wcpierson

Im trying to diagnose some hesitation on my car when the rpms are under 3k and I wanted to know how can I tell if my MAS is bad and also is there anyway to clean it properly?

Garf

iTrader: (1)

by MAS do you mean mass airflow sensor? (commonly called MAF here) If your MAF(S) is bad the car won't rev past 3500rpm IIRC. In your manual it should show how to test with a multimeter, i can't remember off the top of my head what the resistance should be.

Also if you haven't already done so, you should check the ECU for codes. on the top of the 3rd gen forum in the stickies there is a general maintenance FAQ thread with instructions on how to pull codes from the ECU, the codes will hopefully tell you what's wrong with the car.

I experienced chugging/hesitation at low rpm's in my max due to a bad o2 sensor.

wcpierson

Yes MAF im from the DSM world and we call it MAS. Thanks though Ill try to get the codes pulled tomorrow and see what happens. My car smells like gas too so maybe its the o2 sensor.

sb_max510

probably fuel injector or fuel filter

internetautomar

iTrader: (30)

the MAF if disconnected will limit the engine speed to approx 2k. to test it, you unplug it and see if your issue goes away in that idle-2k rpm window. If it does, then your MAF is bad, if it doesn't then you need to keep digging

wcpierson

Ok I checked the ECM and Im throwing a code 33 for the o2 sensor

Garf

iTrader: (1)

you can get a new one at a local parts store for less than $100, simple 10 minute fix. Just jack the car up on the front pass. side, and on the passenger side of the exhaust toward the rear of the front tire you'll see the old o2 sensor in the exhaust, it's a 17mm IIRC. Follow the wires from the o2 sensor (about a foot or 2) to the harness, just disconnect the wire harness( can be a real ***** once dirt gets in it), unbolt the old one and replace with new. Be sure to thread in and tighten the new o2 sensor BEFORE attaching the wire harness to avoid twisting/bending the wires. Also, be sure to tuck the wire up along the same path as it had prior to removal. Drop the car down and Bob's your uncle

BenStoked

iTrader: (7)

^^^ plus some penetrating oil (WD-40, pb blaster, etc) will make the job 100x easier.


(btw, Bob's NOT my uncle... it's Bill, or John)

burhan92SE

Time to clean iacv as well

wcpierson

Did that already with some carb cleaner, on a very cold day too...couldnt feel my fingers

wcpierson

How do I know which o2 sensor is giving me the code? Dont we have more than 1? Total newbie question. sorry

BenStoked

iTrader: (7)

my parts car didn't have but one o2 sensor, just before the cat.

Garf

iTrader: (1)

yup, our cars only have 1 o2 sensor afaik.

internetautomar

iTrader: (30)

either did any other 3rd gen maxima or camaro