gen1

Okay. You've diagnosed you problems to the MAF.
If the MAF has never been replaced, you are most likely looking at it having some significant wear on the potentiometer carbon trace. But not to worry, because with a very little bit of work you can extend the life by at least a factor of two.
You will need some rudimentary test equipment - a digital VOM - can get a cheapie from Radio Shack or Canuck Tyre.
In order to work on it, it is easiest if you remove the MAF from the car. The pin numbers are clearly marked on the outside of the connector. First do the routine checks on the resistance between pins 33 and 34, this should be somewhere between 100 and 400 ohms. Next measure the resistance between pin 34 and pin 35, this should be between 200 and 500 ohms. With the entire assembly at a nominal temperature of 68 F (20 C) measure the resistance between pin 25 and pin 34, this should read below 2900 ohms (colder temperature should yield resistance above 2100 ohms but less than 2900).
Now the hardest part. You have to remove the plastic cover from the bottom of the MAF. Nissan just glues this on with some sort of silicone based sealant. To do this you will need a very sharp knife and a wee bit of patience. I used a box cutter knife - yes of the terrorist variety - and just slid it along each joint, keeping the blade as tight against the aluminium case as possible. Take your time and do several passes, because you want to remove all of this adhesive material and get under the edge of the plastic cover about 1mm (1/16th inch). You can also use something like a dental pick to scrape the sealant from between the case and the lip of the plastic cover. Once you've done this it is possible to gently pry the cover off the case.
Underneath you will find the potentiometer and a circuit board about 3 x 1 inches (7.5 cm X 2.5 cm). The wiper of the potentiometer runs along the carbon trace on the edge of the board. You will see that the wiper is split and each segment has a small bead that forms the contact with the carbon trace. You will also notice that over time this bead has worn a groove in the carbon trace. You can measure the resistance across the potentiometer, as you move the flapper on the MAF. You will see the resistance go up and down several times on the full range of motion of the flapper. If in doing this you see the resistance go to zero ohms, you will know that the wiper has worn its way through the carbon trace and is contacting the substrate - this just confirms the MAF diagnosis.
All you have to do to fix the MAF is to shift the location of the circuit board every so slightly so as to get the potentiometer wiper to contact, previously untouched carbon trace. Loosen, but don't remove the three screws that secure the circuit board to the housing, sufficiently that it is easy to shift the circuit board. Now you should be able to push the circuit board towards or away from the connector, whichever is easiest for you. You should be able to shift it 0.5 mm easily in either direction. Hold the circuit board tightly in the direction that you have shifted it and carefully re-tighten the screws.
To see that you have affected a change. Test the resistance across the potentiometer as you move the flapper. You should see higher resistance values than initially, and you should not see any zero ohm readings. Fixed!
Before you glue the plastic cover back on make sure you clean out the housing of any little bits of residual sealant. Clean off the gutters on the plastic cover, and the outside of the housing. Take a quick-clamp (IRWIN) large enough to grip the girth of the MAF and use it to hold the plastic cover onto the housing. Then apply either an acrylic sealant/cement or a polyurethane cement as original. Allow to dry. Reinstall and enjoy driving your practically new car!!
Note - Given the dimensions of the carbon trace it should be possible to employ this technique at least twice before contemplating replacing the circuit board (part # A31-8412RA 3706). That works out to approximately 450000 km life for the average dinosaur MAF.
-like have a nice day eh! bob

E-CARP

Bob, Thanks for the info, mine has some hesitation while accelerating at part throttle, and it sounds like the flapper is hitting the stops, either the wide open, or the idle, I can,t tell which? When I have some time I'll take it apart, as it's now over 170,000 miles,
Earl

Maxwell Smart

I assume this will work on other year MAF/Maximas?

gen1

Sorry, only for the 1981 through 1984 Maximas, 1983 280Z and earlier L-jetronic systems. In 1984 Nissan went to hotwire anemometer for airflow measurement in all other models, the Maxima changed in 1985, when it switched to FWD, VG30.
-bob

Maxwell Smart

Pitty. Thanks for the info before I started hacking up my old T.U. MAF.

Bleach

well, my advice is to open it up and clean those contacts really good but do not adjust anything unless your displacement has changed. A freshly cleaned AFM is basically like a rebuilt unit.

mango22au

i have 1988 pu11 vg20et i live australia and i need afm my is the hotwire type dose any one know of a suitable swap for these cars as we have very few of these models in aus i cannot belive how hard it is to get any thing for these cars think i might have to get a simpler car like a ford v8 get anything anywere

maxitech

iTrader: (7)

Could you offer any MAF advice to a 3rd gen driver?

gen1

I believe that the MAF employed on the VG30et is very similar to that used on the VG20et. There should be more than adequate supply for that model. You must appreciate that it will take a lot of digging around on your part to keep your vehicle operational, as the manufacturer has not really published anything at all about the functioning of any of the computerized equipment. Other than to let you know what some of the diagnostic codes actually mean. Schematic diagrams of the ECU and MAF would really aid in the diagnosis of these systems.

-bob

josah

I got the right resistant on the 33-34 (203); 34-35 (311), but when I check the air temp sensor 34-25 I get 1880 (air temp is 80 F). I cooled down the snesor and it went to 0. Is there a way to get one of those air sensors? Anyone know?

josah

in my Hayne manual, it says that 32 - 34 it should read 0 (while moving it). Mine reads 56 and moves up as I move it. I have 2 used MAF and both are acting this way. It ran fine while it was cold but now that it's warmed up I can't get it to run well at all. Are both these toast?

HowlerMonkey

There should be plenty in the junkyards.

Someone stated that nissan went to hot wire on the maxima in 1984 but it was 1985.

josah

howdy, Ordered a reman. MAF and all the resistance test are the same. Air temp one is still off. Car won't run in the warm weather. I repaired the MAF with the above info. (thanks again) I drove my 84 maxima all winter here in MN with only problem being that it was hard to start after the engine warmed up. Changed the engine temp sensor twice,didn't help. (Thermotime, water temp, fuel regulator, what else is there to change?) Now with it warm outside it starts (after sitting a few days) and warms up and tries to idle down and dies. Idle bounces up and down and dies. If I get it to start just runs bad and dies.
Any ideas? they would be helpful. Thanks.
have 2 used MAF and both do the same thing. Now the remanufactored and same. Planning to replace the air regulator cause it only opens a little.

gen1

I had similar problem, the car ran just great during the winter, but as soon as the air temperature got above 70F the car would inexplicably die, usually in stop and go traffic, but occasionally on the fwy. Finally traced it to a bad ignition switch. Note that the ignition switch runs the ignition and EFI relays directly, and if these little buggers shut off EL AUTO NE FUNCTIONADA!

-bob

josah

Thanks, I'll check that.

kassim503

The AFM is a great place to pull a little power, if you decide on pulling the afm there is a big gear on the inside, that is connected to a w-shaped wire. If you want to pull a little more horsepower you can unscrew the w shaped wire and turn the gear clockwise about 5 teeth and screw the wire back in. But when u do this you need to hold on to the gear and not let it spin, what this would do is lower the spring tension on that little door inside the afm so itll give the car a little more gas.
You might fail emmissions, just might, I ran mine 5 teeth out and I checked it and I came mighty close to the edge of the NYS emmssions test.

sixty8panther

Wow... very cool, I mioght try that soon.