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1991 Mercedes 190E 1.8L
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25 Posts
Discussion Starter #1 (Edited)
After I bought my first car I noticed my fuel economy on my 1.8L auto 190e was pretty bad, was maybe getting like 15mpg at most (city, no heavy foot).

First of all I noticed the engine had too much oil, which I flushed and put back the correct amount back in, this reduced some engine vibrations but theyre still there. The oil pressure gauge is always at 2 (idle) then jumps to 3 (driving) is this normal??

Next I found the EHA was leaking and mechanic I took it to saw that my fuel accumulator was busted, replaced both (+ Fuel Filter) for $550 including labor :mad: and there wasnt much of a difference afterwards.

Next I replaced the NGK resistor spark plugs with BOSCH H8DC0 non-resistors, I actually noticed a much smoother idle right after, but it seems to have gone back to its normal rough idle the next day :(

Another thing I notice is a 'hesitation' in acceleration. As im accelerating constantly, it feels kinda slow then "boosts" into normal acceleration after a while.

I also hear a faint "hissing" sound somewhere near the vent (Australian RHS Drivers side) - vacuum leak? How do I go about diagnosing vacuum leaks, all I know about are the breather hoses and the ones that go to ICV, what others are there?

I've been researching for hours on end but I don't know what to diagnose and how. I'm not in the best financial situation right now and don't wanna be dropping another $500+ for parts that may not even fix anything.

Please help :(
 

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1991 190e 2.6
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25 Posts
http://www.benzworld.org/forums/w201-190-class/1670956-190e-idle-vibration-cure-found.html

Here's my 2 cents....... Try it out it might work for you too... Just a 10 dollar investment...

Vacuum leaks are most often a source of rough idle. But to an extent, i couldnt get into the passenger compartment and cure that vacuum leak. So didnt bother.

But i tried to get to the root of the problem, small vacuum leaks contribute to very minor idle vibrations. So i went ahead and did the things plugs, wires, rotor, cap....I spent over 1500 dollars in repairs when i got my 190e... Includes everything except antifreeze and suspension.

now how to do this, take of your air cleaner, clean the MAS plate (its in the center of the cleaner), how i did is - i used silica gel packets to absorb as much moisture they could, over night (make sure you cover the thing with plastic so that nothing gets in there and seal the silica gel tight). Silica gel is a good dessicator and absorbs all the moisture.

Then take out your AICV, see if its rotating nicely.. If not, then clean with solvent (brake cleaner) and lubricate it.

Now put it back and attach the breather hoses back, inspect any cracks or anything and seal them using silicone sealer for temporary purposes and replace them ASAP.

Check for leaks in the little vacuum hoses too, the 3 mm ones.

Now run the engine. Gas it a little, open the main brake booster vacuum line and add moisture repellant to your intake.

shut down your car, and let it stabilize and mix the water with it.
Rev high on IDLE to see if any moisture is being expelled.
Drive your car on high revs (in 2 and 3) for about 20 minutes, and then see if it idles ok.

Its a cheap fix, but getting to the root of the problem is hard.
 

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1991 Mercedes 190E 1.8L
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25 Posts
Discussion Starter #3
I'm planning to replace the brittle vacuum hoses I can see on top, with part numbers

102 094 19 87


102 094 21 87


102 094 43 87


Are these considered the 'vacuum' hoses? What other ones are there? I know there seems to be another one or two under the ICV (which I'm planning to clean, but I don't even know how to remove it).

I called a few places and was getting quoted the first hose at $50-70 :mad:

But after a few other calls I managed to find a nearby Euro Parts dealer in which I can get all 3 for $40.

Any other suggestions?
 

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1991 190e 2.6
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25 Posts
to remove the vacuum hoses just pull them off from their nipples. The hose from the ICV is a breather hose. The ones in the images above look like they are ICV breather hoses. 3 mm vacuum hose is very small and can be pulled of straight away.

Hoses are a good idea to replace if they are cracked. Examine your breather and vacuum hoses and replace them if you need to. Dont just go about spending money on everything. Try swapping the old hoses with new ones and see if there is a difference in the idle when you swap/remove/install them.

AICV is a simple device and a small leak can trigger an idle vibration, its a matter of eliminating the most probable causes till you're done and have solved the problem. Moisture can come from a lot of places. (washing the engine and a leaky hose sucked some in the intake/ did you do that ? )

I think price of the hose is alright, i order them online and they're cheaper Auto Parts at AutohausAZ - OEM Auto Parts - Discount Replacement Parts, Resources and Car Care Tips ,

what i would do is swap them and see if there is a difference, if there is them keep them otherwise return them as defective and get on to finding the root of this problem.

I'm pretty sure its a leak. very sure about it.

Do you have surging idle or any other symptoms ?
 

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1991 Mercedes 190E 1.8L
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25 Posts
Discussion Starter #5
I just bought the breather and 1st and 3rd from the pics above for $40.

No, I don't have surging idle issues, I'm not sure what my idle RPMs are, I have a big clock instead of RPM gauge (my car is essentially the poverty 180E sold in Australia).

I haven't done anything regarding moisture yet, I will try and take that into account after changing the hoses I just got. I'm hoping the middle hose isn't cracked (im pretty sure it isnt) and hopefully I'll see an improvement.
 

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1991 Mercedes 190E 1.8L
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25 Posts
Discussion Starter #6 (Edited)
Okay so I finally replaced the hoses (1st and 3rd from pics), I left the middle connecting one in there, looks to be in good condition, however it is very hard, is it meant to be flexible or plastic-like?

Results: Rough idle seems to have lessened, but still occasional 'bumps', which after closer investigation I'm leaning towards the engine mounts being worn.

Here is the remains of the old hoses, I had to pry off some of the ends that were rock hard
http://i.imgur.com/Y5bgz.jpg

Also, how am I supposed to remove the ICV for cleaning? I now see that the cylinder can slide out of its plastic holder, but there is no room to slide it out completely. I also noticed it has another vacuum line under it which could also be leaking but how am I supposed to get to it - is there any online DIY's for removal/installation of M102 ICV?
 
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