car seems like it wants to die in traffic... - PeachParts Mercedes-Benz Forum

sjsfiji · #1 03-24-2004, 10:24 PM

Hi All,

After driving for 'bout 10 miles then hitting traffic the car seem like it wants to die. The RPM drops then comes back up. It only happens once after slowing to a stop. It happened today and yesterday. While in traffic, stop and go, all seems fine... suggestions please or can this be normal behavior?

thanks,

ymsin · #2 03-25-2004, 12:40 AM

We recently acquired a 190E that had some similar problems.

It runs fine till we come into traffic and then the rpm flirts with 5 before dying. Sometimes it acts fine.

On advice, the idle sensor was cleaned (some call it the idle control valve), but to no avail. The engine also had a re-tune.

Eventually, the problem was expertly zeroed in on what was called a decelarating sensor. It is a small plastic (sensor) component located directly behind the vdo (instrument cluster). Detach the small piece of plastic from the vdo and put in a new one (quite cheap) and the problem never re-occured.

sbourg · #3 03-25-2004, 02:12 AM

Just a note. The idle control valve is NOT a sensor. A sensor is an input device, intended to relay some bit of information to the ECU, or perhaps directly control some other device. The ICV is an output device, controlling the idle air flow around the throttle valve under direction of the ECU. The sensors which provide necessary input to the ECU to do that job include temperature sensors, engine speed sensor, airflow meter potentiometer, throttle position switch, and others - including perhaps an accelerometer?

Steve

SHYNE · #4 03-25-2004, 09:19 AM

I was wondering about some of the components of the charging system in your car.

How old is your alternator?

Would the voltage regulator be the same age as the alternator?

How old is the battery?

What does your economy gage read when the car is about to die?

Have you measured what your charging system is putting out?

I had a stall once in traffic. It was at a stoplight. I was able to restart the car but, it would want to die idling in gear. The car would have a stumbling idle and the economy gage would be at half-way or worse into the red. For me it turned out to be the alternator. It was old and could not maintain a charge. I first tried the cheap to replace voltage regulator which is near the alternator. It improved but, did not keep the charge up high enough in gear. I replaced the alternator with the newly purchased voltage regulator and I had success.

Good luck with your diagnosis.

Mike McKinney

cc260E · #5 03-25-2004, 12:26 PM

Quote:

Originally posted by ymsin
[
Eventually, the problem was expertly zeroed in on what was called a decelarating sensor. It is a small plastic (sensor) component located directly behind the vdo (instrument cluster). Detach the small piece of plastic from the vdo and put in a new one (quite cheap) and the problem never re-occured. [/B]

Hi ymsin
I have similar problems and cant find the way.
what is this decelerating sensor behind the vdo ( btw: what is vdo?)
Have you bay picture of the replaced sensor?

Thanks

pentoman · #6 03-25-2004, 12:40 PM

VDO is the manufacturer of the instrument cluster (speedo etc.) - if you look you will probably see VDO on there.

I'm am not sure if 'behind the VDO' means in the engine compartment directly in line with the VDO, or means removing the VDO.

I've never heard of the deceleration sensor - what's it for?

sjsfiji · #7 04-01-2004, 12:41 AM

Hi All,

I found the sensor and it's called a "speedomenter sensor".

The car almost died at a stop sign after 30mi of fwy driving. Before I dish out the greens, anything I should check?

ICV? How to check? Clean?

Alternator? How to check? If need to replace... 70 or 80 amps?

Batt (1+ yr old made for 300E). How to check...

Mass Flow sensor... How to check? Where is it...

OVP. How to check? Where is it...

Please help...

thanks,

sbourg · #8 04-01-2004, 10:37 AM

The search engine on this site works better than average. The specific answers to all your questions can be found with accompanying pics, diagrams, and detailed instructions and anecdotal information. Happy hunting!

Steve