DFW floods - High water and car running rough now

katapaltes

'03 P5, '17 Miata, stock AF
:
Dallas, TX
:
2003 Protege5
Well, it flooded here overnight and the underground parking sump pumps at the apartment weren't working. (I woke up around 5:00 feeling something just wasn't right, and when I went downstairs water was halfway up my calf.) The P5 had water in the floorboards, and I drove it out of the garage carefully. I went to Lowe's and got myself a Shop Vac. After many hours of vacuuming, the car is mostly dry, but the car is having trouble so I haven't been running it.

Anyway, I have a P0302 code and white smoke coming out the tailpipe in puffs. You can smell the unburnt fuel and see it on the wet pavement around the tailpipe. I was getting a *flashing* CEL (and I turned the car off soon after), but that has gone away. Below are some videos of the behavior. Why would high water result in a misfire (P0302)? Certainly, I don't need to replace a coil as I normally would with a P0302, right? Any ideas on what I might need to replace, or do I just need to let it dry out more?

Engine a bit shaky:



CEL, and the shifter a bit shaky:



Big white puffs of smoke and fuel on pavement:

 

Attachments

  • engine shake after flood.mp4
    14.4 MB
  • white smoke puffs after flood.mp4
    19.5 MB

pcb

The Diagram Dude
:
2002 MP5
I'm guessing that it may just need to dry out more.
Your ECU may have gotten wet and the 12 volt signal going to the coils may be shorting out.
I think you should check your ECU and see if it's wet. Maybe pull back the carpet and blow a fan on it.

The misfiring may have fouled the cylinders a bit.
Maybe a new set of spark plugs might fix the problem.
That's cheap and easy to do.
 
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katapaltes

'03 P5, '17 Miata, stock AF
:
Dallas, TX
:
2003 Protege5
I'm guessing that it may just need to dry out more.
Your ECU may have gotten wet and the 12 volt signal going to the coils may be shorting out.
I think you should check your ECU and see if it's wet. Maybe pull back the carpet and blow a fan on it.

The misfiring may have fouled the cylinders a bit.
Maybe a new set of spark plugs might fix the problem.
That's cheap and easy to do.
OK, I peeled back the carpet over the ECU (I'd replaced it with one from an MP3 a year or two ago). Even with the massive amount of towel-dabbing and extremely vigorous Shop Vac'ing I did yesterday to the carpet, there was still plenty of water in the padding. I detached the battery and put the original ECU in, and then the car ran smoothly - albeit with a continuous white smoke show instead of a pulsing smoke show. :) I put my hand in the exhaust flow and felt drops of moisture, but upon smelling my hand it smelt like exhaust and not like unburnt fuel. So I was pretty sure it was just water in the exhaust system. The "smoke" went away and the car continued to run smoothly, and I'm letting the MP3 ECU dry out fully. If the ECU is a loss, I won't bother finding another one; I'll just run with the original.

I'm running the car with the A/C on full blast now, trying to dry out the inside. If I can get past these next few rainy days and back to our 90-plus-degree heat, it will dry out in a snap. As always, thank you for your help, PCB. :)
 

pcb

The Diagram Dude
:
2002 MP5
,.. I'm letting the MP3 ECU dry out fully. If the ECU is a loss, I won't bother finding another one; I'll just run with the original.

Just run with your original ECU.
Your car is fixed, it gets more MPG and you don't have to buy premium gas anymore.
Gas is like $100 a gallon now. Lol


I'm running the car with the A/C on full blast now, trying to dry out the inside.

Turning the AC on with the temperature dial at hot dries it out the fastest.

Open your windows so that you don't pass out behind the wheel. lol
 

katapaltes

'03 P5, '17 Miata, stock AF
:
Dallas, TX
:
2003 Protege5
Just run with your original ECU.
Your car is fixed, it gets more MPG and you don't have to buy premium gas anymore.
Gas is like $100 a gallon now. Lol

Turning the AC on with the temperature dial at hot dries it out the fastest.
Open your windows so that you don't pass out behind the wheel. lol

I'll likely put the MP3 ECU back in after it's dried out. If it doesn't work, then that's the end of that adventure. Even if the MP3 ECU is a loss, it was sure nice to have had another ECU sitting on the shelf, ready to go. That was truly a blessing.

The main motivation for getting the MP3 ECU was my JDM engine that wants high-octane gas or it will ping a bit. My thinking back then was "If I have to run the good stuff anyway, I may as well get the MP3 ECU." If I do have to return to the original P5 ECU, I'll still run premium or more likely mid-grade (probably a half-tank of 93 and a half-tank of 87 for best value). 😀

Here's a pic of the car in its current state. I was too lazy to remove armrest and the water was "only" in the floorboards, so I have simply propped up all the carpet around/over the armrest. The padding is mostly dry. I wish there hadn't been that rubber barrier between the carpet and the padding. I likely could have dried it out completely without removing the carpet using a Shop Vac and this infernal Texas sunshine.

