Starting a Mazda RX-8 with a flooded engine

October 12, 2010 · Posted in Transport 

Mazda RX-8

Mazda RX-8

A few weeks ago, I made the mistake of moving my RX-8 a short distance and didn’t allow the engine to warm up before switching it off. It’s well-known that this can lead to a flooded engine and this time was no different. :-( I knew it was a mistake, but I was in a hurry!

I’ve only had this happen once before and, as then, I couldn’t get the engine restarted using the manufacturer’s technique of fully depressing the throttle (should cut the fuel), cranking the engine for 10 seconds (should clear the flood) and then cranking as normal. Having tried this a couple of times, I soon ran the battery flat and so had to recharge it overnight.

Next day, I tried the tips from this excellent blog post. It describes how to unplug the air pump and remove the fuel pump fuse to assist with starting. I tried this but again failed, mainly due to lack of charge in the battery even though it was fully recharged. The same technique was used by the RAC chap who got me going the first time this happened – it took him about 20 minutes and of course he had access to a much better power source on his van.

Now out of options, I called the AA. The chap they sent out took a rather different approach which I’ll attempt to describe here in case anyone would like to try it:

RX-8 fuel pump cover under seat

RX-8 fuel pump cover under seat

1. Remove the nearside rear seat base cover. The lower seat cushion simply pulls up (see comment 57 from KenF below).

RX-8 fuel pump cover without screws

RX-8 fuel pump cover without screws

2. This reveals an access panel which is held in place by 4 sheet metal screws. Remove these screws and the panel.

Underneath RX-8 fuel pump cover

Underneath RX-8 fuel pump cover

3. There is a single electrical connector (black plug with 3 cables connected to it) on the pump assembly that provides power to the fuel pump and readings from the left-side tank level sensor. Take a moment to learn how to disconnect and reconnect this connector.

4. If possible, connect an additional power source to the battery (another battery or another car via jump leads).

5. Position yourself in the driver’s seat with your left hand stretched behind you (assuming you have a right-hand drive vehicle) ready to connect/disconnect the fuel pump. Keep it in the disconnected position.

6. Apply around 1/3 throttle on the accelerator pedal. Use your right hand to turn the ignition key.

7. The engine will turn but not start. After around 10 seconds, connect the fuel pump for a few seconds then disconnect.

8. You may need to repeat this a few times. Don’t crank for more than about 30 seconds at a time though to save your starter motor!

9. After a few tries, hopefully you’ll hear the engine getting close to starting. The point of connecting and disconnecting is that you are trying to clear the engine and then reconnect at just the right time to get the fuel pumping again (see Andy’s comment, 8 below).

The AA chap said that using this technique he can usually get RX-8s restarted in around half the time it takes using the fuse removal, etc. Apparently he learnt this from a chance conversation with an engineer from Mazda. I suspect it’s the sort of thing you need to try a few times to get it right, but it certainly seems to offer more control over the process as you can access and change all inputs at the same time (fuel pump, throttle and ignition).

Let me know if you try it. As always though, it’s at your own risk – I don’t want any repair bills for a knackered fuel pump or catalytic converter :-)

If you leave a comment below, it would be great if you could add which country you are in, there are quite a few here already!


218 Responses to “Starting a Mazda RX-8 with a flooded engine”

  1. CJ on November 13th, 2013 23:14

    West Central Florida, US
    Finally made it to the college. The short of it, it is running again. But took a lot to get it there. a couple hours one evening just trying to dry it out with a half discharged battery and a weak booster set up, then the next day about three hours. Doing process exactly as written above did not work (although it was trying to), but a combination of that and another post above did. Spinage’ got me almost to where it would stay running but didn’t quite get over the hump. What worked:
    Trickle charged the battery overnight. Got a big @$$ battery charger/starter (150 amp) and connected. Cranked engine for 15 to 18 seconds with fuel pump disconnected (did not connect pump at all) and shut off key. Wait min of 2 minutes (104K on it everything is getting a little weak so going easy). repeated 15 times until engine was almost running on it’s own for a few seconds. Yes, it did that with pump disconnected, that’s how I knew I was getting close to clearing all access fuel out. Cranked engine about 5 sec, plugged pump in while cranking. No joy. Engine stopped trying to start. Repeat clearing process 6 times. Second time I took a piece from Mark B. (post 107) and did not press the pedal at all. It fired up slowly and as rpm increased I slowly pressed the gay. Spun up to 5K and the party began. I think mine took extra time because it is old and cranking speed was a touch low, even with the big jumper.Here’s some observations:
    1. The fuse pull and pedal to the floor methods probably work too, but people give up on it too early after not enough tries (guilty). But it is easier to choreograph the key, fuel and pedal at once using this method.
    2. cranking RPM is everything. If it’s even a little low, it will prolong the time it takes to clear the engine.
    3. When cranking, resist the temptation to release the key when there is a little sign of it trying to start. Hold it until your ready to rest the starter, no matter how much it sounds like it is starting. You’ll know when it’s ready to take off and run. The more it belches, the better.
    4. Be prepared. Especially when in an apartment complex parking lot. Two things to think about – restroom and drinks. You don’t know how long you’ll be there. Nearby woods will work, and I think a six-pack would suffice.
    Cheers spinage. didn’t work perfectly (as every car is different) but you definitely got me where I needed to be and saved me some serious coin. Thank you.

