Fuel efficiency degrading

[Ozwolfbane]

Hi,

MY Prelude fuel efficiency has been degrading slowly....I am using 10w 30 oil , i am not lead footing it or anything....what things can i get checked out ?? its gone from about 10km/l to about 8k/l now !!!

Its a 1993 4th Gen with a JDM H22a

ta

[bennjamin]

replace spark plugs , airfilter , fuel filter...change fuel type...maybe o2 sensor is buggerered / catylic convertor is gone.

any smoke or soot on the rear bumper ?

[SINISTR]

Throttle Body Clean!

if you haven't had that cleaned for a while, there are carbon deposits around the butterfly preventing it to close properly - so during idling its using a bit more fuel than it should as a compensation for the extra air that its getting.

once you do the clean - don't expect for have an immediate change in consumption - it will get better after the 2nd tank tho.

Also as Benn said - plugs, filter etc is also essential for a good burn!

[Ozwolfbane]

replace spark plugs , airfilter , fuel filter...change fuel type...maybe o2 sensor is buggerered / catylic convertor is gone.

any smoke or soot on the rear bumper ?

Plugs are NGK Iridums last 100'000ks used maybe 10'000 so they should be alright , filter is K & N panel filter i'll clean and re-oil it ,
what affect does fuel filter have on fuel efficiency ??

nah no soot....how do i know O2 sensored is buggered ??? Engine light turns on when faulty ??

Whats a throttle body clean and how much is that ? My car idles at 700 RPM,

[SINISTR]

Yeah - if the O2 sensor goes you will get the engine light on and the car will drive like a snail!

Throttle body clean is a simple operation.

this is a DIY taken from WAHONDA - thanks to the author INTEGGRA

http://www.ozhonda.com/forum/showthr...ottle+body+diy

*edited link for 56k's sake!*

[bennjamin]

Plugs are NGK Iridums last 100'000ks used maybe 10'000 so they should be alright , filter is K & N panel filter i'll clean and re-oil it ,
what affect does fuel filter have on fuel efficiency ??

nah no soot....how do i know O2 sensored is buggered ??? Engine light turns on when faulty ??

Whats a throttle body clean and how much is that ? My car idles at 700 RPM,

A diry air filter OR clogged/old fuel fitler or o2 sensor etc all decrease efficiency. Your ECU will probably run richer giving less k's to a tank.
To clean the throttle body ~ look at this DIY - its relevant.
http://www.ozhonda.com/forum/showthr...ottle+body+diy
Cleaning the throttle body removes carbon build up on the throttle butterfly.

[luggie]

Be sure to check your tyre pressures also... shoot for 35-38psi

Hi,

MY Prelude fuel efficiency has been degrading slowly....I am using 10w 30 oil , i am not lead footing it or anything....what things can i get checked out ?? its gone from about 10km/l to about 8k/l now !!!

Its a 1993 4th Gen with a JDM H22a

ta

[Limbo]

As above & Check your timing also.
How old is the battery? i've noticed on 2 different cars i owned that after i did a complete service and cleaned the injectors etc... i still had incresed fuel consumption.

Then the battery died and i got a new battery the fuel consumption actually improved. Prob. gives better sparkage to the plugs or something. Just something i picked up and might be worth a shot.

[aaronng]

A 93' on the original fuel filter is trouble. I pulled off the fuel filter from our 94' accord and the filter was gelled up. After replacing it, engine had more power at high loads. I suspect fuel economy will improve since the engine efficiency at high loads (standstaill starting, uphill, freeway acceleration) increased on our car.

[spetz]

As above & Check your timing also.
How old is the battery? i've noticed on 2 different cars i owned that after i did a complete service and cleaned the injectors etc... i still had incresed fuel consumption.

Then the battery died and i got a new battery the fuel consumption actually improved. Prob. gives better sparkage to the plugs or something. Just something i picked up and might be worth a shot.

I think maybe with a new battery there is just less drag/draw from the alternator?

[saxman]

check the pcv valve