Most common causes of high fuel use?

[clintondane]

I\'ve recently got a "new" car after writing our Blitzen off. I got another one, Lol. Anyway this new one goes incredibly well but it uses quite a lot more gas than the old one. Don\'t ask for exact numbers but I know it\'s using more. One thing I\'ve noticed is that at highway speeds the engine revs a little higher than the old car but only by about 200rpm so that doesn\'t really seem like the culprit? It uses no oil and the water level is rock steady, the brakes aren\'t binding at all, the tyres and whels are factory size too. Obviously dirty air filters, munted AFM and O2 sensors can cause issues but there\'s no codes showing up. I need to get it in to a mechanic for a scan but until then it\'d be good to at least know what might cause higher fuel use. I\'m going to guess it might be a sensor on the way out and it\'s just not throwing codes yet?

[Guest]

AFM and O2 can slowly slide out of calibration causing it to worsen before it gets to throwing a CEL. Its not running higher boost?

[Marky]

Yeah what he said

If in doubt do an ecu reset, clean the afm, and then monitor it

Will use more in hot weather too

[Fastfour]

The right foot???? Thought that was obvious!

[clintondane]

HAHAHA the old right foot, how dod I not think of that? Lol. I don\'t think it\'s running higher boost, it feels no different to the last car and there is no boost controller to be seen in the car. It\'s a 2000 Blitzen that\'s only just done 110ks. Full receipts for cambelt about 6k ago and the gearbox had a full service about the same time. Car is super tidy and doesn nothing out of the ordinary except use a fair bit more gas than our old one.

Definitely a scan needed, will that show a sensor on the way out? Could the oil be a contributing factor? There\'s the remainder of the oil used in the last service left in a 5litre bottle and I can\'t think of the brand but I think it\'s 5w-40 semi synthetic. I always used castrol edge 5w-30 in our last car.

[clintondane]

Also how the hell do I do an ECU reset and is it something I can cock up and lead to big repair bills?

[Guest]

Some people are amazing with their senses and come back swearing that an oil change makes it run nicer/smoother/better. #W30 is a fuel efficent thing which is where the FE comes from. Had a guy in a terrano do a change to agip just what it should have in it and he would have to be in 4th to get up a hill. Straight after the change he was in 5th no worries up the same hill with a car load of people. Explain that...

[Timmah]

I think getting a scan is going to be your best bet.

Daily, around town only driving, I only get 370k per tank. Little bit of spirited driving with far too long spent crawling in traffic.

[Guest]

 Timmah said:

I think getting a scan is going to be your best bet.

Daily, around town only driving, I only get 370k per tank. Little bit of spirited driving with far too long spent crawling in traffic.

Wow. I would get 550-600km V5 TD04 stock with any sort of driving with a fair chunk of boosty. Same goes for foz of same era.

[Marky]

Define a fair bit - without some kind of benchmark for all you know it might just be a dent in the gas tank or a pessimistic gauge, they arent linear and dont seem to be all that consistent from car to car

Like... how far off 10l/100k are we talking

A scan can "sort of" pick up dodgy sensors but the biggest contributor is the driving style

Are tyres all pumped up

How sure are you about the gearbox rpm being different - is it engaging the overdrive lockout thing at higher speed?

Ecu reset you cannot get wrong or break anything, takes 5 min and is simply plugging in a plug under the dash

[Timmah]

 evowrx']

[quote name='Timmah said:

I think getting a scan is going to be your best bet.

Daily, around town only driving, I only get 370k per tank. Little bit of spirited driving with far too long spent crawling in traffic.

/quote]

Wow. I would get 550-600km V5 TD04 stock with any sort of driving with a fair chunk of boosty. Same goes for foz of same era.

https://www.fuelly.com/driver/timmahnz/wrx

My fuelly for the past few months.

God damn that\'s a difference between our cars. Did you have any mods?

[Guest]

 Timmah']

[quote name='Timmah said:

I think getting a scan is going to be your best bet.

Daily, around town only driving, I only get 370k per tank. Little bit of spirited driving with far too long spent crawling in traffic.

/quote]

Wow. I would get 550-600km V5 TD04 stock with any sort of driving with a fair chunk of boosty. Same goes for foz of same era.

https://www.fuelly.com/driver/timmahnz/wrx

My fuelly for the past few months.

God damn that\'s a difference between our cars. Did you have any mods?

No and you have issues. Car ones I mean that isnt right at all.

[Timmah]

 evowrx']

[quote name='Timmah said:

I think getting a scan is going to be your best bet.

