Deflooding RX8 Engine – Step-by-step guide

A few days ago I did the dreaded thing; I flooded the engine in my RX8. I had to move it no more than 5 foot, which normally isn’t a problem for my car, after all, I live on a hill and regularly stall it time after time, with restarts no more than 10 seconds from the previous (if I’ve completely forgotten that I’m driving a wangle to defend my driving ability :p ), or having to move my car to a different parking space at work.

The difference on this occasion, it was cold and wet both when I moved my car and when starting the following day. When I shut the engine off from the short move, the chock was still active idling around 2,500 rpm causing a flood of fuel to enter the engine without being burnt. When I started, chock was needed as it was again cold, pumping extra fuel in addition to the existing fuel already present within the engine, resulting in the starter motor turning the engine, but no life whatsoever in the engine. What a bummer.

After just two attempts to start the car, I realised what I had done, and knowing rotary engines don’t deflood themselves by simply leaving them for a period of time, I didn’t try again to prevent additional flooding. This was the first time I had done such a thing, so I looked online for a solution, to which there were a few suggestions, but no real step-by-step guide which is my motivation for this article. (I also found a suggestion about attaching the washer fluid to an engine inlet which sounds very suspect. No doubt it works, but I wouldn’t like to try this for chance of engine damage, but I’ll accept comments to the contrary.)

I later called Mazda breakdown who sent a non-Mazda mechanic. This was a mistake as they refused to follow the steps stated within the handbook, and didn’t know how to unflood the engine except by turning the key, and keeping it going until it starts (which in my opinion is near on impossible / takes upwards of several hours and probably a rather ill starter motor at the end of it).

The Renesis engine within the RX8 is prone to flooding with excess fuel during cold weather and when making very short trips (ie several feet), short enough that the automatic chock has not disengaged before the engine was turned off. This was a common problem within the RX7, but Mazda included extra measures within the RX8 to prevent this from happening, however occasionally it does happen due to the amount of fuel that needs to be pumped into the engine to start and maintain it in colder weather.

The solution to this problem when it occurs is as follows:

The first few steps is to follow the instructions within the handbook. Please note that if you haven’t got the engine running within two or three minutes of the starter motor being run, you must connect alternative power to your battery (ie via jump leads) otherwise you risk damaging your battery. If you are jump starting using another car and are at the later stages of this guide, make sure the engine is running and that when the starter motor requires power the other car is revved up to 2-3 thousand rpm to supply the majority of the power, as idling will still heavily rely on the battery.

  1. Make sure the key is not in the ignition, depress the accelerator fully (this will tell the computer not to supply as much fuel when starting), and then start the engine either until it has started or until 10-15 seconds has elapsed. If the engine starts, get ready to reduce the throttle as it rises. Repeat twice if unsuccessful
  2. Try starting normally for 5-10 seconds (this step pumps more fuel in, so limit the time if there is no life)
  3. If the engine is sputtering, it is not badly flooded, and the following steps may only need to be done once or twice.
  4. Remove the fuse for the fuel pump. There are two fuse boxes in this car, one in the cabin, and one in the engine compartment on the right hand side as you face it. The fuse is labeled fuel pump and is number 22 (tbc), which can be verified within the vehicle handbook. A small flat headed screw driver will aid in leveling the fuse out.
  5. Start the engine, turning the starter motor for 15 secs. If the engine starts, leave it until the engine dies naturally (if a second person is available, the fuse could be inserted quickly before the engine dies). If not, repeat this step three or four times, allowing 10-20 secs recovery time between attempts so not to damage the starter motor / revive the battery.
  6. Replace the fuse, and try step 1 again. You will probably at least get some splutters, and maybe some catches which do not fully lead to anything – don’t be tempted to apply extra gas if your foot is not already depressed, you don’t want to make things worse again. If still unsuccessful, repeat steps 3-5.
  7. Deflooding your engine within 30 minutes is good going and completely possible if you have been careful not to make things worse. When cranking the engine for periods, you will smell petrol as it exits the engine, this is normal and is what you are attempting to remove. It is also normal for the car to not start even after a successful step 4; it seems a bit wrong, but you are getting close and may just need to proceed with the last steps one more time.

Again, it is helpful to rev assisting engines that are supplying power when the starter motor is in use, especially during the important steps 1 and 2 or if you are allowing limited recovery time between attempts.