  2. Mark Mumford on November 24th, 2013 23:19

    Although this was posted in 2010, it lives on so long as RX8s continue hum along the roads. I was wondering if anyone has tried this method using a modified fuse which is inserted in place of the 20 amp fuel pump fuse. The modified fuse has the fuse element severed so that there is no current flowing between the fuse contact blades. The blades are wired via a long lead that reaches into the driver’s position and at the end of the lead is a switch. Rather than disconnect/connect the pump through the hatch under the rear seat (as described in the post), the disconnect/connect operation can be achieved via the switch attached to the modified fuse. Comments?

  3. Lori on December 11th, 2013 03:40

    Hello Spinage
    You are my hero. Last week, I moved my rx8 from drive way to my garage after washing it and it wasn’t started. I tried the Mazda way, pedal to the floor with no luck. Tried to remove the pump fuse after removed and cleaned spark plugs, it didn’t work either. I started thinking about $500 to fixed it by Mazda. Came to your method. Removed the seat ( the one behind driver seat because I am in USA) It’s very easy, just pull the front of the seat hard up. Removed the cover, found more problem. Got fuel leak from the outlet of fuel pump. No wonder it used a lot of fuel. Temporary fixed it by epoxy and fishing string. At the same time I Cut the black wire and made a switch (I could not reach the pump plug as you showed. I did not cut the hot wire because I afraid it can affect another components). Cranked engine three times. Fourth time I started turn on switch after 10 second cranking. After 3 times, engine seem like want to go and at the fifth time life came back to my engine ! Not a lot of smoke came out because I did clean combustion chamber by compressed air when I removed spark plugs. It took me only 10 minutes to get the engine running.Now my car goes like before. I am going to keep my switch in my car but hope that don’t need it one more time.
    You saved me a lot of money and headache

  4. spinage on December 11th, 2013 08:38

    Thanks Lori, some helpful extra tips there.

  5. nc on December 14th, 2013 21:11

    just found your thread. Read it all. I have definately flooded my 2007 rx8, as it has never failed to start before. yesterday, moved it on my drive. engine only on for 15 seconds. today – wont fire all all. tried pedal to floor. tried fuse out. battery pretty flat now.
    I will try this tomorrow, with jump leads.
    I hope i am not the first one to fail after so many successes!

  6. nc on December 15th, 2013 14:47

    Amazing. I was a bit cynical before, in case this was some kind of weird cult, but it is true.
    Getting to the pump was easier than I expected. My jump leads are the cheapest ones, and my other car is a new but small Nissan juke.
    Took me a minute you have to put your hand through the steering wheel and not around it, if you are to reach the ignition and fuel pump at the same time.
    I needed to do a LOT of cranking to get anywhere, all with the pump disconnected. It just turned over, and over, and over without firing for ages. I kept the cranking to ~ 30 second bursts to avoid melting starter motor, and waited 2 minute gaps to allow starter to cool.
    After long cranking, it does slow, but I think this is serious draining the helper battery, rather than cleaning the rx8 of fuel. Another reason for controlled bursts on the starter.
    Only when I heard it kick a fire from the sparkplugs did I push the fuelpump connector in. Had to repeat a few times, and it took me about an hour altogether. Most of the cranking with pump disconnected, only connecting when I could hear it ‘firing’ in addition to just turning over.
    I think this is a better way than taking the fuse out, as with the fuse method, you have to stop when you hear it firing, and go and put the fuse in. With this you can keep cranking, and push in the connector. As said in other posts, do keep starter motor going on ‘crank’ for a short while after engine starts, to support it during early struggling period.
    Thanks so much.

