1989 190E 2.6 - Weird Fuel Pressure Drop

[John5788]

I'm trying to diagnose a strange problem, wanted to see what you guys think.


This car has sat for 10+ years, first sign of no start was fuel pumps not working. Swapped them out with a spare pair, still won't start.


Installed some test gauges on the fuel distributor test ports and jumpered the fuel pump relay to supply power to the pumps with an external battery.


I am seeing very slow build up of fuel pressure, then once it hits 48 psi, it drops and starts over again.


Going to swap out the fuel pressure regulator tomorrow, but any other ideas besides just throwing new parts at it?


Video of issue: https://streamable.com/1lf3p0

[nulu]

There is a gas tank strainer it's probably getting clogged , clean the tank then replace the strainer