At operating temp, The car runs fine while driving. When stopped at a light or in park, The idle plunges to below 500 rpm and then surges to just under 1000 rpm. It will eventually stall out. This has been a fixer upper project for me and is my first Benz. Any suggestions? Thanks

1988 300TE

Hi,

Congrates on getting your fist benz!

I had mine hunting when I first got it. Now its gone after the mec fixed it.

Few places to look from what I gathered;

1) OVP behind battery with 2 fuses on top. Check for rattle or bad fuse.
2) Remove air cleaner and look backwards towards windscreen and find the ICV with 2 hoses attached to it. 1 visible and 1 below. Tap it when engine is running. any changes? If yes, remove it and try to service it by carb cleaner.

3) Check for sticky throttle mass air flow sensor; the plate opened a gap below the air cleaner. Spray carb cleaner and make sure its clean and moves freely.

4) Bad o2 sensor. Below floor well on driver side, pull up and expose the plastic conduit and find the green wire which has a connection to the o2 sensor. disconnect when car is running. any difference?


5) There is a air/fuel mixture screw which you can attempt to carefully tweak the mixture if all else are operational. You have to get a the right procedure doing a serch for it.

I hope I got you started on the right foot.

Thanks and enjoy!

__________________
1992 200E
M102
102.963
AKA Silver Old Grumpy
Always hope I can freeze someone with the aircon- Just change the compressor again, Subseal leaked with a psssssssss sound.
Its the NON-3 Pointed star items on my car that cost more to repair.$%^&%%*^&

Well, after poking at the car for a while, I decided to adjust the idle up to see if things would smooth out. HUGE MISTAKE! The worst thing I could have done was mess with what is apparently a factory setting not to be played with. All I can say is that I love the guy who invented the 5 degree indexing ratchet wrench. Not an easy little nut to get to and almost no room to do anything with.
After getting the idle back to where it was, I discovered that the molded hoses for the ICV has cracks on both of them. With out a store with an inventory of near 20 year old benz parts on hand, I opted for digging through my electrical supplies and pulling out the cable splicing tape to wrap the hose with.
The car ran better at idle not ramping up and down as much and held at just over 500 rpm while at stops in drive. With out knowing what it is supposed to idle at in that situation, I'm just happy it's not stalling out now.

Hi,

I have checked out the ICV before. In BMW, their ICVs were tightened with hose clamps which makes it very secure.

However in our cars, its just a ribbed rubber hose that connects. I have been thinking whether should I put some hose clamps to tightened it...

However the rubber hose going to the air mass meter plate is hard to get to ....

I am still trying..

Thanks and enjoy it.

__________________
1992 200E
M102
102.963
AKA Silver Old Grumpy
Always hope I can freeze someone with the aircon- Just change the compressor again, Subseal leaked with a psssssssss sound.
Its the NON-3 Pointed star items on my car that cost more to repair.$%^&%%*^&

On my '93 190E 2.3, I remove the top ICV hose first, the connector, then I can reach under the front of the air mass meter and disconnect the hose, then remove the ICV with the bottom hose still connected. Small hands help.

__________________

1993 190E 2.3
2001 SLK230
1971 LS5 (454) Corvette Convertible