RiceRocket

how often should a rotary flood? my car floods when i try to start it sometimes. i can't pinpoint why. any help would be appreciated it. it will also "die" if i don;t let it warm up for about 15 mins. if i dont it is like the load is too much and it will choke itself off

No7Yet

I'm guessing that you have an S4 (86-88). This is very common, and addressed in the FAQ on Felix Miata's site - look into it

It's caused by low engine compression, leaky injectors (usually secondaries), faulty engine control programming, or any combination of the three. First, try some fuel injector cleaner (most like Chevron Techron - the real stuff, not the watered down crap) at about double concentration. Make sure to keep the car revved above 4000 RPMs for a long time to make sure that the secondaries get cleaned real well. If that doesn't help, remove your injectors and have them professionally cleaned. If that doesn't help, a fuel pump kill switch will band-aid the problem.

The second part is also a FAQ - you need to use the search feature. In short, the ECU gets stuck in "warm up mode", and will inject way too much fuel the next time you start the car. This is bad, as it washes away any oil left in the combustion chambers, which causes unnecessary wear. The solution? Let your car warm up completely before you either drive it anywhere or shut it off - yes, even if it's just to move it out of the driveway.

Brandon

Jacey

My 7 used to die a lot if it wasn't fully warmed up or if I had the a/c on. Turned out to be that the idle air fuel mixture was off.

NZConvertible

As mentioned above, low compression, dirty injectors and suspect software are the three main causes of flooding in FC’s.
Short of a rebuild, there’s not much you can do about low compression (except maybe the AFT trick). A compression test will show how bad this is.
I wouldn’t bother with in-tank cleaners except as regular preventive maintenance. If the injectors are the cause of the flooding, only a professional clean will cure it.
There appears to be a bug in the S4 ECU that causes the engine to flood if the engine is started and then turned off without letting it warm up. The next time you try to start it, whether a minute or a month later, there's a good chance it'll flood.
However, in my experience, the motor doesn’t need to need fully warmed up. I do a <1km drive from work to get lunch most days. It has never flooded doing this. Also, it doesn’t appear to flood if the ignition isn’t switched off. My car has stalled while cold countless times (a problem I’ve now fixed!), but has never flooded from this. However on three occasions I can remember, starting the car to manoeuvre it in the driveway or carpark has caused it to flood on restart. I just make a point of not doing that now and it hasn't flooded for over six months. Idle problems when cold are usually related to the thermowax, which uses coolant temp to increase idle speed when cold. Get the FSM and follow the trouble-shooting procedure. Or search for “thermowax” on the 2nd Gen forum, you’ll get lots of hits.