Mass Air Flow Sensor

Post by **Nitrus0nous** » Mon Jul 05, 2004 6:32 am

My 89 hatch has some idle problems from time to time, but they can usually be fixed by jiggling the wires coming from the mafs. Now sometimes, when i mess with the wires, it fixes the idle, but then my car will stumble/stutter very much when im trying to drive....usually not until 3k-4k rpms. sometimes the only way to get around the stuter is to floor it, but even then it still might do it a little bit.

I have been thinking about replacing this part, but have not gotten around to it yet. I'm definately not an expert when it comes to engines and whatnot, but if wiggling the wire that comes from the mafs works, one would have the tendency to think that the problem is being caused by that part.

I was looking around on courtesy nissan or whatever the site is, and saw a price of 400+ for a new MAFS.

I never even thought that the price would be this high for the part. I would really like to get it replaced so I dont have the problem anymore, but 400 bux seems like a lot. I know i could opt to buy a used one, but then i might still have the same problem. but if used is a lot cheaper than 400 bux, i might just have to go with that.

now if my assumption is wrong with it bein the mafs, does anyone have suggestions as to what else might be causing the problem?

Post by **Nitrus0nous** » Mon Jul 05, 2004 6:32 am

when it is idling like crap, it usually jumps between 500-1000 rpms, and sometimes lower. also, i can see a bit of blackish smoke coming from the exhaust. but like i said, wiggling the wires seems to get rid of it.

Post by **Ubernoober** » Mon Jul 05, 2004 6:32 am

Go ahead and price one from a recycler and see how much it is. It might be cheap enough that you can buy it to replace/diagnose your problem. It is unlikely that a recycler would give you a bad one and if they do, they have 90 day returns (for credit unfortunately).

You diagnosis sounds good so far.

Post by **kyle1911** » Mon Jul 05, 2004 6:32 am

Running rich it seems, check the MAF voltage with a multimeter i forget the correct voltage it is suppse to have so hopefully someone else can help me out on this.

Check your O2 sensor as well thats on the lower portion of your exaust manifold.

Post by **Nitrus0nous** » Mon Jul 05, 2004 6:32 am

yeah, i have a new 02 sensor sitting in the garage, but i dont have the right socket. and i couldnt find one when i went to home depot. i wont have my car back till tomorrow, gettin new front tires. but then its probably goin back to a transmission shop to see wtf is wrong with it and why it wont shift outta 2nd gear.

Post by **180fan** » Mon Jul 05, 2004 6:32 am

clean the plug, why buy a new one when you can just scrape away at the green corrosion and then use a small screwdriver to tighten down the connectors on the plug side?

Post by **Nitrus0nous** » Mon Jul 05, 2004 6:32 am

i had actually planned on cleaning the plug once i get my car back. i hear people say to use 'brake cleaner', but i dont really know what to get

Post by **frapjap** » Mon Jul 05, 2004 6:32 am

The MAF is really, really sensitive. Some cars aren't so bad, but the ones in the 240s are ridicilious. If theres the slightest leak, hiss, movement of it, it WILL stumble. Mine was crap when I put a conical on it. The adapter wasn't PERFECTLY lined up, so it stumbled all over itself and stalled. Try making sure any and all bolts are tight, wire harnesses too. It doesn't ever hurt to replace that 02 sensor either.

Post by **C-Kwik** » Mon Jul 05, 2004 6:32 am

Check the wires and the terminals. Make sure the connections are solid and the wires do not have a break in them. Replacing the MAF will do nothing if either of these are the cause.

Post by **xns** » Mon Jul 05, 2004 6:32 am

I may have an MAF for you, cause I have an 89 too, but I performed a swap to 91, so now I think I may still have the MAF, I will check for you.

Post by **Nitrus0nous** » Mon Jul 05, 2004 6:32 am

awesome. let me know when you find out

Post by **Yorb** » Mon Jul 05, 2004 6:32 am

i'm interested in this too. i'm going to pick my car up today after a successful timing chain replacement (bleh, there goes the bank). but i was having major problems stalling all over the place beforehand, and now the mechanic seems to think its the MAFS going bad. =( I don't want to spend another $500 or whatever on this mafs crap.

where is it, so i can examine it and jiggle the wires and stuff when i get the car back? =/

Post by **xns** » Mon Jul 05, 2004 6:32 am

If the MAF goes bad you usually will need to replace it... however, I have heard of people in the past that just messed with the wires and had stuff correct itself. As for where it is... Coming out of the throttle body there is the intake pipe right? The MAFS is the only metallic part of the whole intake tubing. Its on the right side if you are facing the front of the car, and connects the intake pipe to the intake box... Time for some ASIIC...

intake pipe- ||_____ \_____(( >to the intake box ^ MAFS

wow i suck....

does someone have a pic?that did not turn out

Post by **Yorb** » Mon Jul 05, 2004 6:32 am

wow your ascii makes no sense whatsoever ;D

i think i know what you mean though... between the air box and the rest of the black plastic intake tube theres a silver connector thing. right?

Post by **Nitrus0nous** » Mon Jul 05, 2004 6:32 am

On my cardomain page, the last picture at the bottom is a picture of my intake. The MAFS is the metal peice right after the k&n filter/adapter plate. There is also a plug and a little black box type thing that are hidden behind the red tube and white peice, but they're there.

Post by **Nitrus0nous** » Mon Jul 05, 2004 6:32 am

I seperated the MAFS from the filter and the intake pipe today. I cleaned my filter with the k&n cleaner crap that comes in a kit. I also wiped down the inside of the MAFS. There was lots of gunked up black crap inside. There are two holes on the inside, and you can see something in each. Is there any way to 'clean' these peices without damaging them?

