Hi, first time post. This site is invaluable!! Within the past year i have purchased my first 2 MB. I live in western pa, i found a 1971 220d in naples fla which is my 16 yr old daughters first car and a 1987 300d in las vegas nv. so i am trying to get up to speed. the 300d had all the normal issues which i was able to fix most myself thanks to you guys and girls.

I have a stalling issue with the 300d . there are great posts that i have found one being the adj on the ip. with the elr set at factory 4/5 and the car idling i take the plug off the actuator and the car completely dies. in the posts it says there should be a small drop in rpms. does this mean it's still not adj correctly or is the acuator bad? i can move the elr and the rpms do change. i'm terrible with checking ohms and amps so i hope i can keep it from going to the garage for service. stumped. also the guy i bought it off of had 3 MB service manuals which i now have, w124 chassis and body 1 and 2 and the diesel engine 602 and 603.

It has nothing to do with the actuator, once its unplugged it doesn't do anything.

Without the ELR, the rpm should be 570, check your tach. You can manually adjust the elr-less idle with the screw and locknut pointing backwards just above the actuator.

Course something unrelated probably caused the rpm to go down to begin with, so it might be good to figure out what that is and adjust back down again. A bad injector or bad compression on one cylinder, etc.

thanks! so are you saying the car should stay running when i unclip the plug from the acuator at the ip so it can be adjusted with out the elr involved? this is when the car completely stalls out. i was able to turn the screw and tweak it, the car does not stall out but it won't shut off now!!! ahh thoughts?

should clarify, the car only stalled when moving at slow speeds ex. backing out of the driveway i quickly take my foot of the gas or in stop and go traffic or if i am in park and rev the engine it stalls other wise it runs like a champ. i put 150 miles a day for my commute. never stalls. always starts right back up. more annoying than anything. there is also an exhaust leak at the flex tube on the right side of the engine. has a crack almost in the middle of it not sure if that can contribute

The shutoff valve is nearby, maybe you knocked the vacuum hose off of it, causing it to not shut down.

Actually without ELR the idle speed is 500 RPM. If the engine dies it means the pump is either super worn out or the basic idle speed is set wrong.

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

triple a good news is it looks like i didn't disturb and vacuum hose. compu85 the car shut off with no problems before i started playing mechanic.it just stalled at certain times. so i'm thinking the ip is ok and it just the basic idle setting but how do i adj if the car shuts down when i pull the plug on the acuator? do i increase the setting on the back of the pump while the car is off? trial and error? do i keep adjusting until the car stays running while the acuator is off and then start fine tuning? i don't want to blow the thing up!!!

I believe you turn the screw outward to increase the rpm, I ended up trial and erroring as well. Maybe have someone inside the car push the pedal a little to keep it from stalling. You want to avoid turning the screw out too far, where too far is >1000rpm.

good idea!! once the car stalls without the plug on the actuator, i can start it and keep it running with slight pressure on the pedal. i will try that tonight when i get home!!

Results of the test. i was able to adjust the ip to where the car stays running without the acutator plug on, i was also able to adjust to around the 500 mark. i plug the actuator back up car runs fine. THEN, i try to turn it off and it will not turn off!! it's like it wants to stall but it's a very weak idle. could there be an adjustment prior to the pump that needs to be sequenced with the others?

I still think you have a vacuum leak. Check it with a gauge.

If you can manually shut it off with at the fuel pump, but it won't shut down when you use the key, then there is some type of a vac leak. I would start at the shut off valve and work your way back to the brake line T. (Be careful those connectors and hoses get brittle with age). I've had to change the brake vac line because the T-connector broke on that line. The brake line vac booster line is the one that drives the SOV circuit.

__________________
92 300D 2.5L OM602 OBK #59

ok , i will start down that road . i'm afraid to touch any of those lines some seem really soft. probably just get some new line and like you guys say just start working back replacing what i can!! more to come thanks all!!!