ridinwitha35

iTrader: (1)

I did a MAF swap today & the results were so drastic I was feeling nice & decided to do a little write-up of the swap. Flooring it knocks me in at least 6k rpms with no hesitation (only floored it twice though); I used to floor it & get 5k rpms with good pull and then at other times it was if there was a brick wall at 3.5k rpms & it would slowly accelerate from there. Many have done it & this isn't anything new to the regulars, but for noobs out there like me who like seeing stuff step by step, here it goes...

I'm sure the elite can do this without taking everything apart like I show, but that's just what I did. Whole process takes less than 15 minutes.

If you don't know what this is about, this is a procedure for 5.5 gen Maximas [2002,2003] & I35s [NOT I30s] where you buy a basic version of the MAF and swap over a part from your old MAF to that new MAF, essentially making it a complete MAF as far as the ECU is concerned. This "basic version" does not contain a thermistor, which is a temperature-controlled resistor, known to the ECU as the IAT, or Intake Air Temperature sensor. The thermistor/IAT converts the air temperature into an electronic signal the ECU understands. This "basic version" is what is used on regular 5th gens & I30s without modification. A "complete version" can be purchased, but at the moment, there's a $300+ price difference, making it more economical to buy a "basic version", and swap the thermistor from your old MAF to it, turning it into a "complete version". This basic procedure details how to remove the old MAF & swap the thermistor over, but it has pics.

Parts:
- MAF: 22680-2Y001 (2k1) replacing my 22680-AM600 (2k2) maf; got mines for about $90
- All bolts are 10mm/phillips-screw combos...I used sockets cause some of 'em were rusty
- Collars are flatheads
- MAF sensor is secured with T15 torx screws


New maf includes the sensor & housing:


Good thing it includes the housing...screens side by side (new & old):

ridinwitha35

iTrader: (1)

Steps:

Unclip the MAF connector; remove air box/maf housing/intake tube by removing these bolts & loosening the collar's flathead. ALSO don't forget to take off the hose that connects from the intake to the front valve cover (I think)---the spiggot on the intake is the upper-most red circle. Then remove the whole thing from the car:


Remove the bolt & loosen the collar with a flathead to separate maf housing from intake tube:


Remove these bolts to separate maf housing from air box:


View after maf housing removed (can see the filter):


Remove the 2 torx screws, turn the connector a quarter-turn, and wiggle/pull the sensor out:

ridinwitha35

iTrader: (1)

The maf sensor once removed from the maf housing:


New (2k1) vs. old (2k2)


Electrical connection is via the metal clips squeezed around the leads of the thermistor


Separate clips using some side clippers...like you're removing a cotter pin.


Clips separated; also cut the plastic at the base (at the curved part)..be careful not to cut the leads!

ridinwitha35

iTrader: (1)

Note: might be best to handle the themistor with small pliers...I just used my hands & you can see I bent the leads - straight wires mean jack in terms of electrical conductivity...

Thermistor free...removing:


Thermistor in place on the 2k1 maf:


Squeeze the clips together once in place on the 2k1 maf:


Use something to hold the top of the thermistor in. Whatever you use, make sure you give it enough time to set, otherwise you'll hear a rattle on throttle (like I did with super glue gel...)


Put everything back together now...but don't forget to transfer the rubber gasket from your old maf housing to the new housing:


...looks like the maf that was on my car may have been from a junkyard...


There you have it. Start the car up. I did an ECU reset so it could get used to the more accurate airflow measurements. Go ahead and enjoy your new car.....

zidave

What exactly does that little wire do?

AEMAXIMA01

iTrader: (3)

It measures the temperature of the air coming through the MAF. He is using the 2k1 MAF bc the 2k2/2k3 MAF's are $400+ and the 2k1 is ~$85-90.

ninja edit

edgar5453

iTrader: (1)

Not to mention that you'll need to send in your car to the stealership for an ECU "update" since the newer 5.5 maf's usually require it.

I still think Nissan should provide any ECU updates for your model for free...

ridinwitha35

iTrader: (1)

I've heard about that & there was a paper in the new 2k1 MAF's box that said the same. After researching, some people didn't get it & some did. I personally won't get it 'til I have a reason to believe I need it (like if later on down the road I get an SES or fuel economy seems horrible).

So far so good - after 30 miles, no SES, all monitors already complete, intake air temperature is giving signal (as viewed with my OBDII scan tool), as well as the MAF (in spec 2-6 g.m/s at idle).

Rochester

iTrader: (3)

This was a fantastic write-up. The close-up photos are excellent. I've been wanting to see this stuff in detail for quite a while. I was confused at first with the thread title, thinking you went in the other direction. (And yeah, that would have been weird, unless you were junk-yarding parts.)

So I've got a question: is the plastic retainer at the top bend in the wire open on the 5.0 MAF, but molded closed on the 5.5 MAF with the wire going through it? Is that the way the 5.0 MAF came? It seems so odd that Nissan would build support for the 5.5 IAT sensor, when designing the 5.0 MAF...

