Bleeding fuel on 420SEL.

I changed my fuel filter, vent valve, and rubber shocks (buffers)
for the fuel pump/filter assembly.
What I can not find in the manual is bleeding the fuel system.
I do have the factory manual on CD and have read the part for replacing the filter but have not found the general instructions for bleeding the fuel.
I should point out that I have done some extensive engine work as in replacing the heads, cams shafts, timing chain, etc. so my fuel injection system has been off for about 8 months.
I put the spark plugs back in last night and am down to bleeding the fuel for the initial start after 8 loooooong months of not being able to drive my car. My pumps run for about 5 seconds and then shut down and I assuming that they feel the pressure is good enough so they must be seeing air. I would further assume that there is a pressure switch that must be temporarily bypassed for this task? The line is disconnected and pointed into a can for bleeding but no fuel.
Any remedial points for this topic would be greatly appreciated as I am an aircraft mechanic but am not schooled on the Mercedes product.
Thanks in advance.

Locate the fuel relay at firewall area , relay has number like 003 545 25 05, its not the relay thats next to it that says kLIMA, pull relay out locate adjacent pins 30 and 87 they are directly across from each other bridge those , preferably with a fuseed wire, dont short those to ground, or try and jump with bad pumps you can melt the wiring!, you will see with a test light that pin corresponding with 30 will have voltage , key on or off i believe , pin 87 sends power to fuel pumps, once you supply power you can disconnect fuel line at fuel distributor and pump it out, careful a lot of fuel comes out ,be safe.

nulu,

Thanks so very much for the quick response.
Is this the normal procedure? I only ask as I am not educated on this process at all and have never done it before. I am very familiar with the concept on diesel engines so safety is the key.

I assume that there is a pressure switch that the relay also powers and hence the reason for removing the relay.

Regards,
jimm1009

PS: You profile does not say where you are located in the world. Just
curious.

I would just cycle the key. Its a return type system. And it should not take too many cycles. The pumps, by design, run for a short period when you turn the key to prime the system. If the car does not actually fire up, they turn off. This is incase of an accident - no engine running, no fuel.

I have worked on a few engines that were depleted of fuel. In all cases just a few turns of the key would be enough to get fuel pressure back up. They were all return type systems.

__________________
1991 560 SEL / 185k miles
1992 750il / 17k miles - project car

The reason to remove relay is just to gain access to sockets that relay would normally plug into, find those 2 sockets, bridge them and the pump/pumps will run, and yes thats the shop method to purge fuel or
test , you will notice there are ports at fuel distributor that you can monitor
fuel pressures with, the mercedes diagnostic manual shows how, try to find
one of those manuals.

I have the genuine Mercedes manual but I could not find that information.
Even in the area where is states how to change the fuel filter. Put it on and have a nice day.
No explanation on how to bled the system which would have to be done since you have introduced a large amount of air into the system.
I put a 5 amp DC circuit breaker on two male pinned wires, plugged them into the female pins 30 & 87 and gently pushed the breaker in a little at a time.
I may have a seal bad though.
There is a black colored module on the left side of the injection housing and it may be leaking.
I though that I hear air and then moisture there. It may have been another line that was lose too so I will investigate further in a few minutes.
I am off to purchase two gallons of distilled water and then add my antifreeze as the engine is still dry.
jimm1009

That is theEHA, electro hydraulic actuator , common to seep or drip when bad , some people just replace the two small orings behind it , but that usually wont fix it,about 175.00 $