5.0Thunder

finally had the head gasket replaced on the ol' 01 EX. Had some gnarly idle surge issue afterward so homeboy replaced the intake manifold gasket and cleaned the IAC. All better now, drives normal, plus I threw some new NGK Iridiums in it.

I'm picky but now when the car settles down into its normal low idle, it has a rhythmic vibration, reminiscent of a cammed car (chop-chop-chop noise). once you tap the gas or even when the AC kicks on and the idle raises, the "chop" goes away. No hesitation or misfiring upon accel or decel. Pop the hood and the engine doesn't really make any audible vibrating/sputtering noises. Actually sounds pretty smooth.

Anybody have any ideas on what this could be or have you experienced it?

I replaced the spark plugs to no avail. Should I run some seafoam through the fuel system? I'd rather not just try a bunch of stuff if somebody has a viable explanation, but I'm not afraid to.

Colin42

timing slightly off?

5.0Thunder

I can't modify the computer commanded timing so I imagine you're talking about the timing belt being off a tooth? possible, but does that produce the conditions I'm seeing here?

5.0Thunder

valve adjustment? need to do idle relearn procedure? Ezone? Lol

Colin42

yeah i was thinking maybe the belt is off by a tooth (because the head was off for the HG), can check relatively simply, remove the upper timing cover, set #1 to TDC (pulling the spark plugs helps) and verify the timing marks.

Can also try doing an idle relearn

ezone

Is it just typical vibration and harmonic resonance?
Are you questioning the mad skillz of "homeboy"?

.......... complicated by the fact someone JUST had your engine apart so you're looking for any and all possible noises and feels that were there all along but you never paid attention to before....but notice NOW because you're all super-sensitive and watching like a hawkboss for every little quirk and nuance right now?





Neutralize the mounts?
Idle relearn?

5.0Thunder

Noted, likely will check cam timing here soon.

Unnnnfortunately not my hawkboss senses this time. :/ It used to be smooth as silk at all times, and ran great as long as I kept the coolant topped off. When it settles into a low idle it rumbles pretty hard, rhythmically, and shakes the car. The Honda tech currently known as "Homeboy" is thinking the valves need readjustment and says he'll look over it this weekend. These are all things I'm comfortable doing myself, but I paid him for the initial job and don't want to touch anything until he's satisfied his work is done. I appreciate his efforts throughout the whole ordeal. Just posted this thread to grab some more ideas from you experts.

ezone

Is it even possible to make a recording/video that would clearly demonstrate the issue so the rest of us can experience it?

Note, my laptops and phone suck for sound reproduction.

5.0Thunder

I can sure try at least. From the engine bay you probably wouldn't hear it and the engine doesn't shake that much (good mounts?) so probably wouldn't see it either. From the cabin though it's pretty loud so maybe the phone will pick it up. If so I'll poast it today and show you how it boogies.

5.0Thunder

Well I took vids but you don't really hear or see the vibrations in them (you can see the engine shaking in person). You do however hear the hood rattling due to the engine vibration but it's not going to help you diagnose engine problems. Just proves it's shaking.

Homeboy is wanting to check the valve clearances today so I'll let him do that and ensure they're within spec'd values. I'll update the thread when this is done.

The car does feel more sluggish also. I thought I felt it but wife also commented on it after she drove it solo (it's her daily). I'm not toooo picky about this because the car barely makes much power in the first place so it's really hard to tell but I thought i'd throw it out there if it benefits diagnosis any.

ezone

Hasn't anyone triple checked the cam timing yet?

5.0Thunder

Valve lash and cam timing are currently being checked right now.

5.0Thunder

Update: Valve clearances were out of whack and corrected. Cam timing was correct. The vibration is reduced and the car has it's power back. Engine also visually smoothed out. There is still a slight vibration that wasn't there before but at this point I may just live with it.

UPDATE EDIT: IT'S STILL VIBRATING.

The low end pepped up a little but there is a mid-range flat spot now.

Going to try Idle Relearn tonight, likely to no avail.

5.0Thunder

no avail. May try cleaning injectors and checking air filter this weekend. :/

ezone

Your mechanic isn't finished with the job yet?
Mechanic is broken, replace with known good?



Were any mounts replaced? Aftermarket is known to be harsher than factory

Neutralize the mounts

5.0Thunder

Genuine OEM Honda mechanic! Should I try aftermarket mechanic? At this point I'm in the DIY zone.

Mounts weren't replaced and ARE oem but I considered that as well, especially since one had to be removed to to the job (at least one right?). Maybe it had a failure point that propagated during dis/reassembly or something. My only hangup is I don't actually know how to tell/test the mounts. The hydraulic one near the timing belt cover looks to be pretty squashed down but maybe that's normal?

