Cat-bypass and PSE mod caused CEL - 986 Forum

steve00s · 02-05-2006, 09:32 PM

I was told it could never happen but after installing Fabspeed's cat-bypass pipes along with a new Porsche Sport Exhaust (I didn't hook up the vacuum/electric switch) the CEL came on after only 10 miles. How is this possible? I did not touch any of the sensors. I already have an EVO high flow intake so thought maybe the increased air flow may have kicked the air/fuel ratio out of some parameter but kind of doubt that. I do plan on having the GIAC chip upgrade in the next couple of weeks but want to work out this bug first.

The car was sitting for several months before the install so could that have had anything to do with it? What should I try to resolve this?

On the positive side, the Fabspeed part is a beautiful piece of workmanship. It is a shame one cannot see it under the car. The chrome is first rate and the fit was perfect. I didn't expect too much HP increase without the chip upgrade but it was noticeable and the sound was a definite improvement. Absolutely no resonance with the top up.

xclusivecar · 02-06-2006, 02:18 PM

Code!?!?!?!?!

steve00s · 02-07-2006, 07:57 AM

My shop cannot get me in to read the code for a few weeks. They did say that if there was moisture or some other problem that is no longer occuring the code will discontinue after three or four drives. I guess I'll cross my fingers for now.

xclusivecar · 02-07-2006, 08:41 AM

A few weeks?!?!?! Do you have a place such as autozone nearby? Many times they will read the code free of charge. No sense in guessing. Get the code and go from there...or better yet, invest in a code reader and reset the CEL yourself.

blinkwatt · 02-07-2006, 08:53 AM

Go to the auction site and order an Actron. Any will do just make sure it has the 16 pin connector.

steve00s · 02-07-2006, 08:20 PM

Its a small shop and one of the mechanics got hurt recently. They do great work and are usually pretty busy so thats why the delay. Thats a great idea to get a device so I can read the codes myself. I guess I just assumed that they would be very pricey. I'll check it out.
Thanks.

JP-s-in st. louis · 02-08-2006, 07:07 PM

Quote:

Originally Posted by steve00s

Its a small shop and one of the mechanics got hurt recently. They do great work and are usually pretty busy so thats why the delay. Thats a great idea to get a device so I can read the codes myself. I guess I just assumed that they would be very pricey. I'll check it out.
Thanks.

Screw that! go to an Auto Zone or other part shop nd they will tell you what code it is.

steve00s · 02-09-2006, 02:33 PM

I bought the code reader today. A pretty good investment with these code happy little buggers.

What I got was P1128 O2S RANGE 2 Cyl. 1-3 and P1130 O2S RANGE 2 Cyl. 4-6. Which as I understand it the air/fuel mix is too rich. I thought it would run lean if anything with the increased air flow unless the system is overcompensating for it.
I still don't think that the O2 sensors all just suddenly went out. I guess
I'll erase the codes and keep my fingers crossed. I am getting the GIAC upgade soon so maybe that will help.
Thanks.

AUDIOGUY · 02-09-2006, 02:40 PM

Steve,

I have had code 1128 before and it occurred after I did the Evo intake and B and B exhaust. I dont have a cat bypass. I cleared the 1128 once and it hasnt returned.. I have had a 1127 code for MAF or air fuel mix metering issue. I cleaned the MAF sensor and reset it this weekend with good results. You should disconnect the battery for 20 or so minutes and then reconnect it. Start the car and let the computer re-learn the system with the new intake and exhaust. This may correct the fuel air mix a little. Dont worry about the car running rough for a few minutes after you first start it. This is normal and will correct itself. Maybe this will help!
P.S. dont forget to get your radio code before disconnecting the battery. You will
need it when you reconnect power.

Best of luck!

xclusivecar · 02-09-2006, 03:19 PM

OK...there have been lots of posts on O2 codes and my 2000S Just had the 4th replaced this last weekend. Its good that you cleared the codes. If they return like mine did, you either have a bad O2 or MAF from my experiences. Start with the O2 sensors and test as MNBoxster has described in an earlier thread. Find the bad one and replace it. Chances are that withen 2 weeks of replacing one you will get another code because the others are much older and can't keep the computer happy. Result...you will end up replacing all 4 sooner than later.
How many miles do you have? I had 53,000 and all previous threads noted the O2 sensors will last approx. 60,000 miles. So I was in the ballpark for replacing mine. My MAF also went out. This also set O2 codes but the dealership figured it was the MAF initially due to the fact that I had a terrible idle on cold starting and rough idle throughout my drive. Further tests proved it was the MAF. The O2 will run you approx. 200 each and the MAF could be 300 depending on where you buy your parts. Replace them yourself and save big money on easy labor!

kias@tampabay.rr.com · 02-09-2006, 03:47 PM

I had no problems with my Fabspeed cat-by-pass pipe but I used Fabspeed muffler together. I also have the EVO with ECU update. My Boxster-S is clocking around 4.9 second for 0-60 without putting too much effort in to it (GTech).

