Jason's 99 Boxster doc thread

[blue62]

Originally Posted by Radman

Replaced the crank position sensor, upstream O2 sensors, and the purge valve under the left side intake manifold.

P0446 code went away but I get O2 sensor codes without a CEL. Hopefully it's not an issue with the wire harness but once I get new anchors installed for my lift I'll start rotating the O2 sensors and see if any codes follow particular sensors or not.

On the bright side, the car drove much better. Very happy to be able to take her out for a spin again.

If you do a little research on how the Durametric or rather "Porsche" portrays or interprets fuel trims you can use the Durametric to tell which O2 sensor or sensors are causing the codes.
Not hard to do you just have to understand Porsche's fuel trim methodology and the relationship between O2 sensors and fuel trims.

If you have access to an OBDII scanner that shows fuel trims as a percentage rather then the Porsche Durametric method it is a little easier to interpret the fuel trims.
fuel trim data can be very useful in diagnostics of engine performance (running) issues.

Although switching sensors around to see if the signal or code follows a sensor is a common practice it is not a good one. It can cause other issues.
Everything on these cars and any modern day car is electronic so they can be tested with a scanner or Oscilloscope or something as simple as a Digital Multi Meter.

I take it that if your not getting a check engine light but your seeing codes....So your looking at pending codes???? What are the codes specifically.????

How many miles on the O2sensors????
They tend age or the signal from them tends to begin to slow down as they age.
Usually starts around 100000 miles

[Radman]

Originally Posted by blue62

If you do a little research on how the Durametric or rather "Porsche" portrays or interprets fuel trims you can use the Durametric to tell which O2 sensor or sensors are causing the codes.
Not hard to do you just have to understand Porsche's fuel trim methodology and the relationship between O2 sensors and fuel trims.

If you have access to an OBDII scanner that shows fuel trims as a percentage rather then the Porsche Durametric method it is a little easier to interpret the fuel trims.
fuel trim data can be very useful in diagnostics of engine performance (running) issues.

Although switching sensors around to see if the signal or code follows a sensor is a common practice it is not a good one. It can cause other issues.
Everything on these cars and any modern day car is electronic so they can be tested with a scanner or Oscilloscope or something as simple as a Digital Multi Meter.

I take it that if your not getting a check engine light but your seeing codes....So your looking at pending codes???? What are the codes specifically.????

How many miles on the O2sensors????
They tend age or the signal from them tends to begin to slow down as they age.
Usually starts around 100000 miles

Yeah, I had to google how to find fuel trims on the durametric lol!

The 2 precat O2 sensors are brand new, but not Bosch. Basically bought them for troubleshooting purposes. No idea if the others have ever been replaced but the car only has 75k miles so I doubt it.

Yes, the codes are pending.

They are:

P0131
O2 sensor ahead of Cat conv. Cylinder (1-3)

P0137
O2 sensor ahead of Cat conv. Cylinder (1-3) short circuit

P0151
O2 sensor ahead of Cat conv. Cylinder (4-6)

P0157
O2 sensor behind of Cat conv. Cylinder (4-6)

I don't need emissions so in a perfect world I could just get rid of the O2 sensors and the cats.

[Bush Pilot]

Originally Posted by Radman

Yeah, I had to google how to find fuel trims on the durametric lol!

The 2 precat O2 sensors are brand new, but not Bosch. Basically bought them for troubleshooting purposes. No idea if the others have ever been replaced but the car only has 75k miles so I doubt it.

Yes, the codes are pending.

They are:

P0131
O2 sensor ahead of Cat conv. Cylinder (1-3)

P0137
O2 sensor ahead of Cat conv. Cylinder (1-3) short circuit

P0151
O2 sensor ahead of Cat conv. Cylinder (4-6)

P0157
O2 sensor behind of Cat conv. Cylinder (4-6)

I don't need emissions so in a perfect world I could just get rid of the O2 sensors and the cats.

You mean in an "imperfect world". Why do you want to purposely pollute our air?

[blue62]

Originally Posted by Radman

Yeah, I had to google how to find fuel trims on the durametric lol!

The 2 precat O2 sensors are brand new, but not Bosch. Basically bought them for troubleshooting purposes. No idea if the others have ever been replaced but the car only has 75k miles so I doubt it.

Yes, the codes are pending.

They are:

P0131
O2 sensor ahead of Cat conv. Cylinder (1-3)

P0137
O2 sensor ahead of Cat conv. Cylinder (1-3) short circuit

P0151
O2 sensor ahead of Cat conv. Cylinder (4-6)

P0157
O2 sensor behind of Cat conv. Cylinder (4-6)

I don't need emissions so in a perfect world I could just get rid of the O2 sensors and the cats.

