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Discussion Starter #1
I have a Range Rover Vogue V8 2002 (52) with a BRC LPG conversion that works well and the car runs smooth and powerfully on Gas. Problem is the Engine Management Light is on (has been for a while) and the LPG fitter said this was due to different fuel flow using Gas. Not sure this is true - any ideas on the subject?
 

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I would have the fault codes read and see what has caused them to be flagged up. I would suggest it is a mixture problem or a weak lambda sensor. The gas system may need re-calibrating.
Stewart.
 

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Discussion Starter #3
SGW said:
I would have the fault codes read and see what has caused them to be flagged up. I would suggest it is a mixture problem or a weak lambda sensor. The gas system may need re-calibrating.
Stewart.
That a very helpful reply I thought it may be something to do with mixture or Lambda sensor but have no real experience. I have an appointment on Wednesday to get it checked out. Many thanks Stewart.
 

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It's also worth getting the PCV Hoses checked out - if they haven't been replaced yet on a 2002 they will more than likely be leaking and letting air into the system. This messes with the emissions and can throw various codes which most garages diagnose as lambda sensors or HG failure!

viewtopic.php?f=2&t=28533&start=0&hilit=pcv+hose
 

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Discussion Starter #5
Having it checked by local Land Rover specialist tomorrow. They will have a good look around and check out EML codes to try establish the reason. Having spoke to the owner who knows most of what their is to know about Land Rovers he is pretty sue its a mixture/trim problem as apparently its quite hard to get it just right on a LPG conversion.
 

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I thought that the LPG system emulates values for the lambda sensors? I may be outdated on this though, maybe it depends on the kit?

D
 

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I had this problem when I first had the LPG system fitted. It turned out that the auto-calibration was not tight enough and it would just jump off the map occassionally when in cruise mode (this is when it really tries to screw down the mixture). In the end we fixed it by manually mapping the ECU and it was fine for the next 3ok miles. Just the other day the light came on again and I think it is because the inline filters need changing and probably the injectors need cleaning too. I'll let you know after Friday :)
It is true that LPG systems suffer a bit more from dirty gas (Shell in my experience) and this can cause mixture problems but after the inline filters were fitted the problem went away.
 

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Discussion Starter #8
Visited local Land Rover specialist yesterday and the codes were related to Lambda Sensors (Due to LPG) and and a secondary Radiator Thermostat that is apparently only used when the engine needs to lose/gain heat quickly as in when driving like a nutter on a cold engine. Apparently neither were a major problem and can be easily fixed/adjusted at the next service.

The light stayed off after re-set for about 2 hours driving then came back on as expected.
 

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Discussion Starter #9
Dan_UK_1984 said:
It's also worth getting the PCV Hoses checked out - if they haven't been replaced yet on a 2002 they will more than likely be leaking and letting air into the system. This messes with the emissions and can throw various codes which most garages diagnose as lambda sensors or HG failure!

viewtopic.php?f=2&t=28533&start=0&hilit=pcv+hose
Just had a reply from www.lambdapower.co.uk and they said:

"I think the fault codes you have are P1174 and P1175. This indicates the "fuel trim" for both banks one and two has reached its limit. This can be caused by faulty sensors or air leaks in the induction system."

This relates to:

Group 11: Engine
Bulletin Number: 11 04 97
Woodcliff, NJ
November 1997
Product Engineering
SUBJECT:
Intake Air System - Un-metered Air Leaks
MODEL: E39, E38, E31 with M62 engine
Situation:
Check Engine Lamp is illuminated and fault codes 27 (P1174) and 35 (P1175), oxygen sensor control adaptation, are set in the Engine Control Module (DME).
Cause:
Un-metered air leaks may occur in the following areas causing the above situation:
1. Intake manifold gaskets may be leaking.
2. Plug cap(s) and the vacuum hose for the fuel pressure regulator on the rear intake manifold cover (crankcase ventilation valve) may be torn or missing.

THERFORE: I think you were right "Dan_UK_1984" about it being the PCV Hoses and I have booked it to have them checked replaced on Monday!!!

Could this also be the cause of the Vibration when at standstill in Drive Gear?
 

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Discussion Starter #10
Gazellio said:
Dan_UK_1984 said:
It's also worth getting the PCV Hoses checked out - if they haven't been replaced yet on a 2002 they will more than likely be leaking and letting air into the system. This messes with the emissions and can throw various codes which most garages diagnose as lambda sensors or HG failure!

viewtopic.php?f=2&t=28533&start=0&hilit=pcv+hose
Just had a reply from http://www.lambdapower.co.uk and they said:

"I think the fault codes you have are P1174 and P1175. This indicates the "fuel trim" for both banks one and two has reached its limit. This can be caused by faulty sensors or air leaks in the induction system."

This relates to:

Group 11: Engine
Bulletin Number: 11 04 97
Woodcliff, NJ
November 1997
Product Engineering
SUBJECT:
Intake Air System - Un-metered Air Leaks
MODEL: E39, E38, E31 with M62 engine
Situation:
Check Engine Lamp is illuminated and fault codes 27 (P1174) and 35 (P1175), oxygen sensor control adaptation, are set in the Engine Control Module (DME).
Cause:
Un-metered air leaks may occur in the following areas causing the above situation:
1. Intake manifold gaskets may be leaking.
2. Plug cap(s) and the vacuum hose for the fuel pressure regulator on the rear intake manifold cover (crankcase ventilation valve) may be torn or missing.

THERFORE: I think you were right "Dan_UK_1984" about it being the PCV Hoses and I have booked it to have them checked replaced on Monday!!!

