190e 16v problem ???
 

hello,
i have a 86 190e -16v ,5 speed, when i come to a stop or when I am driving and push in the clutch the idle is staying at
3000 for few seconds then drops very slowly , or sometimes it just drops to 2k and stays there and at the next light it goes
back to 1k? , so i have been controling idle with the clucth , ouch,
I have cleaned the air flow sensor,(very clean), microswitch is clicking on , and is about a year old, ) 02 sensor is new with a catless system, If anyone has had this weird idle problem or
if you know what it is enlighten me please
thanks
1986 190e-16v
1974 IROC 911 rep
1984 benson gyrocoper

Have you also checked the idle control valve? I have read stories about clogged valves that won't do their job right. Just my 0,02

Dave, I've found that 90% of the time that problem is caused by the air-flow position sensor.
In fact I've had that problem on my street car & know that Benzmac also had the same problem.

Not a cheap OR easy repair

Is the air flow position sensor that whole unit under the fuel
distributor, or can i just bolt a new sensor to the housing?
You woundn't know the part # , i looked for airflow poisiton sensor with fastlane and didn't get anything?
thanks for your help
dave

Available only thru the aftermarket. BOSCH part number 3-437-224-035, very hard to calibrate.

MB part number 000-074-23-14 for the complete housing.

the temperture outside is 40 and warmer now , and the high idle
problem is GONE!!! It has not done it once???
Would the air flow sensor change in the colder minus 0 temps ?
any advice?
thanks

Dave,

Sounds like you had condensation and thus an ice build-up on the air-flow sensor or your linkage. Glad to hear it is back to normal.

Check the lube on your linkage and look and see if the sensor or the air boot going to it has moisture on or about it.

Haasman

today it was back to 20 deg out side, and the idle is back up to
2500, 3000? Any idea's I did clean up the air box, I did have some ice in it mixed with oil . I was almost thinging the
K&N air filter is letting water into the airmeter and and gumming it upon cold days, I fully cleaned it out, running with cleaner
but, still high revs
thanks

Perhaps the picture will explain things better.
Is there a procedure to calibrate it?
(we already know is hard, just out of curiosity)

Dave,

Disconnect the throttle position sensor on the side of the throttle body, not the decel switch, and report back.

Read here:
http://www.peachparts.com/shopforum/tech-help/52787-masking-faulty-air-flow-meter.html


Tinker

Hi Tinker:
I believe that your car is running VERY Lean at a duty cycle of 78%, not richer.
The MB manual clearly states:
"leaner = high ON/Off Ratio"
Since you find no difference in performance, may be the closed loop is compensating with enough fuel such that the performance is not affected, since the compensation goes from 10% to 80% (according to the graph below). I do not know how much this stresses the system.
Experts like stevebfl can give a better explanation.

Pesuazo,

I know, it seems completely opposite to what I have also read throughout this forum. BUT turning the mixture adjustment to the right (counter clockwise) results in lower % duty cycle reading on my car. Any thoughts? The only thing that crosses my mind is the cars attempts to compensate for the lean mixture but adding fuel through the EHA.

I had the car adjusted to the factory specified 50% duty cycle and near 0 ma at the EHA prior to its biannual smog check. It failed and they LEANED it out. I checked the duty cycle when I got it home and it was near 20%. Go figure. Completely inverse to what one would expect.

Look at the graph you just posted. 78% is on the left side of the graph, the rich side. Am I reading that right???

Tinker

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Davect,

How is the performance of your 16vlv. Does it feel as if it is struggling to pull in the higher RPM range? Say like 4,000 on up?

My car has the exact same issue with it. I replaced the airflow meter w/ a known good one, but I still have that same problem. My car will not decrease idle from 3k, then all of the sudden it will drop back down to 900-1000 rpm.

My car feels like it is experiencing a lack of power. It in no way feels like a 16vlv should. When in 3d - 5th the car no longer wants to pull up through 6700rpm. She is acting like a dog.....!:confused:

pat

my 16v is sluggish at low RPM it sometimes bucks like a old 123 around 1500- 2000 rpm ,but high revs it really pulls about 4500-5000. Gas miles lately have been about 10 -15 miles a gallon?
thanks
dave

IDENTICAL ISSUE AS MY CAR !!

What you are explaining is almost identical to the problem which I have been chasing for a while. Please keep us posted !

:)