560SL stall at idle

[vista598]

My 560sl stalls at idle after I have driven it for awhile. Run fine on the road and start right back up when it stalls. Idle at 500 when in drive and 700 when in neutral. Any ideas? Thanks

[mbdoc]

Sounds like the idle valve is possibly sticking.
Try cleaning w/solvent 1st.

Also there is a plastic line that allows air by-pass between the 2 idle valve hoses,
possibly that is plugged.

[vista598]

Thanks for the help. I'll give it a try and hope it solves the problem.
Thanks again

[vista598]

Cleaned the idle control valve and checked it to make sure it works also checked the plastic line as suggested. Found a cracked 3 way vacuum fitting and replaced it. Also changed plugs to platinum Bosch W9PC. Now it idles below 500 about 300 and stalls. Also runs rough like it is missing. Any ideas? I'm a newbie to Mercedes always had British roadsters, much easier. Any help is greatly appreciated.

[Cal Learner]

Uh-oh, platinum plugs!

[mbdoc]

Rough idle is almost always related to a secondary ignition system issue.

In what condition is the rest of the ignition system?

[mbdoc]

If you un-plugged the idle valve & the idle did not increase??

Then either the valve is stuck closed OR the fuel mixture is WAY off.

Yes, put copper core plugs back into the engine.

[vista598]

I have no voltage at the idle control valve. What should I check. Would it be a bad fuse on the OVP relay? I'll get copper plugs and replace the platinum. The wires and distributor cap look in good condition.

[ds190]

Also, unplug and clean the terminals/jacks on all electrical connections to your ignition module. Plug back in.

The OVP relay will not block current to the ICV only.

[gatopardo]

I am having axactly the same symptons in my 1988 560sl. What finally fixed the problem? It is not clear to me from reading the posts.
Thanks for any info you care to share