...or, is it possible that they consolidated the design of the two MAF's for their parts supply? Oh wow, if that's true, that explains why this simple fix works. Although it doesn't excuse Nissan for charging an extra $300 for the IAT.

Rochester

iTrader: (3)

No, I believe that little wire is the IAT sensor. The MAF sensor is inside the tunnels of the plastic housing.

ridinwitha35

iTrader: (1)

Yes - on the 2k1, the plastic seat at the bend is just an open "U". On the 2k2, it seems as if it's more of an "O" but not sure if it was a single mold or a "U" with some top hat or clip. I think it could've been rubber as when I was clipping it, it was not brittle like plastic is, but it is a tiny piece. I just kind of had the intention of cutting it out from the get-go...should've probably taken more care to analyze how exactly it was secured. Would be nice if those who have done it could detail how they secured the IAT on the seat & how well it's held up.

As far as why the 5.0 MAF works...it's possible the 5.5 design (IAT affixed to the sensor) was first but they encountered some distribution/manufacturing problems and then resorted to an alternate design (the 5.0 design). I don't see why they would design "for the future". However, it does give those with malicious intent charging someone 400 + labor bucks for something they can get for 100 & almost no extra labor.

jasonmax

iTrader: (2)

thats a IAT sensor
but my 2002 has different MAF for some reason?

knight_yyz

iTrader: (40)

excellent write up!! That sensor wire that was swapped actually measures the temperature of the air going through the maf. The 2k0's and 2k1's have an external sensor. The2k2's and up use that thermistor to measure the temperature of the air which is required for the AFR.

ridinwitha35

iTrader: (1)

Is it a 22680-AM600?

Mine IDs as such:


Yours could be a 22680-6N201 if you have a build date prior to Dec. 2001 and are still stock. Based on this post, 2k2s prior to Dec. 2001 have 22680-6N201, while 2k2s after & 2k3s have the 22680-AM600.

But based on the bright yellow writing on the housing, it's possible the previous owner grabbed my old maf at a junkyard. Go figure...

Rochester

iTrader: (3)

"Replacing the MAF" is a concept so freaking pervasive in this forum. Any thread that starts talking about an engine's running performance or problems, someone, somewhere starts talking about replacing the MAF.

Since the 5.5 MAF is prohibitively expensive ($400), this write-up is invaluable for people who need some confidence in converting the 5.0 Gen MAF to a 5.5 Gen ($100).

This thing should get stickied. And OP, you should make sure those images are stored somewhere with some permanence in the web.

ridinwitha35

iTrader: (1)

Closeup of what the seat looks like on the 5.5; kind of hard to tell if that's still just plastic or something else (rubber?):




Comparison closer:

Rochester

iTrader: (3)

It looks like the manufacturing process for the current replacement MAF in the entire 5th gen line diverts because of the IAT. There must be another step whereby the IAT sensor is capped at the bend, melted into place maybe.

I'm pretty sure the 5.0 MAF was a slightly different design. It doesn't look that way anymore, with the only difference being inclusion (or exclusion) of the IAT sensor.

It all makes perfect sense from a manufacturing point of view. What doesn't make sense is charging $400. Seriously, that's not right. Nissan should be cognizant of this observation.

knight_yyz

iTrader: (40)

i think they might just touch it with something similar to a soldering gun. I'm going to do this soon, and I'll just put a small dab of plastex on there.

BTY In Canada, Nissan charges 500+ for either MAF, whether you get the 01 or the 03 model it costs the same. I'll be visiting Buffalo soon for a replacement.

jasonmax

iTrader: (2)

I think youre right, is there a difference between the 22680-6N201 and 22680-AM600?

knight_yyz

iTrader: (40)

the tube is the same, the sensor is different

jasonmax

iTrader: (2)

how do I tell if the MAF is going or not?
my car does 0-60 in 6.8s auto, and its still on stock MAF.

knight_yyz

iTrader: (40)

car won't go into the high rev's it will start to buck and stall

ridinwitha35

iTrader: (1)

I think you guys are right...they probably do melt the plastic to hold the thermistor steady at the top. I think I'm gonna just clip the leads of my thermistor & seat it so that actual thermistor is between the two clips, and solder it down; I think it will be better supported that way. Doesn't seem like the thermistor needs to be in the direct path of the "wind" especially since thermistors suspended in air usually have slow response times (>5 seconds)...it just needs to be in the intake tube. If I do mess something up, I'm sure I can grab a 2k Ohm @ 25 Celsius axial, DO-35 packaged thermistor...just gotta figure out the Beta values & other specs.


I think there's a couple classifications of the MAF:
- brand new / perfect
- dirty but cleanable
- dirty & uncleanable aka slightly damaged
- damaged

Damaged: Most likely get an SES or idling problems & the ECU will resort to fail-safe mode (2400 rpm limit).

