I've found numerous threads on how to fix flooding issues, unfortunately, early this week I experienced both Carbon Lock and Flooding for the first time with my 2004 RX8 at 75,400 miles. I have on many occasions moved my car only a short distance for many reasons, it's something I'm sure many of us are guilty of, this time it bit me in the *** two fold (I suppose I had it coming!).

I'm starting this thread because while I found numerous threads on deflooding, I was unable to find a single thread on how to cure carbon lock! (in fact I was unable to find much useful information anywhere in the internet).

I've done quite a bit of research and would like to thank Dan at 'Atkins Rotary'. I called him in desperation and he was kind enough to give me a few pointers that made all the difference! Below you'll find what I now know about these problems and I hope that they help someone avoid the week of frustration and long walks to parts stores that I've endured...

Other members please feel free to add any information you think may be useful or helpful.

Before I get down to it I must add... my 04' engine is under warranty til it reaches 100,000 miles, while that warranty doesn't cover flooding, Carbon Lock I've found is a gray area... I called two dealerships, one told me Carbon Lock WOULD be covered under the Engine Core warranty, and the second shop told me that it was on a case by case basis and that Mazda will sometimes cover it ONCE! unfortunately, in the beginning I assumed they wouldn't, and only found out about this 2 hours before I finally got my car started (the tow truck had just called and was 10 minutes away!)

alright! drum roll please!

 

dumdumdumdumdumdumdudmdmudumdumdduumdudumdumdumdum umdumdumdumdumdum

 

first, there are two kinds of carbon lock.

one kind of carbon lock is where your engine is literally jammed with carbon and will not even turn over!

the second (and the problem I had) is when the combustion chamber is filled with little granules or chunks of carbon that cause the apex seals to be unable to seat against the rotor housing and causing you to lose compression!

I discovered this because the engine spun too freely and when I pulled the spark plugs I could see they were covered with bits of carbon granules.

the first step is to open your hood and remove the fuse to your fuel pump (#22) in your manual.

the second step is to jack the front driver side of your car up and remove the front driver side wheel, block your wheels, and use a jack stand in the name of safety, if you don't have a jack stand I found that my removed wheel and a 2X4 (to protect the rims edge) worked equally well as a jack stand lol! you don't want 3000lbs landing on you, it will ruin your weekend!

now let's do a tool check... you're going to need a ratchet and I highly recommend 34 inches worth of extensions, to remove your spark plugs you're going to need a 13/16 plug socket, and you WILL need a swivel head! DO NOT USE A WOBBLE! I tried to use a wobble and it broke one of my plugs, don't take the chance! nobody carries our plugs in stock except for Mazda, and I was given a price ranging from $65-$138 for ONE spark plug! Napa was able to get me one in 24 hours for $25

it's also a good idea to have a battery charger on hand as you'll most likely go through a couple of charges trying to start your car... I got one for $35 from Autozone.

you will also need a funnel with a nice long tube so you can reach the plug holes, and you'll need either a bottle of Amsoil Power Foam (which nobody seems to carry) or you'll need a bottle of SeaFoam which most parts stores have and is essentially the exact same thing...

the SeaFoam will break down and liquefy carbon... be careful not to get it on your cars exterior as it can damage paint!

now that you've got your tools ready, remove the small rubber flap that keeps debris from flying into your engine compartment...

you'll see four spark plugs, your bottom plugs are your Leading, and your top plugs are your Trailing, the top plug wires should also have colored strips on them and the bottom plug wires should not. carefully remove and inspect all four spark plugs, if they are fouled they can be cleaned in the same way as any other plug, they can be sand blasted, or you can use a medium bristled wire brush and some very fine Emory cloth or sandpaper (I used some 320 grit and it worked perfectly).

now get in your car and turn the engine over in 5-7 second sessions with 5-7 second breaks in between each time (this is less of a drain on your battery and gives your starter a chance to cool down a tiny bit each time and avoid damage). This should expel any excess fuel that has most likely flooded your engine.

now put your bottom (or Leading) spark plugs back in, they'll be model RE7C-L (in case you've forgot).

NEVER put your plugs in with a socket wrench! put them in by hand! only use the wrench to tighten them! do this to avoid cross threading your spark plug or worse, your rotor housing.

now get your funnel, push the end of the tube as far as you can into one of your Trailing spark plug holes but also be careful not to get it stuck (at this point a longer tube makes your life a LOT easier).

now pour about 1/4 of your can of seafoam into the funnel, it will likely overflow and ooze a bit back out (wouldn't be a bad idea to put down some cardboard or something to absorb the spillage), now repeat this in your other Trailing spark plug hole.

now, put your spark plugs back in, attach your plug wires, and put your battery on the charger! you're going to need a strong battery if you're going to get your car started!

I'd recommend leaving wheel off and keeping everything accessible at this point just in case it doesn't work on the first try...

Now, VERY IMPORTANT! go inside and play video games for AT LEAST an hour (feel free to substitute cartoons, ****... I'm not here to judge), this both relieves frustration AND gives the seafoam some time to work!

has it been at least an hour? time to give her a go!

