Stevie Ray

Have an 06 6 speed stock save for a K&B filter and slightly modified air box. Occasionally have the marbles-in-a-can noise with significant loss of power at low RPM but only after driving at highway speeds for an hour or more. Only happens when getting off the highway and onto city streets. Happens at high (90's) and low (50's) ambient temps (Central Florida). I run 93 octane Chevron only, have all the flashes and MSP's. Dealer maintained at all recommended milage intervals and has had two decarbonizing procedures. Anyone have any suggestions?

Razz1

Are you sure it's detonation and not air in the cooling system causing marbles?

Old Rotor

You might try this, it only takes a minute to do. Let us know if it helps.

https://www.rx8club.com/rx-8-discussion-3/no-more-detonation-%2Amiac%2A-121249/

Mazurfer

That's the link to the thread....worth a read, but here is the link right to the bypass.

http://www.rotaryinsider.com/diy-tac...pass-gap29.htm

So where in East Central Florida are you?

Stevie Ray

Palm Bay. Have you done this TB bypass mod?

Stevie Ray

Not sure at all if it's air in the cooling system or detonation. How would one distinguish between the two? Had the coolant bottle replaced to fix the intermittent "low coolant" light. The MIAC noise has happened twice since then (2-3 months). No cooling problems ever.

Stevie Ray

I need a little education before I do a mod like this. Is it that the heated intake air causes the detonation? How cold does it have to get before condensation and ice forms in the throttle body without the heating? I assume the humidity level comes into play but in Florida, there is always plenty of humidity so I'm assuming it's enough to form condensation and ice if it get cold enough. It's in the 30's right now. I'm somewhat concerned about voiding the warranty if I forget to undo the mod before going to the dealer. Is this a common mod that solves the MIAC issue or does it merely help some? Any info would be much appreciated.

Mazurfer

Sorry Steve, didn't see that you had posted back. I work in Palm Bay on Robert Conlan Blvd.
No, I personally haven't done the bypass. I've never had the MIAC experience, so I can't offer much help there.

I would say that the intake gets plenty warm, so I don't think there would be any issue in doing this bypass. Even with our humidity, I just can't see it coming into play at all.

Do some more searches on this subject. I'll take a look as well and see what I find.

I do know that there are many people in Florida running with the bypass and no ill effects, but I can't say whether it cured the MIAC for them.......I just don't know.

Old Rotor

Yes it is the heated air thats why inter coolers help with turbo cars. I live in Northern California and it gets cold here and I have not heard of a problem. It takes a minute to try out and see and if it doesn't help another minute to remove. It might just need engine de-carbon done or a few cans of sea foam run through it. That would get rid of glowing hot carbon that could cause detonation.

Foamy

If the hot water tube to the throttle body is not in series with anything else, why not just put a squeeze clamp on the hose to prevent, or reduce the amount of water passing through it?

Makes it very easy to turn OFF or On - just a thought...

Old Rotor

Try it and let us know how it works.....

Stevie Ray

Did the TB bypass mod. No highway drive time at high temps so too early to know if it helped.
Bypassed with a "patch hose" to keep the original hose and routing in case I have to visit the dealer (engine still under warranty). Even left the original clamps on. I routed the bypass under the TB to keep it neat. Photo in my album. https://www.rx8club.com/album.php?al...pictureid=5028
Will post again when I have real data to report.

Razz1

If you still have a sound, I heard this might work.

Jack up car on one side. Remove Radiator cap. Allow car to heat up. Air will force its way out.

Stevie Ray

I'll keep it in mind. Thanks!

The Underdog

iTrader: (2)

You guys sound like you're firmly entrenched in the throttle body bypass mod but I'll throw this in anyway...Clean your mass air sensor. Use sensor safe cleaner or electronics cleaner that says it leaves no residue. It fixed my problem instantly.

I'm on my second year owning an 04 6mt with a K&N and I always ran it on regular till it started detonating. It started right around the time the gas got real cheap again so I thought they were messing with the formulation of it. So I went to premium gas and it stopped...for a while. Well I was like "ok why would it knock on premium when it ran fine on regular for more than a year?? Something's wrong here" So then I was like ok think back to the turbo days (used to be into that)... What causes detonation? Well, one big thing is lean conditions. Then I remembered how many problems my friend had with CEL's when he tried to put a cold air intake on his Protege. Then dude with a Focus had problems with his mass air sensor when his cone filter was faced forward but not backward. The bottom line is that the mass air sensor that mazda uses is very sensitive and doesn't tolerate any changes.

Here's my theory... The K&N filter has oil in it right? Maybe some oil residue builds up on the mass air's important bits over time and starts throwing it off. Yeah so anyway, that's my two cents.

teknics

that's actually exactly why mazda, and most vehicle manufacturers, advise against oiled intake filters, dry filters are the only way to go.

kevin.

Stevie Ray

Will clean the MAF. What is the best cleaner to use? I've seen posts about CRC MAF cleaner.

Stevie Ray

Cleaned MAF Sensor. Big difference. Much more power, better throttle response. Used CRC MAFS cleaner.

Did some highway driving. No sign of MIAC after throttle body bypass. It was intermittent any way so the jury is still out.