PROPLEM WITH FUEL CONSUMPTION

[SIMON64]

H AM HAVING A BIT OF A PROBLEM WITH MY RANGE ROVER CLASSIC I AM ONLY GETTING 6 MPG ON LPG OR PETAL. I HAVE JUST HAD LAMDA SENCORS REPLACED BECAUSE I WAS TOLD THAT WAS THE PROBPEM BY LOCAL GARAGE AT HUGH EXPENCE NEARLY £300 BUT IT HAS STILL NOT FIXED THE PROBLEM WHAT ELSE COULD BE CAUSING THIS

KIND REGARDS SIMON

[FridgeFreezer]

Welcome!

First:

Second - £300, blimey they done good there, universal Lambda sensors are about £30 each from the motor factors and probably no more than an hour's labour to fit two of them, that's if you have to alter the wiring to suit. I'd be having words with them if I were you. It could be they bought genuine parts sensors or something, but I'd want to see the invoice and the gilded cushion they arrived on.

Thirdly - what sort of gas kit do you have? Is it a vaporiser type (very few electrics) or injection type? (sequential, loads of extra wires all over the place and ECU control modules etc.)

Fourthly - Is your vehicle flapper or hotwire EFI? You can tell by looking at the airflow meter:

Common causes for high fuel consumption on EFI vehicles are the coolant sensor going faulty (it thinks it's really cold so chucks in tonnes of fuel) or the airflow meter being dodgy (also contains air temp sensor which has the same effect as above), if you can borrow a known working one that's an easy experiment.

The coolant sensor (which IS NOT the temperature gauge sensor) is all of about £7 and 5 minutes to change (with the engine cold), I suppose you could ask your local garage for a quote just for the giggle of it

[Roverdrive]

Never tried running mine on Petals. Perhaps you are using the wrong ones? I would imagine chrysanthemums would give a denser charge than rose petals for example, or perhaps that is why yours is running rich?

I have a similar problem with my RRC, in that it is only just scraping in to double figures, but as the pistons are only just on speaking terms with the bores, I think that might have something to do with it.

What state is the rest of your engine in? Does it burn oil etc etc?

[disco_al]

Never tried running mine on Petals. Perhaps you are using the wrong ones? I would imagine chrysanthemums would give a denser charge than rose petals for example, or perhaps that is why yours is running rich?

[SIMON64]

Welcome!

First:

Second - £300, blimey they done good there, universal Lambda sensors are about £30 each from the motor factors and probably no more than an hour's labour to fit two of them, that's if you have to alter the wiring to suit. I'd be having words with them if I were you. It could be they bought genuine parts sensors or something, but I'd want to see the invoice and the gilded cushion they arrived on.

Thirdly - what sort of gas kit do you have? Is it a vaporiser type (very few electrics) or injection type? (sequential, loads of extra wires all over the place and ECU control modules etc.)

Fourthly - Is your vehicle flapper or hotwire EFI? You can tell by looking at the airflow meter:

Common causes for high fuel consumption on EFI vehicles are the coolant sensor going faulty (it thinks it's really cold so chucks in tonnes of fuel) or the airflow meter being dodgy (also contains air temp sensor which has the same effect as above), if you can borrow a known working one that's an easy experiment.

The coolant sensor (which IS NOT the temperature gauge sensor) is all of about £7 and 5 minutes to change (with the engine cold), I suppose you could ask your local garage for a quote just for the giggle of it

hi yes the sensors were £89 each labour costs high because they had mega problems getting one sensor out.

gss kit not got a clue it was on car when i got it i am not very good with mechanical stuff sorry.

not sure what you mean about flapper but am sure it is 3.9 EFI cuz it says so on log book.

i have another airflow meter so will get that changed over to see if it is that .

where will i find the coolant sensor and what is the differance between that one and the the temperature gauge sensor

thank you for your help

kind regards Simon

[SIMON64]

Never tried running mine on Petals. Perhaps you are using the wrong ones? I would imagine chrysanthemums would give a denser charge than rose petals for example, or perhaps that is why yours is running rich?

