Engine popping/ticking

[holla]

I have a 96 Civic EX with 210k miles.

The engine makes an intermittent, random popping noise until it's warmed up. The noise increases in frequency and amplitude as throttle and rpm increase. Once warm, the noise goes away completely. I can prevent it when cold by going really easy (accelerating at 10" hg vacuum or higher), or by warming it up until it idles down to about 1000 rpm before starting out.

It used to only happen under load in higher gears, now I can even get it to do it by pulsing the throttle under the hood by hand. It sounds like it's coming from the intake side of the #4 cylinder (transmission side). I don't hear or feel anything from the injector.

Over the years I've replaced the exhaust manifold, tuned it up (wires, plugs, cap, rotor, timing check), adjusted the valve clearance and none of those had any effect.

Average oil change interval over last 120k miles is 3100 miles so its purty clean. PCV valve is new. Air filter good. No check engine light. NOT CV related

Been reading about sticky valves and recommended fixes using sea foam/ ATF / MMO in the oil. Any ideas?

 

[mechtech2]

Popping where? In the intake? Bad valve. Try an adjustment.
Exhaust popping? Vacuum leak in a line or intake.

 

[holla]

Read the post if you're going to reply. I said it was on the intake side of #4 and that I had already adjusted the valves. It's not a vacuum leak and is not exhaust related.

 

[kc8adu]

crossfiring due to a bad wire or cap?

 

[holla]

Originally Posted By: kc8adu
crossfiring due to a bad wire or cap?


Read the original post, I already eliminated ignition components.

 

[Nick R]

Maybe a warped valve or a bad lifter/valve springs?

 

[holla]

Compression is like new. Wouldn't I have compression problems with a warped valve?

 

[Nick R]

I really dunno I was taking a wild guess. Sorry, lol

 

[mdocod]

Originally Posted By: holla
Originally Posted By: kc8adu
crossfiring due to a bad wire or cap?


Read the original post, I already eliminated ignition components.



In my experience, replacing ignition components comes with a surprisingly high (like say, 30%) probability of introducing a new ignition problem. Part quality out there is really all over the map.

-Eric

 

[occupant]

If it sounds like it's coming from the intake side, maybe there is a small air leak in the intake manifold gasket? Try spraying a wee bit of WD-40 in the area while it's popping and if it speeds up or the sound changes, you've found your problem. This would be something that would be affected by temperature and would cause a "popping" sound. Just sayin'...

 

[bigmike]

Purge control solenoid valve maybe? That's on the intake side.

 

[mechtech2]

holla - Read my post. It indicates adjustment OR valve [sticking, burned, leaking, etc.], either of which it still could be.

And YOUR post does not say where the popping is coming from.
Your original post is not as good as you seem to think it is.

 

[holla]

Originally Posted By: mechtech2
holla - Read my post. It indicates adjustment OR valve [sticking, burned, leaking, etc.], either of which it still could be.

And YOUR post does not say where the popping is coming from.
Your original post is not as good as you seem to think it is.


Sorry, but you told me to try an adjustment when I already said I had done that and it had no effect. And I did indeed say where the noise was coming from in the original post. Reading is hard, I know.

 

[UberxG]

Originally Posted By: holla
Originally Posted By: mechtech2
holla - Read my post. It indicates adjustment OR valve [sticking, burned, leaking, etc.], either of which it still could be.

And YOUR post does not say where the popping is coming from.
Your original post is not as good as you seem to think it is.


Reading is hard, I know.