Jump to content
www.BoXa.net
melillo

986 2.7 2004 - Introduction - O2 codes + Fixing attempts

Recommended Posts

Hello, good afternoon! This is my first post, sorry if I did something wrong.

I am an unexpected owner of a 986 2.7 2004 with 72.5K on the clock.
It was needing some love (I had no idea about what I was doing and had no knowledge about the car)

To not make it too long: Error Code P2096 (seems generic regarding exhaust/lambda), Porsche Bristol told me to replace a specific Lambda Sensor but didn't tell me which one.... I went there and replace all 4. Code erased, was told that the muffler would need replacing soon. Code is back now around 500 miles later.
Based on costs of known Exhaust parts, japspeed, dansk... and the labour cost (been told that could go from 2 to 10 hours, depending on the manifold's bolts, considering the base of GBP100 per hour... 200 to 1K 🤒) . I've decided to go for a cheap/full exhaust on an attempt to fix the issue and have some peace.
 
Didn't find any real world information about the mentioned exhaust (Gravity), apparently made in the UK and Stainless Steel T304. But, as I only use the car on weekends (usually when the weather is good and to go to the supermarket). Thought: Why not 🙂

It has arrived just now. I am trying to book a service to replace it. *I think I will keep the original one for a while in case I have to or decide to refurbish some bit to re-use (does anyone knows if it is possible? to refurb an exhaust part?)

Bought on Ebay for GBP459.99.
OU9NsWu.jpg

aqYwXw0.jpg

bMQf7bh.jpg

a1jhutK.jpg


I will post before and after sound + finds regarding fitting.

*any recommendation and or suggestions are more than welcome.

Cheers!

Share this post


Link to post
Share on other sites

I'm sure others with more knowledge than me will chip in here, but the codes could be caused by lots of other electrical items - MAF sensor etc.

Share this post


Link to post
Share on other sites

Interesting... I thought that was related with the gases coming out only, not the whole in/out process. Thanks for that. Guess it make sense to have it cleaned-up with the exhaust replacement.

Share this post


Link to post
Share on other sites

The exhaust system you've bought looks identical to many other aftermarket exhaust systems available on ebay. From reports on here they are considered loud and droney (at motorway speeds).  Not such a problem  on a weekend car but tiresome on a daily driver.

Share this post


Link to post
Share on other sites

@naim22 could chip in here with his in-depth knowledge.  It could be MAF related if the system is correcting for duff info, you'd notice by a rough idle or miss-fire or hesitation on gear changes which causes then the wrong fuelling which can confuse the system regarding lambda readings.

If you change the MAF, give the throttle body a good clean up too before you reset the codes and the car learns the fuelling all over again.

Share this post


Link to post
Share on other sites

Welcome. Hope you're not using Porsche Bristol for all the work. Much cheaper to use a reputable indy. Most people around Bristol ( and even further afield) use one of the site sponsors, Cotswold Porsche Specialists. And if you're in the vicinity of Bristol then come and join one of our Southwest meets sometime.

Share this post


Link to post
Share on other sites

@Boxob About the droning, I didn't think about it 🙂 the price and the "rust free" promise were too tempting. do you think it is more related with the muffler or another bit of the system?

@1/2cwt. Interesting fact is that the car doesn't show any issue whatsoever, everything just fine, stable and responsive. Only thing I notice is when the service light came up I can smell petrol, on my mind it means that it is the system trying to protect itself. But yes, I think I will go for a good old cleaning of MAF, throttle body/Plenum before buying any other part. About the car re-learning its bits... just a good old drive around at sensible speeds?

@red rocket, HEllo! So, first time was there yes... mechanic was a good guy, explained some bits to me, but I could feel that they don't care about poor me problems 🙂 So I am trying other garages to understand where to go, who to trust. Lambda sensors were replaced by Martin (Porshe Mode) + Headlight refurb/cleaning/protection.  Now, exhaust, I am trying to scheduled with the famous Lee. But I need a full day scheduled with him so I can drive in and out with my car. I live in South Bristol, near Hengrove. So the logistic is important to me as the garage. And Yes I will keep an eye on the events, will be good to chat about SLIM (my car) and its siblings/relatives 🙂

Thanks all. *I clearly don't know how to reply to multiple threads ...

Share this post


Link to post
Share on other sites
5 minutes ago, melillo said:

Thanks all. *I clearly don't know how to reply to multiple threads

No probs. Just click 'Quote' below a post you want to reply to, type reply, click Quote below the next one , type reply etc etc and they'll all come up one after the other then hit Submit Reply.

