After having a conzult check performed on my car, i got the result of O2 sensors, and MAF working correctly.

 

Having not being convinced, i tested the 02 sensors by disconnecting them and runnning the car to see if it made any difference, but sadly it didnt in terms of fuel usage.

 

now would this suggest they're actually faulty? and i need replace them, the only thing left is 02 sensors or MAF to replace as everything else has been done.

 

fuel pump and filter

fuel damper and pressure regulator

fuel hoses

fuel tank

spark plugs.

injectors.

also viscous fan and thermostat have been replaced.

what was your fault?

If you unplug an 02 sensor the default setting for the ecu will be to run that bank rich for engine safety so it will use more fuel.why do you think its using to much fuel though?

its the cost of fuel thats gone up loads in the last 3 weeks i reckon!, or check ect sensor

cost isnt the issue here, its using the same amount of fuel it uses, the problem if i didnt explain it is.

 

is uses the same amount of fuel with the 02 sensors plugged in, as it does with them disconnected, so if once disconnected its running 'rich' why isnt it using more fuel. but apparantly the 02 sensors are fine.

 

milage is the problem i do 160-185 max to a tank and thats 70 quid every 2-3 days, and its tedious watching the gauge to estimate if i can make it to destinations, or need to fuel up.

 

usually get 14-16 mpg, never anymore and that is inclusive of motorway driving, done a 200 mile trip all on the motorway under 75 the whole way and it was in red at about 160 odd so refuled, and came back, same result.

well my n/a with no known faults does 44 miles to 20 quid gentle driving, mines chipped and decats.

 

id say your fuel economy was about right, it is a 3 litre car in a high priced petrol world

JIMMER. i hoped so too, but it actually didnt, use any more than it did with them connected. Hence my little experiment, and this was over a full tank, so brimmed it with 70 quid, then went on my way until i got back on red. 180 miles later!

Is your car Jap or UK,Both can suffer but Uks tend to more,the fuel tanks rust causing fuel leaks,just a thought.

cost isnt the issue here, its using the same amount of fuel it uses, the problem if i didnt explain it is.

 

is uses the same amount of fuel with the 02 sensors plugged in, as it does with them disconnected, so if once disconnected its running 'rich' why isnt it using more fuel. but apparantly the 02 sensors are fine.

 

milage is the problem i do 160-185 max to a tank and thats 70 quid every 2-3 days, and its tedious watching the gauge to estimate if i can make it to destinations, or need to fuel up.

 

usually get 14-16 mpg, never anymore and that is inclusive of motorway driving, done a 200 mile trip all on the motorway under 75 the whole way and it was in red at about 160 odd so refuled, and came back, same result.

 

Yes I agree, your consumption is very high, I can quite easily get 330miles to a tank if driven reasonably and that will include the odd blast, 14-16mpg is American V8 economy, these cars can do 25mpg quite easily.

well my n/a with no known faults does 44 miles to 20 quid gentle driving, mines chipped and decats.

 

id say your fuel economy was about right, it is a 3 litre car in a high priced petrol world

 

Are you serious! Thats terrible economy, so a full £70 tank you'd only get 150miles! Is that lots of town driving?

Like I said above I can get over 300 miles per tanks easily, but to be fair my routes dont include much town traffic.

 

I've just worked out a rough MPG for you of 13mpg - these aren't 6litre V8's you know...

Edited December 14, 201015 yr by turbocraigy

i used to get around 25mpg from my tt auto and that was overfueling. i wold expect around 30 on a run. have you had a compression check, what is your ignition timing set to. was the thermostat changed with a genuine item, could your brakes be binding a little. just some food for thought

brakes are fine, fuel tank doesnt leak and is a Jap imort, and yes im aware 13-18 is shocking. havent had a compression test done, what will this show?

also timing is fine, was readjusted at zworld in October.

Have you actually checked to see if the O2 sensors are working by a consult test or by putting the ECU into diagnostic mode 2? A quick & easy test to see if you have a faulty sensor! :)

both have been done. ecu test 1st, both were fine, then still not convinced so took it to zworld for conzult, still the same result of both fine. i know this seem conclusive but like ive mentioned in the 1st post, with them disconnected fuel usage is the same as with connected, and apparently with them disconnected the car should run 'rich'....

Are you serious! Thats terrible economy, so a full £70 tank you'd only get 150miles! Is that lots of town driving?

Like I said above I can get over 300 miles per tanks easily, but to be fair my routes dont include much town traffic.

 

I've just worked out a rough MPG for you of 13mpg - these aren't 6litre V8's you know...

 

yep this week, 44 miles from 20 quid to petrol light coming on, had a m3 before so thought was about right.

 

the car is just purely town driving to work and back though. but ive put the std airbox back on this week to see if makes a difference.

doubt it will but good luck. let us know.

I've been searching but to no avail! Can someone point me in the direction of a how-to change the O2 sensors on a TT more specifically with pictures to identify them lol

i get around 25 on adverage. do a 30 mile trip 3/4 times to 20/30 quid on adverage and i do give it a poking. my father in laws trans am did more than 13mpg and that was a 6.6 litre lol, on a run anyways

very helpful z32bolt, anymore useful tips!

Hey, Coolq - did you ever solve this?

 

Grimmer - Yep, I'm getting about the same MPG as you from my NA, the thought of getting 300 as mentioned above somewhere seems optimistic if not unbelievable. I'll get 200 miles out of a tank at best.

 

Haven't tested anything yet, but have replaced the air box and old clogged up filters...

I own Grimmer's car now, tonight I've done over 100 miles on £20 of fuel, and a few of those were spirited!

I own Grimmer's car now, tonight I've done over 100 miles on £20 of fuel, and a few of those were spirited!

 

100 miles on £20!? :shifty:

 

Well that's just insanity! lol

 

Do you know what was done to achieve this? As I want to do it a lot!

yea 100 miles on 20 quid is over 30mpg LOL. you were driving the 300zx werent you, not a 1.4 clio :-)

when i had probs the o2 sensors kept coming up when plugged in to cpu in garage,when new ones put in nothing changed mind you i had a small misfire,took it to garage who set up rally cars within hour they said job done maf sensor,got n/a manual does about when i drive it 70 miles maybe 80 on £20 thats urban much better on motorway,doesnt the maf have a super thin wire which when you turn ignition off send a pulse which eliminates contaminants on it over time burns out which causes miss fire ,limp home mode eventually or blown clutch in my case