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  #1  
Old 04-08-2010, 07:12 PM
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A case of the shakes @ 1000 RPM 1983 300D

Just bought a 1983 300D and at 1000 RPM there is an incredible swaying of the engine. Sorta reminds me of the bridge that fell from high winds. Resonance.

Engine shakes a little more than it should at idle, as throttle is increased the shake increases until about 1200 RPM. (I'm guessing at the RPM because the tach didn't work when I drove it home. A quick reseat and she came back to life. But anyway, above 1500 RPM smooth as can be.

Before you all say new engine shocks, the car isn't as peppy as it should be, and on the highway when floored, a bit of black smoke was emitted from the exhaust. To the point where I could see it in the rear view mirror.

Since this is a virgin WVO diesel, I'm thinking maybe put some WVO and let that clean out whatever is causing the shake at around 1000 RPM, as I believe it is fuel related, but I might be overlooking something.
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  #2  
Old 04-08-2010, 07:43 PM
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I think you are thinking Biodiesel, not WVO. They are different. Bio will clean the fuel system.

I would start with valve adjustment, diesel purge, and filter changes. See if that helps. If not it's probably a little deeper. The next thing to look at would be injectors. You have have then tested for spray pattern and pop pressure.
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  #3  
Old 04-08-2010, 08:18 PM
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I would strongly consider replacing the front engine mounts.
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  #4  
Old 04-08-2010, 09:04 PM
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the rythmic swaying sounds like one dead cylinder to me... pull the injectors and do a compression test.
you may also want to crack the injector lines while it's idling and see if any pots fail to alter the idle...
black smoke is incompletely burned fuel... air filter clogged? has the alda been adjusted?
if the thing is swaying, your motor mounts are in need of replacement. shocks too.
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  #5  
Old 04-08-2010, 09:12 PM
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I would start by backing off each injector nut at a time to see if it can be isolated to one cylinder as already mentioned. If it is check the valves clearances and if they are okay do a compression check on that cylinder.

You may also want to find out if that cylinder is getting fuel first. Each injector line should spew about equal amounts as you test each one.
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  #6  
Old 04-08-2010, 09:15 PM
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WVO will not clean it out !!! It may block injectors more or varnish rings.
A burned valve or stuck valve or no valve clearance may cause rough running at low revs. The above posts give you plenty to try.
How easy does it start?
With it running you could loosen each injector hard line one at a time & see if you can work out which cylinder is causing the problem. If its an injector, swapping them around will confirm this.
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  #7  
Old 04-08-2010, 11:28 PM
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Check each cylinder as described.
Does this happen all the time, or just when the engine is warmed up?
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  #8  
Old 04-09-2010, 12:17 AM
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More info on when the shaking is happening; all the time, the same with Engine warm or cold, more at idle than at other speeds; less shaking after the Engine is warm.

The mentioned Injector cut out test to find out if it is a specific Cylinder or 2 causing the problem.

Air leaks- if it shakes all the time

Check the Glow Plugs- If it shakes more cold than warm

Valve Adjustment

Could be Injectors need rebuilding- The stock Injector Nozzles have 1 tiny and 1 larger Hole drilled in the Injector Pintle. On the ones I pulled from my Engine those holes were completely Plugged; also the same with most I have pulled fromt the Junk Yard.
The above and the Valve adjustment took the bulk of the shaking out of my Engine.

But, do the stuff that cost less and takes less equipment first

Slow speed could be due to sloppy Throttle Linkage (this happend to me to) or a restriction in the Fuel Supply System. This includes everything backwards from where the Fuel enters the Fuel Injection Pump.

In the pic is the Central Hole on the Injector Spray Nozzle. There is another Hole inside that is drilled acroosed. I have seen both Holes Plugged with hard Carbon.
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A case of the shakes @ 1000 RPM 1983 300D-central-hole.jpg  
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Last edited by Diesel911; 04-09-2010 at 12:25 AM.
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  #9  
Old 04-09-2010, 08:19 AM
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I appologize, my first post wasn't as clear as it could be. above 1500-2000 RPM there is no shake at all, smooth as can be.

I think I will "pop" test the injectors and adjust valves before I do anything else.

I can picture a faulty injector spring maybe popping too early at slower idle,,,

I literally just drove back with the car. 70 mile trip. Fuel flow is not an issue, as I punched it on the freeway, she down shifted and acelerated decently while emitting a bit of black smoke.

