aryork

I've got a P2097 and P2099 (Post catalyst fuel trim system too rich bank 1/2) with fabspeed sport headers. Installed O2 spacers in hopes of that fixing the problem. Here are some photos. Took both rear tires off and highly suggest that to make install much easier. Had to grind down a 22 mm wrench a bit. The right side was difficult in that the lock nut on the space elbow was hard to reach. Luckily I had an old, small plumbers type wrench that I disassembled to get it in place to tighten the nut.


View is through removed tire/wheel:


View from below:


This one taken from "outside" looking through the rear wheel/tire that has been removed.


Have only driven a few miles since the install, but hoping they will clear on their own soon...

chillindrdude

keep us posted on how they hold up and if/when the codes clear...

there's been more than a few accounts where folks were running sport (reduced cell count) headers and have not had CEL issues.

aryork

I am not sure exactly how many miles I have on the sport headers, but I'd say 3,500 miles max. One of the techs at my dealer said the cats would fail (make CEL light come on) after a year - said they have seen it quite a few times. The other wild card here is the CEL came on two days after I got the car back from the shop - fixing damage from an accident. The damage did not involve the engine in any way - just lot of body and suspension work. The dealer worked it over quite a bit after the shop did their thing - radiator flush/fill, alignment, drove it pretty hard and ultimately asked for one more new tire be put on. They may have reflashed or reset the ECU because I noticed some settings were changed. I need to check. Either way, will keep y'all posted...

One more question though...I assume the software running the car will not try to adjust the mixture as a result of the codes - is that right? The message on the MFD says "...car is driveable." I have not noticed a change in performance.

Found this O2 sensor tool out there while browsing around - seems like a good idea for less than $25. Got one ordered.

997driver

Any updates? Have those mini cats worked? Quite pricey at 195.00

cox1974

aryork

Thanks for the ping. Some updates, but not good news, yet. Recall I got the codes, then got the O2 spacers, and the codes did not go away. 5,500 miles on the car.

I got all the codes reset at the dealer. The tech at the dealer told me the after-cat O2 sensors are basic, heated sensors (thus only use 4 wires), but the ones before the cats are more sophisticated (6-wire I believe). He thought the spacers would solve the CEL problem.

The additional wild card is (not sure I mentioned this earlier) on the left/driver's side (bank 1), the rear-most (post-cat) O2-sensor lead had rested directly on the CAT long enough to melt away about 1.5 inches of the exterior, gray-colored sheath. This was before I installed the O2 spacers. None of the sensor's four wires inside were damaged – I checked these closely, twice now. So, I loosely tied it up and out of the way. Apparently these sensors “breathe” through their wire lead, so it is a bit suspicious. I told the tech about this, and he did not suggest a sensor replacement.

I drove it for a day and a half and CEL came back. I checked the codes with my dongle just today, and I have a new code and two of the same I got before; those are:
P2097 - Post catalyst fuel trim system too rich bank 1 (same)
P2099 - Post catalyst fuel trim system too rich bank 2 (same)
P2272 - O2 sensor signal biased/stuck lean bank 2 sensor 2 (new)

What is bank 1 and 2 (left or right)?

I found two references on a 996 - bank 1 is left side (Driver’s side for US cars). The GT4 Service Information 2016 Technik Introduction says the left cylinder bank is bank 1. That's the same answer, so thinking this is good information. However, the O2 sensor with the sheath issue is the left/driver's side (bank 1), so not the one causing P2272 (bank 2).

I have a problem because the inspection is due this month (January). So, I have to get this resolved pretty soon. I ordered two sets of OEM gaskets which should be here this week. If those gaskets are single use it is possible that is my problem.

I had lost some of the OEM bolts (they fell out when using the original fabspeed-supplied gasket) and I had to use non-oem replacements. When I got more OEM bolts I put them in, which requires all bolts to be loosened to tighten them in the prescribed order - when I did that I did *not* install a new gasket. So, maybe there is a leak. To be honest, it does not seem to be a high chance the gasket is the issue (however, it also seemed to me the oil drain plug should not leak at 25 ft-lb instead of 37, but it did).