Daily, around town only driving, I only get 370k per tank. Little bit of spirited driving with far too long spent crawling in traffic.

/quote]

Wow. I would get 550-600km V5 TD04 stock with any sort of driving with a fair chunk of boosty. Same goes for foz of same era.

https://www.fuelly.com/driver/timmahnz/wrx

My fuelly for the past few months.

God damn that\'s a difference between our cars. Did you have any mods?

No and you have issues. Car ones I mean that isnt right at all.

Sorry clintondane for thread hijacking.

AFM was replaced at the start of the year, o2 was last year. I thought my car was doing alright fuel economy wise *shrug*

[clintondane]

Ok, I remember on our old car used to get about 500ks combined driving to a tank and on the open road upwards of 600km. This new car is looking like I\'ll get less than 450k\'s to a tank and that\'s almost all open road driving. As for the revs, they\'re definitely a little higher. We had out last Blitzen for over 5 years and knew it\'s habits well. Our last car would average about 10l/100ks and was as good as 8.2l/100ks. Being that we had the same kind of car last time, I haven\'t been driving the thing any different to the last one.

How do I do an ecu reset?

[Marky]

Work it as l per 100k not tank size remember

Plus city driving can near halve the mileage in some cars

My last legacy had a pb of 630km to a tank and a worst of 320km... guess which tank was a single open road drive and which was a fortnight of only cold start / short trips and being stuck in traffic. Literally one came after the other.

[clintondane]

Thanks mate, I\'m going to go to the mechanics tomorrow and get it scanned if they have the time. I know I can do a self diagnosti on the car but that won\'t show real time numbers etc. I know the last time I had our old car scanned the O2 sensor was "lazy" according to the mechanic and a change helped fuel consumption massively.

[loner]

Factory tune is obnoxiously rich.

[clintondane]

Yea? I remember our old one used to stink of petrol while it was warming up.

[Guest]

 Timmah']

[quote name='Timmah said:

I think getting a scan is going to be your best bet.

Daily, around town only driving, I only get 370k per tank. Little bit of spirited driving with far too long spent crawling in traffic.

/quote]

Wow. I would get 550-600km V5 TD04 stock with any sort of driving with a fair chunk of boosty. Same goes for foz of same era.

https://www.fuelly.com/driver/timmahnz/wrx

My fuelly for the past few months.

God damn that\'s a difference between our cars. Did you have any mods?

No and you have issues. Car ones I mean that isnt right at all.

Sorry clintondane for thread hijacking.

AFM was replaced at the start of the year, o2 was last year. I thought my car was doing alright fuel economy wise *shrug*

I would get that sort of km\'age out of old libero running evo ecu/afm/injectors/turbo completely untuned raping it like a youthful 17yo does 60L tank or something iirc? Tipped 58L into it once anyway and it hadnt run right out. Something not right there dude thats way bad.

OP letting it warm up before driving can help. Just to get it out of the enrichment tables. Easy way out would be to plum it into parallel then no boosty down low so better economy.

[clintondane]

There\'s a long way to go before I even remotely entertain the idea of parallel twin turbo setup.

[WRXER]

Maybe an injector seal issue?? Maybe not common but was something I had for years without realising.

Years and years I thought my wrx was horrendous on the petrol...When I started the track build for the wrx, my mechanic found that one of my sard injectors didn\'t have a seal and it was "tuned" over, glad I stopped going to that tuner years and years ago as I use to having a fuel flooding issue the tuner was meant to have fixed.

Tony at RDL just randomly rung me and asked if I had ever noticed how bad my wrx was on petrol...Then the penny dropped, use to be two tanks of petrol to just get to Nelson from Chch and that was with only some "spirited" driving.

[clintondane]

Wow! I\'m guessing you can\'t just check an injector easily ?

[Guest]

 clintondane said:

There\'s a long way to go before I even remotely entertain the idea of parallel twin turbo setup.

As easy as swapping a hose I think.

[loner]

 evowrx']

[quote name='clintondane said:

There\'s a long way to go before I even remotely entertain the idea of parallel twin turbo setup.

/quote]

As easy as swapping a hose I think.

You would need the turbos to be the same size surely?

[Guest]

 loner']

[quote name='clintondane said:

There\'s a long way to go before I even remotely entertain the idea of parallel twin turbo setup.

/quote]

As easy as swapping a hose I think.

You would need the turbos to be the same size surely?

I mean that hosey marky thingy one of those writeups he gets all that karma for.