bentleymp21

Hi all,

So the Acura dealer has checked it out, a local mechanic has giving it a go, and my friends have almost gone crazy trying to figure this out.

The concern: every five minutes or so, a strange series of popping sounds starts to sound from the engine. I have described it as muffled popcorn popping sounds. My friend has described it as burping. Local mechanic said it was a misfire, but then could not find anything wrong. There is no check engine light.

The sound goes on with no real pattern for about a minute or two and then goes away for about five minutes. At first, it was just the sound. Now, however, I can feel the car skipping while driving on the freeway. I will be driving around 60 to 65 miles per hour and I feel a skipping/nudging/jerking sensation. I'm getting worried.

Please let me know if anyone has experienced this or knows what it is. Everyone who has checked out the car has no clue and they advise me to continue driving until something breaks so that they can fix it. I don't love that suggestion.

If you need more details, please let me know.

Car is an 01 cl type-s with 127,000 miles on it.

What is happening to my car???

Thank you!

jaeravenal

Hello, there might be a package of orville reddenbacker popcorn left in the upper cylinder. The high compression might be popping the popcorn hence the popping sounds.



No but, maybe your car is knocking or having detonatino issues


"This is a car engine that has a ping. Also called spark knock, preignition or detonation. If left uncorrected it can ruin the motor. Caused by either a lean fuel condition, carbon deposits in the combustion chamber, over advanced ignition timing, wrong spark plugs, or overheating."

hoap it halps

bentleymp21

Thank you for the video and your taking an interest in helping out. However, that is not the sort of sound it is making. It is making muffled bursts of air type sounds, and they are very faint from the cabin. I have tried to make a video from under the hood, but the engine sound was too loud for the video to pick up the popping clearly.

Oh and the noise happens while at idle.


Thank you

ANC297

iTrader: (2)

What does it sound like standing outside the car? Is it during turns or curves or straight road? Does it sound like a backfire?

bentleymp21

The way I described it is how it sounds both inside and outside of the car. It is just much quieter form inside.

From what I can tell, it only happens when you are not gassing the car. Well, maybe it happens while gassing as well, but perhaps the engine noise makes it unnoticeable.

I only hear it when the car is standing at idle or moving a slow speeds before acceleration.

When I went to visit the mechanic, he though it was a misfire upon hearing it. Said it was likely a faulty coil. The next day, i dropped the car off with the mechanic along with a new coil, and when I came back to pick it up, he said I can return the coil as he could not find anything wrong with the car.

Before this noise started, I was having idling issues such as surging and the car would idle very low at stops and then stall. After I replaced the IAC valve, the surging stopped, the car no stalls, but now there is this noise. At the time of IAC valve replacement, I also changed the spark plugs.

Is it possible the IAC valve is faulty? It fixed other issues, so I don't know.

Catfisha

Have you looked at both exhaust manifolds? Are they loose or cracked/damaged?

bentleymp21

Checked last night. No damage or cracks. I made some video of the sound. Will try to upload tonight.

Thank you!

bentleymp21

Here is a video of the sound.







Thank you!

bentleymp21

problem solved! noise gone!

When I replaced the iac valve a few months ago, it was the first time in the life of the car that the throttle body had every been taken off of the intake manifold, and I did not look at the gasket. The iac valve that I installed was not an oem Honda part, so we thought it might be the valve. I purchased an oem valve and two nights ago, when installing it, we realized the original gasket was half stuck to the throttle body and half on the area that the TB connects to. It was destroyed. I do not know why we did not concern ourselves with this the first time. So I replaced the aftermarket valve with the Honda valve and put in a new gasket.

The car is perfect once again. It was likely the gasket the entire time. I do feel better about the Honda Iac valve, even though it was probably fine with the aftermarket one. The gasket was the problem.

Catfisha

YAY!!! I'm glad it was something simple!!!

codehead

Wow, interesting find...my car is in the shop for the second attempt at fixing this problem, which resulted from from a repair visit a couple of months ago...

The semi-long story is that my car was stalling occasionally. After looking online and seeing mention of "main fuel relay", I recognized that as the problem instantly (key symptoms were that it would just die, be unable to start for about a minute, then start up without effort). So, I took it to a local shop and told them it was the main relay. They called me back later and said it's the idle control valve. I muttered something about that not sounding right at all, but decided that they must have found a problem there, so I let them go ahead and replace it, still skeptical that it would fix the dying problem. They also mentioned that it sounded like it could use a valve adjustment, and since I knew that to be true, I had them do that as well.

