another 560sl - year is 1987 - idle = 1500 r/pm

[blueshield11]

thanks guys for the input. will go to work on the car later and get back to you.

[ragtopper]

Have cleaned IdleControl valve three times (as per numerous posts). Runs ok for a couple of days - but then the high idle returns.

HOWEVER, if I disconnect and then reconnect the lead wire (two pins) to ICV, idle immediatley returns to normal and stays great for a few more days.

My guess is that perhaps I have bad connection...or could ICU be sending an intermittent signal/power? Surely not....

Shall I clean ICV again?

Help?

Ragtopper
1982 380SL

[Strife]

IF (if) you have ABS and the light is on, and it happened concurrent to this problem, it's the OVP relay. You engine management is not getting power and the car defaults to "limp home" = high idle.

[ragtopper]

Thanks Strife, but I dont recall seeing an ABS light (and dont think mine has ABS). Are you saying the OVP relay controls (and regulates) power to the ICV?
Sometimes when re-connecting the lead wire/pins, I can hear an audible "click."

Ragtopper
1982 380SL

[donbryce]

I fought my high idle for a year or so, followed all the threads on ICV testing and cleaning, module control box resoldering, temperature sensors, etc. At the end of the day, I followed EBay for months and got lucky with a replacement control module (about $50.00) and a NEW ICV that the PO had purchased from MB dealer, installed to test if it was the solution (it wasn't for him), then couldn't return it. I had it in my hands for $60.00. The module cured some of the problem, the ICV fixed it. Sometimes we have to cough up the going price for these critical parts, which do fail after over 20 years of service. Both of these components are plentiful on-line.

[milbroman]

Check the voltage at the idle control valve by backprobing the harness with a multi meter set to dc volts should read around 4 volts. if nothing check continuity of the black and yellow wire from the idle valve to the idle control unit using multi meter set to ohms should read open. check the black wire in the same way. if the resistance is infinite find and repair the break in the wire. if ok check for voltage on the red and blue wire in the harness at the idle control unit behind the glove box remove the lower cover and the inner cover of the glove box to gain access. if no voltage strip the covering on the red and blue and use a jumper to energize the wire from the fuse block. if this solves the problem trace the red and blue wire back to the overvoltage protection relay and check the function of the relay.