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rangierover
30th December 2008, 07:07 PM
Hey guys and gals, i have been hanging around this forum for a few months now, without posting until recently.

Anyway my problem is how much fuel my 1992 range rover classic is using.
when i bought it about 5 months ago it was very reasonable for a v8 4wd, using only 14-15 litres per hundred with me giving it a fair bit of boot most of the time.
since then i have kept it in service all filters are clean and it has good oil, and runs perfect apart from it is using now 25-30 liters per 100kms. i have since fitted 31 inch all terains. and that is basically the only mod besides little things like draws and batteries.

Any ideas on why it is such a pig on fuel?
is there any way i can tune it at home?

Andrew

BigJon
30th December 2008, 07:24 PM
Check the vacuum advance diaphragm. It is a common failure and causes high fuel consumption.

rangierover
30th December 2008, 07:42 PM
sorry to sound ignorant, but where and what is the vacuum advance diaphragm?

BigJon
30th December 2008, 08:10 PM
It hangs on the side of the distributor. It has a vacuum hose going to it.

It is there to advance the ignition timing at times of high engine vacuum (light throttle cruise), thereby giving better economy.

Grumbles
30th December 2008, 08:33 PM
And when you take it off to check don't lose the little screw which holds it or the lock washer and when replacing Loktite it back in as well.

Rangier Rover
30th December 2008, 08:38 PM
Also make sure thermostat is working ( 83 Deg I think) and test Temp sensor resistance as may be tricking ecu to running cold.
Try all the above with a good tune up etc 1st.

The tyre change should not make that much diference. If were 35's with 3.54 may though.

rangierover
30th December 2008, 08:48 PM
Thanks for your advice guys, ill check all of those things when i get home tomorrow.
Wish me luck!

Rangier Rover
30th December 2008, 08:51 PM
Thanks for your advice guys, ill check all of those things when i get home tomorrow.
Wish me luck!

GOOD LUCK:p

PhilipA
31st December 2008, 07:46 AM
Could be a bad or dirty MAF which causes the ECU to into "limp Home " mode.
Limp home mode is very rich.

So clean the MAF wires by spraying non residue contact cleaner ( available at Jaycar) into the small hole you can see through the screen on the front of the MAF and bend the blades in the connector a little bit to get a good contact in the plug.
Obviously you have to remove the MAF to do it and take out the screen.
You have not fitted a K&N I hope .
Otherwise agree high possibility of dead vacuum advance and /or faulty thermostat or temp sensor.
Regard sPhilip A

PhilipA
31st December 2008, 08:11 AM
Could be a bad or dirty MAF which causes the ECU to into "limp Home " mode.
Limp home mode is very rich.

So clean the MAF wires by spraying non residue contact cleaner ( available at Jaycar) into the small hole you can see through the screen on the front of the MAF and bend the blades in the connector a little bit to get a good contact in the plug.
Obviously you have to remove the MAF to do it and take out the screen.
You have not fitted a K&N I hope .
Otherwise agree high possibility of dead vacuum advance and /or faulty thermostat or temp sensor.
Regard sPhilip A

maxfacta
11th January 2009, 12:35 AM
I'm sorry I have no suggestions for your consumption woes but I will say that I feel a little better about my automatic '95 Classic's fuel consumption of 18lt/100km country and 21-22lt/100km city:( At least these days it only cost me about 25 bucks per 320km's on gas:D:D:D

tarz37
27th January 2009, 02:11 PM
My 1992 auto RR on gas is giving me 30 lt /100km. around town. I have been told that is to be expected. It runs sweet but my wallet is complaining with gas being 55 to 60 cents /lt up here.:mad::mad:

Grimace
27th January 2009, 03:57 PM
Fluffy doesnt use that much fuel but here is something that made a noticable difference to the consumption. I always use 95ron as if I use 91 or 98 the consumption rockets up to 25L/100.

I noticed the around town consumption on fluffy was creepin up by 2L/100. She runs sweet and usually never uses over 20L around town.

My mate nottie advised to check the resistance on the two outer connections on the AFM...I removed the plug and wacked my multimeter on to check it and I got a total resistance of 71.4ohms. Factory specs is 174ohms so I set it too that.

That's all I changed, and so far after three tankfuls I have been given the impression that the fuel consumption is actually better then previous, and that is always gonna put a smile on my dial.

So am gonna wait to use a few more tanks and then check the resistance of other components (tps is next).

Something everyone should be checkin I guess. I was also under the impression that higher resistance was leaner, but rick told me otherwise, so going by that i efectively richened up the total mixture with absolutely no noticable change to the exhaust fumes and better fuel economy.
Power feels exactly the same and engine temps havn't changed either.

big guy
27th January 2009, 09:00 PM
I did same, put proper tyres back on and see the difference.
The old tyre debate is always something that gets me.
Big tyres create drag and are way less efficient.

try it and let us know.

Sure Big wheels look good to some folk but do very little for mech wear and actual handling and off road performance.

Grimace
29th January 2009, 08:19 AM
Sure Big wheels look good to some folk but do very little for mech wear and actual handling and off road performance.

Sorry but I have to dissagree about the offroad performance bit.

Everything else is spot on thou :)

LOVEMYRANGIE
29th January 2009, 11:54 PM
Fluffy doesnt use that much fuel but here is something that made a noticable difference to the consumption. I always use 95ron as if I use 91 or 98 the consumption rockets up to 25L/100.


I noticed exactly the same thing! When fuel prices dropped here, I started filling up with 98 at first to give it a clean and got about the same as the 91, but 95, i recorded down to 16L/100km, and thats after I found out my vac advance isnt 100% kosher!!
Did a country run over New Years with a good 800kgs towing behind, full car and a pod and got 20-21L with 98!
98 really needs a bit more compression to get it to burn well, anyone with a 9.35:1 CR will do well but an 8.13:1 which accounts for all unleaded Classic RR's without a cat convertor, 95 is the shot.

Regards

Andrew

StuRR80
30th January 2009, 01:11 PM
Did you get the them bottom of the problem?

Have you checked your brakes? I know it sounds silly but (please don't bash me for mentioned another marque) but on my Jeep, one of the calipers was stuck, which obviously increased the resistance and therefore fuel consumption. It may not be particularly noticable but add to the consumption.

rangierover
1st February 2009, 03:55 PM
hey guys i changed the spark plugs( forgot to do that with my service, and so far my consumption has droped down to around 20 litres from just that, so when i get some time up my sleeve i will be checking the resistance etc next thanks for your help guys