Could use expert opinion (lil long)

[bschucher]

Hi there... heres the story. Have a 98 MY with 30K miles.. Been having horn prob so last week i attempted to fix the horn. Disconnected batt but was unable to break lose bolts. Hooked battery back up and the car would start but bogged really bad. Had it towed into the shop. BTW... no CEL at this point. There was a CEL prior to disconnecting batt and IIRC it was P1128. Anyhow, garage calls me and tells me the car run fine after warming up and its not throwing any codes.. He ends up replacing some temp sensor and tells me one of my cats ir rattling pretty bad. Says its not the heat shield. I go to pick up car and it starts fine but does misfire and sound kinda bad for first several minutes.. On way home CEL comes back on. I take it to Advanced to get ODB done.. Its shows P1128, P1130 and pending code P0130 (o2 sensor circuit malfunction bank1 sensor 3. I went home and fixed the horn since i had the garage get me the part. Im gonna take it back in but do you think it could be as simple as a bad 02 sensor causing the cold start prob and it doesnt seem to have the responsiveness it did b4. Any thoughts and thanks a ton for ANY feedback..

Brian

Forgot to mention that is has also been running about 20 degrees hotter than it was...

Edited April 28, 2006 by bschucher

[Nick_USA]

Hi there... heres the story. Have a 98 MY with 30K miles.. Been having horn prob so last week i attempted to fix the horn. Disconnected batt but was unable to break lose bolts. Hooked battery back up and the car would start but bogged really bad. Had it towed into the shop. BTW... no CEL at this point. There was a CEL prior to disconnecting batt and IIRC it was P1128. Anyhow, garage calls me and tells me the car run fine after warming up and its not throwing any codes.. He ends up replacing some temp sensor and tells me one of my cats ir rattling pretty bad. Says its not the heat shield. I go to pick up car and it starts fine but does misfire and sound kinda bad for first several minutes.. On way home CEL comes back on. I take it to Advanced to get ODB done.. Its shows P1128, P1130 and pending code P0130 (o2 sensor circuit malfunction bank1 sensor 3. I went home and fixed the horn since i had the garage get me the part. Im gonna take it back in but do you think it could be as simple as a bad 02 sensor causing the cold start prob and it doesnt seem to have the responsiveness it did b4. Any thoughts and thanks a ton for ANY feedback..

Brian

OK when you disconnect the battery the engine loses the throttle placement settings and the octane rating of the fuel. So once you restarted the car before it had learnt these the engine would misfire. The correct way after reconnecting the battery is to turn the iginition on without starting the car for about a minute. After this the car should be run at idle until the revs settle. The fault codes are also lost when you disconnect the battery. However, there is problaly an underlying problem, hence the codes coming on. As for the other problems I'm sure someone else will chip in soon.

Edited April 28, 2006 by Nick_USA

[bschucher]

Yeah... im more concerned with the codes.. It seems there are several things it could be with those three codes... so far ive come up with air/vacuum leak, maf, and 02 sensor. Since it was running fine with CEL prior to batt disconnect, i have to guess not to the leaks.... Is it possible that the car worked out how to run with either a faulty MAF or O2 sensor and then when disconnect batt.. it cant do that now?? I'd hate to start part swapping to find out but that might be the only way..

Im starting to think there are only a cpl things this might be.. MAF, O2 Sensor or Cat.. Which should i try first???

Edited April 28, 2006 by bschucher

[Loren]

P0130 - Oxygen Sensor Ahead of Catalytic Converter (Cylinders 1 - 3) - Intercore Short Circuit or Limited Voltage Increase

Probable causes:

Bad Oxygen sensor.

Bad connection at O2 sensor.

Faulty DME.

P1128 - Oxygen Sensing Adaptation Area 2 (Cylinders 1 . 3) - Rich Threshold

P1130 - Oxygen Sensing Adaptation Area 2 (Cylinders 4 - 6) - Rich Threshold

This means you are running too lean on both sides of the engine.

Probable causes are:

Intake or exhaust leak.

Low fuel pressure.

Your misfires have cleared or there would be codes for them too.

What is wrong with your cat? Could it have damaged the O2 sensor?

I would take the readings again and see if they are consistent with what you have reported here.

Then if the P0130 continues then I would replace the precat O2 sensor on that side.

Drive the car for a couple days and see if the other codes come back too. If so, report them here.

[bschucher]

P0130 - Oxygen Sensor Ahead of Catalytic Converter (Cylinders 1 - 3) - Intercore Short Circuit or Limited Voltage Increase

Probable causes:

Bad Oxygen sensor.

Bad connection at O2 sensor.

Faulty DME.

P1128 - Oxygen Sensing Adaptation Area 2 (Cylinders 1 . 3) - Rich Threshold

P1130 - Oxygen Sensing Adaptation Area 2 (Cylinders 4 - 6) - Rich Threshold

This means you are running too lean on both sides of the engine.

Probable causes are:

Intake or exhaust leak.

Low fuel pressure.

Your misfires have cleared or there would be codes for them too.

What is wrong with your cat? Could it have damaged the O2 sensor?

I would take the readings again and see if they are consistent with what you have reported here.

Then if the P0130 continues then I would replace the precat O2 sensor on that side.

Drive the car for a couple days and see if the other codes come back too. If so, report them here.

Thanks for the reply. The drivers side cat is rattling... something not right inside i spose... is 1-3 the drivers side? Thats the side with the rattling cat? Are the 1128,1130 possibly a result of the 0130?? Thanks again and thanks for bearing with my ignorance with this...

[Loren]

In a Boxster, 1-3 are on the passenger side.

If the O2 sensor is bad then the other codes may or may not exist.