motodave4

Just picked up a 2008 997430 with a fabspeed CAI and Remus Exhaust. She is mint and has only 29.4k on her. On way back from picking it up (100 miles away) it threw a CEL. Naturally this was concerning so went straight to my local dealer. Has many O2 sensor faults. He said the filter looked dirty and the car was running very lean on the computer. Was not overly concerned. Wanted me to clean the filter first and then bring it back. Lean would be too much air so wouldn't a dirty filter help it stay in tolerance?

I called Fabspeed and they claimed to never hear of such a thing. Odd since many threads on here have responses from fabspeed.

I'm not freaking out yet. the selling dealer feels awful. I sold Porsches during the 997.1 gen and the car drives rock solid. If anything she's a bit sensitive feels like the sport mode is on even when it's not.

It also has a remus exhaust. I know if you run lean for too long an just keep clearing codes you can burn out the cats. Perhaps this is why the cat faults?

Does anyone know if this combo is simply problematic? or problematic without a chip to enable the car to add a greater volume of fuel flow than what is within tolerance?

What about disconnecting the MAF Sensor and running like that to see how it runs?

Lastly the selling shop (whom I continue to trust so far) wants me to bring it to his independent to "tune" it for the CAI/Exhst combo....HOW? what can be done to "Tune" a Porsche without a chip? I've never heard of this.

My inkling is to have my dealer go up and down on this puppy ASAP. Any preliminary advice would be helpful. I don't have stock airbox and frankly the sound is AMAZING

DC911S

Clean your TB. Take it off and get some CLC and give it a good cleaning. Could be bad gas too. Go get two bottles of Techron and run that through

Petza914

If that air filter was originally installed with it being over oiled, the oil mist can contaminate the sensitive wire in the MAF and not measure air flow correctly, throwing a CEL. Disconnecting the plug on the MAF will put the car into limp mode, which means it will just use middle of the road fuel trim settings. You can try this as a test and see if it drives better or worse. If it's better, your MAF is probably contaminated. First thing to do would be to buy a can of MAF safe cleaner from the auto parts store, remove the MAF and spring it down - make sure you spray the wire inside, but don't touch it.

The proper way oil these open air filters is with the K&N refresh kit available at your local auto parts store. After removing the filter from the CF pipe, spray it with the K&N filter cleaner, let it soak in for a bit, and them rinse it out with warm water - I rinse from the inside out so the dirt doesn't get pushed further into the media. Then they need to dry naturally, like outside in the sun - you can't use compressed air. Once completely dry, spray the pleats with K&N filter oil following the directions, which means letting it sit and absorb, then doing a little touch up on any spots that are still white or light pink. Then this is the MOST IMPORTANT part, which is not in the instructions - using about 10 paper towels, stuff them inside the filter, wrap the outside of the filter in a few more and leave it like this overnight. The paper towels will absorb the excess oil that the filter media didn't and prevent it from contaminating the wire in the MAF.

You might also want to pick up a K&N hydrophobic pre-filter for the open air filter. These repel water, but let air pass through so that when you drive in rain, the filter media doesn't get saturated in water and helps prevent the engine from sucking in moisture. They come in blue, red, yellow, and black and if you're interested, I can look up which part # fits the Fabspeed air filter for you and you can order off of amazon. The blue one is on my car in the photo below. Good luck.

Regarding the exhaust, does it still have cats? How many cells? If the cats are 200 cell then you should not have issues with CELs. If they're 100 cell or cat bypass pipes, you will need the spacer bungs to move the 02 sensors out of the flow further to try and have them not trip.

Once you've cleaned the MAF, cleaned and reoiled the filter, disconnect the battery for 10 minutes which will reset the fuel trims in the DME - DON'T CLOSE THE FRUNK WITH THE BATTERY DISCONNECTED. Then reconnect the battery and go for a drive. The car may run a little rough at first as the DME adjusts the left and right bank fuel trims, but should in short order sort itself out. Also, don't worry about the PSM failure message when you first start it up after the battery disconnect - that will go away very quickly on its own once you start driving.

I have the same Fabspeed J-Pipe intake on my car along with 200 cell X-cats and do not have any CELs, even with it being supercharged.

motodave4

Petza914 thanks! This is pretty much how I intended to spend my Sunday after reading lots of threads. Fabspeed did say the filter was a “dry” filter and did not require oiling. Mechanic said not to oil it ideally.