  7. spinage on December 15th, 2013 19:12

    Thanks for letting us know how you got on, glad you succeeded!

  8. Marine one on one on December 20th, 2013 00:47

    Thank you thank you thank you…..WOW…WOW…WOW this works…Bloomington Indiana home of the IU Hoosiers.

  9. cleveland, ohio on January 11th, 2014 03:01

    I think your blog is my last cry of desperation for my rx8!! after backfiring and stalling when I went to start it on an extra cold morning this week, I was almost certain I flooded it…after doing the fuses, and everything but jacking up the car in the snow to remove the plugs – I was beginning to wonder if it was something else…in the morning I was going to brave the cold and remove the lower plugs and replace them with new ones, but after reading about you, and all of the people that have left comments, I feel a small flame of hope ignite in my desperate heart that I might be so lucky… instead – I’m going to try your method before digging my car out of the snow…

  10. Jamison Ford on January 21st, 2014 21:11

    Thank you so much for sharing this, after being on holiday for 2weeks I really missed driving the 8 but came back to a flat batt and subsecuent flooding, your a star and have saved me time effort and needless to say money.

    Worked like a charm!

    Thanks again

  11. Jamison Ford on January 21st, 2014 21:14

    forgot to mention I’m in Jersey Channel Islands…

  12. spinage on January 21st, 2014 21:23

    Great to know and glad you got going again!

  13. Kah on March 1st, 2014 11:24

    I flooded my engine for the first time and the Roadside Assistance guy didn’t even try to deflood it. So I turned to the internet and found this. I tried the procedure with great hope, and followed it. No spluttering for about 20 cranks at 10 seconds each. Then followed what other posters had done like foot to the floor and bringing it gently out. About 3 times did she try to catch. Still no success. I went back to the original instructions, cranking it and waiting for the sputtering to reconnect the fuel pump. Still nothing. I would have cranked it 20 times for 10 seconds (with a 2 min rest) and reconnecting after 10s for a few seconds and disconnecting. Then I had to stop as the battery had been used up. I recharged it overnight.
    The next day, I bought another battery as a booster. I also sprayed a squirt of starter fluid into the air intake after the filter. I cranked it for 20s, reconnecting after 10s. It tried to catch once with the foot to the floor method, otherwise, I had the accelerator at 1/3 depressed. Still wouldn’t start after another 10-15 tries.
    I just get the started motor turning, but I only heard the usual start sound a couple times. I am not sure if I am doing this right. Do you wait until you hear it trying to “catch” or the usual starting sound before reconnecting the fuel pump connector?
    Is pushing the gas pedal making any difference since the fuel pump is disconnected?
    I can’t try the tow/push start method as it is in a valley, and I have not time left to try.
    I’d really like to get her started without taking it to the mechanic.. It’s a pride thing. I like being self sufficient.
    So I’ve so far tried it about 30-40 times and spent about 2hrs. I’m jealous of others who have succeeded.
    Any help would be appreciated.

  14. Ade on March 1st, 2014 14:58

    My partner flooded her rx8(blonde) pulling off the drive and not warming the car up first, then informs me car won’t start.
    Had a look and did not know what the problem was, went on line and found some info but did not work looked again this morning and found this link and tried it and guess what got the car going after a few attempts and if you follow the instructions it will work and you can hear it trying and eventually firing up and away you go Thanks for the info, did exactly what it said in the screen.

  15. Debbie Flint on April 14th, 2014 19:49

    Just done it!!! That will teach me not to move my car up the drive and then just turn it off cold. Thankyou so much for sharing xxx Leicester England…..grateful x

  16. spinage on April 14th, 2014 20:46

    Great stuff, thanks Debbie!

  17. Nestor on August 13th, 2014 08:09

    Spinage, you the man. I did the starting-and-stopping-without-warming-up thang and was left with a well-flooded ’04 Rexy. Did usual throttle tricks, did the fuel pump fuse thing. No luck. Did the fuel pump hokey cokey as documented above and was back in business in just a couple of minutes. Thanks very much – this is what the Internet is for.

    Nestor, from England.

    PS using jumper leads from an idling car alongside helps give the battery a bit more poke whichever technique you’re using.

  18. spinage on August 13th, 2014 09:16

    Thanks Nestor, glad you got going again! Good tip about the extra battery too.

  19. russell on September 7th, 2014 19:57

    that was a great tip for starting when flooded. I just kept turning it over and putting the cable switch on and off the connector on the fuel pump until it fired up. with a hell of grey black smoke. thanks for that.

