Hello, I have been getting a code 17 since I put my Jspec engine in. So, I put in a new O2 sensor. Still getting a code 17. Im wondering, the O2 sensor wire coming from the engine harness is shielded. Everytime i try to crimp a butt connector onto this wire, i get some of the shielding in the crimp. Is the outer shielding of the wire grounded? That would cause my problem wouldnt it? Let me know what you think. Thanks

 

Yes, the stock wire is shielded. It's likely you are crimping onto the shield, thus grounding the output of the sensor.

 

Thanks Aaron, thats what I figured. I guess I will just run a new wire from the ECU to the O2 sensor. The wire from the engine harness is getting too short to try to strip again.

 

A new shielded wire...

 

is the shielding THAT important? The wire on the O2 sensor itself isnt shielded. I dont have any shielded wire. Let me know, Thanks

 

Well, the RB header comes with a O2 sensor extension wire, and it isn't shielded. My car ran fine like that, so it shouldn't make a big difference. Just make sure you connect the wires right. Of course I don't believe in crimpers at all, but thats just me.

 

Ok, I opened up the loom where the main engine harness comes from the passenger side of the car up onto the engine... Got the O2 sensor wire out, and snipped it. Stripped the outer coating, back about 2 inches, and cut off all the shielding wire. Stripped the black inner wire, and connected it up to the O2 sensor and BAM, NO check engine light anymore!!!! Yay!!!

I did alot of reading up on O2 sensor issues, seeing if my code 17 could make the car miss and stutter at cruising speeds... Most of the gurus here said NO, it would only do that if the TPS was out of range. WRONG, mine sputtered, and hiccuped and then the check engine light would come on with a code 17 and would run even crappier once the light was on. Fixed the O2 sensor wire, and it runs as smooth as glass.

Thank you all for your help!!

 

The O2 sensor generates very low voltages (<1V) so it's susceptible to the effects of electrical interferance. This interference will alter the voltage seen by the ECU (and A/F gauge if you have one) and hence give an inaccurate reading. The greater the length of the unshielded section, the more interference that can be picked up. It's most important close to the alternator and spark plugs, as these are the main sources of interference.

Removing a short length of the shield is no big deal, but replacing the whole wire (as you suggested) with unshielded wire wouldn't be advised. If it wasn't needed, it wouldn't be there in the first place.

Good to hear you got it fixed though.