Car stumbles/misfires in heavy rain... BUT...

[Jaxx_]

I get what you are saying though. spray bottle with hood open to replicate situation makes sense. I did not think of that.

lol oh i see what you thought I meant. yeah, I don't think a spray bottle on the hood would do very much damage.

[mbonanni]

lol oh i see what you thought I meant. yeah, I don't think a spray bottle on the hood would do very much damage.

It would cool the hood off a little perhaps.

Goodluck getting your problem resolved

[BMWManiac]

This may be random, but check your battery terminals in the rear and make sure you have a solid connection

[InfiniteDice]

Check your O2 sensor leads for cracks, exposure that can short out.

I had this issue after getting a totally custom exhaust with headers that put the o2 sensor further back. I essentially lengthened the leads to the o2 sensor and used heat shrink/tape to seal it.

I was driving through lots of water on the highway to work one morning and the same thing happened. It died, so I restarted the engine coasting on the highway and tried to put it back in gear... if I applied any pressure on it it died again. I coasted off at my exit and restarted at the lights.

I could smell excessive gas, it did restart but I had to feather between revving the engine and letting it slip into 1st to get moving. Once I made it to the parking lot I left it for the day and for my drive home it was totally normal.

The next time it was raining it started doing it again so after some deductive thinking I unplugged the o2 sensor under the hood and drove home... NO ISSUES.

I still need to rewire the leads and what I have planned is to use the heavy duty heat shrink tubing that contains a glue on the inner surface, this really seals and will not allow water to ground out the leads.

The o2 sensor controls your fuel mix, and it is making the computer run extremely rich by sending incorrect fuel/air signals.

Hope this is useful!

[EREKSHUN]

My crank sensor gives me this problem every now and then. If I wash my motor I get the same reaction as in heavy rain.

[Cinnabar325is]

My crank sensor gives me this problem every now and then. If I wash my motor I get the same reaction as in heavy rain.

Interesting. I wonder how the water would interfere unless the wiring/sensor were damaged? My CPS is brand new... but you never know.