V high fuel consumption on 99 civic HB 1.4 (UK spec)

markz1986

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5+ Year Member
#1
hi

for some reason ever since i bought this car i have had very high fuel consumtion around 20 to 14 MPG around town and that when i keep the revs under 3K for the whole tank!, the only mods on the car are 17 in rims and a tenzo back box (4 inch straight through), ive had regular services and have recently had valve clearences done, taken the car to honda but they cant find the problem, all ive been told is that it could be due to the rims (which i dont believ) or the exhaust due to loss of backpressure, what do u guys think?, ive heard the backpressure thing mentioned before so it could be that and ive also noticed when i put the silencer back in the throttle is a LOT more responsive and it accelerates a lot quicker so if this is the case could i solve the problem by removing the centre pipe and getting a larger resonator put in? or will i have to go back to stock to get back the fuel economy?


cheerrs guys
il post some pics of the car soon
 

greenlx777

BigRed is Dead
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#2
check n see if your throwing any CEL's

also check to see if the guy you got the car from didnt pull the engine light bulb
 


Eran

It's on ass-backwards.
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#3
Um .... you're running a 4" straight through exhaust?

Bingo.


A honda should run anything over 3" in the most extreme cases of modification (massive turbos)..... and for a mild/stock, you should run no bigger than 2 1/4"
 

greenlx777

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#4
4" woboy, didnt see that
 


5thGenCX

long gearing owns me.
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#6
:no:

Remove that exhaust and replace it with something with no more than 2 1/4" piping like Eran said.

Unless (just to be sure) you aren't talking about just the tip of the exhaust?
 

markz1986

New Member
5+ Year Member
#7
sorry yea its a 4 inch tip, the backbox i have is this one,

http://www.funkypower.co.uk/catalog...l2=BOLT-ON+BACK+BOXES&level3=&id_product=1300

all the rest of the exhaust is standard, there are no CEL's and when i switch the ignition on they all light up briefly so i dont think theyve been pulled out, and i have had the engine checked but noone can find anything wrong so do you think its the wheels or the exhaust?


cheers
mark
 

manu

New Member
5+ Year Member
#8
when I had 17's on my mileage went down but not by that much... How old are the ignition system components, fuel filter, fuel injectors?

The reason that you would get worse gas mileage with 17's is that you get less torque because the increase in tire size. plus your spedometer and mileage counter is diferent too so when it says you have travelled a mile you would have travelled a different amount depending on the factory tire size which the spedo was caliberated to. Hope this helps
 

stolibears

Use your dipstick Jimmy!!
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#9
also keep in mind, if you haven't gotten your seedometer re-tuned to compenstate for the larger rims and tires, your odometer is also going to be off when your doing the math to get the gas mileage.
 

manu

New Member
5+ Year Member
#10
drive a pre measured distance from point A to B and see how much your car is off by, then youll know if your car is actually getting bad gas mileage or not
 

markz1986

New Member
5+ Year Member
#11
hi i checked on the tire calculator and the speedo is only off by 3 percent so not worth geting adjusted, which also means the odo is off by 3 % - which i have added to the mileage shown at the end of the tank, will check the injectors ect

cheers
 




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