kapflaco

Hoping you all can point me in the right direction to diy/self diagnose. The code appeared within 15 minutes of my first drive after installling the Fabspeed Xpipe 200 cell sport catalytic converter. I pulled the code 208 with my durametric software, cleared it, and it came back within minutes of the next drive.

I spoke with Fabspeed and they indicated that some cars need the O2 sensor extenders even if they are using the sport cats and not using cat bypass pipes. This surprised me as I had not heard or read that before here on this forum...wish I had known prior to purchase. Before I try tricking the system with the extenders:

1. Is it possible that I need to clear the SAI passages and the timing of the CEL with the xpipe install is an unhappy coincidence? If so do I start by changing the check valve? If SAI needs cleaning wouldn't it be likely the car would throw the codes for both banks not just 208?

2. Is there a way to check the health of the O2 sensors with the duramteric software (these are the original factory units)...assuming they could be past it even though there are no O2 sensor error codes?

3. Would a vacuum leak cause this? Any other thoughts before I buy random bits to throw at it?

Thanks RLers

K.

Kika

Clogged SAI codes are P1411 and 0410. P0208 I am not familiar with, Google says it is an injector malfunction for cylinder 8, which on a 993 is impossible.

Are you sure of the code?

When I installed my fabspeed cats, I got a P0126, but it turned out to be a vacuum leak, and unrelated to the cats. Befor purchasing the extenders ($150), I would double check the code.

kapflaco

Thanks Kika....code 208 is secondary air injection system cylinders 4-6 according to the Durametric software. My understanding is that 208 and 80 are the SAI fault codes.

Leander

From the Bentley service manual:

kapflaco

Thanks...K.

Vorsicht

See if you can take a look at the check valve. You may have to remove the air box to see it (or at least the cover). I checked mine a few years back and it was a pile of rust. You might just need a new check valve or the sensor attached above the check valve (which has a vacuum tube attached).

kapflaco

Thanks, will do. K.

John@Fabspeed

K.,

It is true that some vehicles are more sensitive to emissions parameters than others,and due to this in extremely rare cases one of our sport cats can throw a CEL for cat inefficiency (Ferrari's are the worst at this). In this event a set of spacers on the rear O2 sensors should help desensitize the readings enough to put it within spec. However, this would be the first time I have heard of a SAI code being caused by our Sport Cat X-Pipe. Unless there is something I am missing here...from my experience Secondary Air Injection is completely separate from the exhaust system and could not be effected by our Sport Cat X-pipe.

Please keep in touch about this and let me know what the final diagnosis is, very curious to see how this turns out and will support you in any way I can.

nine9six

OT...And apologies to OP for hijacking

Peter,
Please pardon my ignorance, but would you happen to know if this vacuum tube or sensor, has anything to do with the proper operation of the Varioram?

TIA

Vorsicht

I don't think it has anything to do with varioram. It certainly doesn't in my car as I have a '95 It is described as a 'shut-off' valve. The part no. is 99311324501. Number 4 below:

kapflaco

Thanks for the support...I'll report back to the group once I can get to the SAI check valve. My wife says that she and the kids are more important than the 993 right now....

John@Fabspeed

No problem. Lol, I can understand that one! My wife's been throwing her weight around lately as well, lest I forget I am married to her not my Cayman

pp000830

Below is just my opinion, I am not a professional auto technician just a shade tree hobby 993 guy..

I believe if you look for love in the wrong place hard enough some enterprising technician will tell you you found it and it will be expensive!
Get back to basics, you replaced an exhaust component, you then experienced a code related to that system.
It seems to me altering the flow or back pressure on the system can change operating dynamics in a CAT. Also the OE CAT probably has significantly differing gas flow and processing specifications than the aftermarket one. You also may have disturbed the wiring to the oxygen sensors or released some debris or simply burn in gassing out of the new parts in the system that compromised their performance.

Putting extenders as the aftermarket manufacturer suggests clearly is just papering over the issue and most likely, if discovered, is an ilegal alteration of the emission system. It is also a disclosure item when you go to sell the car.

My path would be to rule out any failed oxygen sensor, test the air injector system and if these prove to be OK send the aftermarket exhaust system back to the guys you purchased it from and go OE.

I would think a simple non-invasive way to test the air injector system without special tools or diagnostic equipment would be to detach the hose on the top of the check valve and see if the pump is actuating and making initial flow from the hose for a few seconds from a dead cold (sitting overnight) engine start-up. I would think a quick check of the air injector path is, with the engine off, to attach the hose of a shop vac outlet to the top of the check valve using a home made adapter or simply duct tape. Then go to the exhaust and listen for shop vac air sounds or better yet put a surgical glove over both exhaust pipe tips and see if they inflate slightly.
Then disconnect the shop vac and start the engine and feel for exhaust back-flow through the top of the check-valve, using care to not burn your hand to validate the valves function. If you are getting back flow the valve is bad or dirty.
Other's thoughts?

shadow993

I had this exhaust and needed the extenders as well.

Later on I would get a bad 02 code off and on with the extenders. A full tune-up later with caps, rotors, wires and plugs ...Problem solved.

You can check 02 sensor readings with a simple obd2 reader. Mine shows values and fluctuations. I don't recall the appropriate range, but google is your friend.

e9stibi

Here is a data point. I just took some measurements with the Jennikins tool and saw fluctuations between 0.1 and 0.7 V. No trouble alarms are recorded.