If you haven’t got time to fiddle, a method which will get you instant results is to jump start via a tow. I have not attempted this option, but I have been told that it will not kick in straight away, and that a little speed is required. Knowing that this is a heavy engine, a large drag will probably occur on the car towing, therefore it may be needed to clutch the RX8 in order to prevent a sudden tug and maintain speed in order to keep the engine spinning, although comments would be appreciated on first hand experiences.

Has this helped you? If it has and saved you hundreds in repairs or tow bills, you can show your appreciation by donating a portion of these savings, such as 5-10%, or whatever you think it has been worth to you. Donations are always received with great thanks, and helps out with some of the bills! I’ll even show my gratitude on here ;)

Hope you have enjoyed the read! Radz

Previous Comments

  1. January 11th, 2009 at 11:27 | #1
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    I’ve noticed a fair number of people finding this article by searching for problems with the starter motor turning slowly.

    When I flooded my engine, I did think it was something to do with the starter motor initially, it sounded as though it was simply spinning quietly and not turning the engine. It was however due to the fact that I’d never heard the car not start after any length of time before, and never realised how amazingly different the starter motor / engine turning sounded compared to a piston car.

    So if you think that there maybe something up with the starter, you may have just flooded it – The question to ask is did you turn it on / off quite quickly while the automatic choke was still active?

  2. Chad Yago
    March 9th, 2009 at 22:47 | #2
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    OK can i just say that you rock!!! I wish I could’ve found this a few years ago when i first had this problem with my rx8, instead of wasting hundreds on towing and repairs, as i do not live near a mazda dealer!! This happened to me on Sunday and could drive this AM, but found your instructions here this afternoon. After 3rd try of following your exact steps, she cranked right up!! Just wanted to say thanx soooo much and you rock!!! Have a great day!!!!


  3. Radderz
    March 14th, 2009 at 20:13 | #3
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    @Chad Yago
    Hee, I’m glad I’ve been of help. And thanks for the feedback. Having only done these steps on my car, its nice to know that they work for others too!

    And yes, the breakdown people are complete rubbish! Mine just flooded the engine even more. It ended up taking around 5 cycles of these steps for me, but I was figuring it out at the time, and it was raining (if that counts).

    Good luck with the car, and remember, no turning off the engine if it’s revving above 1.5 rpm ;)


  4. kanobi
    June 21st, 2009 at 17:05 | #4
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    hi the best and quickest way is to tow it down the road with another car keep in second gear and mine started within 500 ft and a big cloud of smoke came out and it ran fine. It’s happened 2 times in 18 months and this way takes less than 3 min.

  5. maz
    July 15th, 2009 at 15:22 | #5
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    you are the best man!!! fukin took ages though it wouldn’t happen then finally worked! thank you very much!!!

  6. Marlin
    August 16th, 2009 at 21:56 | #6
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    Fantastic. Was a great help . Finally got it started . Absolutely required the additional power from jumper leads and I suggest that if you have no one to help race the other car then leave time in between cranks to help build up the surface charge on your battery.

  7. alex white
    September 3rd, 2009 at 11:25 | #7
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    nice one mate you are a legend. the only step by step guide that i could find on the net and it worked exactly as you said, had to repeat all steps 3 times but it went in the end. thanks again

  8. Paul M
    December 28th, 2009 at 22:45 | #8
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    Thanks a million for these steps, used them today.
    Brilliant advice, took 3 times to get it started, but in the end pretty chuffed I didn’t have to pay for a tow to a garage.

  9. Radderz
    January 13th, 2010 at 16:32 | #9
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    Dang it! I went and moved my car back a few feet down the hill in the snow, and stupidly turned the key off straight away.

    It’s royally flooded again, that was silly of me! I’ll let you know how I get on this time :)

  10. babs
    January 13th, 2010 at 21:35 | #10
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    I’ve read many deflooding procedures but i have to say this is the best one. it’s worked for me and has saved me couple hundred quid that would have gone to the dealers.

  11. Monty
    January 16th, 2010 at 13:14 | #11
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    All I can say is that this is the most useful information ever!! Just spent hours trying to start my car, stumbled across this and within half an hour I’m up and running. Thank you so much.