And looks like you have a problem with tagging- need to type e.g. @melillo and wait for relevant name to be highlighted then click on it to display.

  • Like 1

Share this post


Link to post
Share on other sites
16 minutes ago, melillo said:

@Boxob About the droning, I didn't think about it 🙂 the price and the "rust free" promise were too tempting. do you think it is more related with the muffler or another bit of the system?
 🙂🙂

 

I have no personal experience but it crops up on here frequently. Try a search. From what I've read the headers are fine but the mufflers are weak and there is no crossover balance pipe. 

  • Like 1

Share this post


Link to post
Share on other sites
4 hours ago, melillo said:

@1/2cwt. Interesting fact is that the car doesn't show any issue whatsoever, everything just fine, stable and responsive. Only thing I notice is when the service light came up I can smell petrol, on my mind it means that it is the system trying to protect itself. But yes, I think I will go for a good old cleaning of MAF, throttle body/Plenum before buying any other part. About the car re-learning its bits... just a good old drive around at sensible speeds?
 

I'd hazard a guess that it is running rich to keep the data from the MAF in trim.  My MAF must have been failing for some time before a retained data clearance for another reason made it run like a bag of nails highlighting the MAF failure.  The other option is to unplug the MAF and see if it runs better on the default map with no input.  Just cleaning the MAF may well not succeed and if it is faulty the car will run like a bag of nails until you do change it.  I used second hand from a trusted source for about £30, a new genuine Bosch one is about £150 - 180 depending on where you source it and how long you'll wait*. and a Porsche branded on (Bosch) is £400 or something stupid like that.

* I use onlinecarparts.co.uk if I can wait (4-5 days shipping from Europe) as they can be very cheap for the proper stuff, otherwise carparts4less and ECP are usually fair enough and there is plenty of info here and other places to find out who the OEM supplier to Porsche is to avoid the Porsche branding 'tax' but still get the proper part.  That said some bits are cheaper from Porsche... shop around.

Share this post


Link to post
Share on other sites

Looking at that code (P2096), the first thing that I notice is that it is specific to Bank 1. Is there a similar code on bank 2?

If not I would imagine this points to:

- Issue with the catalytic converter

- Air leak on the Exhaust 

- Wiring issue on the lambda sensor

- Fuelling issue on the rail

The first check is to plug in an OBD tool, & watch what the Lambda sensors are doing whilst the car is in closed loop control (warmed up & at idle will suffice). The pre cat ones should oscillate as the combustion controller in the ECU swings between lean (~0.8V) and rich (~0.2V). As these are narrowband this is how the controller behaves. I'd expect the post cat ones to remain constant if the catalysts are doing their job & to be reading fairly lean (closer to 0.8V than 0.2V). Compare Bank 1 to Bank 2 and look for differences there too.

If the precat sensor looks OK, but the post cat ones don't I'd be checking the catalyst & wiring. If both arent behaving as expected but on one bank only, then I'd be checking the fuelling & exhaust for leaks. Whilst the tool is plugged in, also make a note of the Long term fuel trims, are they similar on each bank?

Its also worth checking the MAF values (airflow & Intake Air temperature), although I would not expect a code on one bank only if the MAF was the culprit, as the intake is common to both banks. They do seem to be a weak point on 986s at this age so I wouldnt completely rule it out. I think the later 4  O2 sensor cars may also have had secondary air injection, although again I'd expect an issue with this to show on both banks.

Failing all this, its worth checking the DME Software level, as I believe there was a TSB on the threshold for this very fault being set too tight. What I am not sure about is if this was NAS market only.

The car is always adapting as it drives, however it is reliant on good input information to do so correctly.

Edited by naim22
  • Thanks 1

Share this post


Link to post
Share on other sites

That should read rich (~0.8V) and lean (~0.2V) 

The post cat sensors follow a different characteristic as the effect of the cat averages the values.

Share this post


Link to post
Share on other sites
18 hours ago, ½cwt said:

I'd hazard a guess that it is running rich to keep the data from the MAF in trim.  My MAF must have been failing for some time before a retained data clearance for another reason made it run like a bag of nails highlighting the MAF failure.  The other option is to unplug the MAF and see if it runs better on the default map with no input.  Just cleaning the MAF may well not succeed and if it is faulty the car will run like a bag of nails until you do change it.  I used second hand from a trusted source for about £30, a new genuine Bosch one is about £150 - 180 depending on where you source it and how long you'll wait*. and a Porsche branded on (Bosch) is £400 or something stupid like that.

