Mercedes-Benz Forum banner

Status
Not open for further replies.
1 - 5 of 5 Posts

·
Registered
300TD-T
Joined
·
18 Posts
Discussion Starter #1
617.952 engine has started idling rough after running down the highway at high speed for a while. When I stop at a toll booth it runs rough as though it is misfiring, but with normal around town driving it runs fine and idles smooth. I've never had any prob lem like this before for years--always ran great--I use Red Line Catalyst. could injectors be getting too hot or what? This is a new one for me!
 

·
Registered
300 d turbodiesel
Joined
·
52 Posts
this is most likely a vacumn problem. I had my mechanic make an adustment in the vacumn [so, now my doors don't lock all at once...i have to lock them manually]. Now, it idles smooth as silk. Mine is an '83 300d with 250,000 miles on it.




617.952 engine has started idling rough after running down the highway at high speed for a while. When I stop at a toll booth it runs rough as though it is misfiring, but with normal around town driving it runs fine and idles smooth. I've never had any prob lem like this before for years--always ran great--I use Red Line Catalyst. could injectors be getting too hot or what? This is a new one for me!
[/quote]
 

·
Registered
300TD-T
Joined
·
18 Posts
Discussion Starter #3
runs rough--vacuum

Thanks for the reply. I'm not sure how vacuum can affect the idle in one of these engines but I can help you get your central locks working again. Here is a great source of parts and information. http://www.mercedessource.com/ Their book "Vacuum Door Lock, Advanced Troubleshooting and Repair" is very good. I've found all of their "stuff" very good and a good value too. You must get yourself a vacuum testing hand pump/guage unit in order to find the leak in that system. Here is a Snap-On tool- a bit pricey of course but I have seen others (mabey Sears or Mac Tool) that are plastic and work fine.http://buy1.snapon.com/catalog/pro_det.asp?tool=all&item_ID=11108&group_ID=1422&store=snapon-store&dir=catalog.[:)]
 

·
Registered
s500- 300td
Joined
·
92 Posts
having a vacaum leak in these cars is very common, I had to get rid of power door lock a...

having a vacaum leak in these cars is very common, I had to get rid of power door lock and now it too run fine. 82 300td with over 240k. runs like a champ
 

·
Registered
Joined
·
5 Posts
I have three of the 300Ds. The first one I bought with 43k miles on it. Runs great, good acceleration, good milage, but takes spells of having a very rough idle. I will fiddle with it, and it clears up somewhat, for a while, then comes back. So I don't think that I've actually ever helped it any. With that said I will tell you what I have done,...

At about 120k, I replaced the injectors, but I can't say that they helped any. I have ran the injector cleaner that Performance Products sells, but can't remember the name of it. I keep the valves adjusted, and since it runs well, except idle, I don't much think they are the problem.

I have speed up and slowed down the idle speed at the injector pump, adjusting the control rod, #41, when I do so, so that the control rod fits back on the pivot points with no binding. And I have adjusted the control nut on the back of the injector pump. All with limited success.

Because I can ease the throttle down a little and get it to smooth out, I feel that the issue is in injector pump. I don't believe that I am giving it enough throttle to do more than change the pressure/tension on the linkage. So I'm kinda leaning toward something in the pump having a little too much wear.

I read one or two responses that said it was a vacuum issue. Of my three cars, I've had numerous vacuum leaks over the years, and only one of them exhibits this behavior. So I can't quite figure out how the vacuum system would be the cause behind my idling problem,... but at this stage I can't find much reason to disagree.

In the event you do find a solution, I'd be very interested in hearing about it.
 
1 - 5 of 5 Posts
Status
Not open for further replies.
Top