Knocking noise from inside the Intake

[rigol2000]

Hello, here once again with a maintenance issue. The other day while researching another issue, I noticed a knocking coming from my Intake. It was not loud, but loud enough for me to notice when the hood was up. It is coming from the area above the "24" on the front of the intake near the secondaries. It does not sound as though it is coming from below the valve cover. It does keep rythm with the RPMs. But I don't hear it much at higher RPMs, mostly at Idle. A friend of mine suggested it may be the secondary butterfly rattling. I can see the secondary "rod" turning at the right time between 3000 and 4000 rpms. So it does look like they are operating.

Anyone had something similar? It looks like it would be easy to get to the secondaries if there is something that I can check.

Thanks once more,
Chris

 

[SuperHO]

three things.....unplug the IRCM (lil round thingy on the back of the intake manifold). if it's still there, take off your valve cover and check the timing chain tensioner between the two camshafts.....but before you do any of that, take a look at your crank pulley to see if it's wobbling...

Mine's been doing the same thing for about 3 weeks now, and after tearing apart my tensioner to find out nothing was wrong with it, I found out that my crank pulley wasn't installed properly and had come loose a little bit, with the possibility of the engine being cashed.

 

[jammin]

my crank pulley has a weird wiggle also.....sho shop pulleys.....how do I fix, now I am scared.......

jason
92 with mods

 

[SuperHO]

do a search on "crank cancer".....you'll find all you need to know....unfortunatly, I let mine go too long and may have offed the motor...don't make my mistake.

 

[Paul]

A knock on top can be a crank/rod/piston. The rod knock sounded to be coming from the intake or head. All the valves checked out good. tensioners good. if you suspect this, try pulling a plug wire off one at a time at the coil and see if this lessens the knock. Try the cylinders near the noise first. Don't electrocute yourself.

 

[pjtoledo]

If you think the secondary butterflies are making noise disconnect and plug the vacuum lines at the actuators. With no vacuum they spring open and the sound should change. BTW, injectors can make ticking noises too.



Perry

 

[Rockledge]

my crank pulley has a weird wiggle also.....sho shop pulleys.....how do I fix, now I am scared.......

The pulley itself could be bad. It doesn't necessarily have to be a case of crank cancer causing the wobble.

 

[SuperHO]

could that also be the case on my bizitch? I'm quite concerned that my 3.2 is toast after spending $1500 on a swap.....



Not to hijack a thread....

 

[BeautifulDisasterSho]

If it wasn't a very loud knock and you haven't lossed any driveability, assume it's the injectors. Probably not the cams because you said not the valve covers.

 

[SuperHO]

Ummm.....read above...if not, read here.....the sound is coming from the crank and travellin up through the block to sound like it's coming from the head....the crank pulley is wobbling around as if it were a bent rim with 1 lug holding it on. I'm surprised I haven't lost a belt yet. And I've NEVER heard an injector that loud....

 

[rigol2000]

As far as the location, my friend used his stethescope (One of the doctor things) that he uses at the dealership, and found the sound at it's loudest in this location. The sound was most defined above the "24". BUT, he could have been wrong. If the sound was resonating from inside the engine, wouldn't it be heard in a more broad area at top? My sound is not that loud and comes and goes every few seconds in groups not in any set pattern.

I'm not sure which is the crank pully. If it is on the access belt of a 3.2L, the only wobble I have is the water pump.

Tomorrow if I get home from work while it is daylight, I'll give these suggestions a try.

Thanks,
Chris

 

[SuperHO]

Yeah...the shop that diagnosed my noise said the noise was coming from the back of the front head by the timing chain tensioner...they used a stethescope, too.

 

[e_clouser]

I had a similar type of knock in my 94 MTX. Was only around at idle, and would come and go. I started to worry about it after my 60k service because it got louder. My knock was coming from the timing chain tensioners at the back of the engine. I tried the stethescope method and thought it was coming from the middle of the engine. I replaced the tensioners and the noise is gone, now only if the Diff pins would stay in place.

 

[BeautifulDisasterSho]

Ummm.....read above...if not, read here.....the sound is coming from the crank and travellin up through the block to sound like it's coming from the head....the crank pulley is wobbling around as if it were a bent rim with 1 lug holding it on. I'm surprised I haven't lost a belt yet. And I've NEVER heard an injector that loud....

Sounds like your motor has spun a bearing.

 

[SuperHO]

yeah....that's what I'm thinkin, too....and if it turns out that the shop who did my swap put that crank pulley on wrong, something brown and ill-smelling shall hit the proverbial fan.

 

[rigol2000]

If you think the secondary butterflies are making noise disconnect and plug the vacuum lines at the actuators. With no vacuum they spring open and the sound should change. BTW, injectors can make ticking noises too.



Perry

I would like to rule this out first. Keep in mind that I am just learning to do this kind of work myself. I should disconnect the lines at the actuators (One on each side of the intake on the inside. Then do I plug the hoses or the actuators? *** NEVERMIND - FIGURED IT OUT***

 

[rigol2000]

I had a similar type of knock in my 94 MTX. Was only around at idle, and would come and go. I started to worry about it after my 60k service because it got louder. My knock was coming from the timing chain tensioners at the back of the engine. I tried the stethescope method and thought it was coming from the middle of the engine. I replaced the tensioners and the noise is gone, now only if the Diff pins would stay in place.

Is there a way of telling this with out replacing the parts first?

 

[rigol2000]

unplug the IRCM (lil round thingy on the back of the intake manifold). if it's still there, take off your valve cover and check the timing chain tensioner between the two camshafts

Do I do this while it is running?

Geez, I'm such a newbie! :shakehead

 

[SuperHO]

Check the IRCM while it's running.....don't, under any circumstances take your valve cover off while the engine's running....in fact, I don't think it's possible to remove it while the engine's running cuz you gotta take the intake off to get it.

 

[rigol2000]

I eliminated the secondaries by unplugging the vacuume hose on the black can looking thing on the back of the intake. The sound continued. Was that the IRCM? I'm looking in the Chilton Book I have and I can't find it. I wish they made a SHO for Dummies book