Mercedes-Benz Forum banner

1 - 3 of 3 Posts

·
Registered
1995 S420, 1987 190e 2.3 16V , 2008 CBR600RR
Joined
·
199 Posts
Discussion Starter #1
First of all, the car spec is 1987 190e 16v 5 speed manual transmission.

The car currently runs fine except for that little issue stated on the title. I have checked for low/tight cable, vacuum leak and plate. Everything seems good and working properly. The car idle well and start without hesitation. Below is some scenarios of the issue. Everything is while car is up to temperature.

1) in neutral/sitting still. i hit the gas pedal, the rpm would rev up. when i let go of the pedal, the rpm would stay around 3k and wont drop or it would drop very slowly. In most case, the rpm would like slowly climb down to under 1k.

2) while driving/speeding up. i depress the clutch pedal to change into the next up gear, the rpm would stay high(roughly 3-4k, where i normally change gear) until i release the clutch pedal and engage the gas pedal.

3) while driving/slowing down. i depress the clutch pedal to shift down a gear/or to neutral (depending if im coming to a stop or just slowing down), the rpm would stay high (3-4k/normal shifting point).

That is it. I never have this trouble before. i have replaced my ovp relay with a working one and it did help with my erratic idle. Like i stated on top, the car runs fine and it sits at idle right under 1k rpm. at cold start, the rpm would hit 1.5k rpm, but it does drop down to normal idle speed after 15-20 seconds.

Any help would be appreciated. Thanks.

regards,
-staff
 

·
Registered
1992 Mercedes 190E 2.6
Joined
·
25 Posts
Sounds like a sticking/binding gas pedal or linkage(s) to the gas pedal, but since you mentioned that you checked those components already and looks good maybe its something electrical that has to do with throttle...

Now I do not know the 16V or how its system works, but try checking the throttle position sensor. Test it with an oscilliscope if you have one, if not, you can substitute for a DMM.

To test:
One probe goes to the signal wire, the other to a ground. Voltage should proportionately increase as the throttle is opened. Key position is Key-on-engine-off.
 

·
Registered
1995 S420, 1987 190e 2.3 16V , 2008 CBR600RR
Joined
·
199 Posts
Discussion Starter #3
Thanks for the reply. I do have a multimeter. Its funny how it don't always do that. Sometime it drive and idle normal. I will have to check the throttle position sensor when i get a chance.
 
1 - 3 of 3 Posts
Top