A million related threads on these components, but here's one direct question I can't find answers to:

Can the MAF or Knock Sensor fail incrementally, or is their functionality in total, meaning either it works or it doesn't?

 

They can both intermittently not do their job.

 

Well, when my MAF failed, it didnt do the usual 3k-3.5k rev limit thing all the time. It would do it very rarely and when it did, i'd just turn the car off and back on. The car reved out like normal though. It was just dead slow at WOT. The car actually felt stronger at half throttle than it did at full throttle. I just swapped it out with a free junkyard one just for the hell of it. The difference from the butt dyno was like if I were to spray a 50 shot.

Before I swapped it out the 3k rev limit would start to happen more frequently. So I guess it CAN fail incrementally. But It can also intermittently do it's job when on its way out like Nmex said.

 

essential's description is of off-again, on-again failure. And I understand that experience, having had the similar behavior with failing coil packs.

But what you're describing is full-on failure, then full-on functionality. What I'm asking is, can a MAF or Knock Sensor fail partially, like where it "mostly" works, but not 100%?

 

Well, yes and no. Remember that I said, even when it would rev out no problem, the car was considerably slower. Like there was no torque available. With the new one it felt like a new car.

Actually, would the lack of power be considered full on failure as is the 3k rpm limit?

 

I've read about people replacing their knock sensor in response to light pinging. Does that make any sense?

 

My buddy had that on his old o3 6mt max. His maf according to a few tuners was "weak". The pulls werent as hard as they shoulda been at wot. I'd say it was somewhere around 70-80% working? Butt dyno proved it but than again that's not the most reasonable proof. However He did drive around like that for 2 months and it kinda died high end. It never fully went out though (to know knowledge).

 

Maybe try this:

http://forums.maxima.org/5th-generat...-write-up.html

 

Oh, nice. Thank you, NmexMAX. Based on this, it appears the MAF can send a "weak" signal, which means it's possible for the MAF to be at less than 100% functionality. I wonder about the Knock Sensor as well?

However, I'm not understanding how the voltmeter is getting a connection to the 4 wires for the reading. Can you explain that? (Dammit, Jim, I'm a Doctor, not an Electrician!)

 

http://forums.maxima.org/1557964-post3.html <-- You might want to check an FSM for proper ranges for our (03) KS.

And this post explains how to check each wire (4).
http://forums.maxima.org/3798707-post12.html

Check each wire individually ... using the battery GND.

I'm not an electrician either, it's called comprehension.

 

Just to follow up on this thread. I replaced my MAF last week with a new 2001 MAF, and soldered on the IAT thermistor. The new MAF works just fine, and apparently my old one worked just fine, too... So it seems all I did was some preventative maintenance for about $100.

So that leaves me to consider (obsess over) the Knock Sensor. To that point again, has anyone ever replaced their KS in an effort to address light, low-end pinging?

 

I had to replace my knock sensor about six months ago due to a SES light (actually the KS, camshaft, and crank position sensors all failed---or were on their way out). I had moderate low end pinging (around 1.5-2K rpms) year-round and it was drastically reduced when the knock sensor was changed. Now I rarely get any pinging, unless it's really hot outside. Also, according to the in-dash mileage calculator, I'm now getting a whopping 15.7mpg as opposed to the previous 14.6mpg.

 

On my 4th gen, I experienced the same thing, no pore pinging.

 

Hmm... moderate low end pinging. That's me. Although it's more like idle-1500, not above.

ridinwitha35 took some great pictures of his KS replacement last Fall:

http://forums.maxima.org/5th-generat...ere-we-go.html

 

Notice any change in performance? I've considered changing my KS to fix the typical 1700k RPM (give or take) ping, and to see if it can help performance at all. My car has been running great lately, but sometimes it just does not pull as strong.

 

This is beginning to look like a few years ago when 4th gen KS's were going out, and a lot of members started replacing them and saw overall improvement in MPG/performance and less pinging. History does repeat itself.

 

Like Nmex mentions above, changing the KS does help performance. However, you should note that I also changed my spark plugs at the same time as part of my 100k maintenance and my car was running pretty crappy before. Nonetheless, my car pulls a lot harder now and I'm happy with the results

 

Here's the specific answer.
http://forums.maxima.org/newreply.ph...eply&p=7579659

 

NmexMAX, you might want to fix that post. Your link loads a reply form to Spock. However, if you paste the link text in your quote into the address bar, you get your 7-year-old entry on testing the KS.

My favorite was your old Groucho quote: "A child of five could understand this. Fetch me a child of five." I feel like I'm channeling Groucho.

 

Ya who cares ... I don't ... point being, you know your resistance values now and that's that.
_______________

 

"I just want to have a beer while I'm caring."

 

Maker's Mark > *

 

KS can be checked with a DMM. The resistance is supposed to be between 400-620 ohms.

As for MAF, you have to check for voltage between pins 2 & 4 and ground. 2 is supposed to be 5v and 4, 12V.

Both sensors play a very substantial role in power loss.

 

Does a dead MAF affect fuel economy much? Mine has been dead for a while now, but I am picking up a replacement from DAVEB soon. Car feels strong until 3500rpms, and I never really go beyond that, but still need to get it replaced.

 

My gen 5 Maxima was knocking even though I only use Sunoco Ultra. Went to 3 mechanics with no luck. Had the car carbon cleaned as a last resort. Then the car developed a stalling problem & I read in one of the posts here to clean the MAF sensor. It didn't fix the stalling problem, but no more knock. Go figure.