Hi, just cleaned the throttle body, MAF, and PCV, all first time at 57000 miles. The car runs a bit smoother now, though the throttle body was not overly dirty at all. PVC and MAF are super easy and straight forward cleaning procedures. I used a MAF/throttle body cleaner and old toothbrush on the TB but no brush on the MAF. Haynes manual does not show this procedure clearly, and YouTube does not have it for Versa.

WARNING! DO NOT attempt to clean ANY throttle body while the battery is connected. The throttle plate is not actuated by vacuum like in the olden days on carbs. A motor is used to move the throttle plate, and if the battery is connected, and your finger is holding open the throttle plate, that motor could cause the throttle plate to cut your finger clean off! The throttle plate has rather sharp edges and the motor is powerful. Also best not do spray flammable solvents with a battery connected. Nissan makes the battery easy to disconnect, so, like Nike says, just do it!


https://photos.app.goo.gl/LnL4jvoDJtMuX2Ms7


https://photos.app.goo.gl/9TQLm7TgPAf7hdx17

Needed to unhook the negative battery terminal. Loosen the hose clamps from the plastic intake where it attaches to the throttle body. Then remove three 10mm bolts holding the air box and snorkel to the car. Remove the air box. That provides space to get at the TB. Use plyers to remove the electrical connections to the MAF and one or two more. I think the TB connector could be removed w/o plyers. Several hose clamps needed removing and the hoses then removed from where they seat. The hoses had all "glued" themselves to their metal nipples, so I gripped them with plyers and gently twisted each to break them free, then they removed easily. All the hoses are pre-formed, so they are difficult or impossible to re-install in the wrong place. The electrical connectors removed are all different, and cannot be re-installed in the wrong place either. Take a picture of everything first. A few drops of coolant will spill, no worry. 4 bolts attach the TB (8 or 10mm?), which now has ez access. Remove TB from car. The crud on the TB took about 10 minutes to rub off. It was difficult to keep open the throttle plate for cleaning, but needs to be done. Won't damage anything. A finger (only when TB is removed from car- see above warning) works good for this. Rather difficult baked on black stuff, it was that needed to come off..You can see a bit of this crud in one of the pictures. Re-installed in reverse order and started up just fine, reset the clock. Runs noticably smoother. I thought gas mileage had fallen a tad, so cleaning was indicated. Glad I cleaned these items not mentioned in regular service intervals. Took about an easy hour and a half. Maybe 50000 for the first cleaning would be best, probably needs to be done every 30000 there after . Battery terminals got cleaned too. Good luck

Nice work. Couple of tips. First, if you hit your engine compartment and under-car connectors with some WD40, it usually won't be necessary to attack them with a pliers. Dirt and dust accumulated between the pawl and tooth is what makes them hard to release, and WD40 will wash that out and make popping the connector much easier. Second, if fuel economy was a concern, do an IAVL in addition to the work you've already done. I had one vehicle some years ago (happened to be a Versa) which showed a 30% before-and-after change in air volume following IAVL, just from aging silicon in the MAF. Your engine takes in about 9,000 gallons of air for every gallon of fuel you burn, so you can imagine the effect if the MAF thinks it's taking in 6,300 or 11,700. In the former case you'll get deplorable performance and a jacked-up long term alpha, in the latter case you'll get carbon buildup and deplorable fuel economy and a jacked-down alpha. IAVL calibrates all that.

Also, I read to place a drop of thin oil on each side of the throttle plate where it hinges. Give each drop a few seconds to drain into the throttle shaft bearing.

https://photos.app.goo.gl/ykziUfX7gw8ggtq16

Oh yeah, I forgot. When re-installing, gently tighten the throttle body into the rubber gasket, tightening diagonally in even 2 or 3 increments of tight, like when installing a wheel and tire. The gasket fits into a slot on the intake, not the throttle body, and is made of soft rubber. Replacement gaskets are not difficult to find, and you should have one before starting the cleaning.

Never heard of IAVL. Does it go by another name? Is it throttle body re-learning procedure? Tell me where I can find the procedure so I can do this, please.

IAVL = Idle Air Volume Learn. If you have CVTz50 to monitor your tranny then you'll find it in work support for the engine. If not there's a manual procedure for doing it without a scanner, although it's stilted enough to be a bit of a PITA. It will be the same on your '18 as a '14, see EC-126 here:
https://www.nicoclub.com/service-manual ... n%2FEC.pdf

Thank you for the explanation and link. Great for whatever ails my Versa.