So first things first
Generic O2sensors are well known for their non compatibility with Porsche systems.
Secondly:
All four codes are pointing to the same thing: This is how it is described in the Bentley Book.
"Short to ground/below lower limit/lean mixture threshold."
So basically three possibilities.....but sense you have used generic brand sensors I would suspect an electrical issue with the sensors......the short to ground.

So first replace the 02sensors with Bosch.....
They developed the first automotive O2sensors so they know what they are doing.
Then go from there as a good starting foundation....

If you eliminate your cats and post O2sensors you will likely always have a check engine light on unless you find a work around..So if you have an OBDII issue you will not know it because the check engine light is already lit.

If you want to learn about "fuel trims" or O2sensor signals and how to read them and how they are related to each other. Go to youtube and look up "ScannerDanner" he is probably one of the best on youtube for teaching automotive sensor diagnostics. And automotive diagnostics in general.
That will allow you use the Durametric to much greater potential.

[Radman]

Originally Posted by blue62

So first things first
Generic O2sensors are well known for their non compatibility with Porsche systems.
Secondly:
All four codes are pointing to the same thing: This is how it is described in the Bentley Book.
"Short to ground/below lower limit/lean mixture threshold."
So basically three possibilities.....but sense you have used generic brand sensors I would suspect an electrical issue with the sensors......the short to ground.

So first replace the 02sensors with Bosch.....
They developed the first automotive O2sensors so they know what they are doing.
Then go from there as a good starting foundation....

If you eliminate your cats and post O2sensors you will likely always have a check engine light on unless you find a work around..So if you have an OBDII issue you will not know it because the check engine light is already lit.

If you want to learn about "fuel trims" or O2sensor signals and how to read them and how they are related to each other. Go to youtube and look up "ScannerDanner" he is probably one of the best on youtube for teaching automotive sensor diagnostics. And automotive diagnostics in general.
That will allow you use the Durametric to much greater potential.

Thanks again for the feedback.

I'll throw the old ones(Which are Bosch) back on and see what happens. If the codes stay I'll order one new one to move around and see if the codes go away. Don't want to spend the $ for all 4 in the hopes it makes the car run better. But, if this is a dumb idea, please let me know lol!

Screw it, just ordered 2 new Bosch units. Will report back.

[blue62]

Originally Posted by Radman

Thanks again for the feedback.

I'll throw the old ones(Which are Bosch) back on and see what happens. If the codes stay I'll order one new one to move around and see if the codes go away. Don't want to spend the $ for all 4 in the hopes it makes the car run better. But, if this is a dumb idea, please let me know lol!

Screw it, just ordered 2 new Bosch units. Will report back.

Your codes are showing that three of the four sensors are having issues.
I would replace all four with Bosch.
Then You have a solid foundation to work from.
An O2sensor and its wiring can be tested with a simple Digital Multi Meter.
Or the signal can be viewed with your Durametric.
If you switch the senor around looking to see if the code follows you have to move
two sensors then take the car for a drive sometimes multiple drives before the code shows up.
Senseless... when you can test them with a multi meter or Durametric in just a few minutes.

[Radman]

Originally Posted by blue62

Your codes are showing that three of the four sensors are having issues.
I would replace all four with Bosch.
Then You have a solid foundation to work from.
An O2sensor and its wiring can be tested with a simple Digital Multi Meter.
Or the signal can be viewed with your Durametric.
If you switch the senor around looking to see if the code follows you have to move
two sensors then take the car for a drive sometimes multiple drives before the code shows up.
Senseless... when you can test them with a multi meter or Durametric in just a few minutes.

You must like spending my money lol! All 4 arrive friday.

[blue62]

Originally Posted by Radman

You must like spending my money lol! All 4 arrive friday.

Not true
I don't like to waste money.
Trying to help you not waste yours.
Trying to point out better ways of diagnosing issues.

Buy quality parts that way you don't buy twice.
In a situation like yours three sensors are throwing codes and the other has 75 thousand miles on it. Buy all four and order once if you getting them on line. Or go to the parts store once to purchase them locally. Saves on shipping or gas which ever way your purchasing them.
It also gives you a solid foundation to start diagnostics of your O2senor codes from.

If you purchase something like a scanner be it a durametric or a foxwell or an oscilliscope like a Pico. Or even just a multi meter learn to use it to it's full potential.To do other wise is wasting money time, and effort in your diagnostic process.

If your into what makes things tick learn the best diagnostic procedure you can.
Then keep improving on that procedure the rest of your life.
Those are just a few of the things I try to do