I get the car back, and it dies on me several times, but on the first or second time it happened, I heard the relay click into play as it started up, which verified the cause to me. So, I stuck my head under the dash one afternoon and figured out how to get the relay out; I resoldered the board and put it back, and it's been perfect since. A little ticked for letting them talk me into the new iac valve, but happy to have a reliable car again.

Except that another problem came back with it from the shop—the muffled popcorn sound coming from under the hood. The car runs smoothly, just, "pop...poppop.pop...pop" when idling.

I took it back a couple of weeks ago, and showed the mechanic that had worked on it. He said, "well, it isn't going to be the idle control valve"...he decided to retrace his steps, and ended up re-adjusting the valves after I left it overnight, that I still had the popping. I took it back in today for further testing, glad I came across this. I have a call into the mechanic to give me a call after he gets back from lunch—they haven't gotten to my car yet today.

Thanks!

codehead

They replaced the valve and the gasket, still does it

aameghoo

Did they replace the valve with an OEM valve?

bentleymp21

I was going to ask the same question... Maybe it just needs a trusted oem iac valve.

I hope you get the issue resolved. If you are anything like me, you will not be happy until it it taken care of.

I know we love our acuras, and like you said, it feels very good to know it is in good health.

codehead

I did mention the OEM valve + gasket to the mechanic by phone. When I called back late in the day, I was told by a service manager that the valve and gasket were replaced, but I don't know for sure if it was the OEM part. My ride flaked, so I left it overnight—I'll ask tomorrow.

aameghoo

let me know what they end up saying, I have the exact same problem but I'm waiting on pulling the trigger for ordering a new OEM valve until I'm 97.4% sure it's my problem

codehead

I confirmed that they used the OEM part, and my long experience with them (Independent Repair in Redondo Beach—dating back to my first car, '75 Civic!) is that they usually do use the OEM/original/genuine Honda parts...

The total work they did, that precipitated the problem, was the IAC valve replacement, and valve adjustment. They've redone both now, but said that they would go back and replace...uh, some gasket, I assume intake manifold gasket? The guy flashed it at me, and it definitely wasn't a valve cover gasket, looked like intake manifold...anyway, he said they didn't really have reason to suspect it before, but wanted to take it apart again and check.

The one thing I have going for me is that they know they caused it, and are trying to figure it out...but it's still a pain that I have to keep dropping the car off.

bentleymp21

That one thing you have going for you is a huge plus though. They seem like good people there. Your long time loyalty is probably helping then feel better about the time they are spending as well.

aameghoo

any update codehead?

codehead

Just got back in from NC, picked up my car on the way back from the airport...wow, I had forgotten how nice and smooth the engine runs, it's been a while!

OK, the problem was indeed a non-OEM valve. The service manager told me that when I asked if it was the OEM part, he checked and it was the identical part number as the OEM part, so he assumed it was the OEM part. But later when he checked (the box I think), he saw it was a Standard (Motor Products, I I think) part—both the first one they put in, and the second. So they got one from the dealer, and everything was good. Standard claimed a very low failure rate on that part, FWIW.

The invoice showed that they replaced the upper and lower intake plenum gaskets, as well as the valve. No charge, of course.

aameghoo

well that's great news, glad you finally got it figured out. Helps me out too, now I'm %100 certain it's a non-OEM valve causing my problem too. Gonna order an OEM one as soon as I get the money and report back as well.

aameghoo

just curious are there any other symptoms or issues that were resolved after finally using an OEM valve?

codehead

No. I didn't have an idle problem when I took it in. I told them that my car was dying occasionally, and I was pretty sure it was the main fuel relay. So I don't understand why they replaced the IAC valve in the first place. I ended up fixing the relay myself, and the issue was about getting it back running smoothly as it was before. It's great now that they put in the OEM valve.

aameghoo

so with the aftermarket IACV it actually wasnt running as smooth?

codehead

Right. It became a popcorn machine when they put in the 3rd party IACV. They replaced it with another of the same, still bad. They replaced it with the OEM part, smooth running.