TriGem2k · 02-09-2006, 04:24 PM

Quote:

Originally Posted by kias@tampabay.rr.com

I had no problems with my Fabspeed cat-by-pass pipe but I used Fabspeed muffler together. I also have the EVO with ECU update. My Boxster-S is clocking around 4.9 second for 0-60 without putting too much effort in to it (GTech).

How much power do you think you are getting out of that thing?

xclusivecar · 02-09-2006, 07:31 PM

Quote:

Originally Posted by kias@tampabay.rr.com

I had no problems with my Fabspeed cat-by-pass pipe but I used Fabspeed muffler together. I also have the EVO with ECU update. My Boxster-S is clocking around 4.9 second for 0-60 without putting too much effort in to it (GTech).

4.9?!?!?!?!...Thats quicker than a 2006 Carerra. No disrespect but that sounds quite a bit generous. What else have you done to the car? All other posts concerning mods to their Boxsters produced little to no difference in performance gain. Some even lost power! Some said a bit better throttle response and a better sound but never a gain like that. This would have had to been a 100+ Horsepower increase! Either your g-tech is lying to ya or the stop watch doesn't start until you hit 30!

No flame intended...just surprised at the claims made.

RandallNeighbour · 02-09-2006, 08:10 PM

Quote:

Originally Posted by xclusivecar

OK...there have been lots of posts on O2 codes and my 2000S Just had the 4th replaced this last weekend. ...Find the bad one and replace it. ...The O2 will run you approx. 200 each and the MAF could be 300 depending on where you buy your parts. Replace them yourself and save big money on easy labor!

Replace all four 02 sensors at the same time. The reaction time of a new one mixed with old ones will throw a CE light and cause havoc.

www.oxygensensors.com sells them for $119 each. Just bought four. Replacement is easy. Took me 45 minutes and I was working slowly.

xclusivecar · 02-10-2006, 01:21 PM

I agree with RandallNeighbour 100%. Change all 4 if possible. All of mine were covered under an extended warranty but they would only cover each individual one as they expired! No cash out of pocket, but LOTS of time in and out of the dealership!

BTW--RandallNeighbour, is that for an OE (Bosch?) sensor? Thats a great price and I believe on my invoice that the dealership would have billed me $245/sensor had I not had the warranty! Makes me rethink the extended warranty I purchased since you can buy parts rather cheap online if you look and can do the labor yourself! Oh well...my first Porsche and didn't want to take the chance of something happening since everything you hear in the auto world is how expensive and how hard these cars are to work on. Obviously not in the Boxsters' case. This has been the easiest car I have ever done maintenance on!

Adam · 02-10-2006, 01:56 PM

Quote:

Originally Posted by kias@tampabay.rr.com

I had no problems with my Fabspeed cat-by-pass pipe but I used Fabspeed muffler together. I also have the EVO with ECU update. My Boxster-S is clocking around 4.9 second for 0-60 without putting too much effort in to it (GTech).

Not really that surpising to me. C&D and R&T are going from 0-60 in 5 sec flat in a 276hp 987S and it weighs more than the older 986. With a proper ECU tune and full bolt ons some people have reported 25-30hp gains.

RandallNeighbour · 02-11-2006, 09:09 AM

Quote:

Originally Posted by xclusivecar

BTW--RandallNeighbour, is that for an OE (Bosch?) sensor?

Yup, Bosch sensors with the proper plugs on the end, just like from the factory. And they work great. No CE lights or problems to date.

kias@tampabay.rr.com · 02-11-2006, 10:05 AM

By replacing the factory muffler and 2nd cats you will lose around 55lb. The PSS9 kit is also lighter than the standard shocks and springs. If you calculate the HP vs. weight, 100lb lighter in the rear means 1 more HP for you to work with. The air is cooler in Tampa, which where I live. I have not done anything else to the car accept what I posted. I only rev the car up to 2500rpm when launched for 0-60 measurement. I have clibrated the G-Tech already. Most of the people that use G-Tech are posting a .1 second accuracy for the 1/4 mile, so I assume it is pretty accurate. Forget the sound, the power that I gained from the mode is very noticable, specially in the 2nd gear.

xclusivecar · 02-11-2006, 03:13 PM

Sounds like you have a nice ride! I usually quote my numbers as published by Porsche forgetting that they usually are very conservative at best.

nastyboxster · 03-06-2006, 10:37 AM

Kias

The Gtech also measures hp and torque. What are you getting on the Gtech? Also, did you get the one that comes with the software? If so, can you post the hp and torque graph? I'm curious to see how accurate the device is and maybe ordering one myself.