BAD FUEL ECCONOMY!

[dirty_86]

CAR: Toyota Sprinter AE86
Engine: 4A-GE from an AE82 corolla
Computer: standard..
fuel system consist of a Fuel Flow lift pump to a 750ml surge tank fed through a VL external fuel pump..

its really bad 200km to a full tank

[SEXY 16]

buy a jdm car and ennjoy all the fruits of glory lol

[Jonny Rochester]

So the car is in perfect condition otherwise? And the motor and computer is all connected up perfectly, just like a factory install? O2 sensor, air temp sensor etc

[Beserker99]

Not leaking any fuel? Does anywhere smell like fuel, could also be loose clamp or hole that fuel could escape and evaporate without ya knowing.

Just a possibility.

[FLT LNR]

yeah that seems way too bad. apart from obvious leaks, i'd be checking every element of the fuel lines as well as elementary stuff like the actual filler cap, and the functionality of the sensors, and corresponding circuitry.
there is certainly a failure when you're getting half the distance you should be....

how does the motor run in terms of smoothness and feel? is there a chance the ecu is hooked up bodgy?

for such a massive loss it points to fuel delivery if not huge leakage....

[yoshimitsu9]

So the car is in perfect condition otherwise? And the motor and computer is all connected up perfectly, just like a factory install? O2 sensor, air temp sensor etc[/b]

02 sensor will do absolutely nothing to fuel economy so forget that.

check the fuel reg, come back and tell us what it is. $10 says its the wrong pressure

[andru_g]

^^^ o2 sensors DO have an affect on fuel economy!

[Driftspec]

Also, and I know this sounds stupid, but make sure there are no physical leaks from the filler cap itself. The previous owner of my Sprinter once had fuel streaming down the side of the car, he had filled the car up, and the vacuum from the lines (or something to that effect; its a 4AC) was forcing fuel out of the tank.

Someone suggested it above, but it might at least give you a clue. Also make sure all fuel line seals are intact, if they are perished it will leak fuel/vapour into the bay.

[yoshimitsu9]

^^^ o2 sensors DO have an affect on fuel economy![/b]

only at highway cruising speeds http://www.ae86drivingclub.com.au/forums/emoticons/wink.gif not general street/city driving and even at that it isnt going to enormously alter the fuel economy to only get 200km to a tank. i dont have one and i get 400+km from a tank

[balistic]

I'm not sure if its the same for the 4AGE, but most O2 sensors are only used for cold start and idle to keep the mixtures correct. You cant waste half a tank of fuel whilst the car is idling before warming up!

I have a faulty O2 sensor in my WRX and havent bothered to fix it, its been like that for 3 years and I havent noticed any fuel economy problems or driveablility issues.

[Bobomacho]

hey guys, correct me if i'm wrong here...

o2 sensor doesn't work on cold start. the ecu runs the engine by predetermined settings in this case rich the 'open loop' setup.

because of this richness of the exhaust the o2 sensor is unable to read the levels of oxygen

ontop of that the o2 sensor will not be hot enough to work at cold start anyway. it must be at a certain temp to function correctly.

[dirty_86]

i will be checking my fuel pressure at work tomorow and will get back to u guys.. thanks for help.. and i beleive that o2 sensor does not effect fuel efficiency?.. i sused it out todai.. no smells of fuel.. im guessing i kinked a line when i put the fuel tank in.. it blows a s**tload of black smoke when i give it a good boot.. so fuel pressure i will check first.. just asked to c what i would check first thats all..

any1 noe the fuel pressure that is reccomended?

[SEXY 16]

just call john up and explane your problem and he will tell you what is wrong and then you can fix it in the knolledge of the master knowen as sprinterman68

[yoshimitsu9]

i will be checking my fuel pressure at work tomorow and will get back to u guys.. thanks for help.. and i beleive that o2 sensor does not effect fuel efficiency?.. i sused it out todai.. no smells of fuel.. im guessing i kinked a line when i put the fuel tank in.. it blows a s**tload of black smoke when i give it a good boot.. so fuel pressure i will check first.. just asked to c what i would check first thats all..

any1 noe the fuel pressure that is reccomended?[/b]

dude its running rich, get your fuel reg, disconnect the line that goes to the manifold and then adjust to 32psi then its done