95 GSR B20VTEC

Hey guys,

I've replaced the exhaust manifold on my 97 DX with one from an EX. As some of you know, the DX manifold has the cat built in, and the EX does not. So at the moment I am catless. Both manifolds have 2 bungs for o2 sensors, the difference is the DX manifold has one sensor going into the cat, and the EX has no cat. So even though i've connected both o2 sensors to the manifold, i am throwing a CEL.

Does anyone know how to remedy this? What do people do when they get exhausts or run testpipes without cats? Any feedback is welcome.

bsmith100

You can either get a test pipe that has a threaded fitting for an oxygen sensor, or ignore the check engine light.

95 GSR B20VTEC

Will the CEL affect my gas mileage in any way?

KillBot

What CEL code do you have?

95 GSR B20VTEC

02 Sensor code

KillBot

Relpace the o2 sensor...might have got damaged when swapping manifolds.

Swap manifolds/swap o2 sensor...its like changing a timing belt and not changing the water pump.

My JDM EJ8

cel wont effect you gas mileage but running no cat. will because thats one of the things that control the air/fuel ratio. Just get a Cat. and extend your O2 sensor

silentone

iTrader: (1)

i mentioned in your other post, that you can just hang your second o2 sensor safe somewhere with zipties and leave it connected. if it doesnt read bad exhaust gases, it wont give you a code.

EJ8_Enthusiast

ive heard similar accounts - but you need to protect it from climates/rain/moisture/etc if tucking it under your car.

if the CEL doesnt bother you - dont worry about it =/

silentone

iTrader: (1)

yehhh...mine was tucked in the engine bay, i just neatly wrapped the wires and ziptied it to the first sensor's wire.

bsmith100

It should not have any impact on fuel consumption.

I know Skunk2 has a test pipe with the fitting for an oxygen sensor installed in it.

There are probably other companies that sell them as well.

That would be the easiest solution.

http://www.skunk2.com/exhaust-2.php?code=EXTEST

DCSportEJ1Civic

the reason for the cel is the secondary 02 sensor. the purpose of it is to read the exhaust AFTER the cat. this is only a test of the cat. the primary o2 is before the cat and reads the exhaust before it goes though the cat. the cel will not effect you fuel mileage and its purpose is to let you know your cat is working. ive had the same set up with running no secondary o2 at all. only the primary and my fuel mileage is great. imo i will be getting a new cat soon, because i dont like how loud my car is. plus if i ever sell it it wont pass e-check. but if you dont have to worry about that it will not effect the drivablity at all.

95 GSR B20VTEC

Cool thats exactly what i wanted to hear.

So if i leave the second o2 unplugged i wont throw a CEL?

DCSportEJ1Civic

yes it will throw a code. but only because its unplugged. if you dont have echeck and dont mind looking at your cel light on dont worry about it. it will not effect how the car drives. to be quite honest even if you did hook up you second o2 with out the cat it will probably still throw a code because it thinks either the cat or o2 isnt working. the secondary o2 is supposed to pick up after the cat. the cat converts certain gases into not so polluting gases and water.if they both read the same the ecu will think the sensor is wrong or the cat isnt working and still throw a code.

reaction360

you could also get an O2 simulator for the 2nd O2 to keep that light off.

95 GSR B20VTEC

I see, as long as it doesnt affect my mileage i dont mind. But id really like to get rid of the CEL if possible.

Ive heard of those but never actually seen them. Where can you find something like that.

DCSportEJ1Civic

yea i know what you mean. if i ever get time i need to put a cat on my car. its brand new just layin around lol. but school and work kill most the hours in my day.

95 GSR B20VTEC

i think my only chance of getting rid of the CEL the right way, is to get an EX cat & midpipe. If anyone has one they want to sell let me know