For a while, I've been encountering the following noise: When the TL is in 2nd or 3rd gear at relatively low speeds, say 25-35mph, many times I can hear from the engine what sounds likes a "diesel engine" noise. No other words to describe the noise. Doesn't always happen, and by the happen I'm at >40-50mph, the noise is gone and the engine is smooth sounding again.

It's been happening for a while, took it in to the stealership a few times, only to have them say they cannot reproduce or find the noise. So no resolution.

So lately, that noise is becoming a little more prominent, still sounds like a diesel, but now it sounds a little more like a "rattle." Same speed range, around 25-35mph and in 2nd-3rd gear.

Any thoughts/ideas? I'm using premium Costco gas and am currently doing the 1,000 mile oil consumption test FWIW.

 

DocBoy, no real suggestions, but I would say to switch from costco. I personally like Shell. Can you tell at all if there is a specific RPM range that it is happening at, or is it really just related to speed? If it speed, I would check tire balance (they can bounce at specific speeds), cv joints, and other drive-train parts. Good luck.

 

I've had a similar problem that took months to figure out. The dealer also questioned what octane gas I was using. It was about the same speed and gear. It had a sweet spot and I think it was roughly around 2800 rpm. Right around when the tranny will up shift from 2nd to 3rd and 3rd to 4th under moderate acceleration. Initially, it sounded like a grinding noise. If you put some pebbles in a tin can and give it shake... that's what it sounded like. It ended up being the heat shield. They found debris in there and it was somewhat loose.

I was told that the heat shield is pretty malleable and can easily bend out of shape when exposed to 2 extreme temperatures.

 

OP, let me guess. A slight tin can rattling/gurgling sound when you put down hard on throttle at low speeds? I had this too. I believe this is pinging.

I used techron treatments twice and I exclusively use 91+ octane fuel from Sunoco/Shell/Mobil and I have minimized this. It only occurs after startup and noise is eliminated once engine is warmed up.

 

Just my guess:

Go back to the dealer and ask them to use their Honda Diagnostic System and go for a drive to detect any cylinder misfires at low engine speeds. Somehow the on-board diagnostics do not detect some misfires. I believe there are some threads about this (search for "misfires"). Main reason this is happening is because of improper installation of the spark plugs (... they slammed them in the cylinders during installation and some ended up with a bent spark plug tip). Worse comes to worse, even if they can't re-create it, ask them to pull out all the spark plugs and measure the gap. If the gap is messed up then they pay, if not you pay. Simple.

Just my guess.

 

Hard to say if it's the heat shield or octane related. Both above response seem to approximate what I'm experiencing. Low "rattle" or "diesel sounding" that occurs generally at low rpms/low mph. This sound never appears above say 35-40mph.

I guess one thing I can do is to try Shell/Mobil gas one of these days and see if the sound disappears. If so, then problem detected.

 

I have a similar issue with mine. When it happens there is a vibration as well. With all the talk of torque converters having issues in that speed\rpm range I am beginning to suspect that. I'm just waiting for it to slip out of gear as others have experienced.

 

I have what sounds like the same problem in my '10 4G. It is an intermittent vibration and grinding-like sound. Did you have Acura fix this? If so, what were the repair costs?

 

Just bought a '10 SH-AWD and it has this rattle clunking noise between 1000-2000 RPM under light acceleration. Now if I take off quickly I don't have it at all. What can this be? Doesn't sound like pinging or an engine knock to me.

 

I notice a rumbling sound/feel if I'm slowly accelerating around 20mph and the car is between gears. I thought I read somewhere on this forum that this is a characteristic of the AWD system?

 

The rumbling noise is more than likely the torque converter. Many here have had this problem. Do a search. There are many threads on this issue..

 

I have the same pinging sound when I accelerate
dealer told me the same thing to use top tire gas station
and I am using 94 octane from a top tire gas station from last 4-5 months
It still does it I also changed the timing belt waterpump tensioner
every fluid too

still does it
i also checked the heatshield its not loose and no debris

It started doing this at like 94000km now I am at 111000 km

help anybody???

another thread with same issue
"https://acurazine.com/forums/showthread.php?t=910539"

 

Yup. This too, I'm noticing more and more. Right around 20-25mph, and I'm very very light on the throttle, I hear a low rumbling growling noise. I'm usually at 2nd or 3rd gear, and goes away when the car is at higher speeds.

I don't think it's related to the the torque converter. I have a 6MT and the 6MT does not have a torque converter.

 

Rumbling/growling sounds like a heat shield to me. Tinkling or pinging is an issue I had upon acceleration too and I just had it fixed with a software update. Might give that a try.

 

so guys I finally have an answer for you

I went to talk to a trusted acura mechanic who worked for acura for last 12 years and just opened his own shop he said its ECU timming issue and acura released an update for it and zdx had this issue a lot all the guys who r experiencing yhis issue have there ECU update wrongly done by dealer or never recieved it

this thing is confirmed by other acurazine member I am pasting what he said to me here
"
Hi! I just got back from a dealer 300 miles away from me. They FIXED the problem! There is a software update for the ECU and it helps with mapping (or something like that). Either way, it was free to me and the service adisor said most cars are covered for 8 years on this. I'm so happy now. I'm going to submit a formal complaint to Acura about the other dealership who kept telling me it was "normal." Lazy! So next time you're in for service, demand that they check for a system update. Good luck!"

I remember i never had this issue untill they did some update last summer
and probabely screwed the ECU mapping that time
I am taking it in tommorrow morning

 

^ If it is related to the torque converter software update, give it some time after the update is done for the ECU to adjust. Some accelerations and deceleration in 2-3 drive cycles will do the trick. Now, if it is still grinding a little, the process Acura dealerships have been told to follow is to collect the "freeze frame" data and send them to their engineers. If they determine you need a new torque converter then you have the option to get one under warranty .

But, most likely they'll tell you to do a 3-4 times tranny oil change (probably you pay) to get oil everywhere that hasn't lost its properties. My belief is that the issue is the small tranny oil cooler. This tranny oil when too hot is losing its pressure properties fast and there isn't much you can do even if you change the torque converter. Thats my theory.

I am personally looking for a larger tranny cooler to install in the next few months to see if that makes a difference because even after the 3-4 oil changes and the software update, on hot days or when I drive the car 2-3 times a day, at the end it still vibrates at low speeds in 4th gear.

 

Is there a TSB # or other name for this fix? I have a feeling if I walk into the dealer and tell them to apply the "ECU update," they'll look at me like I just walked off a spaceship.

 

You don't have to go to the dealer to find out. Call Acura Client Relations, give them your VIN and they can tell you if there are any outstanding software bug fixes for your car: http://owners.acura.com/help/client-relations

 

I went to dealer yesterday and they kept my car for 4 hours and then said there is no update available for my car I still have the problem and now I called Acura Relations they are looking into the issue

 

I did that and they mentioned the 8/2012 update, but that's it.

 

Apprently this spans across honda and acura cars. I have the SAME EXACT issue wiuth mine. Have taken it to everal dealerships and have replaced:

• Transmission/Torque Converter
• • Tenisoners, and ALL belts
• And a cracled Engine mount

All thinking it would fix this metallic gargle rattle sound.
Its very hard to replicate for some reason when a tech is in the car
but it does it under load. SO ANNOYING. But SEVERAL techs have told me its
a NORMAL sound for the car when Under load. But im like, how do you have such a wonderfully
tuned car and allow a rattle into the scenario? WHAT THE HELL?

ive heard aclogged EGR valve could also cause it. So far no dealership had been able to fix it.
The fact that so many of use have this issue makes me thing its a faulty build of some sort.