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

irieite · 10-27-2002, 10:52 PM

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]

livendie · 10-28-2002, 12:42 AM

You could try adjusting the jet for the air/fuel mixture on the throttle body. Thats probably what it is

irieite · 10-28-2002, 11:39 AM

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

aander · 10-30-2002, 02:12 PM

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.

irieite · 10-31-2002, 12:32 AM

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?? [^]

jreate · 11-01-2002, 03:03 PM

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.

livendie · 11-02-2002, 09:30 AM

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

irieite · 11-02-2002, 04:31 PM

Only problem is, I'm living in Arizona right now and the CA ECU is not easy to come by in the shops. [:(]

irieite · 11-02-2002, 04:34 PM

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..

Ignatz · 11-03-2002, 05:47 AM

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.