Could this also be the cause of the Vibration when at standstill in Drive Gear?
www.lambdapower.co.uk said (by email):

It's certainly worth checking this out first. I wish I could offer help of a more concrete nature than this, it's a car i'm not overly familiar with. Having said that, we often find a RR will develop lambda problems shortly after being fitted with LPG, the LPG system often seems to tip a worn sensor 'over the edge' as it were, but vacuum leaks are never good no matter what the vehicle. Manifold leaks can be traced by squirting a can of something thin and oily, wd-40 perhaps, at the suspect gasket - if the engine note changes due to wd-40 being sucked in, there is a leak. With the other hoses it's simply a case of checking the rubber doesn't crack when you squish it, temporary repairs can be made using insulating tape, although I would say the hole is going to have to be quite large to affect the ECU in this way

It can still be caused by lambda though, but i agree you should eliminate some of these simpler explanations before chucking money at it.

I'd be interested to know how you get on
 

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Discussion Starter #11
More info from Lamdapower:

The fuel trim is an automatic function used by the ECU to keep the fuel mixture within specified limits. It controls the trim using feedback data from the lambda sensor. However, a bit like a volume control on a hifi, it can only adjust the mixture so far before it can go no further. If this happens too often, the ECU will log a fault code and illuminate the warning light

I assume you would have said if the temperature of the engine seems suspect - the electronic thermostat fault needs investigating too. Does the car use way too much fuel? I know it's hardly a frugal vehicle but it has an advanced engine and I would expect at least high teens MPG
I replied:

The Engine temperature gauge shows a perfect reading at all times at exactly half way between hot & cold.

The Electronic Thermostat is not the main cooling thermostat according to Local Land Rover garage – “its additional and used when engine under stress”. It still needs replacing though!

Fuel consumption on Gas seems OK although I have not worked out exact MPG. Computer says 18mpg since I bought it 3 weeks ago and second reading set when I got back from Glasgow gives 15mpg for mainly local use in last few weeks.

I have set the trip for last three fill ups and I got 580 miles from about 210 litres of gas. I thinks that’s about 13mpg but it was nearly all urban/local/school run. That does not include the petrol used while LPG warming up so this may be a bit on high side?
 

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Discussion Starter #12
Dan_UK_1984 said:
It's also worth getting the PCV Hoses checked out - if they haven't been replaced yet on a 2002 they will more than likely be leaking and letting air into the system. This messes with the emissions and can throw various codes which most garages diagnose as lambda sensors or HG failure!

viewtopic.php?f=2&t=28533&start=0&hilit=pcv+hose
Just had Kings Langley Land Rover http://www.kllr.co.uk/7601/kingslangleylandrover.htm check the PCV hoses and guess what.......Both are totally Knackered and will be replaced tomorrow - should be problem solved so thanks again Dan_UK_1984 :D

PS: Worth noting that the car was making a slight roar on acceleration similar to that on a big V8 with a cold air intake system (due to the split hoses.)
 

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Gazellio said:
PS: Worth noting that the car was making a slight roar on acceleration similar to that on a big V8 with a cold air intake system (due to the split hoses.)
The LPG people often remove the sound deadening foam from the acoustic cover to make foam for the LPG injectors and pipes, this coupled with leaky PCV hoses does make quite a racket!

I want to try and get the foam back under there because I find the engine noise intrudes into the cabin too much for my liking.

Dan
 

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Discussion Starter #14
Dan_UK_1984 said:
Gazellio said:
PS: Worth noting that the car was making a slight roar on acceleration similar to that on a big V8 with a cold air intake system (due to the split hoses.)
The LPG people often remove the sound deadening foam from the acoustic cover to make foam for the LPG injectors and pipes, this coupled with leaky PCV hoses does make quite a racket!

I want to try and get the foam back under there because I find the engine noise intrudes into the cabin too much for my liking.

Dan
Dan, Sorry to be a dummy but where should the acoustic cover be? Are you talking about the underside of the bonnet? :doh:
 

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Its the massive black plastic cover that sits on top of the engine with a big BMW logo on it, see Here
 

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Discussion Starter #16
Dan_UK_1984 said:
Its the massive black plastic cover that sits on top of the engine with a big BMW logo on it, see Here
OK and they take the acoustic lining out of it when completing the LPG conversion then? Bit drastic :?
 

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Yup, the lining is quite thick, a couple of inches I think at least. You can see all my extra cables and hoses on the PCV post I linked to, this basically means it wont fit on without the foam being taken out.

I'm going to try and cut away at some bits or re-route the pipes to try and get it back on though, need to buy an engine cover with the foam on already, that's the problem.
 

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Both of our 02s did not have any foam from new, maybe this came later. When I fitted the lpg systems everthing fitted just right. My friends 03 BMW X5 did have the foam which I had to remove for the conversion.
Stewart.
 

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Discussion Starter #19
SGW said:
Both of our 02s did not have any foam from new, maybe this came later. When I fitted the lpg systems everthing fitted just right. My friends 03 BMW X5 did have the foam which I had to remove for the conversion.
Stewart.
Have you checked/replaced the PCV hoses on your 2002 cars?

Interestingly since discovering the holed hoses this morning I have run the car on Petrol and the Engine Management light is still out. I am actually hoping it come on to help confirm that the PCV hoses are the only problem :eek:
 

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Yes replaced them 2 years ago, I used 2 ply oil resistant hose, not the oem ones that disintegrate. I have had no problems since.
Stewart.
 
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