I've had the car about 5 years now I think and only twice has it rained hard enough over a period of time that I ended up with standing water inside the car. Last time I threw some Damprid containers in there and it did a pretty good job of getting the moisture out of the car. I don't believe I drove the car until it had dried out. Well, with all the recent rain, I had some standing water inside again. I bailed out as much as I could with a little bucket and then set about to drive to the bank and get some gas.

It stalled on me at the end of my street when I stopped and some of the water still in the car that I couldn't bail out sloshed forward. It started right back up but I drove it around the block and stopped at home again to check some things. The coolant reservoir was empty which was odd but I went ahead and refilled it. Oil level was fine too, figured I'd check it while I was under there even though I didn't think it was related.

Anyway, so I then start driving to the bank and while stopped at a light, when it turned green I pretty much had no power and it was sputtering pretty badly. I managed to get it into a parking lot and it started intermittently blowing white smoke with a little bit of a blue hue to it. Not fully blue smoke like badly burning oil.

When I had first started up the car before leaving the house, the air bag light was flashing and I didn't realize until later that it was throwing a code and trying to tell me. Now the air bag light doesn't flash like before. I might have to put it in diagnostic mode to check for codes once I get it home.

So the ideas I'm throwing around are...

-ECU might have been damaged by the water because it's on the floor up front on the passenger side where all the water is and where all the water rushes to when stopping.

-Head gasket maybe blew, not sure why it would have happened right now but some of the symptoms fit.

So I'm going to tow it home tonight and let it dry out and see what happens. I'll pull the ECU and check it for corrosion and water damage and maybe once it dries out it'll be fine, especially since the floor flooded this badly once before and it was fine, but I had let it dry out first before driving it last time too. I'm also going to get a compression tester and see what the compression looks like in all 4 cylinders. That could help diagnose a head gasket issue if that is what's happening and it would just be good to know anyway.

As for the cause of the flooding, I'm not sure if the rain rail was installed incorrectly when I had the top replaced, or if the drain channels are just clogged up so the water can't get out and backs up into the car. I need to figure out the cause of that too so it doesn't keep happening.

After doing a little more reading on miata.net and hearing other people describe the sloshing I've had off and on for forever, I'm pretty sure my drain holes under the car are clogged. They just aren't clogged completely so it does drain out eventually, but with the large amounts of rain in a short timeframe lately, it filled up before it had a chance to slowly drain out. Plus the car sits facing down a hill so if the front ones are really clogged, it won't drain out until I drive the car around and get it level and facing uphill and such just driving around to get it all drained out.

My fault for not looking into those drains sooner when I heard the sloshing before. I'll post back when I get under the car with a coat hanger and see if that gets the water out. Then I'll have the task of air drying the car and possibly pulling the carpet out. We'll see if I can get it dried out with DampRid first before I start looking into replacing carpet.

Let me know if I can be off help!

it does sound somewhat like a head gasket.

That sucks. Hopefully it's an ECU thing, but I have to agree with Chris as well in that the symptoms do sound a bit head gasket related.

I was worried about my car flooding as well, but all was mostly good. It gets wet because I need new soft top seals/weatherstripping, but it drains well.

Found the drains and got them opened up. Also found the rubber plug in the floor pan. The car is sitting in the driveway peeing all over as we speak. I'm going to leave the top down in the sun and hopefully dry it out some today.

It started right up and seemed fine pulling it into the driveway. Then after about 15 seconds of idling, the airbag code (6 blinks, faulty airbag module or poor connection of clock spring connector) showed and it started idling very rough again. But the normal start up and normal idle at first makes me think that maybe it's not a problem with the engine itself. It idled rough like this when we did the engine swap and I forgot to plug in the MAF on first start up which makes me think it really is related to not being able to get a good A/F mixture going due to an issue with the ECU.

Time will tell once it fully dries out.

it could be a relay or something that got really wet.

Good luck. Hope it's just the moisture problem.

It seems to be mostly dried out now. Carpet is no longer damp. It runs and idles fine for a couple minutes. Haven't tried longer or driving down the street yet. It does smell strongly of gas when running though. Not sure what's causing that, unless the ECU is only sort of working and it's running very rich. Where's my OBDII reader to check AFRs, oh wait, I can't use that on this old ### car, lol.

Time to break out the paper clip and count check engine light flashes. Was that a long flash, or a short one... Ha!

Huzer wrote:Time to break out the paper clip and count check engine light flashes. Was that a long flash, or a short one... Ha!

I've done that before so I'm familiar with the process, but right now the airbag light isn't flashing and the CEL isn't on either and the CEL never came on through this whole ordeal, so I'm not sure if it will give me any info. Can't hurt to try though I guess.

Well it's fully dry now and I drove it around the block yesterday, not wanting to go far and be stranded somewhere. Seems to run fine, no sputtering or loss of power. Granted I didn't go above 25 but still it seemed normal. Did blow a fair amount of white smoke at first, but that stopped by the time I got back home, so I don't know if there was just some residue in there from when it wasn't running right that needed to burn off or what. Still not quite ready to trust it on a longer drive, but I think I will at least drive it around the block again today and see if the white smoke is still happening.