I know all about going over water in a somewhat moderate steady good speed....however, I am having an issue. I had to cross a water mud trail with faster speed than usual (no other way out)...automatically as soon as I crossed that mud hole (only 1ft deep or so with another .5ft-1ft of water) truck cut out.

Now I popped the hood, nothing...not a single trace of water or mud. (I have a custom intake with duct work that keeps my intake spotless from water all the way up to my hood). Let it idle for about 5 minutes and cleared right up

My question is..what sensor can cause an abropt cutout to happen from about midway down the engine. I was thinking o2 sensors but I crossed 2ft water (slowly steadly) before and it has never cut out on me.

Maybe I was just going too fast and not creating a nice steady wave but like I said...I did not see any water/mud get around my engine

 

Water may have entered the ECU - there have been posts about making it water tite, people in heavy rain on the highway having problems, etc.

 

Does it die completely? I'd think maybe crank sensor.

Or does it just start to run rough?

 

You were going to fast.
Water got sucked into the intake.
Crank sensor got wet.
Most likely water got sucked into the intake.
O2 sensors and get submerged and do nothing.

 

I know I went too fast.

ECU is waterproofed

Nope intake was bone dry..no water (we pulled it)

It just runs rough...it doesnt idle above 1000rpms..than 30 sec goes by to 1200rpms, and so on...until it clears up.

I was thinking o2 sensors but...this rover has been submerged in 2ft of water crossing (slow and steady) before with zero issues.

It could be the crank sensor

 

My old 96 used to act kind of that way when I had a bad cat. But, I think I read that you had new exhaust.....

 

Yup new cats...it did this before and after I replaced them

 

Are you still running the old grey factory plug wires, that would cause it cause they leak real bad.

 

What about wiring or seal around the Vehicle Speed Sensor on the transfer case? When they go bad they can make the truck lose power at a certain rpm, what would happen if they were water shorted out? Not to many other sensors besides crank sensor that have to go under water while wading.

 

Brand new spark plug wires...havent checked the VSS...ill take a look, where is it located exactly