1991 190e faulty O2 sensor symptoms?Post your opinions, please!Quick!
 

Ok guys.

These are the symptoms on my car today.Looking to confirm if they are similar to the symptoms of a faulty O2 sensor :

1 When engine is cold, idling a little rough (almost
unnoticeable).The drive is normal.

2 When warm, idling is very rough.Hesitation from standstill.Drive
is very rough (engine idles roughly).

3 Degrading fuel mileage.2 weeks ago, i could get 450km+ on a
full tank.Now i can only get 260km.

4 Exhaust smell is stronger, and exhaust note seems louder;like
the car is running rich.

Your quick opinions, please.

Thanks in advance to everyone!

:D

Start by looking for a vac leak...

Checked...well, physically anyway...
 

Took the air cleaner off and inspected all hoses.

Started engine and did not find any leaks...so far...

Took the car out for a short drive and confirmed that once the engine is warm, it starts to run rich (exhaust is a dead giveaway).

Already went the injector cleaner route and no dice.

Keep 'em coming guys!:D

C'mon guys...
 

seems to me like a dead giveaway!

Just like to hear others' opinions/experiences.

:D

O2 sensor - ECU - EHA. This loop fine tunes your mechanical injection. Idle, running, and most functions should run fine - not excessively rich - with the loop open. If running does NOT improve with the EHA disconnected, then look first for a problem unrelated to the O2 sensor and other loop components.

Steve

Cool...
 

I'll give it a go!

Keep it coming!:D

Anyone ever experienced the same symptoms?

When my spliced O2 started leeking vlotage the car would hesitate. Easy way to check is unplug it when the car is warmed up and see if the symptoms go away or not. Could have different results then on my 85 due to the limp mode adjustment.

But you can easily check the O2 with a multimeter. Readings are supposed to be from 0 to 1 V. If I remeber correctly, very close to 0 at idle, and when you floor it it should go almost up to 1V.

xp

xp

Curious, specifically how did you check the sensor? I understand using the meter but where did you place the contacts to get the reading?

Haasman

How many miles on the current O2 sensor?

Oh jeez....
 

I don't have a cat on my car (1991 190e 1.8 Euro).

I checked the exhaust manifold from the downpipe all the way to the rear silencer.

NO O2 SENSOR!

So do I like for an alternative device?Would it be on the intake manifold instead?

Anyone?:confused:

Damn, it was staring us in the face the whole time . . 1.8L . . . carburetor!

Nope...
 

It is 1.8L but it's a fuel injected car.

Bosch KE-Jetronic fuel injection with EZL ignition.

MTI,

Thought you had it figured out, didn't you?:D

Anyone?

azhari,

did you make any adjustments to the mixture before you develop these symptoms or did the fault appear spontaneously?

check the following.

plugs,

spark plug leads,

rotor,

distributor cap.

cold start valve-may be it continues to spray extra fuel even when your car has warmed up-hence the the uneven idle and rich mixture.-try unplugging the connector when the the car is warm. it is located on the fuel rail near the injectors ,has a bluish connector on my car ,so yours should be similar.

mine is a 1993,1.8 litre fuel injected and with a cat and hence an o2 sensor.

my gut reaction is a sensor of some sort is malfunctionoing-do you have acess to a fault code analyser to plug into the diagnostic plug in the engine compartment

hope you get a result

I just thought I might point out that the symptoms described are about as general as one could make them.

Absolutely every possible defect to combustion are possible. I see only one hint from your general description. That is that the car runs worse warm. Thats it, what can be made from such info.

Not much, the car runs richer when cold so my guess is that you are too lean.

You have given us little more than to say your car is broken and ask what is wrong. I don't wish to be negative, but it is insulting to think that people think automotive technology is so easy. No wonder people think auto repair cost too much. Listen to simple description of problem, move car to shop, wave ones hand, and come out with a big bill. I'd be pi**ed too.