* I use onlinecarparts.co.uk if I can wait (4-5 days shipping from Europe) as they can be very cheap for the proper stuff, otherwise carparts4less and ECP are usually fair enough and there is plenty of info here and other places to find out who the OEM supplier to Porsche is to avoid the Porsche branding 'tax' but still get the proper part.  That said some bits are cheaper from Porsche... shop around.

Nice, thanks for the idea. I will replace the exhaust, have it booked for the 29th. Clean up the bits, clean the log and pray 🙂

Share this post


Link to post
Share on other sites
16 hours ago, naim22 said:

Looking at that code (P2096), the first thing that I notice is that it is specific to Bank 1. Is there a similar code on bank 2?

If not I would imagine this points to:

- Issue with the catalytic converter

- Air leak on the Exhaust 

- Wiring issue on the lambda sensor

- Fuelling issue on the rail

The first check is to plug in an OBD tool, & watch what the Lambda sensors are doing whilst the car is in closed loop control (warmed up & at idle will suffice). The pre cat ones should oscillate as the combustion controller in the ECU swings between lean (~0.8V) and rich (~0.2V). As these are narrowband this is how the controller behaves. I'd expect the post cat ones to remain constant if the catalysts are doing their job & to be reading fairly lean (closer to 0.8V than 0.2V). Compare Bank 1 to Bank 2 and look for differences there too.

If the precat sensor looks OK, but the post cat ones don't I'd be checking the catalyst & wiring. If both arent behaving as expected but on one bank only, then I'd be checking the fuelling & exhaust for leaks. Whilst the tool is plugged in, also make a note of the Long term fuel trims, are they similar on each bank?

Its also worth checking the MAF values (airflow & Intake Air temperature), although I would not expect a code on one bank only if the MAF was the culprit, as the intake is common to both banks. They do seem to be a weak point on 986s at this age so I wouldnt completely rule it out. I think the later 4  O2 sensor cars may also have had secondary air injection, although again I'd expect an issue with this to show on both banks.

Failing all this, its worth checking the DME Software level, as I believe there was a TSB on the threshold for this very fault being set too tight. What I am not sure about is if this was NAS market only.

The car is always adapting as it drives, however it is reliant on good input information to do so correctly.

Wow @naim22 Lot's of detailed info. Thanks a lot for that.
I am not sure if my ODB reads live values.
"Air leak on the Exhaust/Issue with the catalytic converter " - are the reason I decided to go for the full exhaust, I think it might be the cause. But I will ask for all those validations during the exhaust replacement.

And, will post here anything I find.

Thanks, have a good one.

Share this post


Link to post
Share on other sites
1 hour ago, melillo said:

Nice, thanks for the idea. I will replace the exhaust, have it booked for the 29th. Clean up the bits, clean the log and pray 🙂

That exhaust will be very loud which is fine on a weekend car when you’re just thrashing around, but if you’re doing other stuff in it, I’d be tempted to keep the back box from your existing system. Whatever you do, don’t let the garage throw the old back box away as you may want to swap it back.

Share this post


Link to post
Share on other sites

I have the same year and model and just replaced the rear section with the Dansk box which works really well. Please let us know how the manifold bolts come out, that's the bit that will eat up time and money 

 

Steve

  • Like 1

Share this post


Link to post
Share on other sites

live data.ts

Hey Chaps

My 03 986 S keeps throwing this P2096 code every 500 miles 

I have attached the live data (warm and at tick over) , any help would be amazing 

Bank 1 is different to bank 2 but not alot . 

I also note the MAF reading seems high but not really sure what the range is

  

Share this post


Link to post
Share on other sites
On 2/19/2020 at 2:29 PM, Nobbie said:

That exhaust will be very loud which is fine on a weekend car when you’re just thrashing around, but if you’re doing other stuff in it, I’d be tempted to keep the back box from your existing system. Whatever you do, don’t let the garage throw the old back box away as you may want to swap it back.

Loud sweet, like this one? 🙂😃🤠

Share this post


Link to post
Share on other sites
23 hours ago, Concrete-crusher said:

I have the same year and model and just replaced the rear section with the Dansk box which works really well. Please let us know how the manifold bolts come out, that's the bit that will eat up time and money 

 

Steve

I will, my money$ that I don't have are counting on an easy/quick job.

