boredguy77

I finally completed my car and am driving it daily. I still cannot boost because Turboboss.com is the worst company on earth. The guy promised me he would finish my i/c pipes two sat. ago, but still no pipes. There is one cool guy there, but the rest suck. Anyway, after driving around for a couple of days, MY check engine light came on. I checked the code and it is code 25. I figured it was because I had not connected the removed o2 sensor with the one on the downpipe. so I connected The two ports on the pic and reset the ecu. yesterday the code came on again, and it is 25 again. can you guys verify the way I have connected the two ports? All I used was a straight wire from on to the other.

boredguy77

pic would help

Bean

iTrader: (1)

scott will chime in any moment; but i plan on doing it at the ECU...

siniquezu

I looked up a diagnostic code 25 and the manual says that it's a lean air-fuel mixture.

boredguy77

It also pulls that code when both of the main oxygen sensors are not within 20% of eachother.

Bean

iTrader: (1)

maybe the connection is bad or something?

SC300T

Did you accidentally short one of the two 02 sensor leads? The two 02 leads going to the stock sensors are COAXIAL. If you just cut them, you'll short them to ground. There are two conductors within the wire that looks like a single conductor. You can verify with an air fuel meter or a volt meter connected to the appropriate ECU leads. You should be getting a fluctuating voltage when the engine is under load. If a sensor is just lazy, the voltage may not change much at idle or may change very slowly. Code 25 would result from a two time event within the ECU. When running at freeway speed for a certain period of time, if the ECU doesn't detect a voltage swing, it stores an error. On the second time this event happens, an error code will result in the MIL and a code 25. You may not get this code if you just run small trips around town and idle frequently. To get the code, the engine must be running a certain rpm over a certain period of time (don't remember specifics). At any rate, the single sensor is intended to feed both front and rear 02 signals to the ECU via parallel connection. That way both 02 inputs to the ECU see the exact same signal and everything stays in check. Right off hand, I don't remember what pins on the Diag. connector correspond to the front and rear 02 signals, but just make sure that the lead that remains unconnected to the harness is indeed not grounded and that the lead that is connected to the existing 02 sensor on the downpipe is indeed feeding voltage to that terminal.

boredguy77

I finally figured out the problem!! why does it always seem that the most complicated problem has an easy as hell answer? I undid my connection of the diasgnostic port, and did it at the ecu, still check engine code. checked to make sure unused plug wasnt grouned, which it wasn`t, so I ran out of ideas. pretty soon I was desperate. Finally it dawned on me to check that the oxygen sensor was plugged in. I guess the exhaust shop I took it to forgot to plug it in. So on to my question, will the fact that I ran my car for over a week without any oxygen sensors hurt the engine? I never raced or got on it, and only occasionally reved it up to 3.5-4k to hear the turbo do you think that the computer just richened up the mixture when it was not getting response from wither o2 sensor? Should I run a compression test or similar?

Bean

iTrader: (1)

no; the ecu would have run off of its stock maps which are rich and with less timing