I plan to remove injectors this weekend and back-purge them with some carb cleaner. I absolutely don't mind swapping the mount if that is known to be an issue.

Colin42

pictures, i know the mount between the rad support and the engine at the front of the car is prone to failing

5.0Thunder

I'll take a pic today. The smashed one is between timing cover and chassis (bolted to head ?). The others, from what I remember, still looked intact.

could IAC valve be a culprit here? I intended to perform Idle Relearn but the idle acts normal.. cold start brings idle up a touch over 1000RPM and as it warms, it eventually settles down to 700. Needle stays steady as engine vibrates. Doesn't hurt to try it but is that a logical step?

Colin42

it won't hurt anything

ezone

Here's a pic someone posted after Mr Goodpliers did a head gasket job, can you spot the problem? (besides the pic is upside down)




I found this pic while looking for something else, just tossed it on this post for no reason.

Are you down to vibration complaint?
Is it minor or major?
Is it better or worse than an identical car?
How much is normal, how much is too much?

This 4 cylinder engine was never glass smooth at idle.

AC pipe is secured in its holders?
Plate between head and pipe behind the PS pump is installed?



Link that explains neutralizing drivetrain mounts and suspension bushings:
https://honda-tech.com/forums/honda-civic-2006-2015-79/engine-vibration-stops-2447527/#post36669793

5.0Thunder

Wasn't able to get a pic of mine yet, although mine is actually bolted on.

At this point I'm thinking vibration is likely NOT due to engine combustion issues, like timing or fueling. It seems to run pretty well and the tach needle stays dead steady as it's vibrating at a low idle. This could mean it's a mount issue so I'm on board to test them, neutralize them, or replace if broken.

Have you ever seen an old mount crack when doing a head gasket? Does removing the head cause an imbalance in support that would stress an old mount enough to break it (I ask since you've probably done over 100 of these)? When I take a pic of the squashed one, I'll check all the others as well. I think the 8th Gen cars had a peg that would rest against the base of the mount when the mount went bad, sort of like an indicator. Idk if these cars have that.

The vibration is major in my opinion. Before the job the car was super smooth. I really was proud of our 155k mile civic being such a reliable and smooth daily driver. I know it obviously can't be vibrationless, but it really did fire up and run like a newer car so I just want it to feel like that again.

5.0Thunder

also, shout out to Ezone and Colin for keeping up with the thread and helping.

5.0Thunder

First pic shows what appears to be a cracked front mount.

Other pics show the hydraulic mount that appears to be squished due to lack of support from the front mount. look at the bracket and how close it is to the frame. Can anybody confirm that this will be okay when the front mount is replaced?

I put a wood block on a jack and lifted the engine until the front mount unloaded and I think it "killed the vibe" so I'm moving forward with mount replacement at this point.

ezone

Image fails?

5.0Thunder

tinypic givin me the business. gonna use photobucket

5.0Thunder

srybotdah

ezone

1st mount pic is shot, rubber split apart


pics 2/3..... Is the upper (engine) bracket actually sitting on and making contact with the bottom half?

EDIT: you don't want the L shaped mounting bracket to rest on the chassis, transferring all of the engine vibration to the chassis.
As a test I wonder if you could take off the single nut, lift the engine up and slip a washer or two over the stud (watch out for a locating pin, don't damage it), reassemble, this should raise the bracket up a few mm and see if vibration is reduced

Still have a couple more mounts to check.....one on top of trans and one at the rear of the subframe

ezone

No, the miles put on before the work is what wore it out.


No.
See above.
I can't speak for anyone elses work though. I've seen some crazy stuff over the years.
Not a peg....just look for the lack of a gap between halves of the 8th gen engine mount (see pics here <--link)

I don't have any pics of 7th gen though.

5.0Thunder

I checked the other two as well and they seem okay so I didn't post the pics. :P

One thing I noticed is that when raising the engine to unload the front mount, the hydraulic mount did decompress and overall, the vibration was reduced/gone. By putting washers/spacers under the hydraulic mount bracket, won't it just further compress the mount and risk damage? Or no harm? I couldn't tell if the bracket was actually touching the frame. from the outside it looked to have maybe a millimeter of space but the bracket could just be thinner on the sides so that it gives the illusion.

Yeah, the lack of gap is the concern for me but it could just be due to lack of front mount support... or should it also hold the engine up on it's own?

What I notice about these front mounts is that they basically have 2 rubber tension members within the round profile so I'm afraid if I install a front mount and the hydraulic mount is blown, it'll overstress these tension members and just break it again. if the hydraulic mount naturally compresses like this when a front mount breaks, then it may be just fine as-is. may just act like a shock absorber where the rubber mounts act like a spring?

Colin42

yep they're toast, when my front mount was broken my other mounts were still ok, make sure you tighten the bolts all the way or you'll get some weird noises