HELP: fuel relay 350SL

I've got a wierd problem I'm trying to track down and could use some advice.
My 350SL won't start. Traced problem to no fuel. Checked power at pump and found that the fuel pump was only getting
power for maybe 1/2 second when ignition was first turned on, then it goes away. Tracked down the fuel pump relay, and sure enough, it shuts off after being on briefly. Tried substituting a known good relay and fuse....no change.
I then discovered the fuel relay is controlled by the ECU. Is there a fault condition that the ECU detects that would turn off the fuel pump? I don't think the ECU is bad because the engine will run with a squirt of starting juice. There is no fuel under pressure in the fuel lines, and plenty of gas in the tank.
This is driving me nuts. HELP!!!!
Steve
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I am not familiar with 350SL... what year is it?
In any case, what is the fuel pressure when engine is off? If you can get the engine started and stay running with starter fluid, then it is most likely to be two thing... warm up regulator and/or fuel pressure regulator.
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The 350SL was only built in 1971 as far as I know. Identical to the 450SL. The Euro version had a 3.5 liter engine, but the US version had the 4.5 liter to overcome the smog junk. Engine output was 230hp which was the most until the 560SL was introduced. IMO, one of the most desireable of the series (I have 2).
The problem was the fuel pump. No fuel pressure was being developed.
A warning to folks changing out the fuel pumps in these beasts. Drain the fuel tank first OR have something to catch the fuel handy. The hose leading to the pump makes an effective siphon. Luckily this was a shade tree project, and I had a container handy.
Steve

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Ahh... so you figured it out... good. Yes, For MB with the fuel tank in the trunk... if you have to replace the fuel hoses below it or the fuel pump, everything will drain out... so be sure to empty the tank out as much as possible.
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