Increase in mpg on 4.6 HSE?

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.
S

Sparkystu

New Member
Posts
12
I am looking to increase my mpg which seems to always be about 13-14. Driving round town and on motorways seems to make no difference at all.
I know the car is due for a good service so what sort of things should I be looking at replacing to improve this mpg? I want to do the work myself.
I do not use air con as the condensor leaks so it can't be this using all my petrol! It seems to run smoothly and has power when I need it although I am sure the kickdown could be improved to be a bit more responsive.

I am looking to have an LPG conversion in the near future but I want it running properly on petrol before even thinking about LPG!

Any help would be appreciated!
 
cam mid valve heads auto box is ecu controlled, good all oil change service,kenlowe fan k&n filter i get 22-24 mpg no gas no point
 
oxygen seniors and reset of adaptive values works really well with increase in mpg. Mine went from 14 mpg on highway or city to 20 mpg on highway at 140 km/h. City is 14 to 16 now.
 
Last edited:
iv done naff all been stood 9mts when i got her ,put batt in started on 4th turn ,
anyway done nothing to engine yet and get 16-17 and 20-21 and its done 240000,and last owner from new only did head gaskets once.can't bet a good one but you realy don't want a friday one .
 
996TURBO said:
oxygen seniors and reset of adaptive values works really well with increase in mpg. Mine went from 14 mpg on highway or city to 20 mpg on highway at 140 km/h. City is 14 to 16 now.
Click to expand...

Is it possible oxygen sensors are faulty? Where would I find them?
I didn't understand the "reset of adaptive values". Please explain to a ficklad!!

Thanks for the reply.
 
I replaced mine and a friend's after the MOT told us emissions were too high. The engine management system adapts itself over the time so your engine runs well, but if you go beyond some values because of a bad element such as oxygen sensors or MAF, you won't benefit of the replacement of those.
Reset of adaptive values can be done with Testbook or Faultmate. Engine will run strangely during couple of miles then it'll tune itself and give you good economy and power.
 
Last edited:
I agree with vougese39, Ive got magnecor blue leads, platinum tipped plugs, tornado chip set, free flow filter and janspeed exhaust, and have replaced cam, followers, push rods and rockers. Ive seen mid 25's on a run. Dont bother with gas. You can achieve more with engine mods to improve volumetric efficiency, gas flowing, larger inlet trumpets and valves. Depends how much you want to spend.
 
Sparkystu said:
I am looking to increase my mpg which seems to always be about 13-14. Driving round town and on motorways seems to make no difference at all.
I know the car is due for a good service so what sort of things should I be looking at replacing to improve this mpg? I want to do the work myself.
I do not use air con as the condensor leaks so it can't be this using all my petrol! It seems to run smoothly and has power when I need it although I am sure the kickdown could be improved to be a bit more responsive.

I am looking to have an LPG conversion in the near future but I want it running properly on petrol before even thinking about LPG!

Any help would be appreciated!
Click to expand...

make sure you give it a damn good service using good quality parts,when thats done check the brakes to make sure they are in good condition and not binding,lastly make sure the tyre pressures are correct and kept that way.if you have got a lead right foot you will always have poor mpg.:);)
 
Mine was the same and the plugs as black as charcoal. Was doing aorund 12-14.
I then had all the faults cleared from the ecu and what a differance. Now doing 17 aound town and 20 on a trip doing 70 - 80.
wants a good service with good plugs and leads.
You may have a problem thats causing this. My heads were leaking gas on 2 cylinders so more fuel being pumped in. If you know how to take plugs out buy a comprssion tester take out fuses 28 and 39 and see if you have any problem cylinders.
 
O Bife said:
...I have just installed one of those K&N air filters and I have found a huge difference.

She used to do around 20MPG (14.2 L/100Km) urban and about 25MPG (11.3 L/100Km) on a motor-way run (avg 105Kmph).

Now she is doing just under 28MPG (10 L/100Km) urban and around 30MPG (9.4 L/100Km) on a motor-way run (avg 105Kmph) and even less on "A" roads (33MPG @ an avg 90Kmph).

Mine is a 2.5DSE...
Click to expand...

Don't know if that helps, but that is what I've just done (2 months ago)
 
That's got me thinking - I have only had the car two weeks, so this evening I popped the air filter cover, the filter was well mishaped and I am sure a bird must have been nesting in there :mil90:

New KN Filter ordered
 
You must log in or register to reply here.

Similar threads

T
P38 top end stripped lpg advise
Replies
5
Views
241
thegasman
T
J
MPG Info
2
Replies
37
Views
2K
rich28uk
rich28uk
MrMatt83
L322 3.0 td6 gearbox problems
Replies
12
Views
408
pwood999
pwood999
I
Replacing/repairing BCU (Body Control Unit) on 2005 RR HSE
Replies
9
Views
339
invisible999
I
M
RR p38 HSE 4.6 1996
Replies
9
Views
907
Datatek
Datatek
Back
Top