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Shake Not the milk kind

1K views 17 replies 7 participants last post by  300Dman 
#1 ·
I have a 1981 300D with 197k injectors look to be original. I have a small shake that comes and goes at idle. Sometimes it shakes sometimes it does not. The injector closest to the front of the car as a leaky body. Is it time to change the injectors?
 
#4 · (Edited)
I doubt the two are related. More likely you need new motor mounts. There are two mini-shock absorber mounts. Inspect them for rupture like you would with a conventional shock absorber. If they're clean, inspect the two hard rubber mounts. At 197k, I wouldn't be surprised if one or both pair may need to be replaced.

//greg//
 
#6 ·
If the Injector is leaking between the Injector Nut and the upper body you might try removing the Injector and torquing the Injector Nut (27mm ir 1-1/16 half inch drive deep socket).
If you remove the Injector you will need to replace the Heat Shield that seals the Injector Nozzle down in the Prechamber.

The Crimped area around the little Nipples that the Fuel Return line hooks to sometimes becomes loose and leaks. There is no fix for that except that a member of anthe Forum welded over the Bad Nipple area and move that Injector to #5 cylinder.
 
#7 ·
The body of the injector is leaking. It is not leaking at the top injector nut and it is not leaking at the thread the goes into the block. I have a torque wrench, heat shields, new return lines (because it came with the kit), the injector socket and a little instruction book on how to change the injectors
 
#9 ·
It still works when I re-prime the system, but when the system is full the primer leaks, so I think I am going to replace that just because I can. I replaced the two rubber fuel lines coming from the metal lines and to the top of the fuel pump
 
#10 ·
Besides motor mounts/shocks, you may need to replace the rack damper bolt located at the rear of the mechanical fuel injection pump.

I had the same problem and replacing mine helped a lot. If I recall correctly, they are available from Diesel Giant for $85 or so.
 
#12 ·
So would that rack damper bolt actually behave where the problem would come and go?

How hard is it to swap that bolt? Does it just come out or is the oil filter housing stoping it and it's a huge job to do? Curious, as mine shakes too. I've adjusted that bolt 6 ways to sunday and it's never solved it for long, but it always seems to fix it for that day.

Dave
 
#13 ·
I don;t believe that engine has a rack damper bolt/pin, as it doesn't have a turbo, correct sethwm2?

Also, yes a new primer pump should be in your future.

Dave, the two MB in your sig have it. The pic shows one, with the "O" ring (6x10) and 14mm lock nut. The bolt itself is 12mm.

Loosen the lock nut, then remove or adjust it.
 

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#14 ·
Non-turbo

Another thing that happens. It has also been intermittently hard to start in the morning. I should not need the idle speed control knob turned up when it is warm out. With it turned off I am cranking and cranking and it catches a little bit but only if I put my foot on the pedal. Or if I turn the knob on it starts of OK not great but OK. I switched from 5w 40 Rotella t6 synthetic to 15w40 non syn. Also I used the OEM mercedes inline fuel filter which is dramatically skinnier than others. It is between 40-50 degrees f here.

One thing that I was worried about that I might have damaged something, when I last added oil I ended up putting in two quarts too many :( and I am worried that I may have damaged something?

Please help because it was not like this at all before I switched to the thicker oil and I accidentally overfilled it.

The glow plugs were replaced at the beginning of the winter and so was the starter
 
#18 · (Edited)
Once your Car has you hooked it is not going to let you off.:)

After my Car sat on Blocks for at least a month while gathered the parts and did the worke replacing a B2 Piston in the Trans mission, a U-joint that was not supposed to be replaced and the Drive Shaft Support and Bearing the unexpected happend.

One of my Windows stopped working.

It worked before I put it up on Blocks?

Well the Window if fixed now. It turned the screws were loose at the Window Motor Terminal Box.
I wonder what will be next?:surrender:

I forgot I know one of the things that is next. While I was removing the Drive Shaft I noticed one of my Differential Seals is leaking. This means with the trouble to do the job got Differential seals should be changed.
 
#17 ·
Check the dip stick for the amount of oil.

Test your glow plug system, even newer plugs have been known to fail, at least the cheaper ones.

Do this using a multimeter, check for resistance with the ohm setting. You're looking for less than 1, make sure to subtract the meter itself. Touch the two leads together, is there a reading? If so, subtract that from your final reading.

Also check the strip fuse, visible when you remove the cover of the relay. Check for voltage too. To complete this step, use your multimeter on the DC setting. Turn the key so the light comes on. Touch the red lead to the end of each glow plug with the black to any ground. You'll have to be fast, but once a good ground is established, you can complete the test while the glow plugs are still engaged, about 30 seconds.
 
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