Strange noise when starting engine

[JackbNimble]

While driving home my '90 GGSX last night there was a strange noise that began coming out of the engine. Sort of a chatter and I can't seem to find out what it is. It usually happens when starting the engine, at low RPMs, or when giving a quick burst of gas. We took a video of it to see if any of you might know what it is. You can really hear it at about :08 of the video.

click

 

[cspetros]

Are you referring to the low pitch "vibrating" sound that starts at 0:07 seconds and goes away at 0:10 seconds? Or the sounds heard best after 0:10 seconds? There is also a higher pitch noise that starts at 0:06 seconds; a sort of metallic sound.

No rod knock sounds here, /ubbthreads/images/graemlins/worthy.gif.

 

[JackbNimble]

The noise that starts at :07 and goes to :10. It also does it in the beginning, but is somewhat overpowered by the belts squeeling.

 

[cspetros]

It sort of sounds like an exhaust related sound...

It doesn't vibrate the whole car (possible balance shaft issue), does it?

 

[belize1334]

It could be an accessory like your PS pump or something. How's the PS fluid level? You could try removing all the accessory belts one at a time and see if it goes away.

 

[JackbNimble]

Nope, doesn't vibrate the whole car.

 

[cspetros]

Can you tell where the sound is coming from? Timing belt/accessory belts area, exhaust manifold area, under the engine/car, etc...

/ubbthreads/images/graemlins/smile.gif

 

[JackbNimble]

Right hand side by the timing belt, almost like it's by the balance shaft.

 

[cspetros]

Check your harmonic balancer (the crank pulley). They tend to separate when they get old; if it comes apart while it's spinning, it can really screw things up. I've read that it can cause the timing belt to jump teeth if it flies apart.

Watch this vid

How long has that belt squeal been happening?

 

[JackbNimble]

Heh, pretty much for a while. We've had the alt/PS belt snap twice. And the A/C belt just snapped earlier in the day yesterday.

Oddly enough, that exact thing happened with my timing belt I'd say around two months ago. We just attributed it to the auto-tensionor, but now you have me thinking...

 

[belize1334]

Hm, if you're snapping belts I would guess that either one of your accessories is messed up (hard to turn and stressing the belts) or your crank-shaft pulley is boned which causes belts to wear badly.

 

[JackbNimble]

Well, we ran an oil pressure test and it's showing 90psi, but this is from a cold start and not revving the engine. I don't believe that's normal.

 

[JackbNimble]

Well cspetros, you were right. The harmonic balancer pulley was in two pieces. The outer rim has almost a rubber sealent on the inside which attached to the part that goes on the crank. That seal was broken so the part attached to the crank was free spinning until it heated up enough to bond to the outer rim, atleast that's what I am assuming. It also ground into the timing belt cover quite a bit, which is why the A/C belt snapped earlier. I'm also assuming that it is possible this was the cause for the timing belt skipping teeth about two months ago, along with our belts squealing since we've basically had the car.

My local NAPA store has them in stock (atleast that's what the site says), so I'm gonna go down there tomorrow and try to get her up and running. I'll let you guys know.

 

[cspetros]

Glad to hear that you found the problem /ubbthreads/images/graemlins/smile.gif. I think Napa has their harmonic balancers listed for about $80. It's a good thing you found this before something catastrophic happened.

Go Nordic Blue!

 

[JackbNimble]

Well, she's fixed and running. Although the oil pressure being at 90PSI still worries me. I'm assuming this isn't normal, correct?

 

[turbowop]

Is it just 90psi when you first start it up and the motor is still cold? Mine is near 100psi when I leave my driveway. Once the oil warms up it's just fine. I wouldn't worry about it if yours acts similarly to mine.