O2 Sensor Readings - P1125 and P1132 and Other Readings

[yummyporsche]

Running into DTC's in pending for P1125 and P1132 and can't get the I/M readiness monitors for emissions testing. DME 7.2. Driven this thing a lot trying to get emissions going, but decided to get a scanner to check out the readings.

I got an Autel MD802 and got these readings in red:

O2 Sensor Bank 1 Behind Cat. Conv: R= 320 ohm , V = 0.7
O2 Sensor Resistance behind Cat. V. Bank 2: 192 ohm, V=0.7

Throttle Plate Angle Potentiometer #2: 1.6%
Carbon Canister Load 126.72
Engine Roughness Cylinder, 0.3 - 0.5 l/s^2

Other Information:

MAF: 5.7g/s

Seems unlikely that both my O2 sensors would be bad, or that both my cat. converters would be bad. What would cause the carbon canister load value high, and engine roughness cylinder?
+ also tried to take them off for cleaning but they're seized in there and can't get em out.

[blue62]

Originally Posted by yummyporsche

Running into DTC's in pending for P1125 and P1132 and can't get the I/M readiness monitors for emissions testing. DME 7.2. Driven this thing a lot trying to get emissions going, but decided to get a scanner to check out the readings.

I got an Autel MD802 and got these readings in red:

O2 Sensor Bank 1 Behind Cat. Conv: R= 320 ohm , V = 0.7
O2 Sensor Resistance behind Cat. V. Bank 2: 192 ohm, V=0.7

Throttle Plate Angle Potentiometer #2: 1.6%
Carbon Canister Load 126.72
Engine Roughness Cylinder, 0.3 - 0.5 l/s^2

Other Information:

MAF: 5.7g/s

Seems unlikely that both my O2 sensors would be bad, or that both my cat. converters would be bad. What would cause the carbon canister load value high, and engine roughness cylinder?
+ also tried to take them off for cleaning but they're seized in there and can't get em out.

Codes like the ones your getting are not immediately harmful to the cats.
So the first time an event happens that can trigger the codes.
The ECU stores the codes in it's memory (pending codes).
If the same type of event occurs on two back to back drive cycles the ECU moves the codes to permanent and turns your check engine light on.

If you have pending or permanent codes your I/M readiness monitors associated with the codes will not reset.

The codes your getting are indicating an overly rich fuel/air mixture
The voltage readings on the O2 sensors are confirming the codes.

Do you have a stock air filter?
Or after market?
Is it Clean?

You could try cleaning the MAF sensor with a spray MAF cleaner. Cheap easy first step.

What year is the car?
How many miles on it?
Have you done any recent work on it?

[yummyporsche]

Originally Posted by blue62

Codes like the ones your getting are not immediately harmful to the cats.
So the first time an event happens that can trigger the codes.
The ECU stores the codes in it's memory (pending codes).
If the same type of event occurs on two back to back drive cycles the ECU moves the codes to permanent and turns your check engine light on.

If you have pending or permanent codes your I/M readiness monitors associated with the codes will not reset.

The codes your getting are indicating an overly rich fuel/air mixture
The voltage readings on the O2 sensors are confirming the codes.

Do you have a stock air filter?
Or after market?
Is it Clean?

You could try cleaning the MAF sensor with a spray MAF cleaner. Cheap easy first step.

What year is the car?
How many miles on it?
Have you done any recent work on it?

Yeah I didn't think the monitors would reset if I have an associated code with it. :/
I believe so, I just bought the car and the prev. owner did a recent engine swap 100k miles. I doubt he wouldn't put a new air filter in - but I will have to check, the cabin air filter looked new.

MAF sensor is a few months old - prev. owner replaced it.

Car is 2001, boxtser 986S.
213K on the odometer, 100K on the engine.
I've recently taken the seat out to look at the alarm system, and have installed new hood struts but that is all. I have attempted to remove the O2 sensors for cleaning but it is seized in there.

[blue62]

With both of your post O2 sensors showing 0.7v I suspect you are running slightly rich.
Your sensors are faulty.
Or your Cats are faulty.
That's why I asked about the air filter.
Dirty air filters restrict air flow and after market filters that use oil on them ruin MAF sensors.

Does your scanner show live data?
If it does hook it up.
get the car fully warmed up and at idle look at your pre Cat voltage signals.
They should switch above and below .450v every few seconds.
If they stay high constantly that indicates a rich condition.

Here is a test to try. If you have live data.
Hook up your scanner so you can watch your O2 sensor voltages.
Get the car fully warmed up.
Then create a good size vacuum leak. This will create a lean condition.
Voltages on the O2 sensors should drop down close to 0.2v

Pre Cat sensors should see the lean condition very quickly.
Post Cat sensors will take a few seconds to see the lean condition because they are behind the Cats.
If they don't or they respond slowly the sensors probably need replaced.
Or in the post Cat case the Cats could be faulty.

I hope this all makes sense.

Also there may be some issue with your Evap. system.
But I am not up on Porsche Evap systems so I would be of no help there.

[yummyporsche]

Originally Posted by blue62

With both of your post O2 sensors showing 0.7v I suspect you are running slightly rich.
Your sensors are faulty.
Or your Cats are faulty.
That's why I asked about the air filter.
Dirty air filters restrict air flow and after market filters that use oil on them ruin MAF sensors.

Does your scanner show live data?
If it does hook it up.
get the car fully warmed up and at idle look at your pre Cat voltage signals.
They should switch above and below .450v every few seconds.
If they stay high constantly that indicates a rich condition.

Here is a test to try. If you have live data.
Hook up your scanner so you can watch your O2 sensor voltages.
Get the car fully warmed up.
Then create a good size vacuum leak. This will create a lean condition.
Voltages on the O2 sensors should drop down close to 0.2v

Pre Cat sensors should see the lean condition very quickly.
Post Cat sensors will take a few seconds to see the lean condition because they are behind the Cats.
If they don't or they respond slowly the sensors probably need replaced.
Or in the post Cat case the Cats could be faulty.

I hope this all makes sense.

Also there may be some issue with your Evap. system.
But I am not up on Porsche Evap systems so I would be of no help there.

Ahhhhh unfortunately won't be able to do that anymore. The coolant tank in the trunk just exploded from the pressure. Car is currently undrive-able. YIKES.

[blue62]

Originally Posted by yummyporsche

Ahhhhh unfortunately won't be able to do that anymore. The coolant tank in the trunk just exploded from the pressure. Car is currently undrive-able. YIKES.

Well that's no fun

[mikefocke]

So the amount of unburnt gas is overwhelming the ability of the CATs to reduce the unburnt hydrocarbons and the secondary CATs are both reading high.

So why? Air leak or bad MAF are the usual suspects. My bet the former.

Is the car stock? What air cleaner? Any recent work done on the top of the engine?

[blue62]

When you replace the coolant tank go OEM.
A little costly but the aftermarket tanks don't seem to hold up well.