BenzWorld Senior Member
Date registered: Jun 2004
Mentioned: 0 Post(s)
Quoted: 17 Post(s)
RE: newb checking in...first benz...got some questions about a '75 240d
My experience with this type of injection system is based on the older 200D, but I believe yours uses the same concept. If it is the line from the throttle body (with the butterfly) to the back of the pump, taking the line off usually makes the engine run faster as there is no vacuum at the diaphragm and the engine get more fuel. Not sure how plugging it made it run better. Maybe we're talking about different lines. Anyway, here are some answers for you:
1. Injection timing can be done with ordinary tools, though the manual says you need some special tools, specifically a drip tube. You can fabricate one, or just adjust so the fuel just stops coming out of the #1 nipple on the injection pump (with the internal nipple valve removed). I would suggest you read up on this in the manual before adjusting, as there are a few other steps involved. Caution: never adjust the timing with the engine running. This is dangerous and can cause the pump to self-destruct.
2. You can check around this site to see if they sell parts. Also check out this site: http://www.*****************/shopforum/index.php3
I've heard good things about the parts they sell. You can also get a copy of Hemmings Motor News, available at book stores, as many parts dealers advertise in there. And there is always the Mercedes dealer. Sometimes the names can be confusing, but you just have to muddle through.
3. For manuals, I recommend genuine Mercedes, either hardcopy or CD. Chilton is also helpful, but does not tell you everything. Genuine Mercedes manuals are split up into the chassis (sometime two),engine, and climate control, though the CD has them all. The manuals can be bought directly from Mercedes, Ebay, or some other places that sell parts. Adsit Company, Inc. (on the internet) carries some too.
4. Pumps: Primer Pump, located on side of main injection pump with a plastic knob. Delivery Pump, located on side of main injection pump that the primer pump screws into. Main Injection Pump, delivers fuel to the injectors. And the Vacuum Pump, located on the front of the engine ahead of the main injection pump and creates vacuum to operate all vacuum components. There is a diaphragm in the vacuum pump that also splits and causes oil to get sucked into the engine and into the vacuum system (very bad). The diaphragm is available seperate and is good preventative maintance for a 30 year old car. The diesel injection pump diaphragm and pneumatic governor diaphragm are the same thing.
5. If you run out of fuel, fill the tank and try to start it. If that doesn't work, uncrew the knob on the primer pump counterclockwise and pump to get fuel up the the injection pump. Then push the primer pump down and screw clockwise till it tightens. The worst case is that you will need to loosen the air bleed screw on top of the primary fuel filter, pump fuel till only fuel comes out, and tighten the bleeder screw. The owner's manual should give you the procedure, and manuals are usually available from the same places you find the repair manuals.
Hope this helps.