I have removed the ICV to clean it out due to rough idle. Unfortunately while twisting the ICV out off the 2 rubber connectors, the small tubing that goes accross the 2 rubber connectors broke-off, so now I have to remove the 2 rubber connectors. I have decided to replace them as they are hard as rock.

I cannot seem to remove the rubber connector(elbow) from the fuel distributor body with some moderate force. I do not want to put more force because i do not want to hurt the distributor. It appears that there is a metal sleeve where the rubber connector slides over. Is there a proper way to remove this connector? Will the metal sleeve stay with the distributor or will it be removed with the rubber connector?

I am soaking the ICV in carb cleaner right now..


your help would be much appreciated.

thx,
emmy

The lower half of the fuel distributor (intake plenum) is actually rubber, probably petrified rubber now. It is on my 420SEL and it becomes brittle just like all the rest of the rubber parts. There is a nipple between it and the elbow you are referring to.

Save yourself some trouble and get the elbow off with any means available, cut it, nibble it away, whatever, without damaging the nipple or the lower plenum or else you will have to replace it as well. The more ya keep digging around in the intake area you will find plenty of other gremlins, rock hard cracked and split hoses, clogged EGR tubes, stripped-out allen headed capscrews, broken coolant sensors,,,,,

__________________
Chas

Had a 380SL, 450SL, 380SEL, 420SEL, 500SEL

Got a Euro 500SEC right now.

thank you. yes, i will cut it open so it comes-off easier.

I managed to cut the connector (using a dremel tool ) off the intake plenum. I found that the nipple holding the connector is ribbed, made of plastic, therefore making it impossible to remove.

Here is my next problem:
If you recall there are 2 plastic connectors where the ICV plugs into. These 2 connectors have a small opening that takes a small tubing. I am trying to identify this small tubing as it is also broken, and needs to be replaced. I tried the regular vacuum tubing, but did not work-the diameter of the regular vacuum tubing is too small. Can someone identify this tubing for me? My local dealer also showed me an exploded view of the parts diagram, but could not identify the said tubing.

thx,

I recently replaced my ICV and the standoff that holds the ICV clamp, the clamp bush, and one of the ICV hoses were broken.

I have just ordered all the replacement parts from the dealer, the small linking hose was okay so I didn't need to order it but it was visible on the parts sheet.

Matt.

I finally completed re-installing the ICV. However my problems persist. There are 2 problems that I observe.

1. Idle is oscillating when not in gear, but seems to diminish when idling in gear.The oscillation appears to repeat every 5 seconds and a cycle is about 1 sec. on the rise and another sec. to drop. The idle is at 750 and would rise to about 850, and would go back down to 750. When in gear, the idle is about 650-700. Since i am focused on the ICV, I also observed that the voltage accross the ICV terminals when idling and at park, also oscillates with the RPM, and varies from about 4.35V to 4.70V. The oscillation is not much but I suspect this is not normal, and would like to understand the probable causes and correct the problem.

2. My other problem is rough idle, both when in gear, and otherwise. I observe that the rough idle is more so when not in gear. The engine does not die, although very noticeable, more so like a cylinder is missing. It runs smooth otherwise and tranny shifts smooth, so far as I can tell.

Steps that I have done are as follows:
1. Cleaned ICV and replaced both rubber connectors.
2. ICV measures about 5 OHMS. Closes fully when 12 volts in applied.
3. Voltage accross ICV terminals at idle and in park is 4.35 to 4.7V.
4. Coolant temp sensor(B11/2 - 4 terminals) measures about 370 OHMS for each pair of terminals measured diagonally. This was after engine was idling for a while. Resistance measurement when cold was very high.
5. Throttle valve switch(S29/2) - The Normally Closed terminal measured 0 OHMS, but would open with a slight movement of the throttle. The Normally Open terminal measured OPEN, and would close only at full throttle. ( ie it stays OPEN intil full throttle is reached.)
6. Pulled the plug wires one at a time at the distributor cap, in an effort to isolate the cause of rough idle, but suprisingly, did not observe any change in idle ( worse nor better...). I do not undertand this behavour at all. I was expecting to observe the idle to get worse, but to my ears, it was the same. Can someone expalin this to me?

7. Next Steps - The air distributor hoses and crossover breather hoses are hard as rock. These may still be the original parts. I am going to replace the hoses plus the injectors, and holders, etc..

I would appreciate your inputs. I am trying to undertand scenario#6 above, the rough idle and the idle oscillation.

thx,
emmy