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dhallworth



Member Since: 10 Oct 2011
Location: Glasgow
Posts: 1295

United Kingdom 2012 Range Rover Autobiography TDV8 Baltic Blue
4.2 SC on LPG cranks for ages & high fuel pressure

I’ve got a 2007 Range Rover Supercharged with a BRC LPG Kit and flashlube system on it.

If the car has been running on petrol it starts first time, every time and very quickly. When I switch it to LPG the car changes over and feels like it’s running perfectly on LPG. However, If I’ve had it running on LPG and switch it off, it cranks for a long time before restarting and occasionally the EML light will come on when it restarts.

It seems to vary between 2 stored fault codes:

P0193-00 - Fuel rail pressure sensor high input
P0088-00 - Fuel rail/system pressure too high

If I use it on petrol I don’t get any codes and it’ll always start instantly on the first turn of the key.

When looking on diagnostics, starting on petrol has a fuel pressure reading, then when it switches to LPG the pressure drops and flat lines which I’d expect but when switching back to petrol the pressure reading stays at the constant and doesn’t respond at all until the car has been switched off and restarted again. If I leave it on petrol the fuel pressure is visible and it keeps varying on diagnostics.

The other issue I’ve noticed is the LPG gauge had 1 flashing LED on it, I filled it up and all 4 of them were flashing. This afternoon on my way home from the post office I noticed that all 4 had gone solid though so am wondering if the pressure sensor in the tank is playing up a bit as the car has sat for a couple of months whilst it was being worked on.

Has anyone got any thoughts or pointers? I’d be grateful for any assistance Smile

David. 1997 4.6 HSE - Oxford Blue with Ash Grey Leather
2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2007 Freelander i6 HSE in Izmir Blue with Ebony Leather
2007 Range Rover Supercharged in Java Black with Ivory Leather
2012 Range Rover 4.4 TDV8 Autobiography in Baltic Blue with Sand Interior

Post #588076 19th Mar 2021 10:13pm
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tb10



Member Since: 17 Feb 2015
Location: Bromsgrove
Posts: 275

England 2005 Range Rover Vogue 4.4 V8 Tonga Green

Hi David,

What BRC system is it? Sequent24 / 56 or Plug and Drive?

I have the Plug and Drive on my daily and all 4 lights flash when the car gets very low on gas. There is a pressure sensor on the rail or near to and they do pack up. You can get the software quite cheaply now but it does depend on the system. Let me know and I’ll look on my laptop for any pointers.

Cheers

John

Post #588077 19th Mar 2021 10:32pm
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dhallworth



Member Since: 10 Oct 2011
Location: Glasgow
Posts: 1295

United Kingdom 2012 Range Rover Autobiography TDV8 Baltic Blue

Thanks John,

I take it the model will be on the ECU? I’ll take the cover off the box and have a look shortly.

David. 1997 4.6 HSE - Oxford Blue with Ash Grey Leather
2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2007 Freelander i6 HSE in Izmir Blue with Ebony Leather
2007 Range Rover Supercharged in Java Black with Ivory Leather
2012 Range Rover 4.4 TDV8 Autobiography in Baltic Blue with Sand Interior

Post #588078 19th Mar 2021 10:33pm
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dhallworth



Member Since: 10 Oct 2011
Location: Glasgow
Posts: 1295

United Kingdom 2012 Range Rover Autobiography TDV8 Baltic Blue

I’ve just been out for a quick run with it on LPG, if I stop it and restart it straight away it fires instantly. If I stop it, nip into a shop to pick something up and come back out, that’s when it turns over for what seems like ages but it probably around 5 seconds or so, maybe a little longer.

One thing I have noticed is that when it gives a fault code, it cranks for a bit longer then normal, catches for a split second and then cuts out again. When restarting the car it’ll turn over for longer then normal and will then run perfectly but with the EML on the dash.

I’ve just had a look at the ECU tonight and it’s a Fly SF ECU that’s fitted to the car. It’s got twin BRC reducers and a BRC change over switch inside the car.

David. 1997 4.6 HSE - Oxford Blue with Ash Grey Leather
2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2007 Freelander i6 HSE in Izmir Blue with Ebony Leather
2007 Range Rover Supercharged in Java Black with Ivory Leather
2012 Range Rover 4.4 TDV8 Autobiography in Baltic Blue with Sand Interior

Post #588090 20th Mar 2021 12:06am
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tb10



Member Since: 17 Feb 2015
Location: Bromsgrove
Posts: 275

England 2005 Range Rover Vogue 4.4 V8 Tonga Green

Hi David,

Damn, that is the only software I don't have.

However, what I suspect is that the parameter for the engine restart whilst on LPG is set to zero seconds when on gas, so it tries to start on gas when at operating temperature, and we know the engine warms up quickly, and that the gas is being evaporated by the heat before it has a chance to ignite. What I would suggest is when you stop, switch off the gas using the manual button, and then restart on petrol and immediately switch to gas. if that works then I suspect you need to reprogram the software to wait for 5 seconds, for example, when warm.

If you look at the attached table, you will see that you can set the changeover time when cold and when hot. As stated above, I suspect yours is set to zero and that is the issue so it is probably a software issue rather than mechanical.

Let me know what happens.

regards

John

Post #588095 20th Mar 2021 1:36am
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dhallworth



Member Since: 10 Oct 2011
Location: Glasgow
Posts: 1295

United Kingdom 2012 Range Rover Autobiography TDV8 Baltic Blue

Thanks John,

The diagnostics socket on the ECU look the same as my P38 does so I’ll see if I can find a copy of the software and will have a look at it.