  20. Mike on September 11th, 2014 18:17

    Thanks very much for the fix, tried allsorts to get it started, was starting to think it was gonna be a huge repair Bill. This method worked and the car is now running……….Thanks again your a star :-) :-)

  21. spinage on September 11th, 2014 19:46

    Great to hear Russell!

  22. spinage on September 11th, 2014 19:47

    Thanks Mike, you’re welcome!

  23. Kenny on October 25th, 2014 03:02

    Ya well i flooded my rx8, from diagnostic to fixing it took me about ten minutee thanks to you man!
    Preciate it , cheers

  24. Kate on November 1st, 2014 18:42

    Thanks Spinage, it worked!

    Just a few tips for those who fall into the same traps I did. Firstly it is not important to reconnect the pump whilst cranking. In fact I found that seemed more likely to re-flood, especially if you’re used to starting reluctant carby cars – I re-flooded by hearing her almost catch and putting in a bit more gas whilst cranking. This does not work!

    In the end it took about 20 mins (after an hour wasted reflooding twice) – now I know how it should sound, if I’m ever stupid enough to flood her again, I have the trick!

    As previous posters have said – connect spare car with jump leads before you start, crank for 10s, throttle 1/3rd depressed, with 1-2 mins rest in between for about 10 times then she should fire and run on the fuel in the D. Once this has happened try dry cranking for another couple of 10s bursts, then reconnect fuel pump, wait 1 min and try cranking. If she doesn’t fire, stop immediately and try dry cranking again. Repeat last two steps until she catches. No white smoke for me and she runs just fine. Engine check light is still on after one normal start after fixing, but from reading other posts it just takes a few start cycles before this should clear, which makes sense given how OBD tends to be designed.

  25. Baz on November 14th, 2014 15:18

    Fantastic tip !!! managed to get the RX8 going last night using this method
    after trying everything else
    Great !!! and thanks for posting this
    Baz uk

  26. Daphne Bull on November 23rd, 2014 16:41

    I also own a mazda RX8… ealier this week when I was driving I came to a stop light and my car shut off and started shaking horribly… now it wont start at all… any suggestions?

  27. Joseph Green on November 24th, 2014 03:50

    Your solution worked brilliantly. Thank you!

  28. Susan on January 3rd, 2015 02:01

    I didn’t use my RX8 for about two weeks and had this issue. I’ve had it happen before when using valet parking (they don’t listen to the instructions!) and have had to pay upwards of $800+ to get it fixed. This time my fab boyfriend found this blog and was able to follow your instructions to get it started. THANK YOU SO MUCH!!! From New Jersey, USA

  29. Tony on January 22nd, 2015 23:19

    I recently flooded my ’04.

    I hooked up my battery charger set at 10amps.

    I removed the fuel pump fuse and cranked the engine twelve times for 10 – 15 seconds waiting 3 – 5 minutes between cranks.

    I slowly depressed and released the throttle while cranking.

    I replaced the fuel pump fuse and volia – she started instantly as of nothing had ever happened!

  30. Sean on February 5th, 2015 21:49

    You are my hero, I did it tonight and it actually worked. Took me about 40 minutes though. One happy chap here :)

  31. Nathan on February 15th, 2015 19:59

    Just a note to say thanks for getting this info out there! Tried the other methods (accelerator pedal, fuse etc) with no luck, but after five attempts and only 10 mins the car was back and running!

  32. LANDRY MCDUFFIE on February 18th, 2015 00:32


  33. keith on March 8th, 2015 10:39

    de flooding remove fuel pump fuse and plugs , clean and place plugs between two hot water bottles while you turn engine over to clear fuel , replace fuse and plugs keep throttle on the floor and try again easing back slowly on the throttle this worked for me first time !

  34. jim in woodstock ontario,canada on March 29th, 2015 19:14

    awesome instructions..i bought this 2004 RX8 in December already flooded and never heard it was brought on a tilt and load..dropped..and left in the snow till today snow all gone.
    .popped out back seat as per instructions..4 screws and unclip the plug..turned it over a dozen times with 1/3 throttle..(audibly heard motor get compression)…put plug back on and fired right up in a cloud of stinky smoke..20 minits start to finish….thank you
    I did try the handbook method last December when car arrived but no go…

  35. spinage on March 29th, 2015 19:23

    Great to hear from you Jim, glad it helped!

