Ok need a some help on what are possible causes of my bad fuel mileage.

[classiccelica]

Ok well being a new father of only one week and one day I have no more brain left over for automotive diagnosis right now. I need some help from my brothers and sisters here at ephatch for my terrible fuel mileage. I am averaging in town very limited highway usage 20 mpg. I have the following mods: Injen sp1576 3" cold air intake heat wrapped, rsx-s specific dc shorty header, stock catalytic converter, greddy evo2 cat back with exhaust leak, 2003 rsx-s six speed with 05 type-s clutch and 10.25 lb flywheel, light wheels with 32lbs of air in the tires. Alignment is correct as well. Have at this, I need some help here.

P.S. I am at around 99670 miles on the original engine.

[FoReVaPmP]

Do you haz K-pro????

[classiccelica]

I used to and got wicked awesome mileage with my street tune I did. I used to get 34 or so city and 40 highway. Now it has the stock ecu but will be getting the reflash treatment in a couple weeks.

[27rocks]

It could be a number of things... driving style, weight in car, spark plugs, bad gas, oil condition etc.. everything added up will hurt your mileage significantly.

[classiccelica]

I use castrol but this time around I put in quaker state, brand new plugs, I drive very softly right now as my 8 day old always rides with me, and the weight is stock as nothing is removed except those heavy ass stock wheels. I put in a fuel system cleaner about a month ago and it seemed ok for a while but power seems down and definitely is not getting good mileage.

[27rocks]

hmmm... maybe its time for a valve adjustment??? I have no idea why it would get such horrible mileage. You obviously dont have a CEL so i have no idea.

[ImportCustomx]

I used to and got wicked awesome mileage with my street tune I did. I used to get 34 or so city and 40 highway. Now it has the stock ecu but will be getting the reflash treatment in a couple weeks.

you just solved your own problem...took out k pro..

once you took out kpro you got shitty mileage..

pretty self explanitory...Kpro was optimizing everything and tuned properly, now its thinking it has stock everything and trying to run it that way so its constantly correcting a/f and injectors etc...your car is thinking to much and just adjusting too often and there ya go. shitty gas mileage becuase its getting all fucked up.

reflash and get it done right or get kpro again and you will be back to normal

if not,

check your plugs, tranny fluid, oil, double check alignment and 32psi on what type of wheel and tire?

[Heitzke]

Are you still on your original primary 02 sensor?

you just solved your own problem...took out k pro..

once you took out kpro you got shitty mileage..

pretty self explanitory...Kpro was optimizing everything and tuned properly, now its thinking it has stock everything and trying to run it that way so its constantly correcting a/f and injectors etc...your car is thinking to much and just adjusting too often and there ya go. shitty gas mileage becuase its getting all fucked up.

reflash and get it done right or get kpro again and you will be back to normal

if not,

check your plugs, tranny fluid, oil, double check alignment and 32psi on what type of wheel and tire?

That doesn't explain for how bad his current gas mileage it. He has very normal bolt-on's and shouldn't cause for the mileage to be this rough. When I had full bolt-ons with the stock ECU, I was still able to get mid-high 20's with mixed driving without issue.

[classiccelica]

Yes I am on my original o2 sensor. Could that be going out and causing a mis-read in the system there? I will be checking the valve lash probably tomorrow. What are the specs for the valve lash? 0.10 intake and 0.18 exhaust?

[ImportCustomx]

just reread OP's post...Heitzke is right..basically you have a header, stock cat, greddy exhaust with a leak...

you should be getting okay mileage..

i didnt even think about the 02 sensor either... i would take a peek at that as well.

[27rocks]

Yes I am on my original o2 sensor. Could that be going out and causing a mis-read in the system there? I will be checking the valve lash probably tomorrow. What are the specs for the valve lash? 0.10 intake and 0.18 exhaust?

Intake: 0.21-0.25 mm (0.008-0.010 in)
Exhaust: 0.28-0.32 mm (0.011-0.013 in)

[classiccelica]

Intake: 0.21-0.25 mm (0.008-0.010 in)
Exhaust: 0.28-0.32 mm (0.011-0.013 in)

Thank you for the specs. I have the pdf manual but I can't seem to find valve adjustments in there.

[classiccelica]

just reread OP's post...Heitzke is right..basically you have a header, stock cat, greddy exhaust with a leak...

you should be getting okay mileage..

i didnt even think about the 02 sensor either... i would take a peek at that as well.

Yes I just have basic bolt ons as of right now, except for the 2003 type-s six speed, which should show me a little better mileage as well. Intake, header, catback nothing super special yet.

[classiccelica]

Does any one know if there is a way for me to check the primary o2 sensor so I don't purchase a 200 dollar part and it turns out that's not it. The little velocity stack looking plastic pieces to the injectors were all broken off when I checked the injectors would that mess it up as well? I have another set of stock injectors ready to put in but I need to make sure they are clean and have the proper spray pattern before I do so.

[classiccelica]

Bump