1661530941702.png
 

katapaltes

'03 P5, '17 Miata, stock AF
:
Dallas, TX
:
2003 Protege5
I forgot about your JDM engine.
I remembered that you have to use premium with an MP3 ECU.
Heh heh... Yeah, our cars get more and more "diverse" the older they get. Anyway, I just slapped the MP3 ECU back in and it's running fine. I opened the MP3 ECU and it was bone-dry inside, so the short you mentioned was likely external to it.
 
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katapaltes

'03 P5, '17 Miata, stock AF
:
Dallas, TX
:
2003 Protege5
Speaking of MP3 ECUs, there's one available on car-part.com right now if you're looking for one. That's how I got mine and the following steps outline the process I took.
- Visit car-part.com
- Select 2001 / Mazda Protege / Engine Computer / enter your ZIP
- Select "2.0L, MT, MP3, ID FS9N-18-881" from the resulting list or try your luck with the "B" or "C" variant listings. NB: By choosing "2.0L, MT, MP3, ID FS9N-18-881" you may actually end up with a newer "B" or "C" variant as I did.
- In the list returned, trust any result that shows a picture of an *actual MP3*
- Ignore any listing that *does* have a model number but that model number does not contain "FS9N-18-881" (e.g. ZM36-18881-E)
- Email or chat with the seller and ask for a picture of the ECU with its label visible; they will be happy to oblige
- Send them the money plus shipping
- Enjoy paying for premium or at least mid-grade gas! :D

Hope I'm not running afoul of the WTS guidelines; I'm not selling the item in question, and just wanted to share.
 

pcb

The Diagram Dude
:
2002 MP5
I'm not interested personally, but maybe @BenjiHoggi might be interested.
I don't remember if he has one or if he has a standard though?
 

BenjiHoggi

OEM+
:
Oregon, USA
:
22v Protege5
I'm not interested personally, but maybe @BenjiHoggi might be interested.
I don't remember if he has one or if he has a standard though?
How dare you tempt me with that proposition. I keep telling myself not to spend money on this darn car...

Mine is just the standard one, mainly because of the cost of premium fuel. But if it's something I can swap out at even some inconvenience, I might consider having it on hand.

I'll take a look. I've always wondered how people get their hands on them these days. I'd love it if I could learn how people flashed the normal ones back in the day.
 

BenjiHoggi

OEM+
:
Oregon, USA
:
22v Protege5
Speaking of MP3 ECUs, there's one available on car-part.com right now if you're looking for one. That's how I got mine and the following steps outline the process I took.
- Visit car-part.com
- Select 2001 / Mazda Protege / Engine Computer / enter your ZIP
- Select "2.0L, MT, MP3, ID FS9N-18-881" from the resulting list or try your luck with the "B" or "C" variant listings. NB: By choosing "2.0L, MT, MP3, ID FS9N-18-881" you may actually end up with a newer "B" or "C" variant as I did.
- In the list returned, trust any result that shows a picture of an *actual MP3*
- Ignore any listing that *does* have a model number but that model number does not contain "FS9N-18-881" (e.g. ZM36-18881-E)
- Email or chat with the seller and ask for a picture of the ECU with its label visible; they will be happy to oblige
- Send them the money plus shipping
- Enjoy paying for premium or at least mid-grade gas! :D

Hope I'm not running afoul of the WTS guidelines; I'm not selling the item in question, and just wanted to share.
Now that I think about it, how did you happen to know that one was available? You don't check car-part for MP3s on a regular basis do you? If so, that sounds familiar to me checking marketplace and craigslist for P5s and other cars I don't need and can't afford...bad habit I guess.

Out of curiosity (and maybe it's not good to post it), are you looking at stock number 00054932?
 

katapaltes

'03 P5, '17 Miata, stock AF
:
Dallas, TX
:
2003 Protege5
Now that I think about it, how did you happen to know that one was available? You don't check car-part for MP3s on a regular basis do you? If so, that sounds familiar to me checking marketplace and craigslist for P5s and other cars I don't need and can't afford...bad habit I guess.

Out of curiosity (and maybe it's not good to post it), are you looking at stock number 00054932?
I just checked randomly this evening. I see folks offer them in the Protege groups on Facebook from time to time, but for a little more money. They seem to pop up every few months.

Yep, that is the stock number I saw. I'm not going to say the mod was life-changing or anything, especially without the supporting mods. In my case it was an easier decision because I need to run high-octane anyway due to my JDM replacement engine, and I wanted to turn that negative into a positive.