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  #1  
Old 05-26-2011, 09:47 AM
JHZR2's Avatar
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Engine shake wierdness

My 300cd has an engine shake, particularly when hot. It is intermittent when cold/warm, sometimes smooth as glass, othertimes some shake is felt.

The odd part is that after 150mi of highway driving tuesday, I had a decent shake that I could feel. Yesterday, hotter - near 90F, sitting in traffic mixed with high speed driving - which is usually a recipe for engine shake, it was smooth as glass.

Valves are adjusted, filters all good, compression consistent, injectors all balanced, engine mounts and shocks less than 5k.

What gives??? No signs of air in fuel lines, and lines around perfumery, cigar hose and all injector return lines are new. Gold rack damper, I'm assuming original.

Any suggestions? Already did the pump bypass spring stretch trick.

TC stretch is non existent when you subtract out the offset from tdc - right?



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Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)

Last edited by JHZR2; 05-26-2011 at 09:58 AM.
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  #2  
Old 05-26-2011, 10:03 AM
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I would take a look at the motor mounts just as a cursory thing to do. Fuel and oil does degrade them. Also how is your transmission mount? I did the motor mounts but had to go back because it still shook.
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1987 300TD 311,000M Stolen. Presumed destroyed
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  #3  
Old 05-26-2011, 10:24 AM
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Quote:
Originally Posted by Aquaticedge View Post
I would take a look at the motor mounts just as a cursory thing to do. Fuel and oil does degrade them. Also how is your transmission mount? I did the motor mounts but had to go back because it still shook.
Them and the shocks are less than a year old and dealer parts. Made no difference from day one.

How do I determine If trans mount is bad? I did diff mount chasing some apparent rear end sag...
__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
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Old 05-26-2011, 10:56 AM
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I would crack open each injector line at each injector when the shake is occuring. If the shake worsens, that injector and line are good, if one barely changes the shake I would suspect either the line or the injector. Much like removing a spark plug wire from each spark plug on a gasser.
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  #5  
Old 05-26-2011, 11:11 AM
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Injector pumps wear like any other part. The rack damper may not control rack movement in a worn pump, when adjusted as the FSM dictates.

I adjust them with the engine running until the smoothest idle is acheived...Robert
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Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership
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  #6  
Old 05-26-2011, 11:21 AM
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Quote:
Originally Posted by Doktor Bert View Post
Injector pumps wear like any other part. The rack damper may not control rack movement in a worn pump, when adjusted as the FSM dictates.

I adjust them with the engine running until the smoothest idle is acheived...Robert
Done that - still shakes. Thus my frustration.

The odd part is why sometimes it's smooth as glass though under conditions that I know typically should induce the shake. That seems to indicate to me something expanding/contracting or sealing/not.

Yet I see no signs of air in the fuel system which is what I'd first assume...
__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
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  #7  
Old 05-26-2011, 11:43 AM
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I am betting on a small Air Leak. Changing the Fuel Inlet hoses with 5/16 Fuel Hose from a regular auto parts store (it is rated for Diesel) is cheap trouble shooting. (Do you still have the Old Style Hand Primer?)

When you had the Fuel Pressure Relief/Overflow Valve a part was the Ball Bearing rusted on any part of the surface. If it is It may not always be sealing.

There could be some valve not sealing well issues in the Fuel Supply/Lift Pump.

I do not know what TDC offset is but your pointer is pointing to about 4 degrees of late timing. But, that is nothing that would cause an intermittent issue.
Also in the Manual whe you aline the Camshaft when you build the Engine it just has to set it at TDC, no mention of any sort of off set.
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Old 05-26-2011, 01:12 PM
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I second what Diesel911 says, particularly with respect to the old-style primer pump if that's what's on your car. That was the cause the second time I had a similar intermittent hot-shake problem on my SD.

Unfortunately, the first time it was an injector that had some sort of intermittent issue. It went away when I had the nozzles done. Sorry, I know you don't want to hear that as you have already had yours done.

I would say that were it a pump governor and/or rack damper issue, it would show up consistently when the engine reached a certain operating temp. That has been my experience, anyway.
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2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

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  #9  
Old 05-26-2011, 03:38 PM
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Perhaps you have already done this, but check to see if there is any fuel drips on the bottom of the screw on (secondary) fuel filter. If so, then its like mine, you probably have a small air leak and will need to replace the bolt/adaptor o-rings.
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1985 300SD "Der Silberne Schlitten" 420,000 mi


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  #10  
Old 05-26-2011, 03:54 PM
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I did have trouble sealing my filter this time. There are no leaks but perhaps that is part of it...

I do have a new primer pump. It doesnt leak and I assume it is in there tight enough...
__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
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  #11  
Old 05-26-2011, 06:48 PM
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Maybe something to do with tranny fluid temp and coupling to the tranny? I presume you feel the shake at idle. Does bumping to neutral stop it?

High ambient temps + high speed driving = reasonable airflow, probably. After the 150 on the highway was the shake immediate, or in stop and go afterwards?

Maybe a fuel level issue and a gummy strainer, or a fuel quality issue? Was the tank low on Tues after the 150? Did you fill up on Tues/Wed? Do you use the same station regularly or somewhere else?
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  #12  
Old 05-26-2011, 08:23 PM
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Quote:
Originally Posted by Yak View Post
Maybe something to do with tranny fluid temp and coupling to the tranny? I presume you feel the shake at idle. Does bumping to neutral stop it?

High ambient temps + high speed driving = reasonable airflow, probably. After the 150 on the highway was the shake immediate, or in stop and go afterwards?

Maybe a fuel level issue and a gummy strainer, or a fuel quality issue? Was the tank low on Tues after the 150? Did you fill up on Tues/Wed? Do you use the same station regularly or somewhere else?
Doubt it's fluid, because for example today it shook at red lights as soon as the car was warm, and continued through the entire drive, whereas earlier after about 100mi it wasn't shaking at all. It is completely random I've found...

Fuel was filled up previously for the other night. No shake. Filled it up today, shake. Tank hasn't been below 3/8 and it has been random amongst all fillips and fuel levels. I use the same few stations, no difference. Ditto with additives.

May be the fuel system but don't think it's the fuel. No sign of bubbles anywhere.
__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
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  #13  
Old 05-27-2011, 08:23 AM
toomany MBZ's Avatar
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A failing rack damper bolt will produce the same symptoms.
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  #14  
Old 05-27-2011, 09:12 AM
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Is the gold one known to fail?
__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
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  #15  
Old 05-27-2011, 03:58 PM
toomany MBZ's Avatar
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Perhaps it needs adjustment.

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