'78 450SL fuel Issues

[Walrus]

All,

A friend has consulted with me concerning his '78 450Sl. The car will start fine, and will idle for a while, then begin to stumble and die. He has had the fuel pump replaced, and has verified fuel pressure, volume and flow from each injector (all working with his indie who is highly regarded). I viewed the car this afternoon and found the car has a smell of being rich when it is running, but it will not idle for more than a minute or less. It refuses to take any throttle and will die when throttle is given. At first, I thought it was starving of fuel, but it smells rich; however, we never got it warmed up as it never ran long enough. When it does die, one has to wait a few minutes before it will start again, as if it were flooded?

I suspect when he and his indie had the fuel distributor off the throttle body, the mixture has changed (the fuel distributor was never opened, just flushed/cleaned). The air plate moves freely (not frozen) and the piston appears to move freely inside the fuel distributor (depressing the plate immediately after running and dying, one feels a bit more resistance and the pressure can be heard bleeding off to the injectors). One can see the air plate slightly moving as the car is idling, and try to open a bit as the car begins to stumble and die. The accumulator is holding pressure as verified when the fuel line is cracked loose from the dist (fuel under pressure squirts out). The injectors have been flushed/cleaned as well.

When idling, for the first few seconds, it idles smooth and seems fine. I tried to gently depress the air plate and the engine immediately died, just like it does with the application of any throttle.

At this point, I am beginning to suspect fuel starvation, and the rich smell is from the cold start circuit/valve; however, I am far from an expert with this system.

The car has been sitting for a while without use, in an enclosed storage garage. Everything has been flushed with new, clean fuel with techron added.

Any suggestions to offer him?

[meltedpanda]

Are the plugs wet or dry when it dies? Wonder if it is flooding? Could also be starved for air, is the aux air valve functioning?
Ignition system OK - points, plugs , timing?

I have some good checklists for the Kjet if you PM me your email

[RadioTek]

Check the fuel return system, also. If you've got something plugged up, the excess fuel will not return to the tank. Possibly charcoal canister, or associated plumbing??

Just a wild guess.