Post by **Nitrus0nous** » Mon Jul 05, 2004 6:32 am

As i just remembered, when i went to Advanced Auto before, i had my friend look up the price for a new mafs. I remember him saying something under 100$. Why would courtesy nissan/everything nissan (cant remember which) charge 400$+?

Post by **Yorb** » Mon Jul 05, 2004 6:32 am

according to the FSM, check the voltage like so:

1. Fold back air flow meter harness connector rubber as shown in the figure if the harness connector is connected.2. Turn ignition switch "ON".3. Start engine and warm it up sufficiently.4. Check voltage between terminal 1 and ground.5. If N.G., remove air flow meter from air duct. Check hot film for damage or dust.

obviously i am too lazy to scan the diagram, so basically just test the wire farthest to the passenger side of the car (it's white for me). with ignition switch on it should be around 0.2v and with engine running (warmed up) it should be between 1.0v and 1.4v (approx).

i'm stupid and never know to use AC or DC, so i just flip the switch on my multimeter until it gives me a believable reading =P with engine running i generally got below 1.0v (0.9v or so), which seems to tell me my MAFS is indeed bad.

anyway. thats that.

Post by **gumby** » Mon Jul 05, 2004 6:32 am

yeah it was $95 + core deposit at NAPA

Post by **Juujai** » Wed Jan 19, 2005 1:01 pm

i had that same problem. i just yanked out the whole aiv thing. its to the right of the exhaust manifold. and it stopped idling weird. it took me a while to yank everything out though search for aiv removing guide in the forums. its around here somewhere

Post by **the_saint** » Tue Mar 29, 2005 4:28 am

Yorb wrote:according to the FSM, check the voltage like so:

1. Fold back air flow meter harness connector rubber as shown in the figure if the harness connector is connected.2. Turn ignition switch "ON".3. Start engine and warm it up sufficiently.4. Check voltage between terminal 1 and ground.5. If N.G., remove air flow meter from air duct. Check hot film for damage or dust.

obviously i am too lazy to scan the diagram, so basically just test the wire farthest to the passenger side of the car (it's white for me). with ignition switch on it should be around 0.2v and with engine running (warmed up) it should be between 1.0v and 1.4v (approx).

i'm stupid and never know to use AC or DC, so i just flip the switch on my multimeter until it gives me a believable reading =P with engine running i generally got below 1.0v (0.9v or so), which seems to tell me my MAFS is indeed bad.

anyway. thats that.

Is this the same procedure for ka24e and ka24de?

Post by **Nismo_Freak** » Tue Mar 29, 2005 7:59 pm

the_saint wrote:Is this the same procedure for ka24e and ka24de?

Yes.

White - Signal White/Black - 12V ConstantBlack - Ground

Same for all 3 wire MAF's.

Post by **maik21** » Wed Mar 30, 2005 10:11 am

you need to put multimeter into dc mode!!!! good luck

Post by **Nismo_Freak** » Wed Mar 30, 2005 11:50 am

maik21 wrote:you need to put multimeter into dc mode!!!! good luck

Werd, cars run on DC.

Post by **benemorius** » Wed Mar 30, 2005 1:31 pm

The maf can be cleaned with carb cleaner. Be gentle. The two protrusions inside are quite sensitive. One of them produces heat and the other reports how much heat it is absorbing. Air flow affects how much heat gets from one to the other. Knowing how the thing works usually gives people much more respect for how clean and precise it must be to properly report the volume of air flowing in.

[opinion] Nissan parts are so much more because they are built well. It would be an equally true statement to say that parts-store parts are so much less. (aka - dirt cheap) Parts from the parts store are hit and miss. Sometimes they're ok; other times they are schite. Starters are one extreeme, and spark plugs are the other. Non-Nissan plugs are ok if you pick good ones, but NEVER buy a starter from a parts store. Does it cost 1/3 of what a Nissan starter costs? Yes. Is it's quality 1/3 that of the Nissan starter? No. More like 1/33 [/opinion]

For anybody testing their maf: A reading that is out of range does NOT ALWAYS MEAN A BAD MAF. For instance, a bit high can frequently be caused by a dirty maf or a bad ground connection to the maf harness, and a bit low can easily be caused by a dirty maf connector or a bad vcc connection to the maf harness. A reading of just under 1v would leave "bad maf" pretty far down on my list of suspicions, fyi.

Post by **maik21** » Wed Mar 30, 2005 4:30 pm

yep , but some sensors work in ac mode!!! .... its not the case of maf!!

Post by **tiger** » Wed May 04, 2005 7:48 am

i hate MAF's. They have caused me so much headache. I'm having the same probs. Nitrus.... irregular idle... jumps from 800 down to 650, then slowly back up. uhhgh! The car shakes and put put's out the tail pipe when i'm slowing down. i BARELY made it in the driveway when my MAF started acting up... close one. i'm not a happy camper right now

Post by **BioHazzard** » Thu May 12, 2005 12:28 am

where did you get your new intake I just moded my but lost the wormer tube skot

Post by **tiger** » Sun May 22, 2005 3:35 pm

one question, where is the ground located for the MAF? Where is it actually grounded?

Post by **NateDogg** » Tue May 24, 2005 8:13 am

It is grounded on the intake manifold above the coolant pipe.

Anyone having MAF problems: -first take off the harness connector and clean the terminals with electrical contact cleaner and/or sandpaper. -Next, push up on the sensor connnectors so they make a solid fit in the harness connector. -You can also use electrical contact cleaner on the heated elements, but make sure you spray from about 12" away and you let it completely dry out before starting the engine.

Mass Air Flow Sensor

Mass Air Flow Sensor

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