Share this post


Link to post
Share on other sites
1 hour ago, Andrewfmg said:

live data.ts 790.92 kB · 1 download

Hey Chaps

My 03 986 S keeps throwing this P2096 code every 500 miles 

I have attached the live data (warm and at tick over) , any help would be amazing 

Bank 1 is different to bank 2 but not alot . 

I also note the MAF reading seems high but not really sure what the range is

  

Um.....this is "worrisome". Thanks for sharing it, where/how can you get this data from?
Did you have your exhaust components checked for leaks?

For my car, I will detail all bits: replacing/cleaning/testing. (to come after 29th Feb).

Cheers.

Share this post


Link to post
Share on other sites
2 hours ago, Andrewfmg said:

live data.ts 790.92 kB · 3 downloads

Hey Chaps

My 03 986 S keeps throwing this P2096 code every 500 miles 

I have attached the live data (warm and at tick over) , any help would be amazing 

Bank 1 is different to bank 2 but not alot . 

I also note the MAF reading seems high but not really sure what the range is

  

Check the catalytic converter is operating correctly & exhaust for leaks on Bank 1

The O2 Sensor reading downstream of the cat looks to be too lean. This should read approximately 0.7V relatively constantly as Bank 2 does (as the catalytic converter by nature averages the O2 value, so you dont see this oscillation on the post cat sensors) & vehicles generally are setup to run ever so slightly rich in closed loop control as its safer for the components. 

The MAF IAT value looks reasonable for a hot & static engine, as does the air flow & as this is specific to one bank, I wouldnt point at the MAF just yet.

I cannot see your Bank 1 pre cat O2 sensor, to see if this is switching correctly. If this was also not switching to similar values to Bank 2, I'd definitely be considering a leak at the manifold or a fuelling issue. The fact the long term fuel trims look okay implies that the precat sensor is reading as expected, but that is assuming they have not been cleared recently.

Failing that, it could be a duff sensor itself, you could do this by swapping the sensors over to the respective opposing banks.

It is also worth checking to see if your DME software is up to date.

Edited by naim22
  • Like 1

Share this post


Link to post
Share on other sites
16 hours ago, naim22 said:

Check the catalytic converter is operating correctly & exhaust for leaks on Bank 1

The O2 Sensor reading downstream of the cat looks to be too lean. This should read approximately 0.7V relatively constantly as Bank 2 does (as the catalytic converter by nature averages the O2 value, so you dont see this oscillation on the post cat sensors) & vehicles generally are setup to run ever so slightly rich in closed loop control as its safer for the components. 

The MAF IAT value looks reasonable for a hot & static engine, as does the air flow & as this is specific to one bank, I wouldnt point at the MAF just yet.

I cannot see your Bank 1 pre cat O2 sensor, to see if this is switching correctly. If this was also not switching to similar values to Bank 2, I'd definitely be considering a leak at the manifold or a fuelling issue. The fact the long term fuel trims look okay implies that the precat sensor is reading as expected, but that is assuming they have not been cleared recently.

Failing that, it could be a duff sensor itself, you could do this by swapping the sensors over to the respective opposing banks.

It is also worth checking to see if your DME software is up to date.

Excellent analysis.

Share this post


Link to post
Share on other sites
54 minutes ago, Happy Days said:

Excellent analysis.

Should be, it's how he earns a living....

@naim22 has been very helpful.to me too recently. Excelent knowledge addition to the pool of info on the forum👍

  • Like 1

Share this post


Link to post
Share on other sites
On 2/20/2020 at 4:51 PM, melillo said:

Loud sweet, like this one? 🙂😃🤠


Original exhaust

RybwAPw.mp4


Toyosport exhaust with SS headers

 

Vg0KYQY.mp4

You need to double click on these to get the sound.

Edited by Nobbie

Share this post


Link to post
Share on other sites
21 hours ago, Happy Days said:

Excellent analysis.

Cheers, It can be a bit tricky with older cars as the measurement devices themselves can be suspect (MAF's in particular are known for this) , but I've always found that its worth following the data first & assuming everything is measuring as it should as opposed to assuming the data is bad first. I always find It soon becomes apparent if there is a measurement problem this way.

20 hours ago, ½cwt said:

Should be, it's how he earns a living....

@naim22 has been very helpful.to me too recently. Excelent knowledge addition to the pool of info on the forum👍

Thanks very much, @½cwt is right. It's a bit of a what I think is called a busman's holiday? 😂

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...