Not MB question

Hi Guenter

I think I don't understand the question, because why would you want to do it?

Anyway, the fuel pump is a centrifugal pump which build up a differential pressure between its input and its output. Two fuel pumps are connected in series to be able to provide sufficent pressure to the injection system.

Each pump has an internal pressure limiter and a check valve at its output. The check valve ensures that the pressure is kept, also when the engine is stopped (a low pressure will allow vapors to build up and consequently cause starting problems).

Btw: In CIS-E injection system, a fuel accumulator is fitted in the fuel system to have a certain volume of fuel to maintain the pressure. In later systems, the fuel rail serves that purpose.

So yes, you can cut the fuel line, and the fuel will be pumped out of the cutted line (so, why would you do that?)

The capacity of the fuel pumps is verified by disconnected the fuel return line and collecting the fuel (whith engine off and ignition on). This check that the fuel pumps can provide enough pressure to overcome the threshold of the fuel pressure regulator, and that it can provide enough fuel flow. The specification is max. 35 seconds to pump 1 liter.

Does that help you?

/Jens

Guenter Scholz wrote:

thanks for that jens, the fuel line (to engine) has a pinn hole leak ..... too much salt on the roads here in Ontario. I need to cut out a few cm or so of damaged line and replace with rubber hose (sutable fuel line grade and high pressure of course). Consequently I need to cut the metal pipe. I'd rather not have gasoline spilled all over in large quantities. I expect some fuel to leak out of course, but was hoping that putting the clamped rubber hose on quickly it might not be too bad. I was hoping that typical fuel pumps might be of the diaphragm type and so assure no leakage.

cheers, guenter

ps this is my daughters Cavalier (Chevrolet) which I hope to make last 6 more months before junking it.

According to GM, the pressure can be released by unpluging the fuel pump connector then running the engine unitl it stalls.

The pump connector is probably around the fuel tank. If it has similar configuration as the Corsica I just worked a few days ago, the tank is before the rear axle and the connector is just above the axle.

Like what Colton said, the residue pressure is not that much and won't last, but the open end must be higher than the fuel level in the tank, otherwise the fule will just keep draining.

I assume the leaking pipe is the metal segment going to engine. There must be a small segment near the tank that is rubber (so the tank can be lowered a little without disconnecting). Crimp the hose there to stop the flow.

Guenter Scholz wrote:

In article , Colton Motor Express #6Here! >diaphragm, it should be OK... if not there could be some fuel spilling out.

thanks for that, appreciated. sounds like I can go ahead and cut the line 'fast' with some snips. then use a pipe cutter on the fuel line after I can bend it away to get access to the pipe for rotating the cutter. Followed by putting the hose on....

cheers and thanks, guenter