idle-rack pin
85 300TD 279kmi

The idle-rack pin is worn and needs to be replaced to smooth the idle.

Q1: Is this something I can do myself at home?


Q2: Can the worn damper pin cause the engine to run rough at higher rpm (2200-2750 rpm while driving)? I know this isn't the tires or flex discs. Motor mounts?

Thanks for your time,

Alec.

You can do idle rack pin yourself, although a little tight for access. Search previous posts in "idle rack adjuster" for details on how to get it right.

The idle rack pin wont effect running at higher speeds. Most likely cause for higher speed rough running is poor injectors....if yours are original, at 279K miles, I would just replace all of the injectors. Prior to doing this, you may want to run a can of Diesel Purge through to see if there is any improvement.

Fuel injection timing may also be a problem....this also would definitely effect operation at highway speeds. If you havent done it or, dont know how or are not equipped to do, have mechanic adjust this....also called adjusting the "start of fuel delivery"

Have you replaced fuel filters?....if not engine may be starved for fuel at higher speeds. Also check your air filter....change if real dirty.

Has a new timing chain ever been installed. At your mileage, the chain should DEFINITELY be replaced if it hasnt!!! If it is original, it is likely stretched beyond spec, and will throw off injection timing and cause rough running. Also, you definitely do not want this to break!!!!

Motor mounts are not likely the cause of rough running at highway speeds, as the engine (if operating correctly) really smooths out at higher RPMs. Bad motor mounts are most likely to exacerbate rough idle, because this is when the engine jumps and rocks

Good Luck,

Mark

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1984 300TD Wagon, 407,800 mi (current daily driver)
1985 300DT Sedan, 330,000 mi (gone to that great autobahn in the sky)