  12. G
    January 26th, 2010 at 10:47 | #12
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    Hello All

    Two years owning my RX8. Learned through one honest and knowledgeable mazda recovery mechanic about flooding the engine and how to fix it on the road not taken to the garage. Yes agree most recovery people turning up and starting the batteries, flooding the engine even more. Last few weeks bad weather and I have been caught again, reminding me of the flooded engine nightmare…. But dumb … not with Mazda recovery this year. I have spent one hour educating the person on the phone what need to be done. Mechanic turns up, trying to start the battery. Had to raise the formal complaint. They sent another one, the one who listens. I am on the road again, thank you Dear who was listening to a blonde at 11pm last night.

    Thanks for your step by step guide too. Will laminate for BB or a mechanic.
    Xxx to all RX8 owners

  13. Radderz
    January 31st, 2010 at 23:35 | #13
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    I used the towing method this time around after I drained the battery down too much from my attempts, even though I had a jump from a second car while it was revving.

    I’m not sure whether it was the jump leads not supplying enough power, or the other car’s alternator was not up to starting the motor in addition to charging the batteries, but once signs of the battery becoming low occurred, it was just taking too long to charge back up for a decent 15 sec attempt.

    Towing is straightforward, just slip it into 2nd when traveling 10-20 mph, and slowly release the clutch to get the engine to start spinning without causing a sudden pull to the rope. Once the engine is running, be prepared to depress the clutch again to prevent the car from jerking forward into the towing vehicle. This can occur where the excess fuel within the engine causes it to rev up.

    Once bump started I found that both traction control and the airbags were disabled. If your battery is not discharged, you can just wait for your revs to die down, turn off the ignition completely and then turn it back on.

  14. dottyrocket232
    February 15th, 2010 at 21:24 | #14
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    Hi, just bought my RX8 232 two weeks ago and have just experienced the dreaded flood, found this thread through google and just wanted to say thank you, my husband followed your advice and bingo away she went.. Is this a forum or club or what? coz it sounds like I’ll be needing advice again. Many Thanks Dot

  15. Radderz
    February 15th, 2010 at 21:52 | #15
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    Hi Dot!

    I’m Radderz, and this is actually my personal blog. I tend to write random stuff that I have found both helpful to myself, and of limited information on the Internet in hope that it will help out others.

    Always please to hear how I’ve helped people out, so thanks for commenting.

    I’ve had my RX8 for about 4 years now, the same type as you (well, the 2003 version). I guess no doubt you’re finding it as fun as the rest of us!

    Feel free to contact me if you have any other queries, or you want tips, I might know or have ideas ;)

    Thanx, Radz

  16. jb
    February 17th, 2010 at 04:08 | #16
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    ok, my 04 RX8 is sitting in my garage for about 3 months now. i can not get it to run. lights turn on, and sounds like it wants to crank, as if the starter is going out, but can’t get it to go. i took it to the dealership last week and they said the starter wasn’t spinning fast enough to get the engine deflooded. they insisted i needed a new starter and it would end up costing over $700!! i found this blog and i’m looking forward to trying it out myself tomorrow. ill let you know what happens. thanks!!

  17. Radderz
    February 17th, 2010 at 06:54 | #17
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    Just remember to allow the battery charge back up in between tries. When I recently de-flooded it, it became too low to crank – maybe it was just the car I was using to jump from, but it needed a lot longer between tries then what I said above.

    I found that if it gets too low, the starter makes a clicking sound instead of turning, but you can soon tell when the starter starts to slow, just be patient and let it charge back up.

  18. mohan
    March 8th, 2010 at 01:44 | #18
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    I managed to flood my 2004 RX8 (for the first time) and your guide was a lifesaver. Thanks so much for putting this up! I followed the instructions to the dot, and got the engine up and running within 30 mins. It was a lifesaver. Thanks again! :)

  19. Rick
    March 13th, 2010 at 17:11 | #19
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    Thank you so much for your posting. I’ve had my RX8 for 5 years and this is my first flooding. It was cold and rainy a couple of nights ago, and I moved my car becasue it was parked behind my wife. It was a couple of days before I needed to use it and sure enough it was flooded.
    It took me about 8 or nine times of following steps 3-5, and I almost got impatient and gave up. I’m glad I didn’t because it finally worked.
    Thanks again!

