Really strange problem in the rain
 

Guys i'm seriously stumped on this. When it's dry the car is perfect. But as soon as it starts raining the car get's a vibration up through the floor, there's some clunking sound under the drivers side, and a rattling noise that sounds likt it's under the shifter. Yes all three of these things at the same time. At first i thought it was a coincidence that it would happen when it's raining. So i drove it in the dry for a few days and nothing. Then yesterday it rains and it's doing it, same with today. It was dry when i left the house, no noise, rain starts, annoying as fuck noises and vibrations.
I have no idea what to even look for or how to diagnose this. Any ideas at all?:wtf:
Edit: it's an s13 hatch, ka and 5 speed

Sounds like your transmission mount, or a series of other dead bushings in your drive train. I'd start at the trans mount tho.

I would think a transmission mount would show a problem all the time, not just in the rain. And the car only has 96k on it.
Any other ideas? It's driving me nuts since it rains a lot in south florida.

Did you check it? It sounds like drive train problems. Like I said, it's a series of old, dry, cracked bushings probably sloshing around underneath your car.

I'll check it later today. Its like right under the drivers seat though and sounds like if the exhaust was hitting something but it's not even close to anything.

I know this sounds dumb, but i have seen it before...

Are your rear tires the same size sidewall?

I have seen it were someones rear tires are 205 45 17 on one side and 205 50 17 on the other.

The larger tire will actually drag the smaller tire so it will making and whopping sounds and skidding sounds as it grabs and loses traction. Obviously amplified in the rain

They're the same size but different brands and one is more worn than the other. But i dont think it's the problem since at idle the shifter with rattle like crazy. It never makes a noise when it's dry.

Is it on or off throttle or both?
Is it only while rolling, or at a stop as well?
If you rev it in neutral at a stop does it do it?

Both
There's a vibration from the floor when driving and at idle but at idle the shifter rattles.
If i rev it the shifter rattle goes away but the vibration is still there

But is it while rolling or at a stand still, or both?

All the time. Idle, driving, rolling, stopping. Any time it gets wet the problem starts no matter what.

have you popped the hood and looked at the motor itself?

Does the motor seem to be shaking back and forth more than usual?

It could possibly getting water into it cause really bad fuel burn

Mounts are good, no movement.
But the last part is a possibility. I don't have fender liners...

I don;t run fender liners either. no bigger.

When your car has been off and it starts to rain. You start it up and the shaking starts? or as your start to drive?

Depending how your plumbing is, you could be sucking up water.

another questions,

are you running map or maf?

The under side of the car has to get wet. So if it's raining and i start it it's fine but as soon as the water starts hitting the under side of the car it starts doing it til it dries off.
I have the stock air box with the big resonator box underneath removed and i capped off that hole in the air box so it wouldn't suck water.

Its all stock under the hood.

so I take it you are running the stock maf?
Also since you have to stock air box, you are non-turbo?

All stock ka dual cam.

hmmm does your intake plumbing have any cracks in it?

is the maf filament getting wet?

If the maf is getting wet it will mess up the readings and make it act funny.


If it only happens when its wet and after you start moving. Its sucking up water, or water is messing up your sensors.

I'll have to look into that. It does make perfect sense.

Thanks for the help. I post back when i find stuff

OK just spoke with a friend that had the same issue when it was wet.

Where the intake plumbing comes out of the air box across the front and to the intake. At the airbox there is an accordion looking section that cracks and breaks and lets water in. fix or replace.... Duct Tape...

If that fixes it, you can get me a 6 pack!!!

Haha sounds good:rofl:
Duct tape is going on today. Now i just have to wait till it rains again.....

just start hosing it down...
simulated rain!!!!

Well!??!?!

Whats going on with it?

There's no cracks or anything. Looks brand new. I give up! :faint:

Look the entire thing over. Take it of if you have to, look for cracks and breaks. Check the air box and air filter seal. It is pulling in water from somewhere.

If it doesn't start doing that crap till after it moves in the rain, its pulling water in.

Alright i'll hae to check it over better when i get home.

I had this exact same problem before. The solution is brand new exhaust hanger bushings. When the old bushings get wet, they develop more play and believe it or not will cause the exhaust to vibrate against the body of the car.

You may also want to check the driver side seat bolt that threads through the body near the exhaust as sometimes the wrong bolt is used and it sticks out way past what it is suppose to, thus getting hit by the exhaust.