David. 1997 4.6 HSE - Oxford Blue with Ash Grey Leather
2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2007 Freelander i6 HSE in Izmir Blue with Ebony Leather
2007 Range Rover Supercharged in Java Black with Ivory Leather
2012 Range Rover 4.4 TDV8 Autobiography in Baltic Blue with Sand Interior

Post #588096 20th Mar 2021 1:45am
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cass



Member Since: 12 Oct 2011
Location: northumberland
Posts: 373

United Kingdom 2011 Range Rover Vogue SE 4.4 V8 Galway Green

Does it seem like it's "flooded" as we would have called it in the olden days?
If so it could be an LPG injector not closing properly - they could need new seals.
I've seen this a few times, runs great on LPG then after you've turned it off the liquid gas left in the supply to the injectors leaks past the injector and fills the manifold with gas which makes it hard to start when it's hot.
An easy (and free!) test, run it on LPG then Isolate the liquid supply from the tank, let it stall then try to restart it on petrol.
If it starts OK I'd put my money on the injectors.

Post #588117 20th Mar 2021 10:22am
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tb10



Member Since: 17 Feb 2015
Location: Bromsgrove
Posts: 275

England 2005 Range Rover Vogue 4.4 V8 Tonga Green

Cass,

There shouldn’t be any liquid in the injectors as the gas passes through the vapouriser, post filter, and converts the LPG to gas. If there is liquid gas in the injectors then that’s a problem.

David is very good at reporting back so we’ll no doubt get an update later.

Regards

John

Post #588130 20th Mar 2021 11:20am
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cass



Member Since: 12 Oct 2011
Location: northumberland
Posts: 373

United Kingdom 2011 Range Rover Vogue SE 4.4 V8 Galway Green

John
I think you’ve misunderstood my point. LPG systems tend to be very badly maintained and as they age solenoid and injector seals start to fail. The very small amount of liquid left in the pipe work from the tank can produce a huge amount of gas. 1L of liquid makes something like 200L of gas so one poor injector seal can cause the “flooded” symptoms.
I can’t speak for all injector types but I have seen this on a few different brands.
If the injectors are noisy this is also a clue.

Post #588144 20th Mar 2021 2:49pm
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dhallworth



Member Since: 10 Oct 2011
Location: Glasgow
Posts: 1295

United Kingdom 2012 Range Rover Autobiography TDV8 Baltic Blue

Well, there is a leak but it’s not an injector.

I warmed the car up this morning until it had switched to LPG, afterwards I removed one of the vacuum pipes and stuck it into a cup of water and could see bubbles escaping.

I took the hose out of the water and put my thumb over it and I could feel pressure building up behind my thumb to the point it became difficult to keep my thumb on the pipe. When I took my thumb off there was a whoosh and when listening I could hear a hissing noise from the pipe. Sniffing it confirmed it was LPG.

I guess the inlet is being filled with LPG and as LPG is heavier then air it’s sitting in the manifold and is what’s causing it to crank for a long time before starting.

If one reducer is leaking, chances are the other isn’t far behind so I’ll replace both of them and then hopefully it’ll be sorted.

As well as having the cars service history, there’s also all of the documentation for the LPG conversion and a service history showing an annual service every year since it was fitted in 2011 so it’s probably a fairly recent leak.

David. 1997 4.6 HSE - Oxford Blue with Ash Grey Leather
2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2007 Freelander i6 HSE in Izmir Blue with Ebony Leather
2007 Range Rover Supercharged in Java Black with Ivory Leather
2012 Range Rover 4.4 TDV8 Autobiography in Baltic Blue with Sand Interior

Post #588194 20th Mar 2021 8:27pm
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dingg1



Member Since: 29 Jun 2013
Location: PORTUGAL
Posts: 889

2007 Range Rover Vogue SE 4.2 SC V8 Stornoway Grey

You can most probably just change out the diaphragms, there's usually gasket kits available for most reducers, but if they're past their best probably just as easy to swap for new.

Post #588200 20th Mar 2021 9:36pm
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dhallworth



Member Since: 10 Oct 2011
Location: Glasgow
Posts: 1295

United Kingdom 2012 Range Rover Autobiography TDV8 Baltic Blue

I’ve rebuilt a couple of them in the past and have never had very successful results. They never seem to be able to maintain pressure properly afterwards.

I’ve ordered replacements and should have them by Tuesday. Hopefully that’ll be the end of the problems.

David. 1997 4.6 HSE - Oxford Blue with Ash Grey Leather
2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2007 Freelander i6 HSE in Izmir Blue with Ebony Leather
2007 Range Rover Supercharged in Java Black with Ivory Leather
2012 Range Rover 4.4 TDV8 Autobiography in Baltic Blue with Sand Interior

Post #588201 20th Mar 2021 9:49pm
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dhallworth



Member Since: 10 Oct 2011
Location: Glasgow
Posts: 1295

United Kingdom 2012 Range Rover Autobiography TDV8 Baltic Blue

Just to draw this to a close, replacing the reducers has indeed cured the prolonged cranking that I was experiencing on LPG.

One issue that I do seem to have crop up intermittently is a P0088 - Fuel Pressure Too High which comes up when it’s been running on LPG. I don’t think this car has a fuel return fitted which is likely what’s causing it so I’m going to look into fitting one.

David. 1997 4.6 HSE - Oxford Blue with Ash Grey Leather
2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2007 Freelander i6 HSE in Izmir Blue with Ebony Leather
2007 Range Rover Supercharged in Java Black with Ivory Leather
2012 Range Rover 4.4 TDV8 Autobiography in Baltic Blue with Sand Interior

Post #589303 27th Mar 2021 11:18pm
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