Like I said at one speed (around 1000 RPM) if kept at that speed, the engine will resonate shaking violently back and forth.

I'm going to take a video of this, after it warms up a bit. Luckily I have a donor 240D parked right next to the 300D. I probably should pull the windshield off the 240D. That, and the gear selector (If I can't bend it back) Apparantly someone stole the radio and instead of taking the car out of gear, they bent the gear selector.
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Last edited by mespe; 04-09-2010 at 08:30 AM.
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  #10  
Old 04-09-2010, 10:23 AM
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You're car sounds like it has almost the exact symptoms mine had/has. Been babying mine for over a year and it's just now coming around. Previous owner ran WVO. I don't know the setup, but it was wrong.

Anyway, some things I've done to correct it, in no order:

Filters
Diesel Purge a couple times
Engine and trans mounts
New Monark nozzles, balanced
Delivery valve seals
Rack damper pin
Cleaned switchover valve and lines
Many valve adjustments (lots of crud on seats it seems)
Lots of MMO and PowerService Diesel Kleen in the fuel
Should have done a MMO cylinder soak - may still

She has shown improvement in stages over the last year plus, but didn't really come back to life and smooth out until a month or so ago. Knowing that things were pretty solid I finally took it up to 90+ mph for several miles one day. Different car ever since. Some days she still sounds better than others, and she still has a little 'wop' at about 1000 rpm (always been the roughest spot vibe-wise), but it's vastly, VASTLY improved.
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  #11  
Old 04-10-2010, 06:53 PM
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Smile the shakes

I don't add much too this but, I will agree to another contributor check the motor mounts, I'm a mechanic, and the KISS rule always comes first.
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  #12  
Old 04-11-2010, 05:13 PM
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The effects of an air leak into the fuel system might cause you more noticeable difficulty at lower rpms as well. . Have a look at the prefilter for a stream of bubbles going through at idle. The constant bubble always present is normal. A stream of small bubbles is not.

Also those older hand primer pumps can also be suspect. Just stretching a balloon over the white handle onto the main cylinder casing and squeezing the air out of the balloon can eliminate that part temporarily from the equation.

Sometimes better than replacing something on spec and even cheaper as well. Another cheap test is to close off the return line from the injection pump. This allows the fuel pressure in the pump to rise.

There should always be a noticeable difference I now suspect. If none at all the feed pressure to the injection pump is lower than it should be. Chances are it is too low to even open the return valve.

In a fairly normal car the clamping off is going to elevate the internal injection pump pressure. So you would hear the engine smooth out somewhat or something else.

The design of the lift pump does allow total restriction of the return line and does no damage to the lift pump. Anytime there is low power on one of these old diesels it is a good proccedure to try in my opinion. Again it is cost effective and does indicate something.

You should ask on site about interpretation of what changes if any you observe though. Some will be normal and some will not be. This is a matter of judgement or at least some of the possible symptoms will be.

Last edited by barry123400; 04-11-2010 at 05:21 PM.
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  #13  
Old 04-25-2010, 02:49 PM
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Did a bit of work to the car, I checked chain stretch (2-3 degrees stretch) I adjusted the valves,

TIP: When adjusting valves, see if the next size up can fit in, if it can, the gap is too great.


But the thing that made the most difference was replacing injectors, smoothed right out at idle, better acceleration too.
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  #14  
Old 04-29-2010, 07:30 PM
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here's the latest,,,

new injector did NOT fix the loaping that happens sometimes. Car does run better with injectors. So I decided to put WVO in. After adding 10 gallons of WVO, (to about 3 gallons of diesel) the engine smoothed out incredibly. To the point that at times, I thought the engine had stalled!!!

Now the bad news, broke the stabilizer bar by the upper control arm,,, car rendered undriveable after 100 miles of WVO
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  #15  
Old 04-29-2010, 08:16 PM
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But?

Quote:
Originally Posted by mespe View Post
new injector did NOT fix the loaping that happens sometimes. Car does run better with injectors. So I decided to put WVO in. After adding 10 gallons of WVO, (to about 3 gallons of diesel) the engine smoothed out incredibly. To the point that at times, I thought the engine had stalled!!!

Now the bad news, broke the stabilizer bar by the upper control arm,,, car rendered undriveable after 100 miles of WVO
O.K. so maybe it's just me but I am not understanding how you broke the stabilizer bar, or how that is related to the WVO
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