My hunch/hope is the dirty filter made a dirty MAF and everyone just needs a bath. Perhaps this is the lucky CEL which lead to the previous owner wanting to sell such a clean car and hence how she found me?

i would have likely closed the boot not thinking about he consequences. This is the best part of your detailed advice!!!!

i feel 1000% better knowing you have the same intake whout issue. I want to get it up in the air and see this exhaust. I was able to find the mobile number and email
of previous owner. I emailed him asking a few questions. So far no response. Fortunately I worked for the dealer who will be maintaining the car and they are extremenly excited for me and generous with their time so far.

all signs currently point to Classic MAF dirtiness. May have harmed the CATs in which case I will be back here asking about part numbers for the best cats ;-)

i will lookup the filter cover this is a brilliant suggestion as well.

We have a dryer dryer with a sneaker shelf what do you think about drying filter this way to speed up the process?

i HATE compressed air on a filter

Petza914

I think a very low velocity air source like a boot dryer is fine.

motodave4

Heard back from previous owner..... oy

so I have reconnected the Battery. Left the hood up!!! The filter was disgusting. Absolute black soot. It’s now a nice gray. I’m going to leave oil off for now and double-check with fab speed. I would love to know the part number for a red hydrophobic cover. Car was wet and the rain dripping onto filter when opening lid went right through the membrane.

sprayed the heck out of the MAF with CRC MAF cleaner. Not sure if this will do much.

If the fikter was really gunked it could have been throwing faults because the fuel reduction to maintain the ratio would have been outside the range.

We will see. I’m feeling like a new MAF cats and O2 sensors may help me sleep better at night.

Filter is drying now (pic). After done I will start it up with sensor disconnected and see how it goes. Will I need to reset the faults with a disconnect after this test? Feel like I will.

Petza914

Since you have the MAF and filter clean and have already disconnected the battery, I would do the first start with the MAF connected and see what you get. If you still have issues, then you can disconnect the MAF and see if there's a difference because by then you'll have to replace something anyway and will have to do the reset again anyway, but if the car runs good and the codes stay away, you won't have to do another disconnect / reset.

The K&N prefilter for that Fabspeed filter in Red is RX-4990DR -
I have that same Fabspeed filter and I oil mine. Can't see how that gauze in a dry state can capture the finer particles. I run oiled versions of these filters on all my cars and none of my Used Oil Analyses show increased Sllica levels which would be dirt trapped in the oil if the filters weren't filtering well.

Also, $2,000 is nuts - you can buy a used OEM airbox in the Marketplace here for a couple hundred dollars. They come up for sale frequently. If you get a CEL again, we need to know the codes to determine if they are being tripped by the intake or by the exhaust (cats, O2 sensors, etc). I would also take a look around to see if you might have small vacuum leak somewhere. If so, that will let unmetered air into the motor and throw off the mixture readings. A few years ago for a couple months I would get an occasional CEL related to mixture and could never figure it out. Then I found a sligthly loose cap on one of my RUF intakes, tightened, it and the CEL has never come back since.

Let us know how you make out once the filter is dry.

motodave4

All I can say is this guy was a RUB and thank goodness he didn’t own the car for very long. Also the dealer is at fault for not being more diagnostic and at least trying a MAF. Parts replacers!!! Here are the results:

Reassembled all the components but left the MAF unplugged. Car started right up was boggy for about 5 seconds then ran perfect. Less touchy on the throttle and it has been too easy to stall lately. Now it ran nice. Pulled strong etc.

Plugged the sensor back in and it ran like compete garbage. Couldn’t even maintain an idle. Throttle response was non-linear again etc. way too easy to stall etc - characteristics of being too lean. It would stall if I didn’t give it throttle. Fortunately I didn’t go very far and got it home. CEL popped up as soon as I hit the driveway.

So the car definitely needs a MAF sensor it would seem. Will have a readout performed to confirm.

Depending on what the exhaust looks like (Cat forward, swapped cats etc) will tell the next steps. Running like this for this long possibly fouled the cats. And likely fouled the O2 sensors which was the bulk of the myriad of fault codes it had when I took it in Friday.

I checked for vacuum leaks but don’t know everywhere to look. Will let dealer check.

They probably harmed the MAF installing the intake or the intake fouled the MAF over time. It should have a hydrophobic cover on it from FabSpeed IMHO.

Good thing I bought the extended warranty so long term engine stuff had 60k miles to appear. Seems just fine.

thanks for the help!!!!

quik update: realized Car prob didn’t like the MAF suddenly coming online like that so I did the batttery reset again and this time she purred like a kitten with the MAF plugged in. I’m going to drive her for another 150 miles and hopefully no more CEL. In meantime I se some Remus systems require a tune. So I’m on a hunt to figure out which one is on Guardtrude here to see if it’s a version which requires a tune and then we’ll know what’s causing this without spending tons of money replacing sensors or heaven forbid cata

motodave4

So CEL came on this AM car ran like crap. Would’t hold idle. Went to Paul Miller Porsche and they were GREAT!!!