I have a similar problem with my RRC, in that it is only just scraping in to double figures, but as the pistons are only just on speaking terms with the bores, I think that might have something to do with it.

What state is the rest of your engine in? Does it burn oil etc etc?

engine does burn i little oil but not a lot the engine is good. fuel problem just started was getting 15 mpg then it just dropped to 6 mpg

regards Simon

[Hybrid_From_Hell]

1st things 1st

1st Post up a picture of your RR engine - that will identify what it is.

Then we can give you some advice as to where next

Nige

[mickeyw]

I'll be watching developments here. I have carp MPG on gas from my RRC 3.9 too, it only manages double figures on a good day It uses no oil and is otherwise in good health. It's a 1990 model, pre cat, so the only lambda sensor is the one for the LPG system. Uses a Bigas vaporiser, I know they're not the best, but that's what it's got. System is a couple of years old, fitted by myself, and was returning as high as 15MPG once.

Is there a way to check coolant temp sensors without going the replacement route? Same Q for airflow meter, and what goes wriong with them?

Thanks in anticipation of a flood of useful answers.

Michael

[SIMON64]

1st things 1st

1st Post up a picture of your RR engine - that will identify what it is.

Then we can give you some advice as to where next

Nige

hi here is a pic hope this helps

regards simonmy rrc

[SIMON64]

and a pic from the front

regards simon

[Hybrid_From_Hell]

Er

as in the 2nd one,

but closer and with the bonnet up, ...............as in a pic of the Engine

Nige

[geoffbeaumont]

Um...Simon, it was a pic of the engine that was requested - the outside of the truck tells us nothing. We could work out what the original engine options would have been (3.9V8 Hotwire, 200Tdi or maybe 300Tdi on an L-reg 100", I think), but many Land Rovers have had replacement engines.

[SIMON64]

hi had a look at you pics then engine it is deff a 3.9 EFI v8 hotwire its the original engine fitted when new sorry dont have a pic

regards Simon

[DC_]

If it looks anything like mine Simon then this is your CTS

[geoffbeaumont]

By the way Simon, if that's your truck in your avatar, you want to get a snorkel before you go nosing it into water that deep. When you work out how the bonnet release works take a look at where the air intake is...

[FridgeFreezer]

not sure what you mean about flapper but am sure it is 3.9 EFI cuz it says so on log book.

I would've though the pictures gave a clue what I was on about - there are two types of EFI which can be identified by the two types of airflow meter (pictured) they are located under the bonnet with minimum seaching. Both were fitted to 3.5 and 3.9 at various points and identifying which you have makes it easier to offer help.

where will i find the coolant sensor and what is the differance between that one and the the temperature gauge sensor

The difference is the gauge sensor just makes the gauge needle move, the the other one tells the ECU how hot the engine is, which it then uses to calculate how much fuel to inject. Faulty sensor = dodgy maths = too much fuel = 6mpg

The sensor is located as per the picture in the post above, it has a 2-pin connector on top. EAC3927L or ETC8496 is the part number, should cost between £5 and £15. If there are two next to each other, it's the smaller one (usually nearest the back), and you have flapper EFI.

Edited to add: Coolant temperature sensor is visible at the top, slightly to the right, in this picture:

It would usually be behind the distributor, but I kinda removed that

[DEANO3528]

I'm well impressed the way you are recovering that 360.

Not so sure about the angle of that bullbar, that definitely looks a bit wrong, or as we say in Suffolk, "on the huh"!

[SIMON64]

hi had a look at you pics then engine it is deff a 3.9 EFI v8 hotwire its the original engine fitted when new sorry dont have a pic

regards Simon

as per this message posted earlier by me it is the hotwire not the flapper

yhanks for the help

regards simon

[Dr W]

Very much enjoying this thread, has the right amount of humour and technical advice being given

Anyway my 3.9 1991 RRC gives about 11 mpg on lpg which isn't a lot and it's been suggested that 14-15 would be more reasonable. Mine is a singlepoint venturi system which runs very well just doesn't do much to the gallon.

