Light tapping but not constant

[Chri5]

I'm a bit of a newb to these cars, but not cars in general but in simple terms I've got a Ph2 172 now, and I've noticed theres a faint tapping noise on idle which may just be normal?

When driving, if @ around 2500rpm, I lift off completely, theres no noise, but If I apply a slight bit of throttle, theres a faint tapping noise....BUT if I then add some more throttle it instantly stops tapping :S

It does it every time and in any gear, any ideas why it comes with slight throttle but goes with 1/2 and no throttle at all?

Could it just be an exhaust blowing slightly at the front? I know this can cause a tap like sound.

Oil level is ok and cambelt & tensioner etc have been replaced @ 70k, car is now on 75k

 

[si82]

the tapping noise will be your charcoal canister rattling in its bracket its a metal bracket that rattles when you give it a slight bit of throttle.hope this helps you my 172 cup does the same only at idle

 

[Chri5]

Not checked the canister yet but from reading other posts the "ticking" noise that comes on after about 20secs is that, so thats solved that one.

This other rattle I think is something else though. After some investigating, when accelerating in, say, 2nd gear to about 3k rpm, then lifting off and letting the revs drop, once it gets to 2k it'll rattle and does so until back to 1k, and it slows down as the revs all fall. It does this in any gear

Its also noticable when static, if you blip the throttle and let it fall, it'll make a tinny rattle as it comes down towards 2k rpm. The engine seems a bit noisy if you blip the throttle quite hard, but this may just be normal, (Im used to a 2JZ GTE 6cyl Toyota lump which is smooooooth lol) so will take a bit of getting used to. I'll try and get a video of it but it doesnt seem to come from anywhere particular on the engine either, it can be heard from both sides and inside the car!:S

There's no terrible knocking noises etc

 

[Chri5]

Been investigating some more today, tried unplugging the canister as been suggested in other threads....same!
Removed engine cover....same!
Seems noisier tonight, I think,it may be something to do with canister bracket but it sounds more like its coming from the top of the engine area, kind of all over?
Oil level is still fine, just under max.

Any other suggestions? Apart from loose spark plug and heat shield, which Ive checked down the back of the engine. Not checked these yet

Its starting to bug me, and is quite noticeable with the window open and more so when driving past walls/cars etc. Its definately a "tinny" noise, rather than a knocking/thumping, and is proportional to engine speed

 

[Mr bean]

i would recommend taking to a garage for a perfessional opinion as its hard to diagnois a noise over the net and threw the fourms :dapprove:

 

[Chri5]

Im fairly "engine minded" so a garage would be last resort!

It seems the tapping is getting a bit louder, unless its my imagination, and is very noticable when decelerating, and in between gear chagnes! definately sounds like its coming from the head if putting my ear in the area, around cylinder 2-3....most likely a lifter?

No abnormal noise around cam belt/pulley area so think its ok there.

 

[Hutchie]

inlet cam varible timing pully, i recon, it gives a slight tapping noise on top of engine.

 

[Chri5]

Well today I took the plenum off and went round all the bolts, spark plugs etc and nothing was loose. Ive also changed the oil from whatever was in there, also using some engine flush (I know not everyone agree's but its never done me harm before), and filled her it back up with some 5w 40 fully synth and a new filter and I have to say its definately alot quieter now, especially on idle

Still a little tappy but nowhere near as noisy now!

Thanks Hutchie, but im pretty sure its not pully related just from where the noise is located

 

[Hutchie]

Well today I took the plenum off and went round all the bolts, spark plugs etc and nothing was loose. Ive also changed the oil from whatever was in there, also using some engine flush (I know not everyone agree's but its never done me harm before), and filled her it back up with some 5w 40 fully synth and a new filter and I have to say its definately alot quieter now, especially on idle

Still a little tappy but nowhere near as noisy now!

Thanks Hutchie, but im pretty sure its not pully related just from where the noise is located

well the tapping you get from the inlet pully tends to resinate from the whole engine, its a well know common fault.

 

[caister]

search for threads on the dephaser pulley and see if that's the noise you are getting.