Please Help!! Damn Crazy Electrical problem!!

[S14Surge]

alright well heres the situation guys...about a week ago i washed my engine bay like i've done a million times in the past, but this time when i started up my car the idle was lower than usual, really erratic and stumbly, and voltage to the ECU dropped from a constant 13.8v-14.0v to 13.0v during the day and around 12.5v during the night with headlights on..and when i rev the engine the temperature gauge in the gauge cluster flutters a bit..I also have this crazy interference with my Kenwood Navigation head unit, when the car is running the screen has all these lines blurring up the display and it gets worse when i rev up the engine, with the ignition on but the car not running there is no interference in the deck display?? There is also a slight humming noise that increases with the RPMs...All this crap over trying to make my engine bay clean:rant2: nice... I've checked voltage coming out of my alternator and it stays at about 13.8v and my battery is the same while running..I know i prolly shorted somethen out I just have no clue as to where to look an what to do about it.. oh an one thing i forgot to mention was that at idle voltage drops alot, but then when i rev the engine it climbs up a bit (voltage drop is way worse at night due to headlights being on)..this is confusing the shit outta me, i would greatly appreciate any help from any one who has had a similar problem or experience in troubleshooting electrical issues..

Thanks brosiffs

-Surge

Vehicle= 1998 240sx/S14 SR20DET

[EnthusiastMan]

Check to make sure you didn't get any water down in the spark plug holes. Esp if it doesn't have the cover over it.

[S14Surge]

valve cover does have the spark plug cover installed..so i dont think that could be the problem..

[jackjack]

^either way, double check. same thing happend to me. water in the spark plug hole.

[GSXRJJordan]

The fact that you're hearing alternator feedback in your audio means the alternator fuse isn't blown... sounds like you got water under an important ground - The head unit grounds through the ECU if you don't have a good ground on it, but you say the head unit is fine when the ignition is to ON, not just ACC? ON means the ECU is powered also, so it should be the same as when the car's on...

Short version is: you've got a grounding problem (or an alternator problem). I bet ground.

[Adikt]

I think you killed ur alternator

[Sir]

the audio stuff is feedback due to poor grounds.
Go clean them up. See if it helps.

[GSXRJJordan]

I think you killed ur alternator

That's what I thought at first also, but he's got to check his grounds first ~

[Heero Yuy]

SORRY to hear about your prob however i would have to say its a ground problem i have seen this this happen to other cars........ not mine however go back and check out all your grounds engine to body and battery to body and any other find them sand them down and see what happens

[S14Surge]

The fact that you're hearing alternator feedback in your audio means the alternator fuse isn't blown... sounds like you got water under an important ground - The head unit grounds through the ECU if you don't have a good ground on it, but you say the head unit is fine when the ignition is to ON, not just ACC? ON means the ECU is powered also, so it should be the same as when the car's on...

Short version is: you've got a grounding problem (or an alternator problem). I bet ground.

the head unit is fine with the ignition on/engine not running, and is horrible while the engine is running.. im going to check all my grounds soon, i think i prolly shorted something out...man i hate electrical work