CSV solenoid

[saygold]

I cleaned the CSV valve using procedures supplied in the Tech manual, and I seem to have a leak in the CSV since then.

I have an intermittent (?) leak when the 5-mm bolt is removed from the CSV in my '66 230SL.  I cleaned then installed the CSV assembly, then checked for leakage through the 5-mm hole - after 10 seconds, there was no leak.  I installed the bolt and started the car.  It almost ran, but did not fire up.  After trying to start several more times unsuccessfully, I removed the 5 mm bolt, placed a piece of paper over the opening and tried the car again.  This time, there was a slight amount of fuel coming out of the hole.

The installed CSV is part no. 0330 106 001 with the shaft measuring approx. 15.2 mm (17.2 mm when extended).  I do not remember changing the CSV since I got it in 1986. 

I initially thought that the shaft might be too long, allowing fuel to get past the valve.  However, I measured the distance between the face of the CSV housing and the needle valve using a toothpick and razor (good method mentioned by others previously).  The marking indicated that the distance was approximately 16 mm when the needle valve was closed.

What should the clearance be between the end of the CSV shaft and the end of the needle valve when the valve is closed? 

Thanks in advance for your help.

Best regards,

Ken
'66 230SL euro, 4-speed

[Benz Dr.]

If you remove the grub screw and try to start your car fuel will emerge; that's normal. What you don't want is any fuel dripping out with just the fuel pump running. If it doesn't leak at the grub screw, and the engine won't start, you may have plugged nozzles inside the CSV. No easy fix for that except to get one that works.

[saygold]

Thanks for the help, Dr.  I thought I had tested the leak with the grub screw off and just starting the fuel pump last night.  I rechecked this after receiving your response, and there was no leak found with the grub screw off and just running the fuel pump for about 15 seconds. 

I have had the car running on and off over the last several months - I have been adjusting some small issues with it. 


Best regards,

Ken

[Tyler S]

Remove the grub screw while the engine is running and put your finger over the hole. You should feel vacuum. If you do the nozzle inside is at least partially clear.

[Benz Dr.]

You would only feel vacuum if the engine was cold, I think.

[Tyler S]

Dan, The CSV has 2 openings/ports that are exposed to manifold vacuum. The fuel nozzel and the surrounding opening that is ultimately connected to the WRD pipe. Air being drawn from the WRD when cold helps disperse the fuel shot from the Cold start valve. Removing the grub screw accesses the fuel section and should always have vacuum if the nozzel isn't plugged.  Regardless of temp.

[Benz Dr.]

Dan, The CSV has 2 openings/ports that are exposed to manifold vacuum. The fuel nozzel and the surrounding opening that is ultimately connected to the WRD pipe. Air being drawn from the WRD when cold helps disperse the fuel shot from the Cold start valve. Removing the grub screw accesses the fuel section and should always have vacuum if the nozzel isn't plugged.  Regardless of temp.

Interesting. I would have thought that those holes were so small that you wouldn't feel anything. I'll have to try that...........