2001 Ticking Noise

[jazzorama_2000]

My 2001 Camry with the 4cyl 16 valve DOHC has recently started making a fairly loud ticking/clacking noise at low rpm (idle to 1500rpm). It disappears when I get above that range. I suspected that it may be a valve clearance issue so I inspected clearances and all fell within the specs. The noise wasn't there one day and was there when I started the car the next day. It sounds like it is coming from the timing belt side of the engine. The belt has just been replaced 10,000 miles ago. No loss of power and engine feels the same when driving. My next idea is that the noise is coming from some part of the valve assembly (bad spring seat or something?)
Anyone had any similar issues. The car has 135,000 mi on it and is the 5 speed manual.

[Burnwithin]

I had the same problem not sure if it will help u but my camshaft gear was rubbing on the black metal plate behind it just pushed it ut of the way with a screwdriver

[Jason.MZW20]

A possibility:

The camshaft sub-gear is pre-loaded with spring tension, so if it lost tension it'll make a racket at low RPMs. If you look under the valve cover, you'll see that the intake cam drives the exhaust cam. One of them has a pre-loaded sub-gear, but I forgot which.

You might be able to reset the tension without removing the cam, if this is the issue. Usually it only comes unloaded when someone removes the cam without locking it with a service bolt.

[carsrus]

Timing belt slapping the cover.

[jazzorama_2000]

Thanks for the tip. I was wondering if you had any suggestions on how to restore tension to the camshaft sub-gear? That would be great if it could be done without removing the cam.

[jazzorama_2000]

I checked out the timing belt cover and all seems well on the outside. It is a new belt and the sound that I hear is very metallic in tone. Is there any specific reason you think it might be the timing belt slapping the cover?

[jazzorama_2000]

I decided a few weeks back to fill my tank with 92 octane fuel and then dump in a bottle of fuel injector cleaner (backwards right?) I was wondering if this has somehow clogged my injectors and if I should pull them out to take a look. Should I use something like Sea Foam to clean these out instead of pulling the injectors? Any suggestions?

[fenixus]

if one of injectors was completely clogged you would feel in cabin the uneven vibrations of the engine running on 3 cylinders instead of 4.

if you have some obd2 scan tool allowing you to see the fuel trims then you could do a simple fuel injector balance test. you simply unplug them one at a time and compare what effect it has on fuel trims. once you unplug the clogged one you will not feel any difference and ECU will not compensate for it as well (because it did already).

[jazzorama_2000]

The problem ended up being a loose camshaft pulley that was rattling around at low rpm's. All that was required was a re-torque on the center bolt. Sounded bad though and could have been worse if it came off!