FOUND FIX FOR K&N CAI - read!!!!!

Guys...I am absolutey thrilled. Long story short. Last night I installed my K&N CAI on my 99 Carrera 4 996. It took me about 2 hours to do and I carefully followed all instructions. The time came to start the car...and boom...the problem a lot of you guys are having: ABS and NO PSM...mine went further throwing a check engine light a few seconds afterwards and my hesitation was poor then. I tried differen things with minimal success and I had decided to go and disconnect the battery for 2 hours like someone had suggested on another post. While I was doing that, it occurred to me that I had a similar situation with my 93 300ZXTT which had a Stillen dual intake. A lot of people experimented really bad hesitation and sometimes blown MAFs if driven during long periods of time as it was suspected that the amount of air coming through the intake and filters was "too much" for the MAF and that the "high velocity" stack that the the intake had as a whole would not allow the MAF to get a good reading. So...I figured WTF... The fix on the 300Z was to cut a couple of strips of duct tape and tape them to the side of the filter to create turbulance as the air entered the MAF...or you could create a small bracket and mount it inside the filter to create such turbulance. First of all, I am NO mechanic, just a car enthusiast so I thought - it is definitely worth a try. I cut a 2 small strips of duct tape and place them on front an side of the filter element/cone. I figured it could be simply too good to be true but, since I had no other choices at the moment, except wait until tomorrow to call K&N and give them a piece of my mind......WELL, GUESS WHAT.... IT FREAKIN' WORKED...I AM JUMPING WITH JOY....I have been up all night but this is definitely made my day. I am going to the store in a bit to create me a bracket that would create this turbulance as the duct tape looks ... er...tacky. I will try to post some pics up in a bit. !!!!!!!!!!!!!!!!!!!!! I am not saying this will work for everyone, but if this is the fix, in fact K&N goofed up big time...can someone else try it and see if we can establish a pattern and then call K&N and *#_*$#_$....!??? Thanks!!

Yeah - let's contact K&N and ask them to add this to their installation instructions I'm currently in contact with both their customer service and tech people. Net, I am returning my CAI and want to be reimbursed for a blown MAF. I'm not gonna start duct taping my intake... Sorry you also have to go through this. Let's see what the coming days will bring. You're not off the hook yet.

the problem does come from too much air, the problem comes from the oil from the filter coating the maf, using tape to reduce flow on you high flow intake, sounds kinda ..................... to throw those faults that that quick there little chane the k&n had anythign to do with it, more likely that you started the car with maf sensor unplugged or loose

I have to fully agree with you...WTF? Step 17: Cut 2 pieces of duct tape and place them 3 inches apart from each other on your filter cone. If your car throws codes and engine lights then spend all night trying to figure out something... You are absolutely right, I am still not in the clear. 99Firehawk is right though, maybe something else was wrong as I took the MAF sensor just to make sure it looked ok and put it back in before reconnecting the battery. I just came back from a 30 minute drive...and so far, so good. The car sounds freakin' amazing...I could not get myself to revving it below 5,000 rpms at which engine speed the car simply screams and sounds .....sounds....I just can't describe it. I am praying to the Porsche Gods that I don't have any more issues with it.... Good luck Yves...I will still contact K&N on Monday to give them a little piece of my mind...

I got a CEL about 400 miles later with the CAI and just pulled the MAF, sprayed it down with intake cleaner, let it dry, re-installed and it runs perfect now. Probably the best thing to do for this kits is not to over oil the filter from the factory or when cleaning it. The oil coats the MAF...plain and simple.

Good to know David...this is probably something I will have to do as well later on. I only drive about 3,000 miles a year or so on the car. Just so that I can be prepared, which intake cleaner did you use? I might have to go and buy one and just keep in handy just in case...thanks!!

Tailwag, I think you may be onto something for a solution, but your conclusions are in the wrong direction. I have personally put down over 500 wheel hp through a single Z32 MAF (no dual intakes) with a JWT ECU program running Nismo 555cc injectors. This is about the limit for the voltage range that this MAF can read. This is why they have the dual intake setup. With 2 filters, the ECU is actually only reading the airflow for half the engine. Beyond this range, the only problem is the engine will lean out since it can't meter anymore air. You are correct that there are issues associated with this. Because of this, JWT has ECU programs specially written with completely different voltage maps for the MAP to eliminate any problems. There are many that have chosen not to use this programming. You will not get a car to run right without have the correct ECU program and yes JWT has programmed the wrong one on occassion. As a result, reading off the MAF at idle is below the minimum range. Basically, the MAF is seeing far too little air, not too much. The ECU doesn't realize it is seeing half the airflow in the engine and tries to adjust the timing and fuel for this lower volume. This causes a lot of the driving issues. This has even resulted in blown engines. You will find many that have used MAF signal modification devices like Super AFR's and Super AFC's to try to correct this, but those device can only correct in 1 dimension. They can't compensate in 2 dimensions like the ECU map does. This does lean to some interesting pieces of evidence. First, let's look at what is common. The overwelming majority of people with problems have early 3.4l 996's. K&N's prototype development was done on an 03' (its on their dyno charts) with a 3.6l. So if the problem is 3.4l related, what is different on a 3.4l over a 3.6l? The 3.4l has an engine with less stroke and displacement. It has a variable intake and variable intake cam timing. The 3.6l has variable valve lift and variable exhaust cam timing in addition. The 3.6l has better torque at low rpms due to sucking more air into the engine. Even at idle, the 3.4l will pull in less air. My first though now on this is that the amount of air the MAF is able to read is based on how much air the engine can suck in split across the volume of space the MAF resides in. Is the inner diameter of the K&N intake tube different from the upper lid where the MAF is mounted on a 3.4l or 3.6l? If so, this will efect the ability of the ECU to compensate for airflow properly. If the tube is larger, the MAF will see less air. If the 3.4l has a map that isn't suffiiciently large enough to hold these values, it would trip a code. The 3.6l due to its variable valve lift and variable exhaust cam timing has a later version of engine management software with additional and modified maps. It may be that the map is sufficiently large to adapt to the change in the airflow on the 3.6l, but not on the 3.4l. Next, I am wondering how many people went to their dealer to have their codes reset when they had problems? With Nissans, a lot of the engine codes have to be reset and won't just go away even if the engine returns to a normal state. Misfire is one of these. There is a procedure using s screw driver to turn a screw on the side of the ECU on Nissans in conjunction with turning the ignition key that will reset codes. The only other ways to reset them is to unplug the battery for over 24 hours, use a Nissan diabnostic tool (Consult) or specialized after software and interfaces (Conzult). I am wondering if the ECU in the 996 works in the same way? If people were getting a code, swapped back and were still getting the code; did they go to the dealer and have it reset or did they order a part? In other words, were the MAF's really blown or was the ECU just continuing to trip the code? This could be verified easily with a proper piece of equipment. For Nissans, the MAF voltage readings can be read actively with a Consult, Conzult software or a Techtom MDM-100 computer monitor. I wonder if they have something similar on the Porsche side? Questions or comments? If the real problem is that the K&N intake is simply too big in diameter for the 3.4l, then applying tape to the filter to direct more air to the MAF in the tube could fix the problem. The downside is it will also most likely eliminate the freer flowing nature of the intake and the use it was purchased for. I have an 02' 3.6l Carrera that is running a K&N 63 series intake. I installed it with a Fabspeed exhaust at the same time. I've had absolutely no problems with my intake and my car dynoed 22 rwhp more with the intake and exhaust on a chassis dyno for reference.

