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Old 12-07-2011, 11:07 PM
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Diesel911 Diesel911 is offline
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Location: Long Beach,CA
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Originally Posted by ChiefRider View Post

Longtime Benz owner, and for better or worse I find myself a Diesel owner again. I started out with a '79 240D 4 speed. While it was a low mileage car, it hadn't had it's oil changed as frequently as it should have, and had a bit too much blowby. In spite of this, I ran the wheels off of it until I didn't need it anymore. After storing it for a couple of years, I sold it to kid who bought it sight unseen, taking a bus here from 3 states away. He arrived with a plate, and left directly to Colorado. He made it, too!

A 300E, E430 and 560SL have all been mine to enjoy since then. Times change and now I have a 1991 350SD. I know this is noone's favorite engine, but it's what I have, and hope to get some use out of!

Here's the situation. The car has 205k miles, and is in outstanding condition. The PO "rebuilt" the engine 40k miles ago. The rebuild consisted of a new cylinder head, a reground crank, 2 new connecting rods and all new rings. He claimed at that time the cylinders still showed crosshatch and checked out fine. Oil changes always at 3k miles.

Here is what I am experiencing. The engine (reportedly) consumes no lubricating oil. Without getting into it, I trust the owner's testimony on that. The engine starts easily and instantly from dead cold, and runs perfectly smooth and smoke free for 10 seconds or so. After this time, it begins to skip and shake, idling quite rough, and puts out a pretty fair amount of whiteish bluish smoke. Car has low power, but is driveable and the engine gets smoother under load- I can do 70 on the highway without any trouble. Occasionally power seems to come up, engine smooths out even more, but then will lose power again.

My indie has "cracked" the injectors loose one at a time and run the car. Only 3 cylinders significantly affect the running during this test; the other 3 didn't make any difference. He deemed this inconclusive.

These symptoms are pretty confusing to me. Anyone with a similar experience and cure?

Thanks much!
When the Injector Lines were Cracked on the 3 Cylinders that it made a difference on those were the 3 cylinders that were working like they were supposed to.

The other part of the test is to remove one of the 3 Injectors from one of the Cylinders showed an effect when the Injector Line was cracked. And, swap it with an Injector from one of the Cylinders that had no effect on the Engine when the Injector Line was cracked.
If the no effect problem follows the Injector it means you have a problem with that Injector.
Do the same with the remaining 2 Injectors.

Also Air Mixing with the Fuel Supply can cause rough running; and would mess with the Fuel Injection.

EGR issue?

Also you did not mention if the Injectors were rebuilt? At 205K I would think they were past due.

Did your Mechanic note if the on the Injectors the line was cracked on that had no effect on the Engine; if the Cylinders were adjacent to each other?
If so it could be the compression test may show a Head Gasket issue.
Trouble shooting this problem is going to be expensive if you are not doing the work on the Car. More so if your Mechanice does not know too much about your Benz.
84 300D, 82 Volvo 244Gl Diesel
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