valves knocking

[silverbullet17]

so i got my broken x3 replaced and the new one works. but my valves are knocking with the custom tunes. especially the 93 octane tune but also with the 87 tune. i currently have 93 octane gass in my car. what could be the problem? thanks alot

[troyerperf]

It's not actually your "valves knocking", but that is a common term people will use - it sounds like what you really have is "detonation" - and a specific form of it called "pre-ignition". That is when the fuel quality (either in octane or energy content) will not support the amount of spark advance being delivered to the engine, and so the mixture ignites before it should, thus you hear a "knocking" sound.

Just in general, any time you are taking a vehicle that has had lower octane in the tank and want to run a higher octane tune, is to make sure that before you try to run any tuning designed for 93 octane, that you first run out the entire tank of lower octane at least until the low fuel light comes on -better yet, a little bit further, jsut don't run OUT of gas. :) Then fill it up with the best quality 93 octane fuel available, and *then* you can load in the 93 octane tuning. Having even just 1/4 tank or even 1/8 of lower octane will cause the incoming premium gas to be diluted far too much in most cases, and you end up with detonation.

The *first* thing you need to do is to get with whoever sold you your custom tuning and go over this with them, as *that* is who is responsible for helping you with this. I have just given you a quick response here as you need to know that something is wrong and needs to be corrected right NOW - do NOT let this "knocking" continue, OK?

Follow up with whoever provided your tuning, and get some Tech Support to find what the problem actually is in your particular case and get it solved for you.

Good luck!