Civic EG

Hey guys, I have 94 civic hatch with D15z1 engine. When I accelerate, 1st and 2nd gears go smoothly but the engine kind of chokes and has lack of power in the 3rd, 4th and 5th gears. some people say it's because of o2 sensor, some say it's the catalytic converter and I was also thinking about reprogramming the whole car computer so the fuel/air mixture is well selected by the computer next time.. Or maybe I should just take the converter out and leave it like that, (don't worry about emission controls) I don't know, can anyone tell me what can be done to fix this? thanks

if your engine is stock, the stock computer is going to control everything way better than you could.

is your check engine light on? if so run the codes.

my buddies EF had a similar problem... it was just down on power and turned out to be the cat was clogged up. looked pretty nasty inside. he punched it out and it made a huge difference. just take it off and take a peek inside

Yes, it's got stock engine and computer in it. As for check engine light, it's not on when the sensor is plugged to the computer but the engine almost dies in that case and when I plug it off, then the light comes on and the engine runs well, (that's how I drive, with the sensor plugged off) but the fact that it's like that, still bothers me. I'd buy a new sensor but it needs 5 wire one and they cost more than 200$ and that's why I was thinking of removing the Cat converter. If the CEL isn't on, doesn't that mean that the sensor is good?

Wow.... I feel horrible for your motor

The o2 sensor is what the ecu reads from to determine the f/f ratio, telling it how much fuel to dump into the motor. By running with the o2 sensor unplugged, your ECU us freaking out, not knowing what to to, probably dumping tons of extra fuel to compensate.
Buy an o2 sensor and plug it in, there's no way around it. I would not drive the car until you do so.
By running rich, youre dumping excessive fuel in, running rich, destroying the cat. If you happen to run lean, that's when shit starts to go boom. Yeah the 5 wire o2 is a couple hunderd bucks because it is a wideband o2 - even more reason not to run without it.

if the CEL is not on when the sensor is plugged in then its not bad.

unless there is a possibility that there is a problem with it that wont throw a code... is that possible Teal?

Oh, I read the post wrong....
Even if the CEL is not on when the o2 sensor is plugged in, the o2 can still be going bad. I had this happen on my car and couldn't figure out what was wrong so I put in a spare o2 and problem was solved.

Thanks for the advices guys. just few more questions:

1. Does the new sensor definitely have to be a 5 wire one?

2. should I get it from ebay or there's a better way to get it cheaper?

3. As I'm guessing it's not the cat that causes all the problems right?

The D15z1 uses the 5 wire, gotta empty the wallet for another 5 wire. The 5 wire is wideband & is much more accurate than the 4 wire. The ecu for D15z1 needs it.
OEM is always the best route, but understandable you might not wanna spend $240+ at the dealer. Ebay should be ok, just be sure it is the 5 wire and not the 4 wire (sellers will list the 4 wire as being for the VX because they don't know better.)
You'll probably be close to spending $200. I searched quick and the cheapest I found on ebay is $189.

Not sure if you have caused damage to the cat yet or not from driving with the o2 unplugged.... only way to tell is to take it out and look inside or fix the o2 and see if it is better.

http://ecomodder.com/forum/showthread.p ... 21933.html

http://www.gassavers.org/f7/civic-vx-ox ... -6448.html
(learned from this link that California VX models got a 4 wire o2)

http://honda-tech.com/showthread.php?t=2893596

Found those real quick on google