roundle

Hi All,

Please help me improve my spare car's mileage.

I have a 1999 Civic LS VTEC-E automatic (D15Z8, European Model) with about 130K KMs.

I am getting about 250-275 KMs per tank. While the car only does city miles, I feel like I should be getting MUCH more from a single tank.

The car runs and drives very well. No check engine lights or anything like that. Green "VTEC" light comes on when the car is driven gently (once warm, of course) so I assume that the VTEC-E" is working well.

I have owned the car for 3 years. Aside from tires, brakes, exhaust, alternator, air filter, and annual oil change (I do about 5K KM per year), I have never done any service.

Any suggestions re what I should do to improve my mileage?

Thanks!
------------------------
*D15Z8
+ Displacement : 1493 cm³
+ Bore and Stroke : 75 mm X 84.5 mm
+ Compression : 9.6:1
+ Power : 84 kW (114 hp) @ 6500 rpm
+ Torque : 134 Nm (95 lb·ft) @ 4500 rpm
+ VTEC Switchover : 4700 rpm
+ Valvetrain : SOHC VTEC-E (4 valves per cylinder)
+ Fuel Control : OBD2 MPFI
*https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/honda-d-series-engine-2409260/

NotARaCist

iTrader: (1)

Spark plugs, wires, ignition cap, and ignition rotor are where you need to start. You should also look into having your injectors professionally cleaned. Also, check your ignition timing.

roundle

Thanks NotARacist.

What about my thermostat, if it were stuck open, would this impact MPG as well? How quickly should the car warm up, and where should the thermo gauge sit?

NotARaCist

iTrader: (1)

Yes, a stuck open thermostat would decrease gas mileage as well. Warm-up time depends on couple factors, and I don't think the FSM specifies a certain amount of time - it usually just says "let the engine warm up". The temp gauge should sit just a hair lower than half.

BeatDX

iTrader: (1)

Yeah, assuming you have a 45-60 l (12-16 gal) tank and only getting 150-175 mi. per tank, that's terrible mileage. I would do a timing belt and water pump as well it should be due for one. You might want to check to see if your catalytic converter is good. They can become obstructed and cause problems as well.

Even my lead footed kid gets 275 mi out of our 12 gal tanked d16y7.

dake7

Replace Oxygen Sensor....

If your European D15Z8 is similar to our USDM D15Z1, then you might have a factory wideband..... so it might be pricy, but is needed for lean burn to work....

Even if it does not have a factory wideband, the sensor can be bad and not throw codes and will definitley affect fuel consumption...

HTH

roundle

Thanks guys. It's off to the dealer, as finding these parts in Europe online is shockingly difficult.