i have a 84 300d td that won't shut off. i have to pop the hood and hit the stop lever. it either needs a new shutoff valve or there's a leak in the vacuum line leading to the shut off valve (as far as i know. i could be very wrong.) at any rate, if it is the shutoff valve/vacuum line is that something that's fairly simple to replace myself? i know you have to the put the valve in facing the correct way or you end up with a runaway motor. but that's all i got. any help sure is appreciated

 

Concerning replacing the Shutoff Valve on the Fuel Injection Pump. What gets people in trouble is when putting it back on is that the Shutoff has a bent End and the Rack has a bent end that has a rectangular slot cut into the bend. Do not stick the Shutoff bent tab into the rectangular Solt; it does not go there.

First of all take a look at the under the hood vacuum lines and make sure none are disconnected and do the same down to the one on the Transmission Modulator. (you did not complain of Harsh down shifts so it is likely it is connected OK.)

The best Tool for testing Vacuum Issues is a Hand Held Vacuum Tester often generically reffered to as a Mighty Vack. It has a Hand Pump you squeez and a Vacuum Gauge on it.

However just to see if your Shutoff Valve on the Fuel Injection Pump is working you can get a separated section of Vacuum Hose and un-plug the Brown with a Stripe onit Vacuum line from the Vacuum Shutoff on the Fuel Injection Pump.

Stick on your section of Vacuum Hose; start the Engine and simply suck on the Hose. If it your Engine shuts off your Vacuum Shutoff on the Fuel Injection Pump is working.

If you have the Hand Held Vacuum Tester you can do the same thing but you can also see if it will hold Vacuum.
On an old Shutoff like mine it will not hold vacuum but will still shutoff; but, that indicates at some future point I will need to replace it. Anoter way to tell is if you pull the Vacuum Line off of the Shutoff and it has Engine Oil in it you have some leaking going on.

Summerize; If you do the above test and the Engine Shuts down it is working. There is also another Shutoff Valve mounted on your Steering Colum Lock and that is the one your Key operates.

So you will look for another Brown Vacuum line that is going through the Fire Wall and connect your Tester to that and start the Engine and see if when you apply Vacuum the Engine Shuts off. If not shutting it could be that Valve or the Vaccum Connections going to it.

To see if there is Vacuum leaks inside of the Car look at the lines going though the Fire wall. There is green line (with stripe?) and 2 Yellow Lines (one has a read strip and the other a green stripe).

Disconnect the green and plug off the Vacuum Soucrce end. See if your Shutoff works. If it does you have a leak in your Climate Control Vacuum System. Leave the Vacuum Source for that plugged for now.

Do the same with the 2 Yellow Striped lines. If your Shutoff starts to work you have a vacuum leak in the Door Lock System.

The other stuff that is left is the Vacuum going up to the little Valves on the Valve Cover. I can't give info on that because I have not tested them for Vacuum Leaks. You sould be able to see which lines to dissconnect and plug.
Note the Black Line is a Vent line and goes through the Fire Wall where it connects to nothing.
If you have a Blue line going through the Fire Wall that goes to an adjustable head rest.

I have assumed from your statment that you are not having increased effort braking. If you are having increased effort braking it is likely you have a Vacuum Pump of Vacuum Pump check Valve issue. If curious check the Main Vacuum Line Vacuum.

 

i've only driven the car for about 20 minutes at this point, but regardless the brakes seem fine as well as the shifting. i'm going to my dad's next weekend (where the car currently resides) and i will find out then whether or not its the vacuum line. are there any other common problems i may currently or in the future run into with this motor?

 

There is some of Rubber parts that need to be checked.

Oil and Transmission cooler Hoses (Removing the Oil Cooler Hose from the Oil Cooler often results in one or more Stripped Aluminum Nipples on the Oil Cooler.)

Motor Mounts (if the left side one is squashed enough it will allow the Power Steering Belt to cut throuh one of the Oil Cooler Hoses.)

On each end of the Drive Shaft is a Rubber Flex Disc. You don't want to see any cracking on them and the Front one is very hard to get a good look at without removing some parts. When a Flex Disc breaks apart it can severly damage stuff.

The Drive Shaft Support Bearing is mounted on rubber look for cracks.

When they come from the Factory the rear CV Axles are filled with a special Oil. When the CV Axle Boots crack the Oil leaks out. The Asian Made replacement Axles seem cheap but they have quality control issues.

These Engines do not have Hydraulic Valve Lifters and the Valve need to be adjusted about everh 5,000 Miles. As the Valves wear the the adjustments get tighter.