fuel pressure over 90?

[exoticcollector]

Hello all. New to this forum. Picked up a 82 380SL that only runs if you dont try to drive it. The car stumbles and stall after driving very far. The fuel pressure is at 100. Shut off engine and drops to 40 but holds. i dont think there is a leak. I am thinking the accumulator or fuel pressure regulator. Is this the correct pressure?

[exoticcollector]

So I started searching and found that 30 - 45 is normal. Does this mean The injectors are clogged and the pump is building too much pressure?

[tram]

Originally Posted by exoticcollector

So I started searching and found that 30 - 45 is normal. Does this mean The injectors are clogged and the pump is building too much pressure?

You have a kink or obstruction in the return line somewhere.

[meltedpanda]

check for obstruction in return lines as mentioned , if ok ( which is doubtful) I'd check regulator, or pump. Is pump new? Could be the wrong one . You must use pumps that fall within MB specs

[exoticcollector]

Previous owner said it was new. It looks to be correct Blue wrap. I will look for a kink but thinking fuel pressure regulator or possibly the accumulator?

[rowdie]

The accumulator is merely a canister with a diaphragm and spring. It maintains pressure in the system to assist in hot starts. It is not your problem.
The return tube in the tank has been known clog if the the tank gets rusty/contaminated.

[RadioTek]

What's the fuel pressure supposed to be on a K-Jet system? I seem to remember that 27 pounds is for a D-Jet, but that a K-Jet was supposed to be much higher, around 80. I'm more familiar with the D-Jet system, so I'm trying to pull something out of a rusty section of memory, don't take this too seriously.

Scott

[Frank Reiner]

Fuel pressure for K-basic and K-lambda is 73 psi. For KE in Mercedes about
92-95 psi.

Yours is K-lambda, ergo, 73 psi.

Look for obstructed return line as mentioned, or a mis-shimmed and/or sticking pressure regulator piston. Regulator located in fuel distributor.

[exoticcollector]

How would I clear the return line in the tank? Simplt pull the line off and clear it or pull the tank and clean?

Also need some headlight bezels and turn signal lenses. Any suggestions on parts?

[meltedpanda]

You could use compressed air for the line. Both ends need to be free. May be tough to do at tank cant remember. What part of headlight bezel do you need?

[Frank Reiner]

Re: Return line
I think that I would follow the line from the engine end proceeding to the back of the car, examining it carefully for external damage, i.e., pinching from a rock hit or a misplaced jack. Next, disconnect at the engine end, remove the gas cap, and blow through line with about 10-15psi air.

If the line seems clear and undamaged, then turn your attention to the system pressure regulator (in the fuel distributor), and the control pressure regulator (aka warm-up regulator).

In the event that you cannot blow thru the return line, you are, at this point, somewhat on your own. If you can locate the connection point of the return line at the tank, and open that connection, a repeat of the blow through test will help to isolate the area of obstruction. It can be in the line forward of the tank but behind the engine, or in the piping that is part of the tank and/or pickup assembly.

[exoticcollector]

I followed what I believe is the return line from the injectors and it goes to the front into an aluminum oval. There is a vacuum line coming off of it that is not connected to anything. I plugged it and did a test drive and for about 15 mins no problem. I followed the return from the rear and it goes to the front driver side into a black canister. Looks to be emissions?

Anyhow I will let you know if any change.

Can anyone tell me where to access the fuel sending unit? The gas gauge is not working.

[abiby]

Originally Posted by exoticcollector

I followed what I believe is the return line from the injectors and it goes to the front into an aluminum oval. There is a vacuum line coming off of it that is not connected to anything. I plugged it and did a test drive and for about 15 mins no problem. I followed the return from the rear and it goes to the front driver side into a black canister. Looks to be emissions?

Anyhow I will let you know if any change.

Can anyone tell me where to access the fuel sending unit? The gas gauge is not working.

The oval aluminum thing is probably the warmup regulator and if so, one fitting isn't supposed to be connected to anything except atmosphere.

There is a fuel return line going from the engine to the fuel tank. It is not the one going to the cannister.

Fuel gauge is accessed from the soft top storage location.

[Frank Reiner]

It may be helpful if you could post a few pics of the engine components you are looking at. If you have identified the fuel distributor (under the air cleaner, has eight small diam. lines exiting the top which go to the eight nozzles at the cylinders, one larger line from the center of the top which goes to the warm-up regulator) then by following the aforementioned line to the warm-up regulator (WUR) you can identify it. Warm-up regulators are roughly rectangular, have two fuel lines connected, one electric plug, and what looks like a vacuum hose fitting. In some models the vacuum fitting is open to atmosphere, in others it is connected to the intake manifold. The second fuel line on the WUR is a return line. It is teed into the return line from the system pressure regulator (located in fuel dist). The combined return line then goes to tank.

[rowdie]

Fuel sending unit is accessed from the soft top storage area. Large plastic cover needs to be removed to view it.