bmac423

Hello All,

Thanks for taking a look at my post. I’ve got a 2003 Honda Civic GX with about 170k miles on it. I bought it early this year with 167k on it. It runs pretty well for the most part, but it vibrates like a madman at idle. I had some vibration at idle when I bought it initially, but it’s gotten worse. After it’s warmed up, it idles right where it should, 700-800 RPMs is about right. On initial startup, RPMs hit all the way up to 2000 RPMs and slowly drop down. It is a bit cold outside right now, so I suspect that could be the reason. It doesn’t really vibrate until it drops down to normal idle RPMs. There’s hardly any vibration while driving. I have no check engine light, and never had. The following is what I’ve done to troubleshoot the problem:

• Replaced all 4 motor mounts with factory mounts
  • None of the mounts were broken
  • There is significant vibration from the engine itself, so it makes sense that this didn’t work.
  • When I jack the engine up slightly to take the weight off the mounts, there is no vibration.
• Replaced the air filter.
• Thoroughly cleaned the throttle body and IACV. Re-learned idle afterwards based on the instructions here.
• Replaced transmission fluid through the Honda recommended method, with one more change for good measure (4 changes).
• Replaced oil and oil filter.
• Replaced coolant.
• Replaced timing belt.
  • I really feel like the timing is good. Piston height at top dead center seems spot-on. Marks are all lined up as well. No check engine light.
  • That crank bolt was one mean SOB, btw.
  • Vibration was happening before timing belt change, but it’s gotten progressively worse over time.
• I took a look at the valve clearance, and that seems ok. I’m planning on taking another look at that.

Here’s a video of the engine noise and vibration:


Double checking the valve clearance and checking for vacuum leaks are probably my next steps, but I’d love to get any words of wisdom you guys might have. Thanks in advance for any thoughts or input. I really appreciate your time.

BlueEM2

iTrader: (1)

Man.. that looks normal to me. Can you feel it inside the cabin?

bmac423

Yeah, it reverberates through the whole cabin. I can feel it through the steering wheel. Passengers definitely feel it too.

BlueEM2

iTrader: (1)

Fair enough. The engine mounts that you replaced did you put OEM mounts back in?

bmac423

Yep, I bought them all through these guys: https://www.hondaautomotiveparts.com/

So, none of the noise/ticking raises any alarms? I thought that might indicate something, but I'm not really sure what to listen for.

ezone

Hey, umm, looks like you are missing one nut from the throttle cable brackets on top of the valve cover, nearest the oil dipstick.

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Looks and sounds like a 4 cylinder to me.
They are not glass smooth at idle. (It is not a Benz!)

You can always feel some vibration.... So the question now becomes "How much is too much?"

I'd say to compare yours to an identical GX and see just how much difference there is.

Exhaust noise? Contacting the body, maybe?

We don't have any CNG cars in my area.
I've only seen ONE GX car come in to the shop here in the 10 years I've been in this dealer.
The rest of the CNG cars I have seen were at the Honda training center.


"Neutralize" the engine mounts?

ezone

Check this link: http://honda-tech.com/showpost.php?p...3&postcount=16

BlueEM2

iTrader: (1)

I just learned something new

bmac423

Thanks for the feedback ezone, and BlueEM2.

I will definitely give the mount neutralization a shot.

Unfortunately, 7th gen GX's are really rare around here. I had to import mine from NY. I do get some vibration from the rear, so I think they're may be some exhaust noise. I'm not really sure what to look for there.

ezone

You make it sound like you shipped it to another country.......

Wait, you actually WANTED a GX car? A used one, at that?

There seems to be absoutely zero demand for them here, and there is no supporting infrastructure (no CNG "gas stations") that I'm aware of in this area. I know there's propane available pretty easy, but haven't heard of CNG.

The one car that we saw here had an extra tank added to it.
I have no idea how far from here they would have to go to find a place to refill.
How about compare to a normal 7th gen car then?

I can't even tell you how different the gasoline version should feel compared to a CNG version. It's been several years since I even sat in one.
I'd hope they would be fairly close to each other though.

bmac423

Necro-bump...

Sorry, ezone. I just saw your response here.

Yeah, I totally wanted this beast, or Princess as I call her due to her finickiness. Natural Gas around here was about a dollar per gallon equivalent when I bought her. It's up to about 1.65 now, which is still very nice.

Update on vibration...

She still has some serious vibration; I mean, there's no way someone would purchase this from the lot with this kind of vibration at idle. It's like getting frothed up like a latte. I have headaches after serious stop and go driving.

I did replace both fuel filters, high and low pressure, on this beast. Didn't help with the vibration. I took her to the shop. They said bad timing side motor mount, which I know is bs, because I replaced it twice.

I'm planning on trying the neutralization this weekend. So, the directions say hand tighten the "primary bolts", I'm not sure what this means. Does that include the bolts that attach to the frame? ...or just the one through the mount itself for the front and rear mounts, for instance?

ezone

I'd think this is the large bolt that goes all the way through the sleeve in the rubber for round mounts.

On the nose mount by the timing belt, the top nut along with the bolt and stud on the engine bracket--because there is a lot of room for movement in those 2 mounting fasteners.