Dirty & uncleanable/slightly damaged: No SES, but you feel that you don't get a smooth response throughout the entire rpm range (while in gear) or you have intermittent power conditions. You clean it & still no change.

I think this is where my old MAF fell. No problems at low throttle, but at WOT:
case 1=good pull, rpms are up there
case 2=brick wall at some particular rpm value (mine was ~ 3500rpms) with slow acceleration & sometimes all of a sudden the power then kicked in.

Did I mention when I bought the car, I noticed it didn't have an air filter in it? Yeah big fail on my part but that can definitely destroy the MAF not to mention the engine. For the record, I did plugs & knock sensor before the MAF. The above two scenarios still existed but the pull was much better (when it kicked in). After replacing the MAF, problem was cured. I still might do the fuel filter just-because.

Dirty but cleanable: You might have hesitation problems or you might not have any issues, but cleaning it makes the car perform better. You just have a little buildup on the screen which has lessened the MAF's sensitivity but values are still consistent for good control by the ECU. Probably best explained by normal "wear & tear".

Brand new: self-explanatory.

jamyers

iTrader: (1)

Where can i pick up a MAF for 2k1 for 90.00 at thinking of doing the swap as well

LongIslandMax

iTrader: (3)

pm Dave B

ridinwitha35

iTrader: (1)

^ What he said. Dave's username is: DAVEB

He quoted me $91 shipped from Texas to Chicago. I however have a hookup at a local dealership where I got it for the same price (cost+Illinois tax = Dave's cost + shipping) & same-day.

evalyn

AWESOME write up, OP!!! Taking my laptop out to the garage right now to have your pictures as a guide.

ridinwitha35

iTrader: (1)

np, but looking over my instructions, I forgot to say there's a hose you have to take off the intake that I think connects to the front valve cover. It's all the way at the top right in the first pic of post #2, I'll update the picture.

Edit: picture/instructions been updated.

Professor

iTrader: (4)

Looks more like a diode then a thermisistor, i dont know about a 2k5 but my iat is in the maf tube further up the line

Scottwax

iTrader: (8)

Someone mentioned getting one for an 00-01 at NAPA and it had the thermister wire already in place.

ridinwitha35

iTrader: (1)

It uses the DO-35 package which is used mainly for diodes, but works well with the environment the thermistor is in since the glass casing allows it to function properly in extreme heat....but not metal-melting heat.

mandyfig

Gotta get this done, I, too have a hook up with the local Nissan dealer....

MIK3

iTrader: (12)

Tackling this same thing next week. Excellent write up and awesome pictures. Thanks man.

2slow

iTrader: (6)

I will be doing this soon, but going from an early '02 to an '01 MAF (22680-6N201 to 22680-2Y001). Hopefully I don't need the flash mentioned in TSB's NTB03-022 & -023 to remedy my Maxima's issues.

After a few quick measurements I believe the IAT thermistor is Honeywell part number 135-202FAG-J01 (http://sensing.honeywell.com/index.c...1&pr_id=145443). Although my reference temperature measurement was a little suspect (Fluke multimeter gave a continually decreasing value). I have a few of these on order and will try with the new MAF.

ridinwitha35

iTrader: (1)

Nice! Good you used a meter...I was gonna do it the poor man's way...go into a hot room, measure temp & resistance, go into a cold room, measure temp & resistance...calculate. Let us know if it works...I see they're about 50 cents a piece from Mouser.

2slow

iTrader: (6)

Well, that's what I did with a Fluke 87V multimeter, just inside and outside; I really need to look into it's temperature measurement abilities. Even if the beta value is off a little, small differences in IAT measurements shouldn't affect cold start & warm-up driveability much. Although, I will also compare the new and old thermistor resistances across whatever temperatures I can generate and through a scan tool IAT readings.

This could be a good low overhead group buy opportunity. Have someone buy a bunch of these to save on shipping and resell them to community for a nominal fee (less than the cost of 1 + shipping). I only bought a few extras to play with.

ridinwitha35

iTrader: (1)

Oh, I thought you had one of those (expensive) thermocoupler/thermistor-measuring meters. +1 on the reselling point.

jamyers

iTrader: (1)

finally did this took like 10 minutes if that and what a diffence it made also my MPG meter on the speedometer updates every 10 seconds compared to what it was like 5 minutes

MIK3

iTrader: (12)

Just finished this as well. Very easily done!

For those looking to properly secure where the wire bends @ the plastic, I suggest RTV if you have a precision-tip applicator on hand. My low end has returned and there were zero issues! Very happy overall.

Dave Holmes

RTV would work, but if some of you get UOA's, it'll show up as elevated silicone in the oil like from a dirty air or coolant leak. You can rule those out by looking at other associated numbers (for example, lead also elevated because of dirt or coolant, and potassium elevated if a coolant leak). Just a heads-up so people don't freak out.
If you don't get a UOA, don't worry about it.
I'd probably re-melt the plastic over it with a blade tip on a soldering iron.