P38 DSE auto idle vibration

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Well that's at least a major worry out the way,engine mounts to go .island4x4 iv used famous four lots they are nice chaps don't forget heat shield above front pipe under drivers seat they rattle too
 
today because I gat the bits.

i removed the viscous fan and put a new water pump in.....I just had a feeling these needed doing. Much quieter (it would be without the viscous raw) but the vibration is still there.

Off to open the two boxes of engine mounts!

Report back soon.
 
mate if you do the mounts.and its still there i think as suggested before your going to have to live with it. otherwise its going to cost a fortune.
 
Having still not cured ilthe vibration on my manual i thought id follow up and see if i can spot common symptoms. Findings as below;

1. Occurs more frequently when warm outside
2. Occurs after a long motorway run
3. Occurs when starting the engine when warm regardless of outside air temp-vibration happens straight away and wont go away until after a run.
4. Doesnt occur at all when the tank is full and is most severe with 20 or litres onboard.

Naturally thought fuel and possible fip cavitation. Starting when cold shows no air in the fuel line between filter and pump but switched off when warm shows air returning from fip back to filter. I suspect when starting this air is forced and trapped back in the fip creating cavitation. Bit like the first shower of the day while the pump works the air out or like an outside tap. No fuel leaks from the fip and mine looks like its not the original as its fairly clean and shiny. Ill change the fuel filter but i suspect on mine there maybe air returning between the block and fip causing the vibration....most likely injector line unions Any thoughts?
 
aerofabrique said:
Having still not cured ilthe vibration on my manual i thought id follow up and see if i can spot common symptoms. Findings as below;

1. Occurs more frequently when warm outside
2. Occurs after a long motorway run
3. Occurs when starting the engine when warm regardless of outside air temp-vibration happens straight away and wont go away until after a run.
4. Doesnt occur at all when the tank is full and is most severe with 20 or litres onboard.

Naturally thought fuel and possible fip cavitation. Starting when cold shows no air in the fuel line between filter and pump but switched off when warm shows air returning from fip back to filter. I suspect when starting this air is forced and trapped back in the fip creating cavitation. Bit like the first shower of the day while the pump works the air out or like an outside tap. No fuel leaks from the fip and mine looks like its not the original as its fairly clean and shiny. Ill change the fuel filter but i suspect on mine there maybe air returning between the block and fip causing the vibration....most likely injector line unions Any thoughts?
Click to expand...

Leak off pipes?
 
No. All done with proper 3mm leak off pipes and end pipe by diesel specialist last month. No pools of diesel or oil in the injector wells.
 
aerofabrique said:
Having still not cured ilthe vibration on my manual i thought id follow up and see if i can spot common symptoms. Findings as below;

1. Occurs more frequently when warm outside
2. Occurs after a long motorway run
3. Occurs when starting the engine when warm regardless of outside air temp-vibration happens straight away and wont go away until after a run.
4. Doesnt occur at all when the tank is full and is most severe with 20 or litres onboard.

Naturally thought fuel and possible fip cavitation. Starting when cold shows no air in the fuel line between filter and pump but switched off when warm shows air returning from fip back to filter. I suspect when starting this air is forced and trapped back in the fip creating cavitation. Bit like the first shower of the day while the pump works the air out or like an outside tap. No fuel leaks from the fip and mine looks like its not the original as its fairly clean and shiny. Ill change the fuel filter but i suspect on mine there maybe air returning between the block and fip causing the vibration....most likely injector line unions Any thoughts?
Click to expand...

I think FIP cavitation would destroy the pump in fairly short order, Aero... Think cavitation on aircraft EDFP as an example...!

On mine, like yours, it is more prevalent when engine is warm. It is definitely the engine itself that is vibrating, I can see and feel it with the bonnet open. It's is much more of a 'buzz' that reverberates through the whole car than a 'shake' or rattle.

At the P38 pub meet, everybody's did it... But mine was much more severe and noticeable, despite my engine actually sounding like it ran smoother than some!
 
