Mercedes-Benz Forum banner

1 - 9 of 9 Posts

·
Registered
1985 California 300 D Turbo Diesel and '85 Federal 300D Turbo Diesel. '84 Cali 300D - SOLD
Joined
·
360 Posts
Discussion Starter #1
My daily driver 300D starts just fine when it's cold (30's), but won't idle. I have to press the go pedal slightly to keep it running and while doing so, it runs smoothly. I have to do this for 2-3 minutes until it warms up a little and then all is well. Any ideas? Search didn't turn up anything.
 

·
Premium Member
Joined
·
496 Posts
What's your RPM at when cold or warm? I know this new wagon I just got idles at ~600RPM and I think just being up to ~750rpm would solve it for me. This is on my to-do's. :)

Dave aka Ghan
 

·
Registered
1985 California 300 D Turbo Diesel and '85 Federal 300D Turbo Diesel. '84 Cali 300D - SOLD
Joined
·
360 Posts
Discussion Starter #3
Idles around 700-750 when warm.
 

·
Registered
´82 230 E
Joined
·
7 Posts
I have the same problem when it's freezing, except I only need to press the pedal ligthly for at few seconds. I believe my idle speed is ok. Hope to be able to leech off your post :)
 

·
Registered
1984 300D
Joined
·
5,070 Posts
If it idles better when you have a full Tank of Fuel it could be a Fuel Supply issue.
The springs on the Fuel Injection Pump Pressure Relief Valve/Overflow Valve being weak can cause idle issues as can Fuel Supply/Lift Pump issues.

Thick Oil can cause idle issues until it warms up also. Members of the various forums claim that using synthetic Oil in the Winter makes a big difference in cold starting and running cold.

Worn Injectors and poor compression can cause the idle issue. When the Engine warms up the Fuel burns better and the problem seems to go away.

Look up some threads on Injectors and find where I posted a diagram of what the stock Injectors Nozzles look like.
The stock Injectonr Nozzles have 2 tiny passages drilled in the Nozzle Pintel. I found those passages completely plugged with carbon on my own Injectors and most of the Injectors I have pulled from the Junk Yard.
The pasages are there for the idle amount of Fuel so when plugged have an effect on the idle.
 

·
Registered
1982 Mercedes Benz 300D Dark Blue
Joined
·
41 Posts
i have an 82 300d with same symptoms, have to depress accelerator pedal to start car and when the engine is cold soaked say 50 deg or less first start of day car has hard time idling, even stalling a couple of times, have to keep slight pedal pressure to keep idle. once car is driven a mile or two and starts to warm up it is fine. i drive the car alot, i have put 29,000 miles on it since april 2009. total mileage is 169,000. since i bought the car then i have adjusted valves twice, replaced all 5 glow plugs and updated to a monarch glow plug relay, done 2 diesel purges, replaced both fuel filters twice and add diesel fuel lubricant additive at every fill up. i will be throwing a lift pump at it this week and i will definately update this page with my result, should have it installed by the new year at the latest. has anybody changed a lift pump before that could give some useful information on what to expect , that would greatly appreciated. if this is not the problem i just hope it is not a tired engine. i guess i will do a compression test eventually to find out. FYI i found the lift pump on europartsdirect.com for $139 with free shipping, comes with gasket and copper washers.
 

·
Registered
1982 Mercedes 300TD wagon
Joined
·
1,048 Posts
Metalhead, I'm curious if you installed the new lift pump and if it cured the cold idle/stalling problem? My car has been doing this for about a month now and I'm suspecting the lift pump might be going bad on my 300TD as well.
 

·
Registered
1984 300D
Joined
·
5,070 Posts
There is a Lift Pump Valves+Springs kit you can buy for around $13 plus shipping but you also need a little O-ring that is not in the Valve Kit.

Links to some Lift/Fuel Supply Pump Threads.

Lift Pump, Fuel Supply Pump rebuild kit
Anybody know a good Fuel Pump replacement DIY page? - PeachParts Mercedes ShopForum

Lift Pump, Fuel Supply Pump about sanding the Valves has the small O-ring size
Lift Pump Rebuild... - PeachParts Mercedes ShopForum

http://www.peachparts.com/shopforum/showthread.php?t=261822
 
1 - 9 of 9 Posts
Top