'94 4.0L automatic 4wd

hey everyone.. ive been chasing a real PITA for a while now
my jeep will run perfect all week long without a hiccup, but when i get her good & wet, she'll start stalling. i can crawl thru deep water up to the headlights, or hit puddles at slower speeds (10-15mph) and it wont affect it, its when i start really romping thru the puddles and splashing hard. it will never stall in the puddle, it will always stall out about 5 minutes later; like i'll slam some foot deep puddles around 30mph, then cruise down a trail and 5 minutes later it'll stall. i know as soon as i start romping thru puddles, i just wait for it to stall, i know its coming. 90% of the time when it stalls, it simply shuts straight off as if i flipped the key. 10% it will suddenly be running on maybe 1 or 2 cylinders for about 5 seconds and shut off.

it will never start back up right away, it has to sit for about a minute or two. if i try to start it back up right after it stalls, it will just crank. there is fuel pressure at the rail, i smell gas when its cranking, but no spark (verified no spark with an ignition tester)

in the last month i have replaced new:

plugs & wires
sealed dist. cap with rtv silicone (did not replace)
alternator
cps
tps
fuel pressure regulator; also verified 40+ psi rail pressure and fuel bleed- down time within spec
battery terminals
starter, radiator, waterpump, tstat

i've tried using a garden hose to spray my engine bay down with it running, but could not get it to stall out even if i drove it afterwards. i also tried wiggling the hell out of every wire under the hood (especially pcm, tps, cps, distributor & coil wires) but again, could not get it to stall wet or dry.

only codes are bank1 lean, and idle air control solenoid shorted.

i know im beating the hell outta my jeep but i would really love to know what i could beef up or replace to make it so i can hit the puddles with confidence.

my next move is to replace the coil, cap & rotor, and resealing it again with rtv. im pretty much throwing darts at this point, so if yall have some better suggestions i'd love to hear em! thanks.

*also, does a 94 4.0L have a cam sensor inside the distributor? ive been told yes & no on this.

 

I don't know if this will help and i don't know why, but when i read your post grounds come to mind. I guess check your grounds and coil too. Just a hunch.

 

Stupid question, but do you change your own oil? Does it look normal?

If you can't be good, be good at it!

 

I just read a bad O2 sensor can do something like that. Maybe check those and there wires. Just going off your list of what you already did. Could it just be a wet alt not giving enough juice? Amps not volts

 

grounds or water getting in air box?

 

the airbox does get a very very small amount of water into it at times cuz i dont have a snorkel yet.. is it possible to get the tps wet by sucking in water thru the intake? i ask that because if the tps is unplugged, the jeep will not start.

i do change my own oil, and changed it about 2 weeks ago. it looked normal coming out.

i have inspected the coil, tried spraying it with water and wiggling it, tapping on it, couldnt make it stall.
i will inspect the engine grounds tho.. can u tell me where the important ones are?

thanks

 

Just changed my O2 and stalling stopped for me.

 

i remember someone mentioning it might be a o2 sensor a while ago.. it is mounted low on the vehicle so it might be getting its *** kicked in the water. the alternator is new, but if it did crap out the engine would still run for a good 15 minutes or so on battery power alone.

i'll try that this weekend and see how that works out, thanks

 

Wasn't sure about where the grounds were, so took some pics of wiring diagrams in my '92 jeep factory service manual.

 

http://www.lunghd.com/Tech_Articles/...und_straps.htm

read his one and only note...

maybe???

 

wow those pictures are really helpful, im gonna go thru all of that tomorow.

thanks a lot!

 

replaced the distributor cap & rotor and sealed the hell out of it. absolutely no water getting in there at all, not even thru the vent cap. also inspected the cam sensor & its wiring, looked ok but im probably gonna replace it anyway. i have inspected a few of the grounds but have more to check..

as usual, ran great till i started rompin thru ~1foot deep puddles around 25-30mph, would eventually cut right out a few minutes later, no spark unless it sits for a couple minutes. did this about 4 times, each stall was about 5-10 minutes apart from each other.

i also bought a coil but i have to bring it back tomorow cuz its the wrong one, ill be replacing it tomorow & im hoping to GOD that its my problem. i go wheeling all weekend, every weekend, and a few times during the week.( yes, i live out in the sticks lol) it happens to me at least a few times on every trip. this has been goin on for about 2 months; very frustrating to say the least.

if i replace everything i can think of and its still stalling, i'm going to replace the whole damn harness along with the PCM.. if that dont fix it its going off a cliff.

a couple of you have suggested the o2 sensor.. but i cannot for the life of me understand how an o2 sensor could possibly cause an intermittent loss of spark.

thanks for the help guys.

 

if water is soaking your alt, is that anything that would show symptoms 5 minutes later, instead of immediately? I like the idea of sucking water through your intake though.

 

water is defnitely soaking the alternator..but its brand new.
if u cant let the alternator get wet, everybody would have my problem lol.

at this point, im thinking of 5 likely possibilities..

intermittent short/open in the wiring harness, or a loose connection in a harness connector, ( inspecting tomorow)

coil cant take a beating (replacing tomorow)

loose/corroded ground (inspecting tomorow)

cam sensor.. doubt it, but replacing it tomorow anyway.

pcm cant take a beating..even tho i can spray it with a hose and bang/wiggle it all day long with no effect

any thoughts?

 

update:

replaced coil, no change.