MAF Question

[SnowSurfLax]

Alright, I've read a bit here about how the MAF can get gunked up. Does the check engine light come on if it fails? My QX seems to idle a little rough at times and I took it to my mechanic and supposedly got the 120K service done when I had my timing belt replaced.

Any ideas why it idles rough when I start it up? I can even feel it when I drive around at idle speed, moves kind of jerky as the it idles rough. Seems to go away after I drive around a little bit.

Also, my engine makes a whining noise at around 2K rpms. Mechanic told me it was the new timing belt. Never heard one make that sound before, myself.

[fueler]

In this order, I would:

use seafoam (in crankcase and in the intake) clean MAF clean throttle body change plugs

change fuel filter drive 50 miles change oil

[SnowSurfLax]

I'm assuming seafoam is a cleaner I can buy at the parts store?

Anything special I should know about cleaning the MAF?

Thanks fueler!

[30bino09]

Do not touch the sensor's coil thingy inside......

[fueler]

yeah u can get seafoam at any parts store, i got mine at Worldwide auto parts on Clairemont mesa but kragen and autozone should have it too. I'm in SD too - particularly Bankers Hill and also Clairemont. If you have some time this weekend you can cruise up to my Clairemont driveway and I can help you do that stuff...

[02pathy]

as far as i know all car idle rough when they r first started and then tend to run normal after they have reached operating temp.

at low speed between 20 and 40 k in stop n go when 1st or 2nd gear goes in and then you start to apply the brakes it will tend to jerk

belts always make some noise when they are new give it some time to wear in maybe a week or two if not then it might beed adjustment

[SnowSurfLax]

Yeah, all cars idle rough at first. But when I bought and for 1.5 years after that, it never idled that rough. It would idle at warm up rpms until it warmed up, everything hunky dory. But about 3-4 months ago, it started to idle at warm up rpms, then would jump up to 2000 rpms and then pop down to idle rpms, then after a few secs would jump up to 2K rpms again and then pop down to idle, etc, etc. until the engine warmed up. I put some Berryman's fuel injector cleaner sometime in Feb and it stopped doing it for a while, but eventually returned.

After I did the 120K and timing belt, it doesn't do it anymore as far as I've noticed. Now just idles a little rough. Could just be old age, but I want my my engine performance back up to normal, instead of this (what feels like) 90% crap.

Thanks, glad to know the belt noise is normal.

Fueler - can't this weekend. What are you doin next saturday?

[fueler]

hmm possibly. what weight of oil are you using?

[88pathoffroad]

If the timing belt whines consistently or sounds like a quiet gear drive, it has been over-tensioned. A properly tensioned belt should not make any noise at all, even when new. An overtensioned belt can break, causing severe engine damage.

No idea on the rough idle when cold. It's tough to impossible to diagnose problems on a car you can't see or hear in person.

Quote »Do not touch the sensor's coil thingy inside......[/quote]BS, you can clean them with a Q-Tip. Just be careful. New MAF's are expensive.

Quote »as far as i know all car idle rough when they r first started and then tend to run normal after they have reached operating temp.[/quote]Again, I call BS. A properly tuned-up and maintained vehicle will idle as smooth when cold as when hot. Mine does.

[SnowSurfLax]

I'm using a synthetic of whatever grade is the manf. recommended. I don't recall off the top of my head. I take it in to get changed because I live in SO CAL and dont' even have a drive way to call my own.

Not EVERY vehicle idles smooth when cold, regardless of being maintained and properly tuned. Depends on temperature and the vehicle. And properly tuned is relative to application.

Anyway, can someone get NISTECH to comment on the timing belt whine? It only makes the sound from 1600 - 2100 rpms and has been doing it for about a month now. I drive an average of 300 - 400 miles a week, so I think I'm past the break in period.

And lastly, Fueler - Where do you take yours to get work done? I don't think I'm that comfortable with my current mechanic

[fueler]

Fueler - Where do you take yours to get work done? I don't think I'm that comfortable with my current mechanic

I go to TK import in North Park 4516 1/2 30th StSan Diego, CA 92116 The owner Ted is legit, funny *** polish dude, hes been in that location for 20 years. I've known him for many years now - doesn't rip anyone off no matter what the situation is. He has done a lot of work on my QX4 including repairing the AC system which i absolutely destroyed in Baja (broke the condensor open with a rock at 100 mph and ran it dry for about another 4 hours - now it is still blowing cold w/ stock compressor 3 years later), all 4 struts and fixed the suspension when i destroyed those in Anza Borrego (you seen my collapsed suspension thread) , the whole t-belt swap, so he definitely knows whats up with R50.

[02QX4ME]

I think when cold, idle rpm is higher, therefore we feel it's "rough" although it's not. When warmed up during normal driving at the same cold idle rpm, the road/wind noise covers the rpm noise so we don't feel it "rough"...

[SnowSurfLax]

Fueler - thanks! I think I'm going to check him out next time.

I should elaborate on what I mean by "rough". Not that the rpm's are high, but that they're not holding consistent. It drops several hundred rpm's for 1-3 seconds before jumping back up to high idle. So when I put it in D before it's up to temp, it'll move forward kind of jerky when the rpm's take their huge drop.

It's probably a dirty something-or-other, but these damn electronics irritate me with this crap. What I wouldn't give for a good carb.

[SnowSurfLax]

Oh, hey! No one answered me about the check engine light. Does it come on if the MAF is gunked?

[02QX4ME]

CEL happened to my 00 RX300 at 45K miles. I cleaned the MAF with the spray from Fry's, reset the CEL, and it never came back.

[nissandoms47]

it shouldn't unless its completely filled up with junk.

[02QX4ME]

When I cleaned my RX300 MAF, the thin wire looking stuff inside was covered with something like epoxy. It was just a little bit in the center of this wire. The wire center is of larger diameter. I didn't use Q-tip to clean it, as I don't know how easily it could be damaged. Just sprayed and shaked really well to dry it. It is the easiest fix.

Not sure about QX4/Pathfinder's MAF but it should be very similar. After RX300 MAF was cleaned, I tried taking QX4 MAF off just to see how clean or dirty it was, but for some reason I couldn't pull it out. Afraid of breaking it so I gave up. "Don't fix it if it's not broken......"