2000 B4 Wet weather Shaking.

[nickmcgill]

Hokay,

So ever since I have owned my B4 over the past uh 10 months or so it has always had a strange problem when it comes to rain / low flooding and puddles.

Basically, When ever the car gets fairly wet it will start shaking when cruising at a speed of say 50kmh or 60 or 70, Doesn't feel like a misfiring shake it is very fast and can be quite violent.

When taking off from stopped eg at a traffic light after aprox 2 seconds of excelerating the car will stop excelerating and roll by it self and then 3 seconds later the car will respond and normally change down to 1st gear and go up to 5-6k rpm. ( Auto Trans )

I have a faulty O2 sensor that comes on from time to time, I have had the CEL come on from the 02 sensor problem and then when I have hit rain the ECU must reset or something strange and the CEL will go out while the car is still running and moving.

I have taken it to several different Subaru places and no one has any idea what it is, I'm guessing that its something electrical since it causes the CEL to shut off.

Washing the car will not cause these problems.

Any ideas anyone ?

It's caused me to have some fairly close calls when I've gone to excelerate suddenly to get out of a sticky situation and the car doesn't respond for 3-5 seconds.

I also apologize in advance for my bad spelling.

[Guest]

Mate, start with the what is causing CEL first !

I'd say many workshops have advised this and you still haven't done it !

Have you taken the car to someone who know's Sub's? and has the correct test gear

Go for a drive with them to simulate fault so they can read the live data

Sounds like TPS fault to me

[nickmcgill]

CEL is being caused by the O2 sensor, I am 100% positive about this, I had it tested by Archibald's a couple of weeks after I got it to try and sus out whats going on and they came back with the following codes;

Brake Control

37 RL Hold valve malfunction ( Latest )

56 G Sensor signal check ( Reference )

23 Mas air flow sensor circuit

32 O2 sensor

66 Twin stage turbo charger system

66 Twin turbo charger system (s)

MAF has been replaced with a new subaru one.

Turbo system was a leaky BOV on the secondary turbo, that got replaced with a second hand one that still leaks.

The rest of them have been cleared out of the system and the O2 sensor is the only one that keeps coming back.

I've been taking it into Stubaru in christchurch now for all technical stuff and he doesn't have any idea what could be causing the problem I talked about earlier.

Another interesting point that I forgot to mention earlier is with the triptronic gear system.

Generally it will work fine but sometimes I will be in 3rd gear, the screen will read 4th but be in 2nd gear.

3rd gear sometimes comes up with a dash and I am able to change down from 4th to 1st while moving at 60kmh.

However it still changes gears when I tell it to, Just sometimes gives me the wrong info and I end up going from 2nd to 1st thinking I'm going 3rd to 2nd.

I have wanted to take a tech out with a machine but its hard to simulate cause I need a large puddle or a pit of some kind to get it wet in.

Edit : 99% Sure.

[nickmcgill]

Just an update, Went in to Stubaru just now to see if he could quickly check the current codes for me and the only one displaying was 32 O2 sensor.

Computer was last cleared on Dec 26th.

[albaru]

So... any chance you'll replace the O2 sensor?

Symptoms for my faulty 02 sensor were that when I'd first start the car, and it was supposed to idle, the engine would cut out. Something like a major electrical system shutdown - not entirely dissimilar to your situation.

As Ichiban suggests, fix one fault at a time, until they all go away. Especially a major recurring one.

(I unclipped the lead for my O2 sensor until I could afford to buy a new one. )

[nickmcgill]

Yeah well I've sorted all the other issues out and the O2 sensor is the only one left, I'm gonna head out soon and try to unplug it.

[nickmcgill]

Right well I've unplugged what I was told was the O2 sensor, Test drove and still came on the same as usual, So how many O2 sensors are there and if there's only one what did I just unplug lol

[funkytown]

ermm i dont think thats your O2 sensor.. o2 should be on the exhaust down pipe or maybe on the uppipe (if mater b4)... i think.

Mine sensor looked just like this

and was located just off the turbo near the brake master cylinder.

[nickmcgill]

Yeap I know the one, From memory its on the uppipe on the passenger side. I'll have to get it outside tomorrow and get the sumpgaurd off and have a look but from memory that cable that I unpluged runs down to that sensor but I will double check it tomorrow.

Also thanks for all the help guys ;D

[Guest]

Yes that is the sensor plug, some models also have another O2 near the junction of the "Y" pipe

[nickmcgill]

 Ichi Ban said:

Yes that is the sensor plug, some models also have another O2 near the junction of the "Y" pipe

I'm guessing thats the part from the 2 down pipes to the join before the catty ? I shall try get under it tomorrow if I can fit and have a good look.

Thanks again everyone for your advice.

[log1call]

Shaking motor, loosing power, CEL on, O2 sensor code in ECU.... it has a miss surely?

O2 sensors being crook won't make much difference to the running of your motor, not enough to make it shake any way. O2 sensors only have a certain range of adjustment they can bring about and even an extreem reading won't make the motor shake.

The O2 sensor is indicating a fault, not causing it.

[nickmcgill]

Yeah thats what I would have thought also.

If any one is in Chch and knows of a water pit or a area thats normally has a semi decent amount of water in it I'll be happy to try and make it play up.

I got under it today and had a poke around and a look by the Y pipe and couldn't see any other sensors.

I will get the sump guard off later and have a look around the up pipes cause I know there is one on the front of there somewhere.

It seems to be an issue of a computer or connector getting wet somewhere and causing it to send funny readings of some kind.

I thought it may be something in the throttle body since it is electronic on the turbo models. Well from what I've read it is anyway.

[log1call]

Have you changed your fuel filter? Have you checked your fuel pressure? Have you tried connecting it to a laptop and checking what your injector pulse width is like?

It could be a lack of fuel making it run bad, the o2 readings go right off the scale, the water on the o2 sensor COULD be cooling it so much that it gets ignored by the ecu and the base/openloop setting is used, the ecu recentres the air/fuel rates and the light goes out..

I have driven subarus through heavy rain and puddles and had the check light come on.... I'd assumed it was the O2 getting wet or cold putting the readings out. I suspect in your case the readings are already out and the wet/cold O2 sensor either puts the figure so far out it gets ignored by the ecu, or, it moves the figures back into a more acceptable range and the ecu is happy again.

[nickmcgill]

Hmm yeah that would seem to make sense.

I haven't done fuel filter yet can't afford to been out of work for 6 months now so no money to spend on it the B4

The 02 sensor will only come when I go up my hill. I can basically pin point with in about 1-2 second on when it should turn on cause its always at the same place.

When I came up the hill just now the CEL didn't come on so disconecting that lead may have unpluged it after all.

What normally happens in the wet when its playing up is when I go up the hill the CEL won't come on and if the CEL has been on and then hits water / rain it will go out.

I will go out shortly and go up and down a few more times to see if it comes on at all.

I even made a video of it;

Update :

Have just been under the car and had a good look around for another sensor with no luck, However under close inspection of the one by the exhaust manifold I have discovered that the wires have been melted on one side and are bare.

Anyone got a spare to test ?