MrGlock

so here I am minding my own buisness on the way back from a family farm house in wisconsin. Boom flash flood and im stuck driving on muddy dirt roads and on my way out i hit a puddle which made the car misfire so i shut it off waited a second, turned it back on, revved that bitch to get any water out and made the 250 mile drive home to a mazda dealer and dropped it off for service that i had scheduled before this even happened. Ever since ive got home its been acting weird.

Ive done everything i can think of, plugs, coils, wires, cleaning upstream 02, and maf, and its still making a popping sound on acceleration. My only other guess would be engine speed sensor possibly is damaged causing the timing to be weird. No noticeable change in power, i have exhaust header, midpipe/cat delete, and megan racing cat back. Any help would be appreciated i do have some shitty footage of the car while driving if anyone wants to see that and you can hear the noise im talking about

spectre6000

"Acting weird" is not a diagnosable symptom. What is it doing exactly?

MrGlock

When accelerating it sounds like the engine is hesitating for a split second, and making a popping noise out the exhaust. Not a loud backfire or anything like that but its still very noticeable in third gear around the 4-7k rpm range

MrGlock

For some reason it wont let me upload the video of the noise its making

Loki

iTrader: (1)

How deep was the puddle? Above the center of the wheel?
A couple of things come to mind:
- cracked exhaust or cat from the immersion, although usually that would make popping sounds on deceleration- spark plugs or coils damaged by immersion. You mentioned a misfire, any others since then?
- cracked engine due to immersion. You would be leaking fluids.

Is the check engine light on? popping om acceleration points to excess unburned fuel in the exhaust

MrGlock

like i said i just did a full exhaust on the car theres no cat and theres no downstream o2 anymore so theres a check engine light, never had a misfire since the one recorded on the obd from the puddle, changed the air filter, and got back on the road home i was 250 miles away and had no choice. I never experienced any behavior like this from the car on the trip there, and a 11 hour straight rally only shut the car off to get gas. I have omp adapter for rotary premix injection and always premix the gasoline. So there could be some fouled spark plugs i changed them along with the coils and wires about 6-8k miles ago. The puddle i hit was maybe a few inches and i highly doubt it got water into the engine because the air filter was dry. I have a leaky oil pan but its always been that way since i bought it. I just make sure to keep the oil topped up inbetween gas tanks. I run full sythetic vr1 20w50 that good ****. I can see how it could be unburny fuel in the exhaust but theres no flames or anything like that i record the car with a 360 camera to see. Thanks for your reply. I really wish it would let me upload the video

MrGlock

uploaded the video this way

spectre6000

When did you change the exhaust/drop the cat relative to the incident? It sounds like you didn't tune it all for this, and it still wants that second O2 sensor. Just because it's not spitting flames, doesn't mean it's not backfiring in the exhaust, which is exactly what it sounds like it's doing. Backfiring doesn't have to be overly dramatic. It's over fueling because it's trying to compensate for that missing O2 sensor, the fuel isn't completely burned, and when it hits the exhaust, conditions resume for combustion. You fuel mileage probably sucks too; same deal.

MrGlock

I did the exhaust probably a month or 2 before the incident with the puddle, and that was my last drive for the season last year. Just recently took it out for the day to test out the 360 camera and how to set it up properly. Also ive never tuned the car or had the car tuned because i live about 300 miles away from the nearest person who has any idea what to do with the car. Ive called dynos and tuner shops in my area and i just get laughed at and told good luck so idk man i guess ill just buy versatuner and give it a shot myself. And i dont mind the **** gas mileage it never was great anyways

(Edit) ive calculated the gas mileage to be about 16-18mpg

Loki

iTrader: (1)

You don't need to tune for an exhaust change. Might want to check the OBD codes, if your check engine light is always on you might not realize there are other problems being reported.

It'll complain about the missing O2 but that's not the one that determines mixture, so shouldn't cause what you're seeing.

​​​​​​While you have the OBD reader plugged in, check your fuel trims on a warm idle (just sitting idle and warm, nothing else). The do a run like this and see what you get for AFR and MAF rate.

MrGlock

Do you know what the fuel trims should normally look like? I cleaned the upstream o2 when i did the header so i know thats solid. Mls gasket and leak test the whole system shes mint. And i know the downstream dosent matter thats why i got rid of it, also the midpipe i bought dosent clear the trans pan with the o2 installed so i just capped it off. Ill do the obd test when i can, the cars still on storage policy so i cant drive it legally yet untill my insurance agent calls me back.

Loki

iTrader: (1)

Fuel trims should be near 0 at idle. +/- a few is ok. +10/-10 or more is no good.

What did you clean the O2 sensor with? Cleaning O2 sensors isn't really recommended, cleaning chemicals can damage it. And it's self-cleaned by exhaust anyway, it's 1800F in there.

MrGlock

carb cleaner ive used it on other o2 sensors without problems, i just sprayed it once or twice let it air dry and slapped it in the new header