I'm hoping those of you who know something might be able to diagnose this for me.

When my '94 LX Wagon's engine is around 1200 RPM there's a knocking sound under the rocker panel. When I'm holding the throttle open I can feel the engine shake slightly, like it is missing a bit. It goes away as long as it isn't in a narrow band around 1200 to 1500 RPM.

Without knowing any better, it seems like the exaust vavle(s) on a cylinder are floating at this RPM and the knocking I'm hearing is exhaust. But if this is the case, why do HIGHER RPMs make the problem go away?

Valves were adjusted and timing belt replaced a year and a half ago at 80,000 miles by a Honda dealer ($$$). Gas mileage is fine and unchanged, car accelerates fine and has 120,000 miles. Exhaust is noisy under a load, but there seems to be no single source for the exaust sound other than the area around the exhaust manifold.

This might be pertinent: I have a pretty bad pinging problem that I'm going to attempt to tackle by getting a tuneup. When the engine is warm I sometimes get really bad pinging under a light load. Downshifting the automatic usually helps. I can't get the 3 distributor bolts loosened to try to retard the timing. I'd rather not have to resort to a higher octane fuel.

Thanks in advance!

 

i dunno....hondas are known for there lifters ticking maybe thats what ur hearing

 

might be a busted motor mount.

 

i have the same thing. might be a wrist pin knock. u can proly just swap a block in

 

pinging sounds like a wrench tapping up against the block, otherwise it's usually just valves clicking or rocker arms. It does sound awefully weird, make sure your timing is correct....and make sure you have adequate oil of course.

- Nathan

 

Wow, it sounds so easy!

OK, you'll have to trust me that it isn't just valve clicking. Oil is OK as well. Also, I don't think it is an engine mount since there are no other symptoms. I would think there would be more shaking than at just that one RPM band (which I've checked again and it is actually around 2,000 to 2,200 RPM)

I retarded the timing and got rid of the pinging (detonation).

So that knocking remains. It knocks more when the engine has a load, like when driving or when the AC kicks in. It sounds like it is coming from a specific location like the 2nd cylinder from the driver's side.

Frankly, if someone else has the same problem and the engine runs well overall maybe it is just me being overly picky. I didn't want to ignore a problem that would come back and bite me some day.

Thanks!

 

When I rev my engine, I hear a knocking that comes in and out between 2,000-2500 rpms, but it only lasts for half a second as im revving the engine up and I dont hear it when im inside driving. I heard it when I first bought the car w/ 35k miles last year, and now have close to 100k... still doing it. My valves make a lot of racket as well, especially when the engine is cold, but none of wich causes for concern. Aluminum engines can be noisy, especially 4-cylinders. Plus, my car is 8 years old approaching 100k miles. It runs like a champ and is reliable.. thats good enough for me.

 

oh sweet i didnt know u had a wagon....me too ....97 LX:thumbup:


wagons are teh ness

 

I had a problem with it at first, but it does look kind of cool, it is definitely distinctive, and you can't BEAT the utility. And, all that room for a subwoofer!

 

I would say.. time for valve adjustment..