Any help or info would be appreciated.
After one of my pre cats went a couple of weeks ago I gutted the other manifold cat and replaced the main catalyst.
Since doing this I have noticed that the engine is now pinking / detonating / knocking when I accelerate. I first put it down to the fact that I now have two empty baked bean cans hanging off my manifold causing a change in back pressure but I now have doubts. s:cry: :cry: s:cry:
The pinking noise only occurs when I press the accelerator past half way (Not audible above 4500rpm). I tried adding a can of NOS octane booster today but this has made no difference at all, which rules out my fuelling and knock sensor theories.
Is there anyone else who has gutted pre-cats who gets this noise?
Anyone with any ideas?
You sure it's knocking?
If so, then it sounds like you didn't catch it in time and you need some serious engine work. If it's just a rattle (and it well could be), then try tighening up all heatshield and exhaust bolts: It's possible one of them is loose and rattling at a certain RPM.
James, seeing as threating my car with a visit to the Toyota garage has amazingly made it behave (still going in and still don't know what the issue was) you are more than welcome to have a listen to my pre gutted engine etc to see if its any different. I also have the JDM main cat here if you wish to try that out just in case its the replacement that causing the bad running.
Have you tried switching the O2 sensors round just incase the one by the collapsed pre cats is completely knackered and causing bad fueling.