matpl500

The coupe i just bought with a b16 motor and gsr tranny has no cat. my gas is being eaten up like crazy. is a tune needed? or i cant really do anything about it?

grumblemarc

iTrader: (4)

Maybe you need a cat. What else is missing? O2 sensors?

matpl500

it has a sensor in the header but no sensor for the cat. there is no check engine light however. this is why im confused on wether i need a tune or not.

grumblemarc

iTrader: (4)

Year? Is your ECU chipped?

matpl500

i have a 97 coupe.I do not know if the ecu is chipped. I bought it like this from a dealer and they said the b16 came out of a 1999 si. Would i be able to buy a cat and a sensor for after the headers? i cant keep buying gas like this.

grumblemarc

iTrader: (4)

OBD2 is supposed to run 2 O2 sensors so I would say yes. How are you not throwing a CEL? Is the CEL light working? If the ECU is chipped already it might have the O2 eliminated.

matpl500

yes the c.e.l does work. When i turn the car on the c.e.l flashes so i know atleast its not pulled or anything

joshd95dx

iTrader: (1)

does the cel flash twice when you turn on the car?
I have a 99 Civic SI which is now OBD1 and does that.
So do you know which ecu is in the car?
That would give us a better idea of what it could be

TwoFaced

Yeah, find out what ECU is in the car and let us know.

Alot of the times dealerships have NOOOOOOOOOO clue wtf is going on with a modified honda.

There was one around here the dealership had gotten a hold, it had an ls with some turbo setup of some sort and a chipped p28. The dealership just knew that it originally had a y7 in it and assumed that's what it was so they advertised it as a turbo charged 1.6 liter...this was a suzuki dealership IIRC.

farfrumugen

if the car is obd2 you should have a pre cat and post cat o2 sensor. that way the ecu will read the gas and adjust your fuel accordingly. not the best for performance but best for gas mileage and emissions
adam jeffery

this only pertains to stock ecu's or chips running stock complete base maps.

matpl500

Thanks guys. I will look at the ECU 2morrow and i will give you all the information about it.

partsme

If its obd 2 and there is only one o2 sensor and no check engine light. I would take a scanner and plug it in and check if there are any codes. There is a good chance that the previous owner got sick of the CEL and just pulled it out.

grumblemarc

iTrader: (4)

Might want to read the whole thread. He already stated the CEL works.

sextav6

quite possible its an obd1, easy enough to figure out. what kind of gas mileage are you getting? if you're not throwing any codes, I would be doubtful that not having a second o2 sensor would be the cause of your mpg issues. even if you were throwing a code, it shouldnt grossly effect it

matpl500

on a full tank which is 12 gallons, i get about 220 miles city driving. Are there certain rpms i should be shifting at? Since the motor is 1.6L and the tranny is from a 1.8l?

sextav6

i have an Si(13.1 gallon i think) w/b18c and I usually get over 300 miles per tank of mixed driving. rpms have a definite effect on gas mileage, theoretically, gas engines get their maximum efficiency at half of the max engine speed. meaning, if you redline at 8K, your max efficiency is at 4K. but sometimes you shift early and sometimes you shift later, its very situationally dependent. needless to say you should be getting better fuel economy

farfrumugen

bump for waiting for ecu #

matpl500

i apologize. ive been so busy studying for midterms. Tomorrow i have a day off so i will check out hte ecu, get the number and get back to you.

SiRCiviC94

hahaha its because your b16 is running rich and needs a tune up and you like to shift around 4-5k. might be time for some new plugs and set up the timing

99gsvtec

Story of my life I get 220 per tank on my built gsr. Expensive fill ups with 91 Chevron hopefully my h22 auto accord will be a lot better

matpl500

Alright fellas i looked at my ecu and its a chipped P28 OBD2

grumblemarc

iTrader: (4)

OBD1. If it is chipped then you need to get your car retuned. The second O2 sensor isn't seen by the ECU-it isn't needed. Your car is probably running on a lousy basemap.

matpl500

how much does a tune cost? around? for a tune like this

grumblemarc

iTrader: (4)

Contact a tuner in your area. Did the previous owner not give you the history of the car? Plan on starting at $300 per hour. Are you running the right size injectors?

matpl500

the person who sold it to me was a dealer and a owned a garage but they were idiots and i doubt they knew what they were doing.