these seem like good next steps. If you have a soldering iron you can re-flow the solder on the fuel pump relay right away and see if that gets you going.

Do you have spark at the main coil wire? what is the age / condition of the cap and rotor? Plugs?

if you're looking for something else to do you can clean all of the engine bay grounding points. There are some on the fenders and some on the intake manifold; a long shot but good to do. have you checked / cleaned all of the ceramic fuses in the passenger compartment?

what brand of power stage did you install? There are power stages going for under $20 on ebay right now. Unlikely that its dead in box but you never know.

keep at it!

this may be helpful if you want to start check continuity of wiring.
http://www.volvowiringdiagrams.com/volvo/240%20Wiring%20Diagrams/Volvo%20240%201991.pdf



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