Boxster 2.5 1999 o2sensor trouble

Zakman1111 · 09-07-2011, 07:17 AM

Just bought a 99 Porsche Boxster...got a good deal and have been fixing minor things...but I need some help and thought this was a good medium for advice. I was getting rough idle and noticed the tube was leaking between the AOS and the crank case so I replaced it. The car now runs smoothly, but I just got 6 more codes. They are:
P0151 Oxygen Sensor Ahead of Catalytic Converter (Cylinders 4 - 6) - Signal Wire Short Circuit to
P1115 Oxygen Sensor Heating 1 After Catalytic Converter - Above Upper Limit
P1117 Oxygen Sensor Heating 1 After Catalytic Converter - Below Lower Limit
P1119 Oxygen Sensor Heating 2 Ahead of Catalytic Converter - Below Lower Limit
P1121 Oxygen Sensor Heating 2 After Catalytic Converter - Below Lower Limit
P1130 Oxygen Sensing Adaptation Area 2 (Cylinders 4 - 6) - Rich Threshold
I have cleaned the MAF sensor...do you think I need a new AOS or CAT??? New sensor Bad or wired incorrectly?
It appears the previous owner replaced the O2 sensors (all 4) with generic sensors because he was having O2 sensor check engine light problems also...we purchased it with this problem.
Any help is greatly appreciated.

paulv · 09-07-2011, 09:03 AM

Start troubleshooting the P0151 (cyl 4-6) code first -- this code gets set when the sensor voltage is below 0.150 volts:

1) Short circuit of signal wire to the ECM ground or housing ground. When this happens, P1115 & P1119 are stored but are not faults.

2) Short circuit of sensor ground to the ECM ground or housing ground. When this happens, all four sensor codes are stored.

3) Short circuit to ground at the ECM.

Good luck -- sent you a PM.

Regards,
paul...

59coupe · 09-11-2011, 09:23 AM

I had similar codes thrown...replacing the AOS solved all issues...without the expense of replacing 02 sensors.
I am no expert...FWIW

Jared at Pelican Parts · 09-12-2011, 08:25 AM

What do you mean by "generic" sensors? Are they spliced in? How did you clean the MAF sensor?

Zakman1111 · 09-12-2011, 01:39 PM

I have been at this one for a while. Did the "tests" and everything seems okay. 444mv/719mv infin ohms on sensor. I hope it is not the ECU
I did pull the sensors and the Bank 2 pre and post cat had a little soot on them. Swiched them over to bank one today. Shortly after start up I got stored codes p1115 and p1119 I'm sure the rest will follow (not check engine light yet)
Sensors when monitored do seem to react.

For other reasons and maintenance, I have replaced the:
Coil Packs
Spark plugs
Spark plug tubes and seals
Air filter
Cleaned the MAF with MAF Cleaner....wouldn't that affect both sides?
AOS lower tube (thought it could be AOS but only bank 2 seems to be rich or have black soot on the sensors) Thought that would affect both banks.
Things seem to be very sealed up. Removed oil cap.... got reaction....opened intake hose....got reaction.

I am thinking that maybe the sensors are incorrect...would that cause the codes to come up and run rich in Bank two? The sensors are spliced in and seem to have diff numbers on them .....017...357 etc..
Could the AOS be failing and only dumping into one side?

Thanks any help would be great!

Jared at Pelican Parts · 09-12-2011, 01:50 PM

The spliced sensors are the problem. You need to use the factory sensors. From the factory manual

“911 Carrera 4 has a new, water-proof oxygen sensor. Water-proof means that the upper sensor section and housing are connected leak-proof with a later welded seam and previous reference air openings are omitted. Reference air is now taken via the connecting lead and plug connection. For this reason it is important to keep contact solutions, lubricants, liquids or similar products out of the 3-pin plug, since they would lead to sensor failure”

We ran into this problem on our own project car after trying to used spliced sensors as well.

Zakman1111 · 09-12-2011, 02:15 PM

Thank you! I will be ordering tonight! I hope it solves the problem!

Zakman1111 · 09-15-2011, 06:07 AM

Sensors went in yesterday and NO CODES! Spliced and aftermarket o2 sensors do not work!
Now it might be a little early to tell if all the problems are gone but before I had a few o2 heating codes stored at star up. The rich fuel smell is also gone.

Thank you Jared and Paul for the help!

What do you think of the injection cleaning kits (air operated, runs off Inject-R-Kleen)? My friend has one and says it works wonders but I am a little hesitant to try it.

paulv · 09-15-2011, 07:12 AM

Quote:

Originally Posted by Zakman1111

Sensors went in yesterday and NO CODES! Spliced and aftermarket o2 sensors do not work!
Now it might be a little early to tell if all the problems are gone but before I had a few o2 heating codes stored at star up. The rich fuel smell is also gone.

Thank you Jared and Paul for the help!

What do you think of the injection cleaning kits (air operated, runs off Inject-R-Kleen)? My friend has one and says it works wonders but I am a little hesitant to try it.

Zak,

You're welcome -- glad to hear it's fixed. As far as cleaning injectors, the best way is to remove them and send them to a specialized cleaning service (approx $100). If you decide to do this, bag each injector separately and label which cylinder they're from. There are several cleaning systems that run off of shop air and I haven't heard any complaints about them. They basically work the same -- make sure you follow the instructions (e.g., disable the fuel pump, seal off the fuel lines, etc.).

Regards,
paul...

Jared at Pelican Parts · 09-15-2011, 07:39 AM

Quote:

Originally Posted by Zakman1111

What do you think of the injection cleaning kits (air operated, runs off Inject-R-Kleen)? My friend has one and says it works wonders but I am a little hesitant to try it.

The only way to really clean injectors is to remove them from the car and have them ultrasonically cleaned.

Zakman1111 · 09-28-2011, 12:18 PM

Problems solved! Generic o2 sensors do not work on Porsches. Only oem (for searchers)
Thanks again everyone! No more codes and I have driven the crap out of it. Runs smooth and gas milage went way up!
I am installing adjustable coil over suspension (bought the car lowered....way to low), new control arms, new tie rod ends as well as a full NHP exhaust next week. Tie rod ends might not be ness but while I have it apart.
I will start a new topic but I am stuck down here in south texas and will be needing an alignment after the parts are installed. Do you think Firestone can handle it....if I give them the specs? I hear the guy is pretty experianced. I am thinking -1.9 rear camber and 1.0 Front. Slight toe in in the from 0 in the back. Maybe -1.9 is too much?? Stock tire size. New Classic 1 chrome wheels 17x7 and 17x8.5. I will not be driving it everyday but when I do I play hard.