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300 d turbodiesel
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Discussion Starter #1
at times, my 300 d turbo has a shaky idle. Is this a sign of bad news? Anybody have any suggestions here?
 

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1985 300D Turbo
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10 Posts
mine does the same from time to time. I was thinking about changing the idle rpm. Just t...

mine does the same from time to time. I was thinking about changing the idle rpm. Just take it to the shop and ask them to raise the rpms about 100. That should do the trick.
 

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83 300TD/97 E320/98 SL500
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I've had an intermittently jumpy engine at idle, rocking the entire car back and forth. Y...

I've had an intermittently jumpy engine at idle, rocking the entire car back and forth. You guys think a valve adjustment might help that? Hasn't been done in a while on account of laziness
 

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300 d turbodiesel
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Discussion Starter #4
Re: I've had an intermittently jumpy engine at idle, rocking the entire car back and forth. Y

I ended up taking mine to a local mercedes-only (Precision Motorcars) repair center. They made some adjustments and mine has been idling very well for an engine with 247000+ mile on it.

sidebar....In fact..... it was on this forum that I learned of this repair center and they have been of excellent service!




I've had an intermittently jumpy engine at idle, rocking the entire car back and forth. You guys think a valve adjustment might help that? Hasn't been done in a while on account of laziness

[/quote]
 

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1985 300D Turbo
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I am almost certain a valve adjustment will do the trick. It seems to me that as the engi...

I am almost certain a valve adjustment will do the trick. It seems to me that as the engine ages, it does not want to idle as slowly, so the fast the better. Also, a faster idle speed would decrease the time needed to warm up the car...but not that much. If you know how to do it yourself, i'd say go for it, or just take it to a dealer and they should be able to do it in about 5 minutes if you tell them what to do and what you need done.[:D]
 

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Mercedes Diesels
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145 Posts
make sure everything is in order, valve adjustment,
both fuel filters, air filter.

If ...


make sure everything is in order, valve adjustment,
both fuel filters, air filter.

If that doesn't do it completely injectors could be worn, dirty. Check dirty first, run techron through, if still not better diesel purge can be run through it.

Mobil 1 15-50 will help too, but can take thousands of miles and severel changes for sticking rings.

An last, drive it like your stealing it.
John Gregg
 

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1983 Mercedes 300D
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I agree..... Make sure you have new fuel filters, get a vlve adjustment, and run a coupl...

I agree..... Make sure you have new fuel filters, get a vlve adjustment, and run a couple of cans of diesel purge through it. I have never heard of using Techron in a diesel engine before... a good diesel purge brand is made by Lubo-Moly.

How are your motor mounts? worn out motor mounts can cause shaking at idle as well...... Haveo those checked out too.
 

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RE: I am almost certain a valve adjustment will do the trick. It seems to me that as the engi...

hi, you seem to know your stuff.i have a question for you.my car (1987 300e) could be used as a rocking chair to put babies to sleep ,thats how much it shakes.do you know why?it has poor accelaration ,it goes all the way to red in the "ECONOMY"dasboard window and at a stop sign feels like it's about to die, sometime die.Theres a few more symptoms...i'll save'em for the next consultation, Doctor.thanks a lot in advance.If not could you point me in the right direction.?
 

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1991 300 SE
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18,534 Posts
RE: I am almost certain a valve adjustment will do the trick. It seems to me that as the engi...

benztece - 11/14/2005 6:04 PM

...my car (1987 300e)
Might want to post in the 124 forum.

In the meantime check the cap/rotor/wires on your M103 and replace if you don’t know when it was last done.
 

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My car does this as well. The fact that it's intermitant tells me that the first place to start is fuel injectors. Poor valve adjustment would most likely result in a constant problem. It never hurts to get a valve adjustment done though, and I fully encourage you to do so.
 

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1982 300TD
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163 Posts
All of the above, and then try replacing your rack damper bolt on the IP. I recently put a new one in mine, and adjusted it in until the idle was as smooth as silk. (ok, wool...)

A new damper bolt is about $100 at the dealer. Worth it for me.


Best Regards,


e

.::.
 

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W-1-2-3 Go!
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If you screw the bolt all the way in the injector pump, the idling will smooth out. Screwing it back out will produce some intermittent shaking. This is with an old rack dampener bolt.

This is logical because with a NEW bolt, the spring is harder. Therefore you don't have to screw it all the way in. That's what I think, I haven't had the chance to replace it yet.

Imagine replacing that bold at night, on a hot engine, in the parking lot... [xx(] (rant off)
 

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So a new bolt would be good, but not always necessary. One should try to adjust it before replacing it. Is that what we should gather from your post?
 

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W-1-2-3 Go!
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Yes, if adjusting it doesn't do the trick, a new one would greatly help. But of course there are other sources that if you think they should be attended to first (like motor mounts, filters, valve adjustment, etc) then do so.

If you purchase a new bolt and still has the shake at idle, then you know your rack dampener bolt is already new and you can isolate your problem. That in turn would slowly restore the car indirectly. [:)]
 

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1983 300td
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One other area you might check besides the others mentioned above - that is the braided hoses going to the injectors. Mine were dry - when viewed by the eye, but when I actually put some hand pressure on the hoses, some of them started releasing diesel fuel - very slight....but probably enough to allow air in. Change them if it helps.
 

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Since those hoses are for pressurized fuel returning to the tank, they shouldn't allow any air into the system. They would simply just allow fuel leakage.
 

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1982 300sd turbo
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my braided lines after l replaced cigar hose started to sweat and pulse,,,,,,,,anyone else seen this?
[8D] n0rt
 

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300SD
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Winston probably means the injector breather lines that run from the fuel filter and then on to each injector and then ending at #5 injector. Replace them if they are leaking, it is a simple job.
 
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