bigd480

A few weeks ago my car started being a little noisier when stopped at a light, like the center dash would vibrate enough to make noise. The car is daily-driven and well-maintained otherwise, so the noise is getting annoying. I thought it was just the stuff in my ashtray/pocket/etc or looser dash trim fitment since I've had the stereo in/out a few times over the years.

However, I noticed it completely goes away in Neutral/Park. It's not an idle issue, as it idles around 800 and it's same whether in Drive or not.

I have new front/top motor mounts, and visually inspecting the rear mount it looked fine. Could this be a transmission mount or is there something else that would cause this? I did the "put car in drive and rev while braked" test and the engine doesn't move at all.

KP11520

sounds like the Harmonic Balancer is starting to break down. It's the pulley on the front of the engine that drives all the belts and such. That's where I'd start.

bigd480

Should have added: it also completely goes away as soon as I give it some throttle. The car spends most its time at 80mph on the tollway so I would have thought a pulley/HB issue would be more noticeable at higher RPM?

KP11520

So try pulling the plug, one at a time on all 6 coil packs and see which has no affect. That's a likely culprit as well.

They don't always throw a code.

bigd480

Thanks! FYI here’s a video of the sound while in drive vs neutral/park:

and the motor mount test:

KP11520

What about reverse? Sound like Drive?

bigd480

I would've said reverse is the same yesterday but when I listened this morning it seemed somewhat noticeably less rattly.

KP11520

That rattle sounds more like something bolted to the engine and when under a little load at idle speed, roars like a mouse. Whatever it is, it's disrupting the normal smoother idle. Resistance can do that.

The fact that you would say yes yesterday and no today but still yes in drive, makes me say also just check the transmission. Maybe something like bearings are worn on the input shaft or first gear shaft. Same with all the engine powered belt driven parts, Alt, PS Pump, AC Comp, Tensioner pulley. Or something off the Timing Chain like a water pump or other moving parts.

Hard to rell by YT video. Maybe have a friend sit in the car with the brakes on (emergency brake too) and in drive as you investigate all the above areas, just be careful not to get sucked into anything moving. A long screwdriver can work as a stethoscope to isolate bearing noises.

Kinda like Murder on the Orient Express investigation. LOL Noises make me NUTS!

bigd480

It is quite a mystery. I do feel that the fact that it goes away in neutral is the biggest clue, because most of those other things wouldn’t change when out of gear right? Unless there is some closed/open loop kind of scenario where certain sensors are ignored when not in gear.

Just checked my tranny fluid, it’s clean/red Mobile 1 synthetic without too many miles on it and I have no other transmission related issues.

Is there a good way to inspect/test the transmission mount? Don’t think I’ve ever laid eyes on it but that seems to make the most sense to check next at this point. Both it and the lower rear motor mount weren’t changed when the other two were (almost 3 years ago).

vqmaxman

I was looking for an answer to this very problem, apparently and i have noticed tnis same exact problem that i am having with my quest van. I have noticed this at stops signs or at stop lights or just at a stopped motion in drive. The car if it's in park or neutral the problem goes away. I am sure it's mount related, i have replaced the front mounts but never the rear or the trans mount it does sound like an metal on metal rubbing or grinding sounds. The other thing i am thinking of is the timing chain belt thats loose because the chains and guides, i have not done yet because of the parts and the expensive parts and the time it's gonna take doing the work on plus i can't work at my home the land lord and the rules they have are very stricked about working on vehicles on your rental property. I am also injured with this rotating cuff issue and the shoulder ligaments and muscles. I am sure that the harmonica balancer is not the problem because i had a corolla with an harmonic balancer issue and that was very violent from the start up and till the idle speeds and if the throttle was used the car would vibrate and scream violently.

bigd480

Yeah thinking through it I’m leaning towards one of the mounts. I would think timing chain noise would be present regardless of gear.

DBear

Something's weird here. Normally the idle will drop when it's in drive, which is why a lot of these problems only show up when you drop it into gear. I think the RPMs in drive should be closer to 650, but I'm too lazy to look it up right now...

KP11520

Well I just had all 4 mounts replaced with the rear seal and transmission reseal all done.

3 out of 4 were bad and he only charged me the cost of the 4th since he had so much apart.

No noises like that!

However, the faster the rpms, the less likely an under tensioned chain will make noise as the rpms expand it to the fullest diameter and equally floating over the entire path. Lower rpms allow whatever stretch be more sloppy.

But it's also rare the chains get stretched in these VQs. But the tensioner does go bad often enough that I would look into that as another possibility.

Drive and not reverse keeps hawking me though.Despite the rpms would be the same.

ONE MORE THING TO TRY is removing both belts and see if it goes away. If not, it's internal engine. If so, something belt driven is dragging.

bigd480

Thanks for the ideas! To clarify, it’s just a little less noticeable in reverse than drive, but both are not as quiet as neutral/park.

chris72

Hello Bigd480, sounds more like plastic vibration than metal, did you have a look at at the how to section ?

bigd480

Thanks chris72 - I will check out those tips about the squeak tape but it's more a vibration causing it (if I press down with some pressure in the pocket the sound goes away but probably bc I'm "mass loading" the whole assembly to absorb the vibration). The thread also reminded me to try to figure out how to keep the recirc motor from groaning/squeaking every time I turn off fresh air.

JvG

I would be looking into igntion miss.

The engine turns a a higher rpm in neutral, so slight missing is not noticable. The additional drag involved once the car is in gear lowers the engine speed. The miss would become more apparent.

I would expect a check engine light soon.

I'd change the spark plugs.if they haven't been done recently. Our cars like ngk plugs.

You might want to smell the exhaust as well.
What is your gas milage like.

So possible causes are spark plugs, coil's or leaking fuel injectors.

bigd480

Hmmm - RPM doesn’t really change between drive and neutral. Spark plugs are always Nissan/NGK platinum.

Gas mileage is usually a consistent ~23.5 (I measure every tank and only use premium, mostly highway driving). Last couple of tanks have seemed a little lower than measured by my Ultragauge.

One problem I’ve had for a while and could be related is slightly hard-starting when the tank is less than 1/4 full (might take 2-3 seconds instead of 1). I’ve replaced the fuel pump, fuel filter, and FPR and that hasn’t fixed it. Starter recently died and new one does the same.

Will try smelling exhaust, but what am I smelling for? Gasoline smell even after it’s at operating temp?

JvG

The sniff test is to detect unburned gas fumes. It would smell like a rich mixture. Put your hand closet the exhaust pulses. They should be even. Caughing or missing indicates misfire. Particularly when paired with strong fumes.

I will eliminate the plugs as the csuse.

Reduced gas mileage is due to either a missing coil or more likely, a leakinginjector. Those fail without setting a code. They are a common issue because they are old. Rebuilding them is affordable.