First! don't forget, you need to put your fuel pump fuse back where it goes (#22) remember? put it back, we need fuel if she's gonna run!

now, re-install your battery (only applies if you removed it for charging...)

get in your car, try to start her up in 5-10 second bursts... she should fire fairly easily since the seafoam is highly flammable... now the trick will be to keep her running long enough to blow out all the crap! she's going to sputter and try to die... rev her up to about 5 or 6k and try to keep it there until it smooths out and feels normal...then keep her at about 2-3k for a good ten minutes!

your RX8 is going to bellow smoke like crazy! this is completely normal!

now that she's smoothed out and you've kept her at about 2-3k for ten minutes (and she's at full operating temperature, about half way on the gauge...) let it idle... while it idles put your little debris flap and front wheel back on and set her on the ground.

if you disconnected your battery then you're steering positions sensor will need resetting, but don't worry about that right now, you're TSC light will be illuminated on your dash but it's safe and necessary to drive your car right now... go for a short (15 minute) but spirited drive, take her to redline often...

now that you're home and parked (with your car still idling) turn your steering wheel all the way to the left, now all the way to the right... now, your steering angle sensor is reset and next time you start your car everything will be back to normal.

(disclaimer) there is a possibility that all of this can cause your car to throw a cel and your check engine light can come on... mine came on about 50 miles after this, I'm not sure if the seafoam caused it, or if the misfiring from the carbon residue caused it... or if I didn't tighten my gas cap enough when I stopped to fill up (it was a touch loose when I checked it...)

I'll post again in a few hours with how to fix a carbon locked engine that won't turn over or is seized with carbon...

 

I called both Ricks Rotary and PR Motorsports as well as Atkins Rotary and they all said that what I described was carbon lock, and that the type of carbon lock I had most likely caused the flooding as well (from trying to start it over and over with no compression caused by the carbon)

 

[B]IF YOUR ENGINE IS CARBON LOCKED AND WILL NOT TURN OVER AS A RESULT[B]


the steps for fixing this are a little bit different and I should note that I have NOT performed this myself.

first thing you will need to do is pop the hood and open the intake manifold, this requires you to remove the black plastic intake portion on top of your engine that has four tubes going into the engine. once you remove that simply pour half a bottle of SeaFoam equally into all four tubes leading down into the engine, let it sit over night, put it back together, and try to start it... you may want to pull your plugs and make sure they are not fouled as well... (make sure you do this PRIOR to pouring seafoam into your engine! otherwise it will end up all over the ground!)

If this doesn't work the first time don't lose hope, some very stubborn carbon locks can take multiple treatments to free up, but don't give up, this WILL work.

If it hasn't worked the first time, do it again, and again if necessary...

If you really are tired of trying it yourself and you live in the CA Bay Area... call PR Motorsports, they're located in Hayward CA, they have a SeaFoam machine and they quoted me $55 to clear my Carbon Lock... pretty cheap if you have a trailer or a tow truck to help get your car there... Unfortunately I'd have had to pay for a tow truck and as far away as I was it would have cost me a couple hundred bucks... so i did it myself...

 

Maybe this should be a STICKY... considering how hard this info was for me to get on my own... and how much easier my life would have been had I found all this in one place... I know carbon lock in the RX8 isn't nearly as common as it is in older rotaries, but it does still happen, and there are not enough resources available on the subject...

I really hope that this info helps someone avoid the frustration I dealt with...

 

It would be nice to know what your compression was after all that!

 

I'd love to know myself... but I only left it in for about 45 minutes... not really as long as I should have, the tow truck was almost there and I was just giving it one more "what the hell" shot in hopes it would start... I am planning to do the full seafoam cleaning through the vacuum nipples on the intake manifold and half a bottle in the gas tank to clean the injectors, hell maybe even a half a bottle in the oil pan to free up any grime that might be in there... I've heard that such a thorough cleaning might free up some lost fuel mileage, which I'm getting 17mpg on the freeway! I'd love to test my compression both now, and after the thorough cleaning! see how much of a difference I get... I certainly wouldn't mind finding out I have bad compression and getting a new motor!

 

I have a master mechanic friend with a Mazda compression tester. After seeing it was low on one rotor I went to a dealer with the results. They tested it and said it was fine. It stopped detonation(MIAC) on reg-87 fuel(I had to run prem-91 before this). I felt they must have done a de-carbon on the engine because it ran much better(but there was no mention of it on the work order). Before I brought it in to the dealer I had coils, spark plugs, and wires installed so that would not be an issue. It's been about 8K miles since that was done and I feel its due for another de-carbon job. I bought two cans of Seafoam and we'll see how it goes....

 

I wonder how much one of those nifty rotary compression testers would set me back...?

 

Never fear, Jedi is here

https://www.rx8club.com/group-buy-center-85/tr-01-rotary-engine-compression-tester-official-group-buy-172238/