When I get on the gas it stalls and backfires at the engine. If I slowly pedal the gas it will slowly gain rpms but when I start up a hill it slows guickly. I checked the pressure from WUR to fuel distributor and here are the numbers. Cold start reading was 20psi and within 15-20 seconds climbs to 50 psi. It held at 50 as the engine warmed and stayed their until engine was shut off. Pressure drops to 0 as soon as the engine is shut off. I tried it both with the shut off valve open and closed on the gauge and went to zero both ways. I don't think that's correct but I need help diagnosing it. Any ideas?

 

my 129 specs for fuel pump is from 29-58 psi, the slk 46-52 w/vac. I'd say you should be at least 29 so 50 is good. I'd start with the basics, fuel filter, pump back-flow valve for the loss of pressure, TIMING, vacuum hoses, distributor cap, rotor, points, plugs and wiring. run car in the dark and look for sparks from all wiring. has the car set for a long time? does the distributor advance when you rev it?

 

Thanks for your input. I think the numbers are good except the one that goes to zero when I shut the engine off. Sure would like to know what parts can cause that one.

 

I'd start with the fuel pump backflow valve