ZakB

Hey guys about 3 days ago I got some water in my cold air intake and my car stopped starting properly. I wasn’t in a flood or anything I think some water just splashed in there. Anyways i opened it up and there were droplets on the maf sensor and in the throttle body and through the 3 tubes at the end of the cai. So I took out the spark plugs, fuel fuse, circuit fuse, and fuel relay fuse and cranked for a bit to get the excess fuel/oil out then put new spark plugs in but the engine still doesn’t start. I’ve tried many deflooding procedures and the cranks barely ever catch/fire anymore. I also did an obd2 scan and got a P0147 error (O2 sensor heater circuit). I’ll attach 2 videos to show you.
https://youtu.be/SMWq4xasg8k
https://youtu.be/Qed0i6DLoVQ

mazdaverx7

iTrader: (6)

If you have a heater circuit failure, I would remove the connector for the oxygen sensor and see if you have water in the connector. This could cause a short and could blow a fuse and cause a hester circuit code. If the connector is clean and dry, you maybwant to run the engine on live data and monitor the oxygen sensor voltage. Ensure the voltage is within spec at around .90V at normal operating temperature.

ZakB

I see I see I'll try that tomorrow thank you so much. You're talking about the front O2 sensor right? A couple more questions too:
if the sensor has water in it would that mean I need a new one or could I just let it dry out?
Which fuse would it connect to or would I just need to check them all?
How would a faulty o2 sensor stop my car from running?

CaymanRotary

I would run a compression test. If water made it to the MAF, it's possible enough water could have sucked into the engine causing damage to the seals. That would be the first thing to do if the deflood procedure doesn't work just to make sure if it is in fact damage to the engine. Those cold air intakes suck for real world driving for this exact reason. Plus it's not necessary in this car as the stock intake is actually really good.

Loki

iTrader: (1)

P0147 is bank 1 sensor 3 which... doesn't exist on this car. Are you sure that was the code? The rear sensor is much lower and more susceptible to water than the front. I would check all fuses just in case, but doubt it's that.

Any other codes? You need spark, fuel and compression to start, see if you can confirm good spark at least? If it's almost catching, do a proper deflooding using the gas pedal. It takes longer than you'd expect but it works.

ZakB

yeah I was thinking about doing a compression test… but it’s not like I was in flood water there were only a couple droplets in the cai and a couple on the maf sensor. Surely that isn’t enough to ruin the engine? Hopefully if I get this back working I’ll put the stock air box back in

ZakB

Ive just checked my obd2 again and it’s 2 different codes. I’ve got P0043 (heater control circuit) and P0047 (turbo/supercharger boost control solenoid circuit). Kinda confused about that last one cause I don’t have turbo or a supercharger.
however I do think I have spark. I checked spark plug and it was sparking normally it’s just weird cause when I’m cranking the engine it doesn’t sound like there’s much firing which makes me think the problem is fuel injection or worst case my compression.

CaymanRotary

Water in the compression chamber can be really bad because it doesn't compress like gasoline which can bend the metal seals on the compression stroke. If you have new plugs in and the deflood isn't working, that's pretty concerning. Doing the compression test at least confirms if the water caused damage plus its good to do anyways from time to time.