A few days ago I did the dreaded thing; I flooded the engine in my RX8. I had to move it no more then 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 then 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 deflood 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.
- 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
- Try starting normally for 5-10 seconds (this step pumps more fuel in, so limit the time if there is no life)
- If the engine is spluttering, it is not badly flooded, and the following steps may only need to be done once or twice.
- 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 levering the fuse out.
- 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.
- 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.
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 appricated on first hand experiences.
Has this helped you?
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