Is there some thing that raises idle speed upon cold start up? I bought a 92 300D 2.5, a wouldn't start craigslist special. Fresh fuel & both fuel filters,and new glow plugs later it starts and runs smooth, WHEN warmed up . Problem is upon start up it dosn't want to idle smooth, when warming up, it will shake and stumble ,and will die.( Idle seems too low ) When warmed up , it idles fine, and is pretty quiet. Warm idles at 750 RPM, is that about right? What should I look at next? I have done the above, and will do oil & trans. fluid & filter change,and I will check brakes. At 229,xxx miles I have read to check timing chain stretch, that is on list. What else would a person do to a new car to check it out? I anxious to get it road ready. It runs down the road great, it's a rocket ship compared to our 83 240D ! Thanks for any help!

I have searched this forum with key words that apply to my problem, and didn't find anything helpfull. I did read a reference to a idle selinoid said to be located on rear of injection pump. I looked at mine , there is something in back and on the side with a vacuum line going to intake , but dosn't look electrical . If I make it stay running by keeping RPM's up until it gets warmed up , it will then run smooth . I just bought the car and it had sit for a while, previous owner said a month ,but fuel that was in it seemed bad or old. The car has ran at least a hour on new fuel and filters. I don't know where to look next. Can anyone help? Thanks, Charlie Klippel

I'm not 100% sure on that particular car, but there should be a 2-wire connector on the VERY BACK SIDE of the injection pump that controls idle speed. This is virtually the same engine as the OM602 as used in the '87 190D 2.5T's. From this connector on the back of the IP, trace the wires to find what I believe is called an ELR (don't know what it stands for). This will be a round knob that kind of looks like the adjustment knob on an air pressure regulator. Pull out on the knob, then rotate it to control idle speed. The knob is marked with a series of numbers, and there is an arrow to show which number the ELR is set on.

The ELR should be mounted on the firewall somewhere. On my cars (W201's), it is over near the battery.

Hope this helps.

SteveM

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'93 190E/D 2.5 Turbodiesel 5-speed (daily driver)
'87 190D 2.5 Turbo rustbucket - parts car
'84 Dodge Rampage diesel - Land Speed Record Holder
'13 Ram 2500 Diesel
'05 Toyota 4Runner

Thank you very much, I will go look around for it now and try to do some adjusting. Charlie

I traced the wires back from the plug on selinoid located on back of the injection pump. The plug has two wires, a brown with blue stripe, and a red with blue stripe. They go into the wiring harness that runs over to behind the battery. I can't see where they come out of the wiring harness or what they go to. Behind the battery area there is two computers, and kickdown relay, also a curcuit breaker? I don't see anything with a knob to adjust any where.

Hopefully someone else will chime in with more details about the W124 cars.

I thought the ELR's were all mounted on the firewall - somewhere. Perhaps over near the brake booster?

SteveM

__________________
'93 190E/D 2.5 Turbodiesel 5-speed (daily driver)
'87 190D 2.5 Turbo rustbucket - parts car
'84 Dodge Rampage diesel - Land Speed Record Holder
'13 Ram 2500 Diesel
'05 Toyota 4Runner