fuel

[aug081451]

hi all. i have just bought a 1.8t auto, but it seems to be using a awfull lot of FUEL , has anyone got any advice how to improve MPG, THANKS peter

[Dave Goody]

hi all. i have just bought a 1.8t auto, but it seems to be using a awfull lot of FUEL , has anyone got any advice how to improve MPG, THANKS peter

MMM how much is an awfull lot? [in mpg please]:}

[aug081451]

hi dave, thanks for the reply, i might only be getting 18-20 miles per gal, peter

[Dave Goody]

Only way to check accurately [ignore the computer] brim to brim. so check mileage fill tank run till amost empty, fill tank again, check mileage and work out mpg. 20 mpg very poor for that engine so do a brim to brim and come back to us. Dave

[92 squadron]

hi dave, thanks for the reply, i might only be getting 18-20 miles per gal, peter

Are you sure you changed out of first gear!:banghead: Only kidding but that is bad MPG

[aug081451]

hi all, yes i thought it was poor, but waited till fuel tank light came on then put £20 in, drove it a couple of days , and it came on again, i had done 76 miles, does it need a service? peter

[keir1163]

i would suggest a leak cos that is aweful!
only other thing i can think of is that the ECU is in limp home mode and compesating by overfuelling.

[flyer_phil]

Hi

I thought I might add my twopenneth.

Its true on the surface that 18-20 mpg from a 1.8 litre engine doesn't seem too good. However don't forget that the 1.8 turbo produces a lot of power - and power has to be paid for. I am not familiar with this engine (I have a diesel) but I seem to recall it produces around 160 bhp. So the economy really is a statement about power not capacity. Also it is an automatic.

For example years ago I had a Pontiac Firebird which I had brought with me on returning from the USA. It had a 5 litre V8 with a manual gearbox. People use to disbelieve me when I told them I got 26mpg in mixed driving and 30 mpg on a run.

However the reason was that it was a big lazy V8 that produced only 175 bhp but a huge 300 ft ilbs of torque and only revved to about 4000 rpm. Had it been an automatic, that would have lost me 3-4 mpg say therefore 23 - 24 mpg.

Now I know people are going to start on about turbo efficiency etc, but I would have thought that you would not get more than about 23 mpg.

I know someone recently bought an Mazda MX5 automatic which also has a 1.8 turbocharged engine producing a lot of power. He too was disappointed at the 20 mpg he got and sold it.

Still I'm sure there will be lots of people on this forum that will be able to advise you on the correct figures you should obtain.

[SD1too]

... waited till fuel tank light came on then put £20 in, drove it a couple of days , and it came on again ...
Peter,

You cannot judge fuel consumption accurately using that method. You need to use the "brim to brim" method as described by Dave Goody, and the more fuel you use for this test the more accurate the result will be.

Simon.

[HarryM1BYT]

That figure is very poor, I could get 27mpg on a decent run in my 3l V6 auto. I could beat your figure by 5 to 6mpg even when towing my caravan. As others suggest do a brim to brim check on the litres consumed and the mileage done, convert to mpg - then get back to us.

[Roverron]

Peter,

You cannot judge fuel consumption accurately using that method. You need to use the "brim to brim" method as described by Dave Goody, and the more fuel you use for this test the more accurate the result will be.

Simon.

He aslo doesn't say where its driven, load carried, saloon or tourer.

20mpg for an auto tourer driven entirely around town is probably not unthinkable.

Ron

[aug081451]

i would suggest a leak cos that is aweful!
only other thing i can think of is that the ECU is in limp home mode and compesating by overfuelling.
hi keir, is there anything i can do about limp home mode? please i would be gratefull for any advice ;

[aug081451]

hi all , what is limp home mode? and also i know what you say is correct about b t b, but i would not like to put 360 PLUS IN TANK TO REACH THE SAME ANSWER, MUCH BETTER SPENT TOWARDS CURE, thanks peter

[aug081451]

hi all , i think i should let you know the 75 is 1.8 t petrol. 60 thou on clock, as i say any advice is good advice thanks peter

[Tatts]

Unless you use the brim to brim method to work out the exact mpg, anything else is just guesswork.

Also, as mentioned earlier, what are the driving conditions? Long run or town/city driving? Stop & start commuting will hammer the mpg.

When was the car last serviced ~ whats the air filter like? Tyres correctly inflated?

[aug081451]

i think iam crossing between threads here, NEW TO THIS, but can someone tell me how to get out of limp mode , or have it checked please , peter

[92 squadron]

[QUOTE=flyer_phil;595539]Hi


For example years ago I had a Pontiac Firebird which I had brought with me on returning from the USA. It had a 5 litre V8 with a manual gearbox. People use to disbelieve me when I told them I got 26mpg in mixed driving and 30 mpg on a run.

However the reason was that it was a big lazy V8 that produced only 175 bhp but a huge 300 ft ilbs of torque and only revved to about 4000 rpm. Had it been an automatic, that would have lost me 3-4 mpg say therefore 23 - 24 mpg.



Heard recently on Top Gear when he was testing a sports Merc I think it was, that the twin turbo's suck over a 125 bhp. out of the engines power to run!!!!:getmecoat:

[HarryM1BYT]

hi all , what is limp home mode? and also i know what you say is correct about b t b, but i would not like to put 360 PLUS IN TANK TO REACH THE SAME ANSWER, MUCH BETTER SPENT TOWARDS CURE, thanks peter

You do not necesarily need to use up an entire tankful on the experiment. Obviously the more you use, the more accurate the figure becomes, but all you need to do is brim the tank stopping at the first click then make a note of the mileage.

You then drive it far enough to make it a worthwhile distance for topping it up again and take it back to exactly the same petrol pump/ same side of the pump and brim it as before, exacept this time you make a note of how many litres you put in and the new mileage figures.

[HarryM1BYT]

i think iam crossing between threads here, NEW TO THIS, but can someone tell me how to get out of limp mode , or have it checked please , peter

Limp home mode is a condition where one (or more) of the engines sensors has failed or producing silly input to the engines computer. Some sensor failures can be compensated for by the engine management system using default figures and allowing the engine to still operate in a 'limp home' mode - but the engine will not perform well and it will affect the fuel consumption.

To have it checked, you need to take it to a garage which has suitable diagnostic equipment. Another alternative is that you can buy a diagnostic adaptor to plug into your PC - look up 'ELM 327'.

[aug081451]

thanks for the replies, i think i understand it all a bit better NOW, but the engine did feel slugish, and of course a LOT of fuel was used, i think it only did 15 mpg! i will try to get diagnostic DONE asap thanks again peter

[T-Cut]

If the ECU had invoked 'limp mode' due to some engine malfunction, I'd expect the yellow EML would be showing. The OP hasn't mentioned it. They can apparently assume a limp-like mode without the EML, but I sense this case isn't one of those.

Have you checked for fuel leaks? The loss of petrol from one of the two tank module seals is pretty common, especially in cars that have had recent tank work done. This causes a strong smell of petrol under one or other rear wheel arch.

TC

[pab]

a brim test needs to be done to determine the fuel usage,any fuel leaks would be apparent by smell.
my guess is that the car is in need of a service,when was the last time one was carried out?

[Synchromesh]

I used to have a ZT 1.8T manual. It did around 32mpg brim to brim.

[aug081451]

hi all, i will have a go at this brim to brim as soon as i get paid, i checked the spark plugs in case the mix was rich but the plug looked clean and dry , thanks for the INFO, peter