996 3.4 fault codes P1124, P1126

[JohnWalsh]

Hi everyone,

Just bought my first Porsche and have some problems already:

My 996 3.4 is getting the following fault codes;
P1124 Oxygen sensing range 1 Cylinder (1-3)
P1126 Oxygen sensing range 1 Cylinder (4-6)
P0441 Fuel tank ventilation minor leak exceeds limit value
P0130 O2 sensor ahead of cat. conv. Cylinder (1-3)

Idles quite poorly, when driving feels normal, at least what I can tell.

MAF and one oxygen sensor has been replaced, no noticeable change.

With my mates Durametric, we got these values;
Oxygen sensing cylinders 1-3 1,00
Oxygen sensing cylinders 4-6 1,25
- after some 10 minutes idle these both go to about same values; 1,03/1,04

FRA 1,03
FRA2 1,04

TRA 0,00
TRA2 0,35

What should I check next (possible vacuum leak)?

Thanks for help.

[JFP in PA]

That is where you should have started as none of the sensors needed to be replaced, but the codes were telling you that the DME had reached its enrichment limit on both banks. That means you have a vacuum leak that affects both banks.

[JohnWalsh]

Originally Posted by JFP in PA

That is where you should have started as none of the sensors needed to be replaced, but the codes were telling you that the DME had reached its enrichment limit on both banks. That means you have a vacuum leak that affects both banks.

Is it possible that evap purge valve is faulty, and causes a vacuum leak affecting the afr ratio at idle?

[JFP in PA]

That would constitute a vacuum leak, but I would check it first before assuming it is bad.

[JohnWalsh]

Originally Posted by JFP in PA

That would constitute a vacuum leak, but I would check it first before assuming it is bad.

So I did the following things:

1. Removed the evap valve from it's place and plugged both ends from the hose that goes into the intake manifold - No effect on idle
2. Tried blowing through the evap valve - No leaks so i guess that's working ok (or atleast not leaking)
3. Tried to use start pilot to look for the leaks near the throttle body - Couldn't find any leaks

Should I use a smoke machine now? What's the best place to put smoke into the engine to look for leaks (Throttle body, oil filler tube)?

What other things should i check? What are the symptoms for bad aos?

[JohnWalsh]

I pumped smoke to the engine via the oil filler tube and the only place I could find that the smoke was coming from was through the sides of throttle body plate. Is there a way to check that idle control valve is functioning properly?

[pessemist]

I am throwing those exact same codes. Did you ever get the problem sorted out? If so, what was wrong?