[TheMidnightNarwhal]

I've had this noise from time to time where it starts going like this at idle.

As soon as I give it gas and starts changing RPM is goes away. Then sometimes it will come back and go away on it's own.

This doesn't really sound like injector tick since usually without this noise at idle I can hear that injector ticking clearly. I didn't have time to pop the hood.

I also thought boost solenoids but it sounds to loud to be that.

So not sure what it is... knocking noise would be more deep right? I just want to clear that out of my mind if it's knock or not.

[upshift_downshift]

Originally Posted by TheMidnightNarwhal

I've had this noise from time to time where it starts going like this at idle.

As soon as I give it gas and starts changing RPM is goes away. Then sometimes it will come back and go away on it's own.

This doesn't really sound like injector tick since usually without this noise at idle I can hear that injector ticking clearly. I didn't have time to pop the hood.

I also thought boost solenoids but it sounds to loud to be that.

So not sure what it is... knocking noise would be more deep right? I just want to clear that out of my mind if it's knock or not.

Definitely not rod knock or spark knock. Rod knock is sharper and louder, spark knock is higher pitched, sharper, and won't happen at idle.

It sounds like it is about 3 Hz, or once every 4 engine revolutions at idle.

[TheMidnightNarwhal]

Originally Posted by upshift_downshift

Definitely not rod knock or spark knock. Rod knock is sharper and louder, spark knock is higher pitched, sharper, and won't happen at idle.

It sounds like it is about 3 Hz, or once every 4 engine revolutions at idle.

Ok thanks for the reassurance.

I have it down to 2 things then:
- Either boot solenoids
- Or fuel tank purge valve - If this is it I'm trying to understand how it works and how it's causing the sound so I can understand

Both these seem to be the culprit. I'll try and listen better and pop the hood next time it does it. Just was having a small heart attack thinking it could be knock but like I said I wasn't sure. Thanks

[upshift_downshift]

Originally Posted by TheMidnightNarwhal

Ok thanks for the reassurance.

I have it down to 2 things then:
- Either boot solenoids
- Or fuel tank purge valve - If this is it I'm trying to understand how it works and how it's causing the sound so I can understand

Both these seem to be the culprit. I'll try and listen better and pop the hood next time it does it. Just was having a small heart attack thinking it could be knock but like I said I wasn't sure. Thanks

Might be belt related too. From some google searching, it looks like the belt is 1855 mm long, and the harmonic balancer on the crank is 141.5 mm in diameter, which means the belt makes its way around in about 4 crank rotations, lining up well with your noise.

[TheMidnightNarwhal]

Originally Posted by upshift_downshift

Might be belt related too. From some google searching, it looks like the belt is 1855 mm long, and the harmonic balancer on the crank is 141.5 mm in diameter, which means the belt makes its way around in about 4 crank rotations, lining up well with your noise.

I took a listen under the hood and my ears seemed to point towards under/near the intake manifold right where the purge valve is.

But yeah I got a new belt and tension sitting at home waiting to be changed for preventative maintenance. Still un sure when to do it, I'm at 107 000KM. I'm thinking 125 000KM.

[type-dRew]

Normal sound, mine does it. Comes and goes at idle only.

I've read its the purge valve.

[TheMidnightNarwhal]

Originally Posted by type-dRew

Normal sound, mine does it. Comes and goes at idle only.

I've read its the purge valve.

Aye,

I'm trying to understand the concept and working of it.

When the sound occurs, is the valve opening and closing quickly which is what is causing the sound? I like to understand how things work, and I'm not sure how it does.

[bbnks2]

almost sounds like an exhaust leak