  20. jb
    March 28th, 2010 at 02:52 | #20
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    Got my car started finally!! I got a new battery and it started right up following your steps.. The only prob is that it truly does drain your battery right away.. Non RX8 owners keep telling me it could also be the alternator as well… I’ll prob end up replacing that anyways just in case and give it tune up.. Thanks for your help!

  21. alfred edwards
    May 25th, 2010 at 02:46 | #21
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    Well I just deflooded my rx8… It was a mission disconnecting the fuse but I was able to get her started… Thanx a mil for your help, what can I say, I’m a first time rotary owner.

  22. michael
    July 13th, 2010 at 19:43 | #22
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    just a simple response to towing a RX8, this is a good way to do, but and its a big but. when you bump the car all the surplus fuel goes into the catalyst and before you know it you have a damage catalyst which equals mot failure.
    i know this from experience, flooding became a regular problem until my mate who is a mazda technician suggested upgrading the starter motor to model no N3Z11. since then i have had not one problem starting for 9 months.

  23. michael
    July 13th, 2010 at 19:46 | #23
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    if anyone would like to buy the upgraded starter motor today i have removed it because i have just part ex the RX8 for a BMW 320D and put the old one back on. it will be going on ebay or if anyone would like to contact me through this that would be good.

  24. LondonGirl
    September 13th, 2010 at 17:25 | #24
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    Hi, I’ve had my rx8 for a few weeks now and noticed that everytime i start the car its taking a couple of seconds for the engine to turn over… took it to mazda who turned it on, switched it off a few times… who then told me my starter motor is getting lazy and this could be because the previous over flooded the engine… anyway long story short.. its getting worse everytime i start it and i’m now resorting to getting a new starter motor which will cost me £450! Does anyone have any other ideas? my mechanic (a non mazda one, guy with a shop round the corner!) suggested I buy a non mazda starter motor which will cost me £250 its a british make lexon or something? Any ideas?

  25. Rog
    September 30th, 2010 at 10:16 | #25
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    Mate you are a LEGEND!!!! Thank you probably saved me £200.

  26. dejones
    November 28th, 2010 at 18:26 | #26
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    Excellent work! You are a saint!

    I flooded my RX8 by starting it, moving it about 30 ft, and turning it off in chilly weather.

    I agree with some of the other comments in that jumper leads are required throughout the process and a second person to rev the jumper car is a big help. I had to repeat the steps 3 times.

    One thing I will say is that once the engine starts to sputter a bit you are nearly there and that it is critically important that you allow enough time in between attempts to allow the battery to fully recover. I waited 3-5 minutes between each start attempt and had full cranking power for each.

  27. Bookz26
    December 29th, 2010 at 19:09 | #27
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    Well 6 months after owning my beloved rx8 it flooded, -4 temp didn’t help it was a quick shut down, in my defence i did rev the engine to 4,500 revs for about 8 secs before shutting down (mazda recommendation)But i think the cold weather assisted big time in the flood.

    I read a lot of comments here’s what worked for me. (this is a 2005 uk model)
    Luckily my cousin helped me out who is actually a mechanic.
    1) When you first do it, get right under the bonnet and pull the 20a yellow fuse pump fuse. This will stop any more fuel being pumped into the engine.
    2)We cranked it a few times acc pedal down to the floor (20 seconds) then replaced the fuse cranked again for about (20 seconds) repeated 3 – 4 times, never worked.

    When that doesn’t work, its most probably your spark plugs are wet with petrol and wont fire. (This was my problem)
    3) To remove spark plugs the easiest way without clawing your hand up through the engine, is to jack the car up, take the front left hand side wheel off, and you can access all 4 plugs very easy behind the wheel.

    4) As they were soaked we dried them off refitted them. Now your battery will not last long cranking so we connected my cousins car up with some jump leads and left them on through the whole cranking process.

    (Note) when all 4 plugs were out we cranked the engine for about 20 secs to spurt excess petrol out)

    5) Ok so after s/plugs were replaced the method we used was to crank the engine for about 20 s with the fuel fuse still in, if it never stared we did it for 20 secs without the fuel fuse just to clear it again. (This does drain your battery so leaving it a few mins before you repeat this process 2/3 times does help build a big charge.

