Howdy, Peter! If the adjustment knob (#1-7) has no effect, you found the problem. Either the ELR is bad (not likely) or you have a bad connection somewhere. I had a broken wire at the ELR on my car, a little soldering fixed things up nicely. The FSM explains how to test the ELR, basically you feed it +12V momentarily and the idle should increase markedly when voltage is applied (a couple of seconds at most!). If not, the ELR is bad, but I've not head of one failing yet. Once you correct the wiring issue, set it at #4 or #5 and the idle speed should pop back up to the preferred 630-650rpm. Oh yeah - when unplugging the ELR, the idle should drop to the 'mechanical' minimum, about 500-550rpm. The system expects electronic control to boost the idle to normal (630rpm). Since the car runs great off idle your injectors are probably NOT the issue.
If your motor mounts are not recent (over 5 years or 50kmi old), measure them and replace as needed - details are here: http://www.w124performance.com/docs/mb/W124/124_engine_mounts.pdf (122kb PDF file) Best regards, Dave M. Boise, ID > ------------------------------ > Date: Sun, 31 Jul 2005 17:17:32 -0400 > From: Peter Arnold <[EMAIL PROTECTED]> > Subject: [MBZ] 603.XXX Rough Idle > > My car seems to be idling too slow (about 600rpm) and is rough. > > It runs fine off idle. > Fuel Mileage is good. > I've changed the "Over Voltage Relay" as suggested. > The idle controller in engine compartment seems to have no > effect. > > Would the engine idle poorly and run smooth with a bad injector? How > do you trouble shoot injectors? > > > Weekend regards, > > -- > > Peter T. Arnold
