Ed Anderson wrote:

>From the looks of this URL page  more fuel can be introduced into the
engine, for what ever reason, then the apex seal oil injector
can cope with. 

This means a constant or intended ratio of oil to fuel is not maintained.

Another very good reason to mix oil with the fuel. If you are mucking
about with the mixture it might be a good idea to use four ounces of
two cycle oil per gallon of fuel temporarily.

Paul Lamar

 
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This increased complexity is due to the way in which the engine lubricates the combustion chamber seals.  To lubricate the apex seals in the engine, Mazda uses oil injection into the rotor housings, which puts a thin film of oil on the inside of the housing.  This oil serves a dual purpose however, because along with lubricating the seals, the oil also helps the seals do their job of compressing the fuel air mixture.

The end result is that when the engine becomes flooded, this thin coating of oil is washed away with unburned fuel, and that in turn effectively lowers engine compression to the point at which it will no longer start.  A rotary with low compression makes a different sound while cranking than normal, and it will often sound higher pitched - as if the motor is spinning faster than normal.  To get it started, you will need to replace the oil that has been removed from the inside of the rotor housings without adding any more fuel.  It sounds complex, but there are two easy ways to resolve the situation.
 

• Solving a mild flooding problem
• Solving a severe flooding problem
• Why does my engine keep flooding?
• Preventing flooding problems

If the engine has only just flooded, and you haven't tried too many times to get it to turn over, it can easily be made to start within a few short seconds by removing only one fuse.  Looking at the photo of the under-hood area, you can see the location of the engine bay fuse block.  Printed on the cover of the fuse block is a diagram with labels of what each fuse protects.  Locate the fuse on the diagram that is labeled "EGI Injection" and remove it.  Return to the driver's seat of the car and push the gas pedal to the floor.  By pushing the pedal to the floor, you move the actuator linkage for the oil metering pump (which supplies oil to the oil injectors) to the maximum position, this is the easiest way to replace the missing oil in the rotor housings.  Then, while holding the pedal down, crank the engine over for 5 to 10 seconds and then release the key.  Wait a second or two, then repeat with another 5-10 second burst.  Replace the fuse in the fuse block and again return to the driver's seat.  Try to start the car while holding the gas pedal to the floor.  In general, a flooded motor will start after you have followed this procedure.  If your tachometer is not working after it starts (reads zero rpm when the engine is clearly running), don't worry, this is normal.  Wait for the engine to warm up, and then after you shut it down, the tachometer will work normally the next time you start it.

If you follow the mild flooding procedure and are unable to get the motor to start, there is another way to replace that missing oil that is somewhat more involved, but is not beyond the abilities of even a mildly skilled mechanic.

This time the trick will be to add a lot of oil directly into the housings via the spark plug holes.  The procedure is simple.

You will need three easily acquired items to apply this method, a 13/16th spark plug socket with a wrench, a quart of motor oil or automatic transmission fluid, and a funnel with a long flexible neck or a piece of hose attached.

Looking down at the side of the engine you can see two sets of two spark plugs, a leading and trailing plug for each housing.  The lower plug is the leading plug, the upper plug is the trailing plug.  Assuming that you have the normal NGK spark plugs in the engine, the trailing plugs will have a blue band around the white insulator and the leading plugs will not.

Remove both leading (lower) spark plugs using the 13/16ths spark plug socket and a short extension on the wrench.  Then insert the end of the funnel into each spark plug hole and pour roughly 1/8th quart of oil or ATF into each housing.

Replace the spark plugs, but before attempting to start the car make absolutely sure that the exhaust is pointing away from the inside of any building, and that there is nothing directly behind the car, because upon starting the engine you will generate a very large cloud of oily smoke from the exhaust for a few minutes.  Once the rear of the vehicle is clear, start the car normally and wait for the engine to stop smoking.  Once it has warmed up, it should be safe to shut it down without it flooding again.
 

There are a couple of factors that can contribute to frequent flooding in the second generation RX-7; leaking fuel injectors and low compression.

Leaking fuel injectors are usually the source of the problem.  If the injector(s) get slightly dirty, they may not be able to completely close.  When the engine is shut down, the fuel system remains pressurized to fairly high pressure levels, and if an injector isn't completely closed, fuel will drip through it into the rotor housings and create a flood condition.

Less common, but also possible, is that the seals in the engine are worn to the point where its compression ratio becomes too low for quick starting.  If the engine doesn't start fairly quickly, it ends up getting a lot of gas that isn't being burned, and that can also cause the engine to flood.
 

Assuming that the problem with your car is that the fuel injectors are leaking when the engine is shut down, there are a wide variety of solutions to your problem, all of which focus on either allowing the injectors to close, or letting fuel pressure drop after the motor is shut down.

The best solution is to attack the problem at its source by dealing with the fuel injectors directly.  You can either replace the injectors with new ones, which is very expensive, or you can remove the injectors and send them off to be professionally cleaned.  Most people on RX-7net use Marren Motorsports when they want their injectors cleaned, and I normally refer people to Rotary Performance because it was through them that I had my injectors cleaned by Marren.  It costs roughly $120 to have all four injectors cleaned, but for those who aren't all that mechanically inclined, significant expense can be incurred when having the injectors removed by a competent shop because the entire upper intake must be removed to access the primary injectors.  Both cleaning and replacing injectors are proven and effective ways to solve the problem in the long term.

I will not endorse, or even suggest, the idea that fuel injector cleaners that you add to the tank are effective.  While I occasionally get email that suggests it works, I have serious doubts about the efficacy of such products because I have personally tried forcing them backwards, undiluted, and under high pressure, through injectors without successfully cleaning them.  That, and the fact that some injector engineers at Bosch informed me they (the fuel additives) don't work, leaves me with a profound lack of confidence in such products.

The other solution is to reduce the residual fuel pressure after the engine has been stopped to the point that it will not leak into the motor.  The downside is that you will have to wait a few seconds for pressure to build up again when you wish to restart the car.  There are three ways to do this.

First, Mazdatrix sells a little bleeder that splices into your fuel lines and contains a small jet connecting the line coming out of the tank to the line that returns excess fuel to the tank.  When the engine is shut down, it bleeds excess pressure back into the tank rather than into the engine.

Alternately, you can remove the fuel pump from the tank and remove the check valve, but you should avoid this method if possible.  The screws that secure the pump to the tank are almost invariably rusted and soft, and therefore easy to strip.  It is also not easy (or reasonably possible) to replace the check valve if you later have the injectors taken care of without purchasing a new fuel pump.

You can also install a simple switch under the dash that disables the fuel pump.  The fuel pump connector is in the rear of the vehicle underneath the carpet that covers the driver's side rear speaker/strut tower.  Using a relay and a switch, you can turn off the fuel pump before turning off the car, which will effectively uses up the residual pressure.

• Attachments-6/flood.html