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1982 Mercedes 300TD wagon
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1,057 Posts
Discussion Starter · #1 ·
My 84' 300D-T (254,000 miles) has always had a bit of a shake which make my passengers feel like Kathryn Hepburn (parkinson's). When the car was converted to a two-tank Greasecar veggie system, the car actually got smoother. However it was discovered that my injection pump (IP) was leaking underneath. I'm pretty sure it was from using biodiesel in a car with over 230,000 miles on the original IP. So the internal seals got eaten up and now it leaks. I no longer use biodiesel because the station is too far from my house and frankly it's like 35 cents more per gallon.

The installer of the kit could never get the car to run smoothly at idle. He rebuilt an injector which was at that time the main suspect but it didn't help. So the verdict was that the IP was allowing air into the fuel system.

I dealt with this annoyance for eight months until recently it seemed to worsen.
The engine shakes from side to side at a really rough idle on either regular diesel or oil. It used to smooth out with the oil but not anymore.

I checked the motor mounts and although one is squashed, the shake seems to come from some inbalance. The motor doesn't move much from the torque of the engine.

I changed all the fuel filters and performed a diesel purge utilizing two full cans of the Lubro Molly cleaner directly into the engine using the fuel bypass system. Nothing changed.

So at this point I'm suspecting a faulty injector or the IP is finally dying.
I also wonder if the fuel booster pump the installers put in to help the oil flow toward the engine might have died? The shaking disappears at higher RPM's.

Should I try anything else?

Thoughts?

Ideas?
 

· Registered
1982 Mercedes 300TD wagon
Joined
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1,057 Posts
Discussion Starter · #5 ·
Really? Interesting theory! It appears the leakage is coming from underneath because looking from under the hood down the IP looks dry.
 

· Registered
1982 Mercedes 300TD wagon
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1,057 Posts
Discussion Starter · #6 ·
I noticed when I started the car this morning it ran smoothly. After I drove it for a while the shaking returned but not as bad. If I were to do a freeway run then it will really shake. Now I'm really confused...it's a heat-related problem?
 

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1982 240d, 2007 e350
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2,070 Posts
^^ hahahahha
 

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'77 6.9, 74 240D, 96 Ram 5.9L Cummins
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2,668 Posts
Was that Madonna back in the 80's? It's definitely not Jerry Lee Lewis!
The motor mount that is collapsed is on the exhaust manifold side.
 

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1982 Mercedes 300TD wagon
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1,057 Posts
Discussion Starter · #12 ·
Fixed!

Well there's some good news for me. The problem was not a faulty injection pump in general but rather the solution came in the form of an eighty dollar 1" idle screw that screws inside the IP. It controls the smoothness of the idle, that's all I know. Anyway the car barely shakes now. The true test will be after a hard run on the freeway. It usually shook really hard after that.

My mechanic also got my vacuum door locks to work properly!

Add this to Paris Hilton going to jail and Isaiah Washington (Greys Anatomy) being fired, all in all not a bad day at t'all!
 

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1978 240D - given to a friend; 1974 450SL
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134 Posts
I replaced my mounts and it didn't help at all. Had to replace my idler cable (the ball on the end of the cable had broken off) and clicked the idle up a couple of notches and that took away about 75% or more of my vibration. The down side is my wife doesn't like riding in the car nearly as much as she used to, especially in bumper to bumper stop and go rush hour traffic...

A bottle of Red Line every other fill up helped as well. For the car.
 
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