NEED AS MUCH HELP AS I CAN GET PLEASE

Hey everyone, I bought a 1982 380sel a while ago and currently trying to get it running good. A little backstory on the car.. it was sitting for more than a decade. I bought it from a guy trying to get it running and he replaced the fuel pump and fuel filter. And visually looks like the FD was rebuilt. I pulled off all the lines off the FD and pushed down on the plunger to verify proper operation and all ports were evenly flowing.



I went ahead and did all 8 injectors and while I was in there, I drained the tank, I flushed out all the injector lines, put new seals, etc.



I also cleaned the WUR filter screen and made sure it wasn’t clogged.



Here’s what I’m dealing with right now:



System Pressure is at 72PSI (5 Bar) which is within spec



I set the cold control pressure at 18PSI (1.2 BAR) at 50F (10C) within spec



Control pressure when warm after running/idling for 2min is at ~55PSI (3.8Bar) within spec



NOW the odd thing is when I go out on a drive down the street and get to operating temps, the car starts sputtering and dies on me while driving (seems like it leans out and dies). When it dies, I start it back up and drives fine for about a 1/4 of a mile then does the same thing again. I’m thinking that after it dies, fuel pressure drops and allows the car to run at the proper fuel mixture, then the sputter and shutdown happens again.



I pull back into my driveway right after all this is happening and hook up my pressure tester and it’s reading at 68-70 PSI (~4.7 Bar) which is wayy too high.



*Fuel pressure readings are all the same as recorded above when the return line is pulled off*



Is there any way to adjust the operating temp fuel pressure? Not sure what to do next. I’m 99% sure it’s fuel related and not ignition. Any help is appreciated thank you!

 

OP how do you know it isn’t ignition?

Cap, rotor, plugs, wires all fresh? Good quality parts?

The pick-up coil that supplies the speed signal for ignition is plenty old enough to be having an issue. Happens when warm? Old electronics do that. The box that gets the signal from the pick up coil is also old enough.
About 40 years ago every shop worth its salt had an oscilloscope we used to monitor what ignition was doing. Museum piece today.

Poor running... Check for false air leaks first. (False air isn’t intermittent). Next we check ignition. Then fuel.

Have you verified the engine is healthy?