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1991 Mercedes 190E 1.8L
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25 Posts
Discussion Starter #1 (Edited)
I've still only had this car for just under a month and I'm still testing it out making sure it's running well... and I don't think it is.

Lately I noticed the acceleration is fairly low and fuel consumption is pretty high.

I filled up 33L of 91 unleaded when tank was just before empty and reset the milage counter.

The fuel light is gonna go on any minute now, and its only done 155km (city driving).

Lets say its used 30L so far, that brings down the fuel economy to:

19.35L/100km or 12.1mpg (US Gallon) which is terrible, especially for a 1.8 engine - pretty much double the consumption it should be going at.

I began researching on the issue, and many with similar issues seem to be having slow acceleration, and now that I think about it, the acceleration is really sluggish.

Research suggested its a fuel issue possibly caused by: Air Flow Meter (AMF), Electro-Hydraulic Actuator (EHA), Oxygen Sensor, Fuel Injectors, etc...

Some info that may be relevant:

-Starts first time every time without a problem (even cold).
-Rough idle/Engine vibrations, sometimes more than others (engine mounts are probably worn though).
-Clean exhaust, minimal carbon deposits.
-Sometimes has rich fuel smell, most noticeable after opening engine bay.
-Pressure "pop" when I open fuel cap.

I can't seem to find much information online such as DIYs on how to remove the airbox, AMF, EHA etc. I don't know where to begin, would greatly appreciate being pointed in the right direction. Most of the information I come across are for 2.3L engines and such, not 1.8 :(

I can't seem to locate the oxygen sensor, is it meant to be under the car? Or somewhere on the intake manifold?

Thanks in advance!

edit:

UPDATE: Post #4
 

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1991 190e 2.6 automatic
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760 Posts
sounds like you have MAJOR issues.. and i wouldnt go look at the tailpipe to make conclusions if it has any carbon deposits.

First i would look at the OVP relay and see if its all good

then would check the spark plugs, wires and distributor cap and rotor

make sure you are running copper non resistor plugs

then i would check the duty cycle to make sure the fuel/air is adjusted correct

check operation of o2 sensor

check your coolant sensor for correct ohms values at diff temps

look at injectors see if they look old... its good to replace them it makes a more smooth idle and better ride

check for vacuum leaks

and finally buy a can of seafoam and run it through your intake lines to clear out the carbon and THEN see the tailpipe
 

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Registered
1991 Mercedes 190E 1.8L
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25 Posts
Discussion Starter #3
sounds like you have MAJOR issues.. and i wouldnt go look at the tailpipe to make conclusions if it has any carbon deposits.

First i would look at the OVP relay and see if its all good

then would check the spark plugs, wires and distributor cap and rotor

make sure you are running copper non resistor plugs

then i would check the duty cycle to make sure the fuel/air is adjusted correct

check operation of o2 sensor

check your coolant sensor for correct ohms values at diff temps

look at injectors see if they look old... its good to replace them it makes a more smooth idle and better ride

check for vacuum leaks

and finally buy a can of seafoam and run it through your intake lines to clear out the carbon and THEN see the tailpipe
Thanks for the response!

How would I go about all of those? Any special tools I need?

I'm still trying to learn about this car as Ive only had it for less than a month, so excuse my poor knowledge.

Any online guides/DIYs that may help me?
 

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1991 Mercedes 190E 1.8L
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25 Posts
Discussion Starter #4 (Edited)
Took off the air filter box and took a look underneath, this is what i found

Photo Album - Imgur (gallery)

I first noticed the breather hose was quite loose, and after pulling it out, it noticed that most of its circumference had been broken off, but it appears that it has been intentionally cut out...(no idea why).

And I noticed that the engine and surrounding components are quite oily, you can see in the images along the line of the engine cover theres a deposit of oil

The fuel distributor, EHA, ICV, etc all seem to have oily residues.

After playing around with the breather hose it cracked (added it to my list of new things to buy), but in the meantime i put a bit of strong super-glue adhesive that seems to hold it well (for now).

I put one of those worm drive rings ( http://www.gd-wholesale.com/userimg/11/700i1/worm-drive-hose-clamps-682.jpg ) around the broken end of the breather hose, seems to be held tighter now.

After I started it up, ran it for a while and noticed white smoke when i revved engine higher, then took it for a spin around the block and revving it again didnt produce any smoke, just clear exhaust (its winter here in Sydney btw)

Idunno what else to do right now, those are my observations, thoughts?
 

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1991 190e 2.6 automatic
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760 Posts
search up all the things i told you.. there is many threads about stuff that i said so look it up and then tell us what happend after u checked it all.
 

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1991 190e 2.6 automatic
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760 Posts
btw for comparison, i have a 2.6L and i get around 10l/100km in 70% highway driving
 

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1991 Mercedes 190E 1.8L
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25 Posts
Discussion Starter #7
UPDATE

jacked up the car earlier and found the damn O2 sensor. I dont have a multimeter to check whether its giving an acceptable voltage range, but I did try and unscrew it to check if it was burnt out... no luck.

Drowned the thing in WD-40 and didnt wanna budge
 

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1985 190E(SOLD 04/14/11) - 1986 190E - 1986 190E 2.3-16
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105 Posts
The broken breather hose is the cause of oil spilling all over. They crack over time, i replaced a lot of them over time. The white smoke at cold start can be just the water condensation inside the exhaust. Check the temperature sensors and the O2 sensor, they can affect fuel consumption.
 

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i have the same problem but when i desconnect the EHA connector the accleration is increase and fuel consumption is decrease
 
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