You definitely bring in a different perspective and I enjoy the read - it makes VERY good sense. I know when I ran the dual POP chargers I had to get a different program for my ECU to match the additional air but the high volocity stacks were part of the problem - while they were able to "get air quicker", the air had little or no turbulance when reaching the MAF...tape was the simple solution to add turbulance or adding some sort of "protuberance" in front of the MAF for the turbulance to be initiated before it reached the device...it worked. I only put down 412rwhp on the Z but I did that with stock turbos...i think having the dual pop was overkill... Just for kicks I disconnected the battery and took the tape off again...started the car...no problem...but 30 seconds into idle the ABS light and PSM off light came on...I have to admit this brought chills into my body as, while I was intrigued it would come on again, it reinstates your possible theory. Shut off the car, put the tape on the filter one more time, disconnected the negative, waited a good half hour and reconnected everything and started the car....let it idle for 2 minutes....no codes, no lights. Took it for a spin to go and pick up the pizza my gf ordered....drove fine, no issues...lots of high rpms (love the sound...!!). Could this really be the issue? What I would like to do is drill a small hole on the tube in between the MAF and the intake/cone and either screw in a long screw or make a pod that will stick in to create turbulance...but I don't want to do something that K&N would consider tampering with...I am sure eventually they will figure out a solution and will come up with a replacement part of some sort. I can definitely feel a difference in power - the butt dyno is pretty accurate. ... the car seems more responsive too... I just don't know -....

The MAF is not a linear reading device and it could be reading and reporting proper airflow at idle and not at WOT or visa versa. On a NA engine, the screen on the intake before the MAF can be critical as it increases the velocity of the air past the sensor. Removing the screen does may increase air volume overall, but the decrease in air velocity can play havoc with the sensor. You are more likely to report less airflow than you are actually getting causing you engine to run leaner at WOT. This is why many NA engines gain a little more power removing the screen. Therefore, by blocking part of the filter, as mentoned above, you are increasing the velocity of the air at low speeds and getting a more accurate MAF reading.

02 Carrera, I had my K&N CAI installed for me by K&N at their headquarters in Riverside, CA. I got to see their prototype folder that they had on file there, showing the different cars that they used when they R&D-ed this kit for our cars. It included 10+ 996's several of them were 3.4l and a few were 3.6l. Mine is a '99 C4 and they had tested it on a '01 C4 along with 2 or 3 '99 vehicles. They (K&N) are aware of one thing already: the tight clearance between the heat shield and the engine pulleys. I intend to make them aware of the MAF getting coated by the filter oil and giving CEL readings. In my opinion, care needs to be taken to not over-oil the filter and wrapping it in newspaper overnight after recharging it before re-installing it back in the car.

i had the problem also and all i did is disconnect the battery over night and no problem ever since.

What about this , or at least a version of it?

On a (perhaps) related note, I swapped out the serpantine belt last friday, wich requires removal of the air box. I wanted to make sure the new one tracked correctly and started the car with the air box off. Of course I got the ABS and PSM lights. The belt tracked well. I reinstalled the air box, and started the car. Same lights come on. I shut the car off and closed the engine hood. Restarted the car and voila, all is well. Go figure? Must take time for the fault to work its way out of the system?????????????? Being use to working on the 928, I have to admit a bit of frustration in having the "system" alarm an element that is not faulty at all, just because something else (air sensor) is not connected.......Where is the logic in that?

The sense in that is when you have the MAF disconnected, the default maps are used by the computer, guessing how much air you have coming into the engine when it is not provided any airflow or intake temperature values. Then the O2 sensors and LTFT values have to deal with the more or less air that you are actually getting. This generally will not harm then engine in closed loop (just pollute more), but can be catostrophic to the engine at WOT is you're excessively lean.

And PSM / ABS fault indications on the electronic dash are related to this in what way?