is then used by the ECM to control the amount of fuel delivered to the fuel rail.
If the FRP sensor fails, the engine will operate at reduced power and a DTC (diagnostic trouble code) will be triggered. The sensor is not serviceable separately, and comes as part of a new fuel rail.



(Item 1 is the FRP sensor). I believe on the 2.4ltr Puma these sensors were replaceable but from what I am reading I do not think so on the 2.2ltr. My 10th Land Rover, but my first Defender.
Post #538384 7th Jun 2016 11:12pm
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The Fox



Member Since: 24 Mar 2014
Location: Shrewsbury
Posts: 93

United Kingdom 2014 Defender 90 Puma 2.2 XS CSW Corris Grey
Sorry to resurrect an old thread - but this sounds exactly like the experience I'm having in my 2.2:

> constant throttle input from pedal (proven using live-data reader)
> Anywhere in the rev range
> Surging/blipping power loss
> EGR actuating as expected
> Fuel Rail Pressure sensor showing 'negative-blip' in rail pressure

I'd not considered the rail-pressure-sensor to be a possibility. I was looking to replace (in order of cost):

VCV
Lifter Pump in Tank
EGR (unlikely to be the source of the issue)
HP Injector Pump

Did you solve the issue in the end?[/list]
Post #829372 5th May 2020 2:28pm
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dannyragsdale



Member Since: 07 Oct 2022
Location: Eastern Highlands, PNG
Posts: 40

Papau New Guinea 2012 Defender 110 Puma 2.2 HT Fuji White
Resurrecting this one again.

Fox, did you have any luck with a fix?
Post #1016796 30th Nov 2023 6:09am
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