MAF Fault was present. We replaced it and it ran well.

Here are the values:



Mass airflow volume at idle should be 16/17. Fabspeed obviously flows more.

the blue lines indicate trim from O2 sensors. +-4 % will not throw a CEL.

We determined (not on lift) Car has aftermarket headers, cats and a Remus Sport exhaust: Remus got back to me and said they made headers and Exhaust but only have a Cat delete option. It is recommended to to an ecu tune.

drove it home and was GREAT. At 38 miles after the second restart on a cold engine I got a CEL. Wondering if ambient load means it trims outside 4%?

So it appears it requires an ecu tune. I’m not thrilled about that. Finding a stock airbox will likely not help. I’m sure it has CAT faults at this point.

Is my my best course of action to replace these cats with 200 cell and will they fit and will that help?

what is the durability of a tune? Will it affect engine life (feel like it will)? Who is the absolute best tuner? Would the tuner need to know exactly what’s on the car to tune it and how would I find that out about the cats?

Petza914

I don't have any experience with custom tunes, but they do scare me a little as they can change fuel trims which could lean out the mixture under high RPM or high load, eliminate the knock sensors from retarding timing when they sense detonation, raising the red line, etc. As far as tunes I've heard people being happy with, I'd say Fabspeed, FVD, and Softronic would be the top 3.

If you're running cat bpass pipes, that's certainly wihat's throwing the CEL and I'm not sure they really buy you much vs a high-quality 200 cell cat from a reputable company that uses high quality catalytic converters like HJS (Fabspeed and others use these). As long as the Remus exhaust is modular and you can buy pieces of it separately, it should be designed to marry-up to the standard exhaust components, so changing the cats should still let you use the rest of the system you have, and if the cat bypass pipes are good quality stainless, someone would probably be interested in buying them from your for their track car, which will help you recoup some of the cost of new cats. Cross-flow or X--cats are supposed to improve performance over dedicated crossover cats by allowing the pressure to equalize between both sides of the motor. If one side is moving exhaust gasses faster that tends to create a vacuum to the other side to help draw them out as well. I think you said you had equal length headers too, which is good - once you connect the two sides of the exhaust you want the exhaust pulses to be lined up so they don't collide and create turbulence within the exhaust system, as that makes egress less efficient. The cylinders have a firing order and equal length, long tube headers allow the timing of the exhaust pulses from each cylinder to "maintain their spot in line" so to speak. When you have headers where the gasses take the most direct route to the merge collector you lose this pulse alignment effect, especially if you allow exhaust from both sides of the motor to merge, like in an X-cat. It would help to have some pictures from under the car of your current setup.

DC911S

ECU tunes are easy with the OBII tuner. You load up the current tune into a handheld device, transfer that to your computer, email it to the tune vendor with a list of your mods, then they send a new one back via email, you transfer that to the handheld device, then load it in. Be sure to do the TB adaption after that. I still say you need to take the TB off and clean it. I have FVD and I'm happy with their tune.

motodave4

well mystery(s) solved!!!!

filter cleaned. Got my hydrophobic sock installed. I also sourced a stock airbox off an '08 C2S complete for only $200 on eBay. So I'll be putting that on for at least the Winter and perhaps non-track days.

MAF replacement fixed the MAF and pre-cat O2 sensor fault issue - even with Fabspeed intake. Still getting CEL's. I had spoken to all the major tuners listed here. Connected well with Scott at Softronic. Liked his style. He wanted to know the codes. As did i so I bought a cheap OBDII reader and resetter.

I had a P0430 code left which he said would likely be the case. Cleared it a bunch of times and it keeps coming back. Oddly far more frequently now that the other faults are gone. Might be the cold weather.

Scott warned me about the "Shoddy" 200 cell cats out there and also agreed the MAF issue could have fouled a cat or two. My warning was right bank.

His 200 cell's are guaranteed not to throw a CEL and for $1,400 the price is right. So i pulled the trigger. Hopefully they mate up to the headers and Remus.

Ideally I want to leave the tune stock but he says he can tune it any way I want and he doesn't write new code only adjusts what code Porsche has there already. I really liked his approach and trust him implicitly. He does not seem like a"hot dog" tuner.

Meanwhile, car is running PERFECT right now. and sounds GREAT!!!! So happy I pulled the trigger. Also happy to have a stock box to play with to see how she feels vs the fabspeed.

Petza914

Glad you're on your way to recovery. Keep us posted on the tune, your airbox observations, and the cats.