I am getting a CEL it throws a 1 code which is primary o2 sensor, I went ahead and replaced the o2 sensor but I still keep getting the CEL, anyone have any advice on what i should do next, this is on a 90 civic with a pr3 computer and a b16. Also the CEL comes on and stays on even before i start the car, i've un hooked the battery and the ecu and then conected everything after installing the new o2 sensor and it still throws a code. please help.

 

Get your battery tested. THe same thing happened to me and it ended up being the battery.

 

How could it be the battery? I don't see the logic

 

I didn't either, but that's what it was, after I replaced the o2 sensor. I guess the o2 sensor wasn't getting enough voltage and the ECU saw it as a bad signal? Just trying to help.

 

see your point but the motor cranks over just fine and it even starts, but just runs shitty

 

That's what mine did, too.

 

anyone else have an idea

 

check wiring

 

make sure you dont' have any exhaust leaks...

 

here's the main things to check before you go ahead and change your battery, I really dont see the logic behind that...but who knows sometimes things dont have logic

could be fuel pressure...swap your fuel pressure regulator
check the ground on the thermostat housing...

those are the two main things

|eb_CRX

 

why would it be the fpr?

 

battery is less than 2 months old and i just checked it, 11.83 volts. is the o2 wire supposed to have power running thru it, how does the ECU know to throw a code is it when voltage drops?

 

not shure...just one of them things, the o2 gives reading as to how it's burning, maybe it's reading too much fuel, triggering a code...honestly I am not shure but I know it has something to do with throwing code1 sometimes

|eb_CRX

 

no the O2 has no power running through it...it 'creates' (bad choice of words, I know) power ranging between 0-1volts and returns it to ECU....well if the o2 is not sending anything back it's clearly dead, flags it as a code1

check the thermostat ground

|eb_CRX

 

are you talking about a ground strap?

 

A good battery at rest should have about 12.66 VOlts, if it is only 2 months old and it only has 11.8 volts, there is either a problem with the battery, alternator, or ground. And a 4 wire O2 sensor does have power going to it for the heater.

 

do you have BOTH o2 sensors installed and wired properly??

 

it could possibly a problem if you have a A/F gauge. My car does the exact same thing. The A/F gauge is taking the 1 volt required to send the message to the ECU.

Good Luck.

Blaze

 

did you replace the right sensor? maybe you repalced the secondary O2 sensor?

how did you tell the two appart???

t..

 

i replaced the first 1st o2 from the manifold, just thinking that it was the wrong one i switched the wires to make sure, also the battery was at 11.8 something volts with the car not running, i start it and it reads about 13 volts. I don't have a a/f ratio gauge so i don't see that as being a problem. This happened after I did the ITR manifold swap, if that has anything to do with it.

 

so you swaped an ITR exhaust manifold?

???

t..

 

no the intake manifold, sorry i should have remembered

 

ttt

 

If the car is only at 13 volts running, you need to go get your charging system checked out. Pep Boys and Autozone will do this for free.

 

it varries from 13 - 15 volts if i remember correctly at least that is what the turbo timer reads