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Maybe ours 'vibrations' are different? Mine looks and feels like the engine is going to self destruct, sounds awful, shakes the entire car and sounds like its on the verge of stalling. However blipping the throttle will cause it to go away. It never comes on suddenly but builds from a small misfire sound to feeling like its going to jump out if the bay.
 
aerofabrique said:
Maybe ours 'vibrations' are different? Mine looks and feels like the engine is going to self destruct, sounds awful, shakes the entire car and sounds like its on the verge of stalling. However blipping the throttle will cause it to go away. It never comes on suddenly but builds from a small misfire sound to feeling like its going to jump out if the bay.
Click to expand...

Sounds to me that you have an engine problem , not running right timing injectors ect ect. Or your idel is so low is almosts trying to stall
 
Trouble is its electronic so lr or a nanocom worth the money if your keeping the car £300 ish for the unit probably £100 inc vat at llr speaks for itself . But I'm not saying its defo that just an assumption by what you say.
 
'84 300sd idle shake - PeachParts Mercedes ShopForum

Good thread here that describes my syptoms but on mercs. Don't know what components are common here but looks like idle fuel quantities through knackered injectors? Or rack damper bolt whatever that is and if it has one?

They can't be too clogged as I run redex (500ml) through every other tank full. I've put nearly 60 litres of the stuff through the car since i've had it for over a year.

Idle shows low on the gauge - 240is at idle. But peaks at 3500rpm so I suspect the gauge is at fault? I can do 30mph in 4th showing 800rpm...that's incorrect no?

When lightly tapping the throttle at idle if you do it too many times in quick succession it dips so far below the idle it stalls.
 
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Go to a garage and just ask them to have a look what does your taco graph/ rev counter say mine says 500 at idle it should be 750 ish but it don't shake like a rattle snake if you get some one to carefully put there foot on the pedal and hold it at say 800 revs per minute and all is good running sweet there is your answer unless whist driving if feels like a lack of power then more investigating is needed.
 
aerofabrique said:
'84 300sd idle shake - PeachParts Mercedes ShopForum

Good thread here that describes my syptoms but on mercs. Don't know what components are common here but looks like idle fuel quantities through knackered injectors? Or rack damper bolt whatever that is and if it has one?

They can't be too clogged as I run redex (500ml) through every other tank full. I've put nearly 60 litres of the stuff through the car since i've had it for over a year.

Idle shows low on the gauge - 240is at idle. But peaks at 3500rpm so I suspect the gauge is at fault? I can do 30mph in 4th showing 800rpm...that's incorrect no?

When lightly tapping the throttle at idle if you do it too many times in quick succession it dips so far below the idle it stalls.
Click to expand...

Nanocom or Faultmate will allow you to see the true idle speed on live data. You can adjust the idle speed electronically to some extent but note down the reading you start with.:)
 
Cool thanks all, whilst most say live with it, sitting in traffic on the m1 trying to keep it under control is a pita. Def worse on a hot day. Will post back when done and if any improvement
 
Hi Guys.

Done the Engine Mounts today. It is better but not the cause. Theya are just doing a better job.
Defender 300tdi. I think you are right. I have now come to the end of what it could be I think and will live with what I have.
Many thanks all.
 
Only thing no-one seems to have tried yet is replacing the crank damper... And at £250 a pop, I can see why... It looks like it's all that's left...
 
donp38 said:
Hi Guys.

Done the Engine Mounts today. It is better but not the cause. Theya are just doing a better job.
Defender 300tdi. I think you are right. I have now come to the end of what it could be I think and will live with what I have.
Many thanks all.
Click to expand...
just as a matter of coarse,what did you have to move/ take of when you done your mounts if anythink at all for the benifit of others.
 
it was a simple task in the end.
15mm drop end spanner required for the one nut next to the turbo.

Undo, both radiator hoses from the rad.
Remover metal and flex pipe to turbo (total removal just so I could see better)
Air filter put undo
Intercooler pipe undo.

that was it.

Car put on stands, Wheels off (but not really needed I think)
Used jack and block of wood under engine. removed all nuts from both engine blocks jacked up one side, replaced and lowered, moved jake did same to other side.

Tighted top nuts, put lower nuts on full nut, reconnected pipes and run engine.

Stopped engine and tightened lower nuts.

Lowered and test run.

Could the vibration come from the Cat?

done enough to it now but its so cloase to being really great. Will post work done in the last 10mths on the running rebuild.
Regards
 
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