Toyota echo 2nz-fe rattling

[Ditlind]

Guys i have a 1999 toyota echo 2nz-fe engine, car runs perfect but on a steady speed i hear rattling from the engine, if soemone can help me diagnose the problem i think its the timing chain loose or stretched, i dont hear the the rattling stationary but only while driving at a certain rpm around 2000-2200 on steady speed, if i goo full throttle doesnt happen. Otherwise rund good, doesnt shake, squeak or smoke.

Edited March 2, 2020 by Ditlind

[Valkie2]

You may have what is known as Pre-Ignition, Detonation, Knock or Pinging:

These are often noticeable at different times or different revs depending on the circumstances and issue.

Pre-ignition is as it states, the fuel burning or cumbusiting before the piston reaches its ideal position (just before TDC) it sounds like a rattle, but usually under load.

It also robs the engine of power, so if you have no noticeable power loss, this may not be your problem.

It can be caused by several things, Carbon build up on the piston, too hot a plug, the wrong fuel, too lean a mix (which in itself brings many many associated issues with sensors and manifolds etc.

Check you plugs, if they are exhibiting signs of cooking or overheating, you need to get things checked out.

Most modern cars have KNOCK sensors as well, these detect the knock and adjust the fuel accordingly to prevent it, if this little gem starts playing up, you will have a problem.

Then there is the MAF, MAP and other sensors, all designed to measure the air and fuel mix to achieve optimum operating conditions, if one fails, everything gets messed up.

Finally there is the oxygen sensor, if this baby clogs, cooks or simply dies, the engine cannot smell its own farts and has a fit. it can cause all manner of issues with fuel and air mix.

Diagnosing a "knock or Rattle" is quite a job, probably best left to experts who have all the fancy gear to check sensors and fault codes. 

Or you can go down the path of replacing things and seeing if it makes a difference. 

For me, that's the hard way, for a few bucks, Id rather have someone else have a look.

Once correctly diagnosed, you can repair at yourself.