Slight shaky idle

myfavecoupe

New Member
Hi guys my 98 civic ex shakes/vibrates a little during idle. It's nothing crazy but not as smooth as I remember where I'd question if it was even on.

The tachometer needle is steady and doesn't fluctuate but car itself shakes slightly like a light putting.

I've tuned it up, new wires, plugs, cap and rotor. Cleaned tb and iacv but still no change.

Any suggestions?

EDIT: Videos included in a later post
 

XpL0d3r

I had a Civic once.
Staff member
Registered VIP
Registered OG
5+ Year Member
10+ Year Member
15+ Year Member
Could be a bad motor mount.
 


XpL0d3r

I had a Civic once.
Staff member
Registered VIP
Registered OG
5+ Year Member
10+ Year Member
15+ Year Member
Yeah, you can visually inspect them to look for rips or tears. If you find one that looks bad, you can fill it with something like 3M Window Weld.
 


myfavecoupe

New Member
Ok will have a look. The engine itself does vibrate a little when hood is open. Thought that was just normal for a car?
 

XpL0d3r

I had a Civic once.
Staff member
Registered VIP
Registered OG
5+ Year Member
10+ Year Member
15+ Year Member
A little vibration is normal sure. Over time those mounts weaken and eventually rip, especially if you're hard on the throttle.
 

myfavecoupe

New Member
I notice my muffler vibrates at the same rhythm as the idle shake I feel.

Would that still be mount related or something else?

I'll check the mounts when I'm off work just seeing what else I could be looking for if need be.

Just looked at the mounts. I couldn't see any obvious tears or rips but with the car on, the engine seemed to shake a little at the top driver's side mount. Not sure if that's normal?
 
Last edited by a moderator:

myfavecoupe

New Member
Had a mechanic check the mounts over since they looked fine to me but just wasn't sure.

He confirmed they were still good.

Any other suggestions?
 

DatEM1

New Member
Unfortunately this could be many things. Mine is doing the same but mine is bad motor mounts lol(getting ES inserts soon). Try a tune up and go from there.
 

bastok

New Member
5+ Year Member
Sometimes, if the valves are out of spec, you can feel that "shaky" idle.
How long from your last valve lash adjustment?
 

myfavecoupe

New Member
bastok said:
Sometimes, if the valves are out of spec, you can feel that "shaky" idle.
How long from your last valve lash adjustment?
Click to expand...

Last adjusted around 110k now at 163k

Would that cause the engine to vibrate though? You can see engine slightly shake
 

bastok

New Member
5+ Year Member
myfavecoupe said:
Last adjusted around 110k now at 163k

Would that cause the engine to vibrate though? You can see engine slightly shake
Click to expand...

Sometime ago i had no time to adjust my valves and i took the car to a shop to do it. They let the lash too closed (i mean if you have for example 0.06-0.07, they leave them in 0.05), a total disaster.

I realized their mistake because the car made some little shakes, very little but noticeable for me and some power loss.
Next Saturday i made my own valve adjustment and left them between specs. No more "shaky", it idles like a charm and my engine running like new.
 

myfavecoupe

New Member
So it shook with valves adjusted too tight?

If mine haven't been adjusted in a while wouldn't that make them more loose?

Do loose valve lashes cause a shake as well?

Last time I had them done (at 110k) it was brought to Honda and the "master tech" did the adjustment on a warm engine. When I got it back I remember the engine shaking. Had them re-do it when engine was cold and all was fine.
 

bastok

New Member
5+ Year Member
In my personal experience, the too tight valve lash made my idle shaking a bit.

But as someone tell you before, there are other things that can cause that symptoms too.

Have your injector cleaned sometime? If some of the four is spraying bad, you will definitely feel it at idle
 

Wreckless Hype

¯\_(ツ)_/¯
Registered VIP
5+ Year Member
Valves have been tightened to 0.01 tighter than spec without issues, a lot of people do this particularly on older cars with noisy valves. It's not best practices, but you can do it without issues. If your guy made it too tight, he likely went a little past that.

If you had loose valves, you'd hear a chatter.
 

Wreckless Hype

¯\_(ツ)_/¯
Registered VIP
5+ Year Member
Should have asked what RPM it sits at. My car sometimes will idle at like 600rpm and it does shake a little bit like that. When it sits around 750, it's way less noticeable.

Have you adjusted your throttle cable at all in the past that would have caused it? I don't really see an issue though, to be honest.
 
You must log in or register to reply here.


Top