johnmasters

OK, my engine light comes on religiously after warming up and driving for about 18 minutes. It stays on until restart and does the exact same thing everytime. The engine codes pulled are 15 & 17(O2 sensor & Feedback sytem)

I installed a new Bosche(couldnt find an NGK) universal fit O2 sensor about one month ago after getting an intermittent engine light at high speed(Code 15). The new o2 sensor got rid of the code.

I have read all of the postings about the possibility of a bad O2 wire.

My question is, Does the consistancy of the engine light explained above tell you anything? If the wire was bad would the light not stay on? Could the Bosche have gone bad already? I just did some work under the hood(New pressure sensor for one) and some of the air intake was screwed up so I just put a cone filter on the AFM for the time being-thus making what would appear to be a HOT air intake- would that cause the engine light?

Any speculation would be appreciated.

andrew lohaus

its possible the exposed wire is ok, but the solder conection inside the ecu or some other point in the wiring harness is going bad, since this happens for various other things. id figure out which trace on the board coresponds to the O2 sensor (sorry i cant tell you myself) and check for continuity.

when my 02 whent bad a few years ago, the check engine light would only come on occasionally also, so its likely its not working at all from some sort of bad connection.

johnmasters

Follow Up...

Although I have done nothing yet, I plan on changing to an NGK O2 sensor(since some of you report that Bosche kicks out a #17 engine code when used) and running a new wire from the O2 sensor to the ECU.

BTW... The engine light only comes on religiously while driving at speed on the highway after about 18 minutes. It DOES NOT come on while driving around the city at lower speeds. Does this mean anything to anyone? Can anyone explain in detail exactly how the O2 sensor works and when it is being used by the car/ECU?

Thanks!

coldfire

iTrader: (1)

it sounds like the closed-loop operation is not working correctly.
you only enter closed loop at cruise (low throttle under a 3500 rpm or so).
this is really the only time the O2 sensor is being used; what happens is that the ECU tries to maintain a stoich voltage reading from the sensor.

- Aaron

johnmasters

Does any of this info help in understanding why I am not entering closed loop?

-New Bosche O2 Sensor
-New Pressure sensor(Due to engine code #13)
-New cone filter(But without cold air box arround it, yet)(IE: Hot air intake)

HAILERS

I use a BOSCH on all my cars and have had NO problem with the car going into closed loop ever. I'm talking the 20 buck Bosch single wire 02 sensor.

The cone filter has nothing to do with your problem. The new sensor should not be a problem unless you have one for a turbo and you own a non turbo or vice versa, THEN I think you would have a problem. Most probably would. Make sure you have the right boost/pressure sensor AND that the 02 sensors output wire is not grounding out due maybe a strand of the shield touching the center conductor.

johnmasters

Will DO!

The pressure sensor is certainly the correct one as I made sure to buy one from a rotary guy and all of the numbers on the sensor are the SAME as the one replaced and the code 13 went away.

Thanks!

johnmasters

Also,

Pardon me if I missed this in the postings regarding running a new O2 wire to the ECU...

What type of wire should I use?

Thanks!