  36. William grant on April 3rd, 2015 13:11

    I have a 2006 6 speed. Man I can’t wait to go home an try this now after reading. My wife crank ours while I was at work an didn’t tell me so I had no idea what happened an after taking tha plugs out an them flooded out an it still not cranking I was ready to sell it!! This is my last hope if it don’t work then u know where to come buy one. Lol were located in NC up in tha mountains. PLEASE let this work. Thanks.

  37. Tony on April 7th, 2015 02:46

    Hi, gonna try this but Rex been sitting for a year, is this safe? Thanks

  38. Tony Donovan on April 7th, 2015 16:45

    Trying this right now, my Rex been sitting for over a year, fingers crossed. X

  39. Chris on April 11th, 2015 21:20

    thank you for blogs like this a real life saver and worked perfectly!

  40. John on May 1st, 2015 18:08

    Fantastic instructions – did the silly thing 09 reg so thought the problem had been solved……wife moved car out of drive to get her car out……so next time I try to start it nothing!! Panic!!!

    Then I read about Mazda charging c£300 for a tow and flood solution, then I came upon this thread. Didn’t work the first time as I didn’t boost with jump leads, but when wifey came home put the jump leads from her car – gave it two 15 sec blasts with the pump unplugged, then within five secs with the plug back in cough splutter and it limped into life.

    Now going great – THANK YOU

  41. James on May 9th, 2015 06:47

    Love all the ideas on how to de-flood. Just wondering…what is the difference between pulling the fuel pump fuse and disconnecting the the fuel pump under the seat? Doesn’t this do the same thing? If not….which seat is the fuel disconnect under?

  42. spinage on May 9th, 2015 22:39

    No difference James, it’s just that the one under the seat can be reached while you crank the engine, giving you much finer control over when to connect/disconnect the fuel. In a right-hand drive model, it’s under the near-side rear seat.

  43. Colin on May 27th, 2015 04:17

    Spinage you are an absolute champion.
    my 04 RX8 has been sitting in my driveway for 3 weeks. after having a mobile mechanic look at it, I was told that it needed a engine rebuild. This would have been costly and he offered to take the car off my hands for $2000. I was mortified and some what reluctant but because he was my mechanic for the last 2 years I trusted what he was saying. The car would have been sold tonight so in one last stitch effort to get it going I read your blog and other people testimony, I figured I’ll give it a shot. And BAM WOW, it kicked over. I’m so relieved and can’t express enough gratitude.

    Thank you

  44. spinage on May 27th, 2015 07:58

    Hi Colin, that’s great to hear!

  45. MJ on June 11th, 2015 01:33

    Thanks Spinage for an excellent post with clear instructions.
    It tested my patience, but after an hour or so of following your procedure, she came back to life!
    Like so many before me, thank you for saving a fortune in towing and garage bills :)
    Thanks once again from a happy RX8 owner in Australia!

  46. Stu on June 12th, 2015 22:15

    Perfect way to solve this silly flooding issue.

    Two flooded rx8 s now all running due to your great work.

    Switches will be added to cut fuel in the week so I can control the fuel on what seems like a colder start or just easy to De flood.

    Thank you.

  47. Jon on June 16th, 2015 10:53

    I flooded my 8 for the first time having owned it for over 2 years, I tried the handbook method then the fuse method with no luck then fortunately came across this. It took 6 minutes start to finish with my 8 connected to a LR Discovery with jump leads to get her running. I’d flattened my battery and 2 jump units trying the first 2 methods.
    Thank you OP.

  48. Xanthum0 on June 23rd, 2015 21:18

    My 2004 Rx 8 is constantly having trouble with flooding. 104000 miles, but we’ll cared for. I was pondering placing a fuel pump shut off switch on center console and shut off fuel to kill engine to prevent flooding on next start…..Will it work or have I overlooked the obvious or perhaps throw trouble codes constantly….If you can think of any reason not to attempt this let me know; Orherwise, she will have a switch as soon as I get back into town.

  49. Manny on June 28th, 2015 14:35

    Thanks this helped, the garage told me it would take them 2 days to get to look at my car with a minimum charge of £70 just to look at it, found your page got car going in 15 mins

  50. Robert on September 16th, 2015 18:25

    Many thanks for this invaluable advice.

    Amazing result-had to turn engine with pump off for about a dozen times before any sign of ignition, then after a couple of times briefly re-connecting the pump, the engine almost caught. Then three or four more tries and the engine fired up. It has saved £50 towage costs and goodness knows how much more.

    I have cossetted my RX8 for ten years and have only flooded it once before and that was while it was in guarantee, so a Mazda guy came out and fixed it – I cannot believe that I did it again!! A very lucky outcome finding your blog.