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-   -   how much damage flooding (https://www.rx8club.com/rx-8-discussion-3/how-much-damage-flooding-15952/)

Thinthi 12-05-2003 01:25 AM

how much damage flooding
 
i know we have all had enough of the flooding issue, but i never thought it would happen to me... well i follwed what was told by posts on this forum, but the car to start and drove it for a while to get rid of all the gas, just burn it all out..... now my q is tomm should i go do anything...... ie get the oiled changed, spark plugs replaced/cleaned..... rotors clean........ also my last q, some poeple on these forums said somethign about cleaning excess gas from the rotors.... how do you do that, sorry if thats a stupid q, i'm just not fully understanding..... thanks for your help

Thinthi 12-05-2003 10:43 AM

please help me someone

RX-8 friend 12-05-2003 11:42 AM

It doesn't take much fuel to flood a rotary. Maybe a few ccs at most. Just drive it. If you take it on the highway, the oil will be warmed up enough to evaporate most of the fuel in it. Once you have it running and warmed up there is no excess fuel in the rotors. If you flooded it every day for a week, I'd change the oil. If just once, it's probably ok till the next scheduled oil change.

To avoid flooding in the future:

0. Follow the starting procedure in the owners manual - ESPECIALLY "do not press the accellerator when starting".
1. Always warm the car up before allowing the engine to stop (coolant temp gauge moves up to normal operating range). This does two things:
a. Causes ECU to switch to non-choke mode.
b. A warm engine evaporates fuel better than a cold one - see below.
2. When shutting off, rev up to 3-4 k RPM and turn off key, letting engine coast down. This should flush out any unburned fuel.
3. When it's cold out, be especially careful to follow the above warmup procedures.

The ECU detects when it's cold, and will inject more fuel into the engine (choke mode - it probably wouldn't start if it didn't). When the engine is cold (below 10C or 50F), it is very difficult to vaporize this fuel. It will build up if you don't get the engine started and warmed up. Liquid fuel will "wash down" the rotor housing (clean off the oil), reducing compression (sealing of the apex and side seals to the housings) at low RPM (250 RPM when starting, for example). This will make it difficult to "blow out" this excess liquid fuel, and it will make it even more difficult to get fuel vapour in the chambers, as it will further cool the intake charge and cause some portion of the vapour there to condense. It's the fuel vapour that the spark ignites, so... the car will be very difficult to start.

As I have said before - Avoid flooding! Do everything in your power to avoid flooding! It's so hard to recover from, and hard on the starter. Just avoid it.

Thinthi 12-05-2003 12:00 PM

i followed all the procedures, i have no idea why it flooded it just did. thats whats scarying me. my friend also told me to clean the spark plugs, but i'm not sure if he knows what he's talking about, if i drove the car for 50 miles it should have burned out everything right...... thanks for your help

Superfan 12-05-2003 02:23 PM

I would clean them just to make sure. The fuel and oil sometimes foul them up pretty bad. When my second gen and third gen would flood I would always clean them after I got it started. Sometimes I would replace them. I used either brake cleaner (get the one that doesn't leave residue) or carb cleaner.

RX-8 friend 12-05-2003 02:26 PM

Yeah, the spark plugs should be fine if it's running ok. In "the old days" the lead in gas would seep into the ceramic and you had to replace the plugs. Not any more.

MEGAREDS 12-05-2003 03:50 PM

Finally, a thread addressing the question I keep asking! I almost didn't buy my car because a salesman went on and on about how to avoid flooding. I thought it was going to be a big problem. It really doesn't seem to be after having done some research. The car warms up quickly. It's not a big deal to remember not to move the car very short distances.

As far as I can tell, getting the car to start after flooding is also not the big deal it used to be. Follow the rather simple Emergency Starting Procedure set out in the manual. (I believe it's on page 7-20 of the U.S. version). I think everyone whose posted about having used the procedure has gotten his car to start within a few minutes. The issue I don't fully understand is whether we're damaging our cars by allowing them to flood. I think the right answer is "not that much, but don't do it."

My plan, if I flood the car, is to not worry about it if the car feels right. Otherwise, I'll go and have it checked out at the dealer. That's my advice to others until someone enlightens us otherwise.

vaughnc 12-05-2003 04:12 PM

Note there's a difference between a "flooded" engine and "no compression flooded engine."

On the flooded, no compression engine... If you drive it 5 feet & shutoff when cold without letting the car warm up, the excess gas sprayed into the engine for proper warm up will eat away the oil lining that helps with sealing the rotor to the sideplates & main housing.

