mdx11

Hi Guys I bought certified 2011 mdx at 60k which is now on 82K. Around 70k on my second oil change i found out my cars is burning oil and was lethargic to gas once in a while. Local Acura dealer ran oil test and confirmed this issue and replaced 1 sleeve and replaced all rings and pistons under my extended warranty. After the repair car sounded horrible, low on power and Engine’s air intake area was making a Puff sound on shut off. On third day after this job Engine light came. OBD2 showing multiple cylinder misfire. Dealer changed all spark plugs the engine light went away and Engine’s original sound was restored. As of now car is responsive and picks up RPM’s when accelerator is pushed but it don’t have the engine power it had before. I am not pushed with force when its RPM’s goes to 3K+. Logically car is supposed to perform better than before but its not the case. It feels car is choked on as if it’s running on extreme dirty Engine filter. I have replaced Engine filter back in April 2016 and has very light visible dirt on it. I am going back to dealer again after two weeks but I want to understand what could be the issue as dealer won’t be interested much to spend time on my car now since the OBD has no error codes now even in pending state.I was suggested to have the timming belt replaced and under the package the change timming belt, drive belt tensioner and water pump where replaced.

I appreciate your help in this regard.



Thanks

Ron A

mdx11: Welcome to the forums.

I deleted your original thread in the new member intro forum because you didn't have any introductory information and you had already posted it again in this forum.

Since you reposted there and you already have a thread in this forum, I have deleted the other thread.

If you want to post there and introduce yourself with some pictures or personal information that will be fine, but posting the same thread in two forums isn't allowed.

Carpayment4life

My opinion is not pro-Acura, this time.

It will be difficult to convince the Acura Service Mngr that "the seat of your pants" can feel less horsepower/torque than you had before.

Even if you put it on a dyno you will have a hard time, with Acura.

If you really feel a difference and can't get Acura to do anything except allow you to sink another $1,500 - $1,800 into a timing belt service...you should trade it in.

Cut your losses, because you'll forever 2nd guess yourself.

CurrentDraw

Sounds like a legit complaint. If you have a good relationship with your service advisor then explain your concern and have them perform a compression test and a leak down test. Those numbers don't lie. Have them document it and present it to you at the end.

If you truly feel like you have a case and feel confident the engine is under-powered in which case the test will perform under-spec, then explain to them that if the numbers test good- you will have to pay for labor on compression/leak down out of pocket (someone has to pay the technician).
If the numbers don't check out then the warranty will pick up the tab for all testing/diagnosis time including engine tear down and repair.

Another important factor since you mentioned that it feels like the engine is choked is to conduct an exhaust back pressure test.
Catalytic converters do not like severe misfire or excessive oil contamination and your engine has experienced both.
As a result the cat can prematurely break down and become clogged causing the engine not to "breathe" properly causing abnormal back pressure in the exhaust system which can lead to engine choking.
Good luck sir!

mdx11

Thanks for the great insight.
@CurrentDraw. Your point makes sense to me about the exhaust pressure. May be because of it engine intake is making burp/air leak sound on shutoff. It wasn't doing it before the piston job and had better power.Dealership focus on issue when I bring their attention to it.
I plugged in OBD2 adapter to my car and focused on the Cat Converter. At present no error codes but Catalyst monitoring is on not Completion status. I will keep an eye on it.( I am sure tech has disconnected the battery for engine repair)
My car cat on average has a temp of 1600 F on highway. 1100F on street traffic. I saw it going to 1700 F for few moments when RPMS goes around 3K i guess. I looked at this first time.
Is this a normal operating temp of MDX catalyst converters?

Attached are Screenshots of OBD2 sensor data of my car.

Thanks in advance.