knocking sound at idle

[ThomasGSX]

Hello all,

I have a 95 Eclipse GSX that has started making a very loud knocking/ vibrating noise. I had thought it was the exhaust leak I had from my down pipe to exhaust dump flange, but I just fixed that this morning and it seems not to be the case. It makes kind of a knocking sound like a diesel at idle, but I am pretty sure it is not rod knock or a spun bearing because it goes away at any RPM above 2k. as you accellerate up to 2k, it makes more of a rattle/growl, and then instantly goes away right when it hits 2k. then as soon as you drop the RPMs it comes back the second it his 2k. Really not sure what it could be. It sounds like it is coming from the timing area. I popped the upper timing cover off and as it runs, I can see the belt vibrate up and down in between the 2 cam gears. It makes no difference whether I push the clutch in or not. It is not causing any form of drivability concerns, but it kind of worrys me because it doesnt sound good. I have been driving it for the past 300 miles like this and it has not gotten worse or better. Also, it cannot be my balance shaft, It has been eliminated.

Any suggestions or ideas of what this may be?

Thank you,

Thomas.

 

[4g63jojo]

any kind of engine knock at any time is never good and you should stop driving until you fix it. Your timing belt has a lot of slack in it, probably jumped or your tension-er has failed or both but regardless it should be repaired immediately or it could cause complete engine failure.

Now the knocking noise is almost for surely from the slack you have in your timing belt this would explain why it goes away at a certain engine speed.

You should do a complete timing belt replacement along with all the pulleys and tension er , this will fix the extra slack in the timing belt, and in turn, hopefully get rid of the knock if it has not already permanently damaged something.

 

[ThomasGSX]

any kind of engine knock at any time is never good and you should stop driving until you fix it. Your timing belt has a lot of slack in it, probably jumped or your tension-er has failed or both but regardless it should be repaired immediately or it could cause complete engine failure.

Now the knocking noise is almost for surely from the slack you have in your timing belt this would explain why it goes away at a certain engine speed.

You should do a complete timing belt replacement along with all the pulleys and tension er , this will fix the extra slack in the timing belt, and in turn, hopefully get rid of the knock if it has not already permanently damaged something.

I just checked the timing belt again after running it, and it seems tight. I checked the allignment marks on TDC and it has not skipped a tooth. I just changed my timing belt about 4000 miles ago. I am thinking maybe the idler pulley maybe bad?

 

[theslab]

could be youre lifters. having the same problem, the stock ones suck and cause that ticking youre hearing. Get the 3g revised lifters.

 

[4g63jojo]

When you say your timing belt bounces up and down in between the cam pulleys while engine is running that means it is jumping, its likely that it was just "chance" that they ended lined back up and tight. Your idler pulley could be bad but Did you replace the tensioner when you replaced the belt? that would make more sense to me

 

[ThomasGSX]

When you say your timing belt bounces up and down in between the cam pulleys while engine is running that means it is jumping, its likely that it was just "chance" that they ended lined back up and tight. Your idler pulley could be bad but Did you replace the tensioner when you replaced the belt? that would make more sense to me

I did not replace the tensioner, but I had it inspected. However, I'm not sure, I think it may just need to be re- tensioned, I am still not 100% sure I set the idler and tensioner pulleys correctly. but it isnt jumping teeth at all. If it were, the timing would be off, and the car would run like sh!t. It isn't making any attempts to stall or die. It's only the sound. and the slack seems bad but not terribly so. It doesnt seem like enough to jump. But I will definitely tear off the timing cover and take a look at it This weekend. And I cannot just simply stop driving it. It is my only car and I work.

 

[4g63jojo]

ok well keep us updated.

Check and see if the tensioner is wet at all, that means its leaking and needs to be replaced, and also see if you can compress it with your fingers or by pushing it onto something, that will mean it needs to be replaced also.

 

[ThomasGSX]

OK, so I tore off the timing cover and sure enough, I had a bad tensioner, it was leaking a thick oil out of it and you could press the push rod in completely by hand, so I went to pick n pull and got one off of another car that seems to be in good condition. Also my water pump was leaking a bit so I replaced that too(thank you lifetime warranty at autozone) along with brand new idler and tensioner pulleys. started it up today and it runs like a champ.

Now if I could only figure out whats going on with my vehicle speed sensor.....

 

[razrman8]

Is the car throwing a code for it? (the vehicle speed sensor) I had that happen to me also a couple weeks back. Was on my way to work with the cruise control set and my speedometer just dropped. Eventually threw a code for it. I ordered a new one, only to find out that it was just unplugged. I would check that first. Doesn't cost any money to look.