CEL P1128 P1130 persistent

[puravidabahia]

Originally Posted by blue62

one would have to look at some data like O2 sensor waveform and fuel trim waveform under various conditions. perhaps something like O2 sensor signal bias is an issue.
Meaning if your O2sensor signals are biased lean then the system will try to adjust by adding fuel. But it is unlikely that both sensors have the same issue and only in a certain RPM range.

The hard starting situation at fill up followed by poor running-- does that only happen at fill up?
How does the car run off idle? Mid range RPM and upper range RPM?
Is the car stock? Stock exhaust? Stock air filter?

Oops sorry just reread your original post and see that O2 sensor was replaced.

thanks for the input, i am certain it was bosch on the maf; i am getting ready to just replace the MAF again along with all O2 sensors to see what changes, if anything; the idling is intermittent but usually acts up after being off when at running temp and if not moving out of gear it will sometimes just stall, forcing a restart;

[puravidabahia]

Originally Posted by puravidabahia

thanks for the input, i am certain it was bosch on the maf; i am getting ready to just replace the MAF again along with all O2 sensors to see what changes, if anything; the idling is intermittent but usually acts up after being off when at running temp and if not moving out of gear it will sometimes just stall, forcing a restart;

and yes, all stock equipment......i just had a minor service, fuel filter and air filter with no change on the symptoms........higher rpm is fine, only the stopped and/or idling has issues plus only the refuel problem but that is only when refueling when it fails to fire up and causes several restarts after cutting out.....once i force it thru that with 1/4 to 1/2 mile of driving that issue goes away

[78F350]

For the re-start trouble, look into "Evap Purge Valve". It's a valve under the left side intake. Here's an article on the basics (not Porsche, but similar): https://www.samarins.com/glossary/purge-valve.html
It may not be the cause of the P1128/1130, but it is likely still part of the problem.

Here's one discussion here: http://986forum.com/forums/performance-technical-chat/50264-success-finally-fixed-hard-start-while-hot-fueling-issues.html

[puravidabahia]

Originally Posted by 78F350

For the re-start trouble, look into "Evap Purge Valve". It's a valve under the left side intake. Here's an article on the basics (not Porsche, but similar): https://www.samarins.com/glossary/purge-valve.html
It may not be the cause of the P1128/1130, but it is likely still part of the problem.

Here's one discussion here: http://986forum.com/forums/performance-technical-chat/50264-success-finally-fixed-hard-start-while-hot-fueling-issues.html

thanks!.....that "hart start" post sounds like the cure......much appreciated!
i'll update once i've tried that

[Steelepuls]

Have you changed the oil cap? Mine had the same codes and I replaced everything you did. O2, MAF, AOS, plugs, etc. I changed the fuel and oil caps to new and it seemed to fix the problem. Looking at my oil cap and fuel cap, there was small cracks on the o rings. My codes seemed to always come up during traffic and city street conditions. Less on highway going at the speed limit or a little above.

[puravidabahia]

Originally Posted by Steelepuls

Have you changed the oil cap? Mine had the same codes and I replaced everything you did. O2, MAF, AOS, plugs, etc. I changed the fuel and oil caps to new and it seemed to fix the problem. Looking at my oil cap and fuel cap, there was small cracks on the o rings. My codes seemed to always come up during traffic and city street conditions. Less on highway going at the speed limit or a little above.

i had done that but with local auto parts store parts; i just ordered factory replacements today as part of the ongoing troubleshooting......thanks!

[blue62]

With the problems at refill that points to the EVAP system. I would check that system out before replacing anymore sensors or other parts.
There are parts of the EVAP system that are under vacuum while running.
Issues with certain EVAP valves will not show up with a smoke test. So you can have a vacuum leak in the EVAP system that is not detected by a smoke test.
A vacuum leak in the EVAP system can cause your codes and all your other issues.

[blue62]

Originally Posted by puravidabahia

thanks for the input, i am certain it was bosch on the maf; i am getting ready to just replace the MAF again along with all O2 sensors to see what changes, if anything; the idling is intermittent but usually acts up after being off when at running temp and if not moving out of gear it will sometimes just stall, forcing a restart;

To just replace parts (sensors) is not a good diagnostic procedure. Testing sensor output and function is the proper way to go.
You have already replaced the mentioned sensors with no change so it is not a problem with said sensors. The problem is as the code says. A lean condition in RPM range 2
almost certainly a vacuum leak. I see you have smoke tested for vacuum leaks and corrected some. But here is the thing a smoke test is not 100 % foolproof. You can still have a vacuum leak. Most likely in the EVAP system as your issues at refill indicate.

Your running issues are at low RPM or idle and you say it runs ok at mid and higher rpm
most likely the more RPM you give it the better it runs. Those are classic indicators of a vacuum leak. It is not a fuel delivery problem. If it was your low RPM running issues would get worse as you tried to give it RPM. Fuel delivery demand increases with engine load and RPM. It runs fine at mid to higher RPM so it is not a fuel delivery problem.

I would look at the EVAP system. There are several components that are under vacuum in that system.
Your issues at refueling are pointing right at this system.
Hope this helps some and give you a better direction to go.