I ordered two sets of gaskets thinking if I replaced the current ones and kept the fabspeed headers, and that did not fix the problem, the backup plan would be to reinstall OEM headers with a fresh gasket.

I believe my plan is:

· Install OEM gaskets and new O2 sensor washers all around
· Get codes reset at dealer (I believe they charge $29 or $39 for this).
· If codes come back re-install OEM headers with new gaskets and washers and go back for a warranty visit.

Any thoughts/suggestions? Should I bite the bullet and get a new left-side (bank 1) O2 sensor since the sheath has melted through in one place?

Here is the best reference I could find for defining bank 1 and bank 2 (I added the front/rear/left/right and cyl bank 1 text):

MarcD147

When I had my o2 sensor melt because of the car on my stock gt4. It damaged the wiring harness and the dealer had a really hard time getting it fixed. It kept throwing codes.
They were about to order a whole car new wiring harness. The region rep came by for a last effort and he managed to fix it.
All has been good since.

Those wiring harness issues are very tricky....

cmosman

Here is some perspective. Keep in mind, the GT4 headers/cats are 981 standard issue.
- Driving around town, I am getting about 20mi/gal. Consider that 1x conversion load on the cat. Results in a particular cat temperature (call it HOT).
- Driving on track at a good pace, I am getting about 5mi/gal. That is 4x conversion load for the cat. Call that temperature Super-HOT.
- Using one of these small aftermarket cats with much less surface area than OE, the conversion load per surface area goes up by the same factor that the area goes down.
Let's just assume that the Fabspeed cats are 1/2 the surface area (probably smaller, actually), the conversion load is more than 8x .. 10x what you'd get in street driving. Call the temperature Ultra-HOT. No surprise - the device fails. Just hope, the insides don't disintegrate and cause havoc in and around the engine. I have heard this happening. No surprise, quite frankly. I would not trust some aftermarket supplier that is a long way from the engineering prowess of the GT guys at Porsche. Your engine is at risk, if you ask me.
Personally, tinkering with the cat in the GT4 would result in removing it entirely. Then the engine is safe. You'll get the lights also, but that needs to be (and can be) dealt with electronically.

jmartpr

Have you checked if the Cats are OK? Trust me on this one.....get one of those small/cable USB cameras an insert it through the O2 holes so you can get a good look at the cats on both sides.
Or....take the exhaust off an look to see if the cats are damaged but the damage usually will start on the front end.
The COBB AP can deal with O2 problems with no CEL but will store the codes anyway.
Send me a PM or e-mail if you need more info.

needapcar

i recently installed 200 cell headers on the gt4 and am getting the same p2099 code. Did you ever resolve this issue?

aryork

Yes, I wrote it up somewhere, but could not find it quickly. First easy step is to make sure all your header bolts are torqued properly.

I ultimately had to get a state inspection so I put the OEM headers back on - the CEL cleared itself pretty quickly - a day or two.

While I had the fabspeed headers off, I washed them out with dawn soap and lots of water. According to a few references, this washing out does not do anything, but I did it anyway. I also had the headers ceramic coated. I put them back on with new OEM gaskets and without the mini-cats and have not had a CEL since. They've been on now for a couple of years and this includes some track weekends. I have over 10k miles on it - maybe 11k or 12k...

Ultimately if you can't get it fixed, you might need to get a tune with a Cobb access port (or similar) to deal with it.

okie981

This diagram is for a 911 car. The 981 (986/987) cars have the engine rotated 180 degrees from what is shown here. This places the 981 cylinder #1 right behind the passenger's seat (talking about left-hand drive US market cars here) and cylinder #4 is behind the driver's seat.

Last_935

Any other sensor spacer/mini cat brands( such as Big Daddy, ProTune...) people have had success with when used with catless race headers?

Thanks,

RobC4sX51

This thread reminds me of why my Indy mechanic said to “leave the stock OEM exhaust and cats alone”! Not worth the headaches.

Fabspeed Motorsport

If these are our Headers, I would love to speak with you and get things puzzled out.
All of our Catted products are no CEL guaranteed.

Cheers, John