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Newbie: Irregular idle in park or neutral; hesitation; rich; '91 190e 2.3

4106 Views 24 Replies 10 Participants Last post by  irieite
I'm a proud owner of a lovely '91 2.3 190e, which I purchased about a month ago. It is a very fine automobile, but it has a strange problem with the idle and acceleration.

When warm (just a couple minutes after cold start) the idle starts to hunt up and down between 1000 and 500 rpms, sometimes stalling when it drops below 500. It idles steady around 800 RPM's in gear. It also tends to hesitate during acceleration at this time and I seem to be running rich.

I have replaced the O2 sensor, plug wires, cap and rotor, plugs and fuel filter, but it runs the same. I've heard that the coil on these cars can produce a weak spark, but I'm getting tired of throwing parts at this car.

Does anyone have any experience with this sort of issue? I've already searched through the forum and have not found any posts with the EXACT same problem.
[V]
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· Registered
2000 c280 Sport
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43 Posts
Discussion Starter · #3 ·
Thanks for the reply. That's one of the first things I tried and unfortunately, it did ...

Thanks for the reply. That's one of the first things I tried and unfortunately, it did not help.
 

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1995E320, 2000SL500, 2010ML550
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87 Posts
erratic idle

Idle speed control (ISC):
You may want to check the Service Manual for
details on how the system works.

My guess would be that it is the idle-bypass
solenoid that needs cleaning. It looks like the
idle speed control works, it just overcompensates
in both directions, that is why you get the wings.
Why it does not do it in drive? The "drive"
condition is another compensation element in the
ISC and is sufficient to bring keep the idle on target... I never cleaned the idle-bypass but understand it's a simple job. Good luck, Tony.
 

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2000 c280 Sport
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43 Posts
Discussion Starter · #5 ·
RE: erratic idle

Thanks for the reply Tony. The Idle Air Control valve is clean and I even had it swapped out with another known good one to test, but got the same result. In fact, there is no difference if the electrical connector is plugged in or not, so I'm starting to think it might be an ECU problem.. [:(] Anyone have a cheap Cal emission 2.3 ECU for sale?? [^]
 

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190E 2.6
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9 Posts
ecu

i think the ECU is the right way to aim, when working at a benz shop many of these types of problems were related to the ecu. your local benz whole in the wall mechanic should have one you can test.
 

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190 e
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15 Posts
I'm sure you checked this but check the timing chain and tensioner. It could be stretch...

I'm sure you checked this but check the timing chain and tensioner. It could be stretched a bit and throwing off your timing.
 

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2000 c280 Sport
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43 Posts
Discussion Starter · #9 ·
RE: timing chain and tensioner

Actually, I have not checked that. However, the hesitation (sputtering) during accelleration is somewhat intermittent. Every now and then, the car pulls away just fine and it always cruises well at any speed. The up and down idle may or may not be related. I dunno..
 

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1993 190e-2.3
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765 Posts
Whenever my 93 190 2.3 sputters and hesitates I use Chevron techron concentrate and the pr...

Whenever my 93 190 2.3 sputters and hesitates I use Chevron techron concentrate and the problem goes away for 6 momths to a year.Im pretty sure my problem is a clogged injector.Two weeks ago the wife called me at work and told me the car ran so bad she couldnt leave the driveway. Like you I installed a new O2 sensor and checked everything. I then added Techron to my gas tank which only had a quarter tank.I drove it around and could bearly make it up hills. I parked the car and tried to figure out how I was going to get it to the dealer without causing an accident. About 2 hours later, I decided to try the car again and it has been running flawlesly ever since. Now because there is no Chevron dealers around, I add 35ml of Chevron techron concentrate to every tank of gas. I hope this solves my problem. Maybe it will help yours.
 

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90 300 SE ,85 300 GD
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1,570 Posts
Fuel Filters Clogged?

I had a 2.6 that just "died" at 75 mph on the interstate for lack of fuel. Filters were clogged to the max! It never was on my list of possibilities. Started out with similar indicatios.
 

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1985 190-E
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1 Posts
uneven iddle

I recently acquired a 1985 2.3 190-E and I noticed that the engine idling seems to drop occassionally (it kinda sputters) as if the engine will die down but fortunately does not. An MB specialist in the area said it could be dirty fuel injectors so I tried a fuel injector cleaner and almost instantly after filling up, the idling got rougher. Is this normal after putting in an injector cleaner? Are there any other areas that I could look into?
 

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2000 c280 Sport
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43 Posts
Discussion Starter · #13 ·
RE: Techron

I did try a large bottle of Techron about two weeks ago and while it did not make a dramatic difference, I must say that the car is running better than when I first bought it, but it still hesitates more often than not and has that up and down idle till it stalls issue when warm in park or nutral.
 

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2000 c280 Sport
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43 Posts
Discussion Starter · #14 ·
RE: Fuel Filters Clogged?

Yeah, I changed the fuel filter when I did the tune up. Unfortunately, no difference in the performance, but I do feel good about replacing it, since it was the original mercedes fuel filter with over 160,000 miles on it. [:0]
 

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4 Posts
I have a problem with the H.E.A.valve that acts similar to your problem, may want to che...

I have a problem with the H.E.A.valve that acts similar to your problem, may want to check it out. This valve is attach to the back side of the fuel distributor. goodluck..
 

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2000 c280 Sport
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43 Posts
Discussion Starter · #17 ·
Addendum

OK, it's seeming to be more like a misfire, rather than a rich condition.. I was concerned about the fuel consumption and thought that might be the case, but the plugs looked normal, not black in any way.

Indeed the car does seem to have a miss at idle and it (usually) sputters or hesitates during accelleration.

Does anyone know if this could all point to the weak spark/coil issue that some others have had? I'd hate to throw another $100 at this car without knowing for sure. Is there an easy way to test the coil for that problem?
 

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4 Posts
you may try disconnect the plug that goes into the E.H.A. valve and see if the problem d...

you may try disconnect the plug that goes into the E.H.A. valve and see if the problem disappears. The E.H.A. valve is located on the side of the fuel distributor facing firewall. I've driven the car with this plug off, that pinpointed my problem.
 

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2000 c280 Sport
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43 Posts
Discussion Starter · #20 ·
Misfire

Another thing I've noticed is that from a cold start, it runs just fine for a couple minutes, after that, as if someone threw a switch, it goes into another mode and I get (what seems to be) a misfire. That is, it stutters when I try to rev it up in park, while in this "warm mode".

Additionally, it idles steady in park at around 1800 RPM, if I don't drive it and just let it warm up from cold. This differs from the up/down idle (between 0 and 1000 RPM) in park or neutral that I get after the car has been driven and fully warmed up.

I dunno, it's strange.. This is about as accurate of a description of the problem that I can give. Hopefully someone who has had a similar problem can help as I've got to get this thing smogged soon. [V]
 
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