The lads at RPi suggested upgrading the ignition system and boosting the spark and making sure the spark plug gap was about 0.8-0.9.

I'm replacing the parts this weekend so will let you know if that improves anything when I do a long run up north the weekend after.

How would you know if the gauge sensor was faulty, is there anyway to easily see without just replacing?

How would you know if the airflow meter was faulty?

As I said it runs fine on both lpg and petrol but just a bit on the low side.

[DaveSIIA]

If mpg on both gas and petrol has dropped alarmingly then it points to something that is common to both systems - ignition, engine core, driver, stuck (hand) brake? - rather than components that affect only the EFI.

Get the bonnet up and take some photo's of the engine, particularly the bits that make up the lpg system. Someone might be able to identify which system it is and hence which bits are common to both petrol & lpg.

[FridgeFreezer]

The lads at RPi suggested upgrading the ignition system and boosting the spark and making sure the spark plug gap was about 0.8-0.9.

Please tell me they haven't talked you into a Mallory distributor?

Can't grumble with Magnecor leads though.

I'm replacing the parts this weekend so will let you know if that improves anything when I do a long run up north the weekend after.

Interesting to hear what you've fitted and what effect it has.

How would you know if the gauge sensor was faulty, is there anyway to easily see without just replacing?

You know the gauge sensor is faulty if your temperature gauge doesn't do what you expect (EG stays cold, jumps to really hot, waves about the place when the engine is just running as per normal)

How would you know if the airflow meter was faulty?

By running through the massive and detailed diagnostics manual that's posted in the technical archive.

[Roverdrive]

Was just going to add that if the problem is on both petrol and LPG then it must be something common to both. My system does not pick up on engine temperature for the LPG, so I am fairly sure that it is a combination of aggressive tyres, viscous coupling, heavy right foot, and worn engine!

On the other hand, a mates RRC which has a hotwire AFM and is fitted with LPG, does sense engine temp, and will not change over to LPG until the engine is at normal operating temperature, so there could still be a common connection there.

As has been said, we need to see what type of system is fitted to be more specific with the fault finding.

[ariane44]

Er

as in the 2nd one,

but closer and with the bonnet up, ...............as in a pic of the Engine

Why? The first pic shows clearly it has the high fuel filler, so it was built between 92 and 94, so it is a hotwire.

Work carefully through the test sheets on rangie.com if the fault is related to the injection system, check timing and O2 sensors.

Cheers

Carsten ;-)

PS: None of my RR ever had a problem consuming fuel - they indeed manage to consume quite a lot of that :-))

[Bull Bar Cowboy]

Why? The first pic shows clearly it has the high fuel filler, so it was built between 92 and 94, so it is a hotwire.

Work carefully through the test sheets on rangie.com if the fault is related to the injection system, check timing and O2 sensors.

Cheers

Carsten ;-)

PS: None of my RR ever had a problem consuming fuel - they indeed manage to consume quite a lot of that :-))

Why ................. because there are a lot of Classic RR 3.9's that have had engine swaps to 3.5 flapper due to block & cam problems with the 3.9 engine.

Ian

[Dr W]

The lads at RPi suggested upgrading the ignition system and boosting the spark and making sure the spark plug gap was about 0.8-0.9.

Please tell me they haven't talked you into a Mallory distributor?

Can't grumble with Magnecor leads though.

I'm replacing the parts this weekend so will let you know if that improves anything when I do a long run up north the weekend after.

Interesting to hear what you've fitted and what effect it has.

How would you know if the gauge sensor was faulty, is there anyway to easily see without just replacing?

You know the gauge sensor is faulty if your temperature gauge doesn't do what you expect (EG stays cold, jumps to really hot, waves about the place when the engine is just running as per normal)

How would you know if the airflow meter was faulty?

By running through the massive and detailed diagnostics manual that's posted in the technical archive.

No not getting into replacing distributor just yet.

I'm doing the leads and boosting spark first then down for an lpg service to check mixture and filters etc.

I look forward to an interest read of the diagnostics manual at some point in the future, just not right now