You will have 0 compression (engine just wirrs) and there's no way the "press pedal to floor for fuel cut" will help. Essentially the air/fuel just blows by the rotor face without being compressed.

This requires squirting oil or ATF into the intake manifold close to the engine block (assuming there's still a nipple for this) which re-establishes the film and makes compression.

The other flooded engine issue can just be to much gas in the engine due to no spark, old leaky injectors, etc... The press pedal for fuel cut trick works fine here.

But the rotary engine's advantages FAAAR outweigh this one nuisance.

Hiro 12-06-2003 04:37 AM

Ok, one thing I'm not clear about.....I understand the startup procedures....I don't press the accelerator at all during warmup...and I allow it to warmup whether I'm moving it short or long distances. Ok....the shutdown part is where I'm confused. Do you rev it up to 3-4k everytime before you shutdown or just if you've moved it a short distance? What if I've been driving an hour or so, do I still need to do this? Also, if you do need to rev it up do I need to keep it at that point for 10 seconds or something...I remember reading that but, the part that is unclear is whether or not I turn off the key while reving it or just after reving it? Hmm...I hope this make sense. I would think you'd rev it up then let it idle back down....then turn the key off. Is this correct or due I rev it up and after turn seconds...before it idles back down...turn the key off. I'm starting to get repetitive now hopefully you guys can make sense of all this. Thanks

RX-8 friend 12-06-2003 11:48 AM

The reving it and shutting down may or may not help, but it will not hurt. Rev. it to 3-4k and turn off the key when it's running at that RPM. The engine will coast down to 0 and while it's coasting down the injectors will not be firing (because you turned them off with the key), so the engine will clear out any fuel that may still be in there. I would do it every time, hot or cold. That being said, I would not shut off a cold engine. I have only done that twice on my 3rd gen. I have never flooded my 3rd gen. but I don't drive it in cold weather either, and that is when it is most likely you will flood the car.

There is a place on the RX-8 you can add oil to the intake - the brake booster port. If you do, I'd use a tablespoon of 2 stroke oil. The renesis will be much more sensitive to port clogging by oil carbon than the older engines, due to the side ports, so only do this as a last resort.

Oh, and yes, getting it to start after flooding is a big deal. It usually takes several minutes of cranking (in 10 sec. intervals with rest periods to allow the starter to cool off). This is hard on the starter and battery.

I'll say it again ;)
Avoid flooding! Do everything in your power to avoid flooding! It's so hard to recover from, and hard on the starter. Just avoid it.

zoomzoomzoom 12-07-2003 12:37 AM

For what it's worth, my dealer said that there was a tech bulletin out on the spark plugs and they changed mine at the 3k mark service. They said the new plugs are less likely to flood (not sure if I beleive it), but once I got the car back, it seems to be running smoother and is more responsive. I don't know what plugs they put in, as service dept was closed when I picked up my 8. I may call then on Monday and find out...

btw- mine flooded once when I got in with heavy work boots on and didn't realize I had touched the accelerator when attempting to start. I'll never do that again...

MEGAREDS 12-07-2003 06:23 PM

Am I correct that trying to start the car normally after a flooding incident may make things worse, by forcing more gas into the engine?

My suspicion is that some people are flooding their cars, then making the situation irredeemable when they try to start the car in a panic, leading to an unnecessary tow. Many people are taught to start a car by giving the engine slight gas... exactly the wrong thing to do in this car. Also, as I understand it, the Emergency Start Procedure requires repeated tries doing something that is admittedly hard on the car -- repeated cranking.

I don't mean to seem insensative to those that have flooded their cars (we all make mistakes), but if there is a reliable way to recover, people need to know what to do and not freak out. If I'm right that the panic is part of the problem, then Mazda is partly to blame by not explaining the Emergency Start Procedure well in the manual and putting the "short-trip procedure" only in the Quick Start Brochure. The two things need to be explained together... since they are related things.

If I had any guts, I'd make a video tape where I purposely flood the engine, then try to use the emegency starting procedure to show that it works... smoke and all. Of course, I'm not willing to do that... anyone? anyone?

SingRX8 12-07-2003 09:08 PM

Hi, my question may seem irrelevant here. Would like to know if i'm gonna park my car (w/o starting it) for a couple of days (going for a trip), is there any precautionary measures in which i have to take inorder to have a smooth start at the end of my trip?
Thks!


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