    Eventually after some teasing the engine does sound like it’ll fire up, but then just dies again, stick with it, after about 10 attempts and towards the end we did leave it a good 5 mins for the charge to build in the battery. IT FIRED UP, you will get a lot of white smoke pouring out the exhausts, its normal its the engine clearing all the unburnt fuel.

  28. Pungza
    January 14th, 2011 at 04:39 | #28
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    Can anyone link me the a pic or where exactly id the 2 fuse located. It was cold and I didn’t know about the whole flooding thing and I started my car after it snowed and put it on the garage and now it crank but it won’t catch. I thought it was the battery but someone juiced it and still it didn’t work. But I believe now that my engine is flooded. I don’t know where the fuse is so if anyone can help thanks a lot. Is there things I shouldn’t attempt when doing this to further damage my car?

  29. Radderz
    January 15th, 2011 at 14:30 | #29
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    I’m afraid my car’s in for body work over the next couple of weeks as someone keyed my car quite badly, so I can’t take a picture.. But I think that fuse no. is 22 (you can verify this in your handbook, it is quite easy to locate the number and position within there, or if anyone else could verify this?).

    As you stand in front of the car and look into the engine, the fuse box is located on the far right hand side in a rectangular box with a black cover over it. Take off this cover, and you should have access to the fuses. You will need a small screw driver or levering device to remove this fuse.

  30. Matt
    February 19th, 2011 at 06:32 | #30
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    I left the car at my parents’ house for the winter. One day the garage door motor gave out so they hired some guys to fix it. My car had to be moved like a foot forward because it was in the way. My mom gave the guy the key, and the car got shut off 10 seconds after it was turned on!

    To fix the deflooding issue, you will need a battery charger of some kind, either a plug-in device or another car.

    It took me about an hour to get it done. I followed this guide but I honestly don’t know how useful step 3 was since step 2 basically does the same thing as 3.

    My number one tip is for step 2. Make sure you press in the accelerator BEFORE you turn the key to the start position to start the engine. If you do it at the same time or after, the fuel pump will not be cut off.

    Patience is key. It probably took me around 30 attempts in total. I had partial turn-overs a few times, and I actually started the engine a couple times for a few seconds before it died again. The main trouble was with the battery. Even with the charger attached, 5 or 6 start attempts drained the battery pretty low. When I finally got the engine running, it was running weak so I made sure to rev it for a while until i trusted that it wouldn’t die once I took my foot of the pedal.

    Deflooding wasn’t a fun experience over all. The engine smoked up with a smell of gas, and when i finally got the engine started, excessive smoke billowed out of the exhausts for a good 10-15 minutes. I waited for the smoke to cease and then I drove around for a half hour to make sure the engine was good and warm before shutting it back down. It is also a good idea to rev the engine to the limit to burn off carbon build-up.

  31. Jennz
    April 2nd, 2011 at 19:31 | #31
    Reply | Quote

    Yay! I missed my rx8 finally got it started after those steps. Thank you so much for posting.

  32. Glass boy
    June 26th, 2011 at 08:22 | #32
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    Just some question. If I set my turbo time to 3-5mins after 5 feet drive. Will it save me from this kind of prob?

  33. dave thorburn
    July 16th, 2011 at 13:20 | #33
    Reply | Quote

    I cant thank you enough for your help, followed your advice, had car
    going within 15mins, i really appreciate your help, and the effort made
    to help others.

    thank you

4 thoughts on “Deflooding RX8 Engine – Step-by-step guide

  1. Found this post through google search. I’m an auto body tech and received a rx8 to repair on Friday. Problem is though that it won’t start, I’m thinking it’s a flooded engine. We pushed it in the shop on Friday but I’ll try these steps on Monday and see if it starts, wish me luck :)

  2. had same experience –just moved rx8 a few feet and flooded —-followed this and WOW all worked really well ..just keep with it and it will work

  3. THANK YOU. Tried all other techniques and got close but none really worked. Tried yours and repeated the steps and within 20mins car was running. It flooded 6 days ago and after getting a new battery and following your steps it all worked. Thank you so much

  4. Hey just thought I would say thank you so much!!!! I flooded my rx8 yesterday and was looking to the internet for a solution and stumbled upon yours!! Worked within half an hour!!! Thanks!!!

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